https://microbewiki.kenyon.edu/api.php?action=feedcontributions&user=Akent&feedformat=atommicrobewiki - User contributions [en]2024-03-28T09:05:15ZUser contributionsMediaWiki 1.39.6https://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80909Spacecraft microbes2013-04-08T20:09:17Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[#References|[8]],[[#References|10]],[[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80908Spacecraft microbes2013-04-08T20:08:37Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[#References|[8]],[[#References|10]],[[#References|15] ]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80907Spacecraft microbes2013-04-08T20:07:57Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[[#References|[8]],[[#References|10]],[[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80906Spacecraft microbes2013-04-08T20:07:09Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[#References|[8]],[[#References|10]],[[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80905Spacecraft microbes2013-04-08T20:06:37Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[#References|[8]],[[#References|10]],[[#References|[15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80904Spacecraft microbes2013-04-08T20:05:42Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [ [[#References|8]],[[#References|10]],[[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80903Spacecraft microbes2013-04-08T20:01:13Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[[#References|8]],[[#References|10]],[[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80902Spacecraft microbes2013-04-08T20:00:35Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[#References|8]],[[#References|10]],[[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80901Spacecraft microbes2013-04-08T19:59:47Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[[#References|8]],[[#References|10]],[[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80900Spacecraft microbes2013-04-08T19:59:18Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [ [[#References|8]], [[#References|10]], [[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80899Spacecraft microbes2013-04-08T19:57:42Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[[#References|8]], [[#References|10]], [[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80898Spacecraft microbes2013-04-08T19:56:40Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[[#References|8]],[[#References|10]],[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80897Spacecraft microbes2013-04-08T19:55:51Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[[#References|8]], [[#References|10]], [[#References|15]]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Spacecraft_microbes&diff=80896Spacecraft microbes2013-04-08T19:54:32Z<p>Akent: </p>
<hr />
<div>[[Image:MIR Amoeba.jpg|thumb|300px|right|An amoeba collected from free-floating condensate on the MIR space station.[[#References|14]]]]<br />
<br />
Spacecraft represent a unique environment for microbes. Spacecraft are generally classified as either manned or unmanned and this distinction carries profound consequences on the microbial ecology of the crafts. As on Earth, microbial communities can have both positive and negative effects. While they present hazards like degradation of equipment, infection, and contamination they also offer the promise for advanced life support systems.<br />
<br />
<br />
==Spacecraft Environments==<br />
<br />
As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The interior of hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations [[#References|[2]]]. The same conditions that create an oasis of Earth-like conditions for humans benefit their commensal microbial partners as well. Conditions inside the craft are aerobic, warm, and generally ideal for mesophilic heterotrophs [[#References|2]]. <br />
<br />
The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey [[#References|2]]. Human bodies provide a rich source of carbon sources and nutrients and the commensal and mutuaistic members of our skin and body cavity microbial ecosystems probably are the most substantial source of inoculation to a craft's interior. However, this of course means that pathogens, particularly opportunistic pathogens, can just as easily enter which has been demonstrated in previous research [[#References|2]].<br />
<br />
Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize infrastructure and equipment are termed <b>technofiles</b> and can be a serious threat to the craft's integrity [[#References|2]]. These microbes can degrade polymers and metal overtime through direct consumption and production of secondary metabolites [[#References|2]]. Polymer and surface corrosion were both observed on the MIR space station [[#References|11]] and technophile bacterial strains have been detected on the International Space Station [[#References|13]]. <br />
<br />
Another target environment for microbes aboard spacecraft are life-support systems. This too can lead to dangers if colonization impairs equipment. Water filtration and regeneration systems and coolant lines must be monitored to guard against biofilm formation that can clog up tubing and prevent necessary flow [[#References|2]]. However it is in life support systems where microbes perhaps show the most promise for occupying a constructive niche in the spaceraft ecosystem. Because microbes play a role in every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight [[#References|16]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Unmanned craft and the exteriors of manned spacecraft represent a far more extreme environment for microbes. This is due to the both the physical extremes of space itself and the rigorous sterilization procedures applied prior to launch [[#References|4]][[#References|8]][[#References|10]] . There are no friendly Earth-simulated environments on these craft and thus bacteria capable of colonizing are usually endospore-forming or extremophiles [[#References|8]]. <br />
<br />
Outer space is a very harsh environment for life in virtually all respects. Microbes face desiccation, strong radiation, extremes of temperature, and scarce nutrients [[#References|4]]. Experimentation has been conducted since the earliest days of space exploration to determine microbial survival capabilities in space. The 1972 Apollo 16 mission used the MEED facility installed on the outside of the command module possessing 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation [[#References|4]]. The most recent experimentation were conducted by the EXPOSE facilities on the International Space Station in 2008 and 2009 [[#References|3]][[#References|4]] . Very few organisms have demonstrated the ability to survive the onslaught of full exposure to space [[#References|4]]. Among them are lichens <i>Rhizocarpon geographicum</i> and <i>Xanthoria elegans</i> and the cyanobacteria <i>Synechococcus</i>, and it should be noted that these organisms were dormant during their exposure and <i>Synechococcus</i> was protected in a gypsum-halite crystal [[#References|4]]. Shielding from ultraviolet light can allow for microbe survival for several years on the exterior of craft[[#References|3]][[#References|4]]. Even if the craft is destined for a celestial body with an atmosphere, the alien atmosphere and surface temperatures could still prove inhibitory for survival and growth [[#References|4]]. For instance, the conditions on the surface of Mars are anaerobic, more UV-exposed, and generally colder than Earth [[#References|9]]. <br />
<br />
[[Image:MEED_Facility.jpg|thumb|300px|right|Illustration and diagram of the MEED facility. MEED was fixed to the TV Boom of the 1972 Apollo 16 Command Module. It was one of the first experiments to test the effects of exposure to outer space on microbes. There were 798 sample cuvettes with varying levels of exposure to the vacuum of space or solar UV radiation.[[#References|4]]]]<br />
<br />
The unmanned spacecraft also represent an extreme environment because of the extensive decontamination procedures employed before launch. This is done to avoid the transport of terrestrial microbes to other celestial bodies, known as <b>forward contamination</b>, and also the hypothetical return of potentially dangerous extraterrestrial life to Earth, referred to as <b>back contamination</b> [[#References|10]]. Protection against forward and back contamination is mandated under the 1967 U.N. Outer Space Treaty for all space travel [[#References|10]] [[#References|15]]. A related motivation is the desire to avoid potential false-positives in life-detection research [[#References|8]][[#References|10]] [[#References|15]]. This concern came to the forefront when it was the suspected that late alterations to the Mars Curiosity rover’s drill may have introduced microbial and physical contamination [[#References|3]] [[#References|15]]. The space craft are constructed and sterilized in clean rooms that are kept low in nutrient content, humidity, and air particulates and are frequently and comprehensively cleaned with disinfectants [[#References|10]]. Quality control checks have traditionally involved culturing but are increasingly employing molecular techniques [[#References|8]][[#References|10]] [[#References|15]]. While these procedures may eliminate most microbes they unfortunately also select for the extremophiles, which are also the most likely group to survive a space-flight [[#References|10]].<br />
<br />
==Microbial Communities==<br />
<br />
As follows from the differences in environment, microbial communities differ dramatically between manned and unmanned spacecraft. The advent of molecular methods has allowed for further refinement of the microbe community composition in these locales. <br />
<br />
===Manned Spacecraft and Space Stations===<br />
<br />
The astronauts themselves likely represent the most fundamental influence over the composition of microbial communities in manned spacecraft [[#References|16]]. The microbes that colonize the interior will likely be representative of the community carried on and in humans, but vacant niches on board invites the evolution of newer strains [[#References|16]]. Other introductions of microbes will likely come from plants, animals, fermenters, and various other organisms brought on board for experiments as was the case when a fungus was accidently released on MIR [[#References|1]][[#References|16]]. Traditional culture and microscopy analysis of free-floating condensate on the MIR demonstrated a wide assortment of bacteria and fungi as well as the presence of protozoa, dust mites, and spirochetes [[#References|14]]. There were 90 different microbial species detected on the MIR space station four years after it’s 1986 launch and that number had risen to 140 by the time of it’s decommissioning in 2001 [[#References|1]]. Concentrations of some bacteria and fungi rose as high as 106 CFUs [[#References|11]]. There have currently been 80 species detected on the ISS, roughly half of which are bacteria and other half being fungi [[#References|2]]. Because the bacterial communities are largely being seeded by human microbiota their exists the risk that pathogenic species will be introduced to the living space of the craft and endanger the health of the crew [[#References|2]][[#References|4]]. Indeed opportunistic pathogens were among the species sampled from the MIR condensate and are present on the ISS and include the genuses <i>Staphlococcus</i> (including meticillin resistant <i>Staphylococcus epidermidis</i>) and <i>Pseudomonas</i> [[#References|6]][[#References|14]].<br />
<br />
===Unmanned and Robotic Spacecraft===<br />
<br />
Studies of community composition on unmanned spacecraft are largely inferred using clean room populations. Recently the European Space Agency (ESA) has begun construction of a public database of microbes isolated from clean rooms [[#References|8]]. Thus far this database has sampled ESA clean rooms in France, Germany, and French Guiana and contains 298 bacterial strains ([[#References|8]]. The majority of the bacteria identified were Gram-positive and included members of the phyla Actinobacteria, Bacteroidetes/Chlorobi, Firmicutes, and 94 species of Bacillus [[#References|8]]. At total of 59 isolates were Gram-negative and represented members of the α-, β-, and γ-Proteobacteria phyla [[#References|8]]. <br />
<br />
[[Image:CleanRoomDiversity.jpg|thumb|300px|right|Representation of phylogenetic diversity of bacteria isolated from European Space Agency clean room facilities in Cannes, France, Noordwijk, Netherlands, Friedrichshafen, Germany, and Kourou, French Guiana.[[#References|4]]]]<br />
<br />
<br />
Beyond a basic understanding of initial contamination populations, it is also useful to concentrate research on those groups that present the highest forward contamination risks. Many experiments focused on this aspect of spacecraft microbiota have used Mars as their reference given the increasing focus on the red planet by NASA and other space agencies [[#References|15]]. Any accidentally introduced microbe to Mars will need to be anaerobic to survive the reducing atmosphere and recent analysis of clean room communities has revealed a very diverse assemblage of anaerobic groups [[#References|15]]. Particularly disconcerting is the presence of <i>Clostridial</i> and <i>Bacillus</i> species whose spores may allow them to survive the interplanetary journey [[#References|15]]. The spores of these genuses survive heat shock treatments and are better able to handle the UV levels found on Mars [[#References|15]]. <br />
<br />
Detection of microbes has traditionally been conducted using culture techniques and microscopy. These methods are biased toward those species that can be readily cultured [[#References|8]]. Molecular techniques targeting the 16S-rRNA genes can provide a more comprehensive snapshot of microbial diversity, but leaves questions of viability and metabolism unanswered ([[#References|8]].<br />
<br />
==Microbial Processes==<br />
<br />
Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of microgravity on cells smaller than 10 µm in diameter [[#References|4]], but later experiments demonstrated an indirect lag on the metabolism of nonmotile bacteria due to reduced material exchange with surrounding fluid made more static without gravity [[#References|4]]. Conversely damage by ionizing radiation is a serious hazard to microbial DNA causing double-stranded breaks, mutations, or irreversible destruction. Bacteria have evolved techniques to deal with genetic damage that include homologous and nonhomologous end-joining and protein-protection in spores [[#References|4]]. Different strains display varying levels of resistance and threshold lethality to radiation-induced damage [[#References|4]]. <br />
<br />
A unique problem for microbes exposed to the vacuum of space is extreme desiccation [[#References|4]]. It induces conformational changes in DNA that make it more susceptible to radiation damage [[#References|4]]. Lipid membranes may change conformation from planar to cylindrical and amino acids, carbohydrates, and nucleic acids may all polymerize together [[#References|4]]. Even UV-shielded but vacuum-exposed microbes (bacteria and fungi) cope poorly with the desiccation and required protecting sugars or salts for their spores to survive [[#References|4]].<br />
<br />
As mentioned, technofile bacteria lead to corrosion of metal and polymer surfaces primarily through metabolic processes. Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers [[#References|2]]. Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality [[#References|2]]. Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids [[#References|2]]. Metal and polymer corrosion was observed on MIR and the same bacteria appear to be present on the ISS [[#References|1]]. <br />
<br />
It appears that endospore formation make a bacteria more likely to survive exposure to outer space. The endospore represents a dormant stage of the bacterial lifecycle for Bacillus and Closridial species that allows the bacteria to wait out long durations of adverse environmental conditions [[#References|7]]. It is also highly resistant to extremes of temperature, heat shock, and dessication making it the most ideal transport mechanism for forward contaminating bacteria [[#References|7]], [[#References|4]]. <br />
<br />
==Current Research==<br />
<br />
Current research in spacraft microbiology is focused on both negative and positive relationships with microbes. NASA is currently supporting research through the Advanced Life Support division of the Advanced Human Support technology program to utilize microbes in bioregenerative and nutrient cycling for long term space travel [[#References|16]]. Research on sporulation and microbial survival under extreme conditions is being researched intensively by NASA and the Department of Homeland Security [[#References|9]]. The unique attributes of clean room extremophile isolates have been suggested as a new avenue for pharmaceutical and biotechnology research and development [[#References|8]]. Future searches for extraterrestrial life will require ever more vigilant and sophisticated methods of forward contamination monitoring as the range of extremes life can tolerate continues to increase [[#References|4]]. It will also be necessary to view microbial communities as unavoidable companions in space stations and manned spacecraft and attempt to exploit their more beneficial behaviors while minimizing the negative [[#References|16]].<br />
<br />
==References==<br />
<br />
[[1]]]2012. “Mutant space microbes attack ISS: ‘Munch’ metal, may crack glass”. RT. http://rt.com/news/iss-bacteria-mir-mutation-765/<br />
<br />
[[2]]]“Biocontamination of spacecraft”. BIOSMARS. http://www.biosmhars.eu/the-biocontamination/biocontamination-in-spacecrafts.<br />
<br />
[[3]]]Flatow, I., and Connelly, C. 2012. “Interview: Mars Rover May Be Contaminated with Earth Microbes”. National Public Radio: Talk of the Nation. http://www.npr.org/2012/09/14/161156787/mars-rover-may-be-contaminated-with-earth-microbes.<br />
<br />
[[4]]]Horneck, G., Klaus, D.M., and Mancinelli, R.L. 2010. “Space Microbiology”. Microbiology and Molecular Biology Reviews 74: 121-156. <br />
<br />
[[5]]]Ilyin V., Korshunov, D., Chuvilskaya, N., Doronina, G., Mardanov, R., Moukhamedieva, L., Novikova, N., Starkova, L., and Deshevaya, E. 2008. “Microbial purification of waste biodegradat liquid products”. Ecological Engineering and Environment Protection. 1: 48-55.<br />
<br />
[[6]]]Ilyin, V.K. Volozhin, A.I., and Vikha, G.V. 2005. Colonial resistance of organism in modified environment. Moscow Nauka 275.<br />
<br />
[[7]]]Mader, S.S. 2010. “Chapter 20: Viruses, Bacteria, and Archea.” Biology 10th Edition. McGraw-Hill Publishing.<br />
<br />
[[8]]]Moissl-Eichinger, C., Rettberg, P., and Pukall, R. 2012. “The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms”. Astrobiology. 12: 1024-1034.<br />
<br />
[[9]]]Newcombe, D.A., Schuerger, A.C., Benardini, J.N., Dickerson, D., Tanner, R., and Venkateswaran K. 2005. “Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation”. Applied and Environmental Microbiology. 71: 8147-8156.<br />
<br />
[[10]]]Nicholson, W.L., Schauerger, A.C., and Rac, M.S. 2009. “Migrating microbes and planetary protection”. Cell. 9: 389-392.<br />
<br />
[[11]]]Novikova, N.D. 2004. “Review of the Knowledge of Microbial Contamination of the Russian Manned Spacecraft”. Microbial Ecology. 47: 127-132.<br />
<br />
[[13]]]Novikova, N.D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I., and Mergeay, M. 2006. “Survey of the environmental biocontamination aboard the International Space Station”. Research in Microbiology. 157: 5-12.<br />
<br />
[[14]]]Ott, C.M., Bruce, R.J., and Pierson, D.L. 2004. “Microbial Characterization of Free Floating Condensate aboard the MIR Space Station”. Microbial Ecology. 47: 133-136.<br />
<br />
[[15]]]Probst, A., Vaishmapayan, P., Osman, S., Moissl-Eichinger, C., Anderson, G.L., and Venkateswaran, K. 2010. “Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms”. Applied and Environmental Microbiology. 76: 2837-2845.<br />
<br />
[[16]]]Roberts, M.S., Garland, J.L., and Mills, A.L. 2004. “Microbial Astronauts: Assembling Microbial Communities for Advanced Life Support Systems”. Microbial Ecology. 47:137-149.<br />
<br />
<br />
<br />
Edited by Adam Wallenfang, a student of Angela Kent at the University of Illinois at Urbana-Champaign.</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=80637University of Illinois2013-04-08T04:40:38Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Acidic hot springs]]<br />
<br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Deep subsurface microbes]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]<br />
<br />
[[Category:Class indexes]]<br />
<br />
<b>Created in 2012</b><br><br />
<br />
[[Aeromicrobiology]]<br />
<br />
[[Aphids and Buchnera]]<br />
<br />
[[Bark Beetles and Symbiotic Fungi]]<br />
<br />
[[Biocontrol]]<br />
<br />
[[Freshwater Lakes]]<br />
<br />
[[Foaming in wastewater treatment plant (WWTP)]]<br />
<br />
[[Legume-Rhizobium]] symbiosis<br />
<br />
[[Meromictic lakes]]<br />
<br />
[[Terraforming]]<br />
<br />
[[White nose syndrome in bats]]<br />
<br />
<b>Created in 2013</b><br><br />
<br />
[[Forest Soils]]<br />
<br />
[[Microbes and Land Use Change]]<br />
<br />
[[Spacecraft microbes]]<br />
<br />
[[Soil Food Webs]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=80635University of Illinois2013-04-08T04:40:09Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Acidic hot springs]]<br />
<br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Deep subsurface microbes]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]<br />
<br />
[[Category:Class indexes]]<br />
<br />
<b>Created in 2012</b><br><br />
<br />
[[Aeromicrobiology]]<br />
<br />
[[Aphids and Buchnera]]<br />
<br />
[[Bark Beetles and Symbiotic Fungi]]<br />
<br />
[[Biocontrol]]<br />
<br />
[[Freshwater Lakes]]<br />
<br />
[[Foaming in wastewater treatment plant (WWTP)]]<br />
<br />
[[Legume-Rhizobium]] symbiosis<br />
<br />
[[Meromictic lakes]]<br />
<br />
[[Terraforming]]<br />
<br />
[[White nose syndrome in bats]]<br />
<br />
<b>Created in 2013</b><br><br />
<br />
[[Forest Soils]]<br />
<br />
[[Microbes and Land Use Change]]<br />
<br />
[[Spacecraft microbes]]<br />
<br />
[[Soil food webs]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=80634University of Illinois2013-04-08T04:38:29Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Acidic hot springs]]<br />
<br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Deep subsurface microbes]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]<br />
<br />
[[Category:Class indexes]]<br />
<br />
<b>Created in 2012</b><br><br />
<br />
[[Aeromicrobiology]]<br />
<br />
[[Aphids and Buchnera]]<br />
<br />
[[Bark Beetles and Symbiotic Fungi]]<br />
<br />
[[Biocontrol]]<br />
<br />
[[Freshwater Lakes]]<br />
<br />
[[Foaming in wastewater treatment plant (WWTP)]]<br />
<br />
[[Legume-Rhizobium]] symbiosis<br />
<br />
[[Meromictic lakes]]<br />
<br />
[[Terraforming]]<br />
<br />
[[White nose syndrome in bats]]<br />
<br />
<b>Created in 2013</b><br><br />
<br />
[[Forest soils]]<br />
<br />
[[Microbes and land use change]]<br />
<br />
[[Spacecraft microbes]]<br />
<br />
[[Soil food webs]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Terraforming&diff=72285Terraforming2012-04-25T06:34:57Z<p>Akent: /* Methanogenesis */</p>
<hr />
<div>{{Uncurated}}<br />
<br><br />
[[image:46068edaa8c3a0a77d8ae5962027c93a.jpg |thumb||800px||right|]]<br><br />
<br />
==Planetary Engineering==<br />
[[Image:Terraformed_mars_3_stage-We.jpg |thumb|500px|right|Artists rendition of Mars terraformation (galaxyexplorers.org).]]<br />
<br>Terraforming or “Planetary Ecosynthesis” is the process of changing a planet’s atmosphere to resemble that of the Earth’s, with the goal of sustaining terrestrial life. It is predicted that establishment of life will be similar to Earth’s history, starting with basic unicellular microorganisms. The most feasible pioneer to begin life on a new planet would be some kind of photosynthetic microbe.[[#References |[8]]]<br><br />
<br><br />
The strategy of using photosynthesis to engineer a habitable planet for humans through photosynthesis would not be unlike the <b>Great Ogygenation Event</b> that took place on Earth 2.4 billion years ago, sometime after cyanobacteria first evolved (2.7-2.8 billion years ago.) This pivotal event paved the way for evolution of multi-cellular organisms and later, human beings.[[#References |[4]]]<br />
<br><br />
The topic has sprung much speculation as well as the ethical debates surrounding the idea, including the impacts on already exsisting life on Mars.<br />
<br><br><br />
===<u>Candidates for Terraformation</u>===<br />
====[[Mars]]====<br />
[[Mars]] is the preferred planet of interest for terraforming because it contains a lot of CO<sub>2</sub>, nitrogen, and H<sub>2</sub>O.[[#References |[8]]] Currently [[Mars]] is very cold (on average 220 degrees K, roughly -63.7 degrees F.) and its atmosphere is relatively thin and mostly consists of CO<sub>2</sub> (95.3%) with very little O<sub>2</sub> and N<sub>2</sub>. Mars only receives 43% of the light Earth gets from the Sun, yet it is still sufficient enough for photosynthesis.[[#References |[10]]]<br />
<br><br><br />
Proposed Terraformation of [[Mars]] would require:<br><br />
<ul><br />
<li>Warming the planet substantially to 290 K [[#References |[1]]]</li><br><br />
<li>Increase atmospheric pressure from 6 mbar to atleast 61.8 mbar which is required for people to live in, 10 mbar is required for plant life [[#References |[1]]]<br />
</li><br><br />
<li>Adding O<sub>2</sub>, about 240 mbar of oxygen would be comfortable for humans</sub>[[#References |[1]]]<br />
</li><br><br />
<li>Melt water (which Mars has frozen in Ice caps)[[#References |[1]]]<br />
</li><br><br />
====Venus====<br />
Venus has been proposed but it’s problems far surpass Mars in that it has a very thick atmosphere, little water, no hydrogen, and it’s temperatures are much warmer than Earth around 730 K. The removal of atmospheric gas would be very difficult.[[#References |[11]]] Venus also has clouds made of searing sulfuric acid, and one Venus day is equivalent to 127 Earth days.[[#References |[2]]]<br />
<br><br>Proposed Terraformation of Venus would require:<br><br />
<ul><br />
<li>Cooling the planet substantially [[#References |[2]]]<br />
</li><br><br />
<li>Removing CO<sub>2</sub> and other poisonous gases from the atmosphere while replacing it with O<sub>2</sub> [[#References |[2]]]<br />
</li><br><br />
<li>Reduce day length to 24 hours [[#References |[2]]]<br />
</li><br><br />
<li>Provide water [[#References |[2]]]<br />
</li></ul><br />
<br />
==Biological interaction==<br />
The interaction of pioneering microbial species within an alien atmosphere will hopefully pave the way for future organisms such as plants and eventually humans to be able to colonize that planet.<br />
<br><br />
The primary function of photosynthetic pioneers would be to take CO<sub>2</sub> out of the atmosphere while adding O<sub>2</sub> to the atmosphere.[[#References |[10]]]<br><br />
Microbes could also be utilized to add greenhouse gases to the atmosphere through anaerobic respiration, as well as contribute to soil fertility simply by producing (and becoming) organic matter.<br />
<br />
==<b>Niche: A New World</b>==<br />
To lay the foundation of microbial terraforming on Mars, requirments include:<br> <br />
<ul><li>the release of man-made and/or microbial greenhouse gases into the atmosphere, heating the planet substantially, [[#References |[8]]]<br />
</li> <br />
<li>Initial warming will then cause CO<sub>2</sub> evaporation from the planet’s own glaciers and soil, producing further warming. [[#References |[8]]]<br />
</li> <br />
<li>Melting glaciers will produce hydrologic cycles and evaporated H<sub>2</sub>O into the air, creating a denser atmosphere. This suggests a global temperature of at least 0 degrees Celsius. .[[#References |[8]]]<br />
</li> <br />
<li>Water will be stable on the surface and temperatures will be more moderate, but the atmosphere will be mostly CO<sub>2</sub> and have little O<sub>2</sub>. .[[#References |[8]]]<br />
</li><br />
So long as UV radiation remains high, microorganisms will be confined to living in or under rocks.[[#References |[5]]]<br />
<br> <br />
UV radiation screens have been proposed for microbial access to surfaces.[[#References |[8]]]<br />
<br> <br />
<br />
Microbial populations set to colonize Mars can expect extreme cold temperatures, high radiation, little to no moisture, and limited nutrients. [[#References |[8]]]<br />
<br />
[[image:Marsview5.jpg|thumb||500px||right|<sub>http://www.antarcticaedu.com/visions/</sub>]]<br />
[[image:Mars2.jpg|thumb||600px||left|<sub>http://io9.com/5655719/terraforming-earth-pt-4-nowhere-to-go-but-up</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br />
==Microbial processes==<br />
[[Mars]] has no tectonic activity and thus no chemical turnover occurs there. It's thought that biological and photochemical processes can run some kind of biogeochemicalcycles on Mars.[[#References |[10]]]<br />
<br><br />
====Carbon cycling====<br />
Photosynthetic microorganisms remove CO<sub>2</sub> from the atmosphere by photosynthesis:<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br><br />
Eventually heterotrophic microbes will release CO<sub>2</sub> back into the atmosphere through respiration:<br><br />
<b>C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub> --> 6CO<sub>2</sub> + 6H<sub>2</sub>O + energy</b><br><br />
Certain Microorganisms such as <i>Matteia</i> have been proposed to release CO<sub>2</sub> from carbonate rock to complete the cycle in the early stages of colonization, just until enough carbohydrate is available to support heterotrophs.[[#References |[6]]]<br />
<br />
<br><br />
[[Image:1995 Thomas 48 415-418-2-.JPG |thumb||500px||right|Thomas, David J. 1995. "<I>Biological Aspects of the Ecopoesis and Terraformation of Mars: Current Perspectives and Research</I>]]<br />
<br />
====Oxygen====<br />
Cyanobacteria and algae will be used to increase O<sub>2</sub> through photosynthesis.<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br />
<br />
====Nitrogen cycling====<br />
Besides CO<sub>2</sub> and O<sub>2</sub>, a buffer gas is needed to support human life, and nitrogen is necessary for photosynthesis at the start of terraformation.<br />
Currently there is not enough N<sub>2</sub> in Mars' atmosphere for nitrogen fixation and therefore, denitrification is necessary as long as the regolith contains nitrate as is proposed.[[#References |[1]]]<br />
<br><br />
Denitrification:<br><br />
<b>NO<sub>3</sub>− → NO<sub>2</sub>− → NO + N<sub>2</sub>O → N<sub>2</sub> (g)</b><br><br />
Cyanobacteria and other Nitrogen fixers can reduce N<sub>2</sub> to ammonia:<br><br />
<b>N<sub>2</sub> + 8 H+ + 8 e− → 2 NH<sub>3</sub> + H<sub>2</sub></b><br />
<br />
====Methanogenesis====<br />
Methanogenesis is a an anaerobic process. Archaeal [[methanogens]] can utilize CO<sub>2</sub> for production of methane which is 20x better at trapping heat than CO<sub>2</sub>. Methane gas also has the potential of being a fuel source.[[#References |[14]]]<br />
<br><br />
<b>CO<sub>2</sub> + 4 H<sub>2</sub> → CH<sub>4</sub> + 2H<sub>2</sub>O </b><br />
<br />
====Sulfur cycling====<br />
Most microbes utilize oxidized sulfur for protein synthesis.<br />
<br><br />
<br />
====Phosphorous cycling====<br />
Phosphates are insoluble minerals that are highly conserved in stable environments but through time losses can be a possible issue for terraformation. This may be the case with other non-volatile, minerals such as iron, manganese, and magnesium.[[#References |[10]]]<br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
Microorganisms are the best option for colonization of a new planet because of their wide range of physiologic and metabolic functions, as well as their ability to conduct <b>horizontal gene transfer.</b> Two strategies have been proposed for choosing the best pioneers. One can either choose a generalist extremophile on Earth that inhabits environments similar to the new planet, or genetically modifying a new species with all the best traits required for the job. (Creating a Genetically Engineered Mars Organism "GEMO")[[#References |[9]]]<br />
<br><br />
<b>Proposed traits of the perfect pioneer are:</b><br><ul><br />
<li>Must be photoautotrophs</li><br><br />
<li>Must be anaerobic and respire without O<sub>2</sub></li><br><br />
<li>Osmotic tolerance</li><br><br />
<li>Resistance to UV radiation</li><br><br />
<li>Cold tolerance</li><br><br />
<li>Tolerance for Nutrient limitations</li><br><br />
<li>Tolerance for water limitations</li><br><br />
<li>Resistance to oxides</li><br><br />
<li>Adaptation to lowered intracellular pH due to CO<sub>2</sub> in atmosphere</li><br><br />
<li>Can form Endospores</li><br>[[#References |[9]]]</ul><br />
<br />
===<u>Proposed Photoautotrophs</u>===<br />
====<i>[[Cyanidium caldarium]]</i>====<br />
A unicellular red algae found in diverse extreme environments such as bogs, wet acidic soils, and hot streams.<br />
It has been found to survive with little to no oxygen.[[#References |[12]]]<br />
[[image:Ideyuk 4.jpg |thumb| |300px| |left| Cyandium Caladarium Algae (Shu Suehiro Botanic.jp)]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Cryptoendolith Lichens====<br />
Literally "hiding in rocks" An extremophile found in porous rock in Antarctica where temperatures are normally -89.2°C to -93.4°C. There has been no rain or snowfall in the Antarctic Desert for over 100 years.[[#References |[3]]][[image:Cryptoendolith.jpg|thumb||300px||left|Antarctic sandstone inhabited by cryptoendolithic lichen communities. Photo courtesy of NASA]]<br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====<i>Chroococcidiopsis</i>====<br />
This primitive cyanobacterium has a high range of variability and may be the most desiccant-resistant of its kind. It is found in extreme habitats such as Antarctic rocks, thermal springs, and hypersaline habitats. [[#References |[7]]]<br />
<br />
[[image:45.jpg |thumb||300px||left|Chroococcidiopsis cf. cubana Komárek et Hindák]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
===<u>Proposed Denitrifers</u>===<br />
[[image:Matteia.jpg|thumb||300px||right|http://www.cyanodb.cz]]<br />
<br />
====<i>Matteia</i>====<br />
Matteia sp., a cyanobacterium found on desert rocks, has been proposed to dissolve carbonate rocks both for release of CO<sub>2</sub> and in hopes of creating a Martian carbon cycle.[[#References |[6]]]<br />
<br />
====<i>Psuedomonads</i> and <i>Alcaligenes</i>====<br />
Psuedomonads and [[Alcaligenes]] could be appropriate denitrifiers once enough oxygen and carbonate are present to sustain them.[[#References |[10]]]<br />
<br />
===<u>Proposed GEMOs</u>===<br />
<br />
====<i>Bacillus polymyxa</i>====<br />
Now known as <i>[[Paenibacillus polymyxa]]</i>, A Facultative anaerobe that can form endospores, can fix nitrogen aerobically and anaerobically, and has tolerance to heavy metals. A good start for an eventual GEMO.[[#References |[9]]]<br />
<br />
<br />
[[image:Superbug.jpg|thumb||300px||left|A better GEMO may do the trick <sub>http://www.usc.edu/hsc/info/pr/hmm/04fall/superbug.html</sub>]]<br />
<br><br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br />
==Current Research==<br />
<b>EXPLORING ICELANDIC SUBGLACIAL VOLCANOES AS ANALOGS TO HABITATS ON MARS</b><br><br />
<sub>Gaidos, E., Thorsteinsson, Th., Wade, N., Marteinsson, V., and Stefansson, A.</sub><br><br />
Icelands glacial and volcanic ecosystems are compared to Mars as well as volcanic subglacial lakes. Objectives include studying the microbial populations established there, describe where they get their energy and nutrients, and finally determine biomarkers for integration on Mars.<br />
[[#References |[13]]]<br />
<br><br />
<br><b>ASTROBIOLOGY AND HABITABILITY STUDIES SUPPORTING MARS RESEARCH AND MISSIONS</b><br><br />
<sub>Foing, B.H., Thiel, C., Direito, S., Ehrenfreund, P., Roling, W., Martins, Z., Sephton, M., Stoker, C., Zhavaleta, J.,<br />
Orzechowska, G., Kidd, R., Quinn, R., Kotler, M., and the EuroGeoMars MDRS Team.</sub><br><br />
A scientific protocal is formulated to simulate future scenarios on Mars or the Moon. The desert in Utah is used as a testing ground as it's terrain is similar to that of the targets. Mineralogy, organic compounds, and microbiology were sampled at 10 locations across the desert. Samples were analyzed in situ first followed by ex situ. Further optimizing extraction procedures is the future objective.[[#References |[15]]]<br />
<br><br />
<br><br />
<b>EXTRACTION OF AMINO ACIDS FROM SOILS CLOSE TO THE MARS DESERT RESEARCH STATION (MDRS), UTAH</b><br><br />
<sub>Martinsa Z., Sephtona M.A., Foinga B.H., Ehrenfreund, P.</sub><br><br />
In the search for life exsisting on Mars, the authors suggest amino acid analysis as an option for future exploration. Soil samples were taken in a Utah desert (a Martian analog system,) and amino acid extraction and analysis were performed. Data suggest that mineralogy may play an important role in future life-detection.[[#References |[16]]]<br />
<br><br />
<br><br />
<br />
==References==<br />
<br />
[1]Birch, P. “Terraforming Mars Quickly” ''Journal of the British Interplanetary Society''. 1992. Volume 45. p. 331-340<br />
<br />
[2]Birch, P. “Terraforming Venus Quickly” ''Journal of the British Interplanetary Society''. 1991. Volume 44. p. 157-167<br />
<br />
[3]Blackhurst, R., Verchovsky, A., Jarvis, K., Grady, M.M. “Cryptoendolith communities in Antarctic Dry Valley Region Sanstones: Potential Analogues of Martian Life-Forms” <br>''Lunar and Planetary Science''. 2003. Volume 34.<br />
<br />
[4]Farquhar, J., Bao, H., Thiemens, M. ''Atmospheric Influence of Earth’s Earliest Sulfur Cycle” ''Science''. 2000. Volume 289. P. 756-758<br><br />
<br />
[5][http://www.users.globalnet.co.uk/~mfogg/paper1.htm Fogg, M. J., "Terraforming" ''Society of Automotive Engineers''. 1995. Warrendale, PA] <br />
<br />
[6]Friedmann, EI., Hua, M., Ocampo-Friedmann, R. “Terraforming Mars: dissolution of carbonate rocks by cyanobacteria” ''Journal of Interplanetary Society''. 1993. Volume 46. P. 291-292<br><br />
[7]Friedmann, EI., Ocampo-Friedmann, R. "A Primitive Cyanobacterium as Pioneer Microorganism for Terraforming Mars" ''Adv. Space Res.'' 1994. Volume 15, No. 3. p. 243-246<br />
<br />
[8][http://www.marspapers.org/papers/MAR98089.pdf Graham, J., Graham L. "Chapter 18: Terraforming Mars" 1989.]<br />
<br />
[9]Hiscox, J., Thomas, D. “Genetic Modification and Selection of Microorganisms for Growth on Mars” ''Journal of the British Interplanetary Society.'' 1995 Volume 48. P. 419-426.<br><br />
<br />
[10]Thomas, D. “Biological Aspects of the Ecopoeisis and Terraformation of Mars: Current Perspectives and Research” ''Journal of the British Interplanetary Society''. 1995. Volume 48. P. 415-418<br />
<br />
[11]Sagan, C. "The Planet Venus" ''Science'' 1961. Volume 133. p. 849-858<br><br />
<br />
[12]Seckbach, J., Baker, F.A., Shugarman, P.M. "Algae Thrive in Pure CO<sub>2</sub>" ''Nature''. 1977. Volume 227. p. 774-775<br />
<br />
[13]Gaidos, E., Thorsteinsson, Th., Wade, N., Marteinsson, V., Stefansson, A.<br />
"Exploring Icelandic Subglacial Volcanoes as Analogs to Habitats on Mars" ''42nd Lunar and Planetary Science Conference'' held March 7–11, 2011 at The Woodlands, Texas. LPI Contribution No. 1608. p.1446<br />
<br />
[14]http://www.epa.gov/methane/<br />
<br />
[15]Foing, B.H., Thiel, C., Direito, S., Ehrenfreund, P., Roling, W., Martins, Z., Sephton, M., Stoker, C., Zhavaleta, J.,<br />
Orzechowska, G., Kidd, R., Quinn, R., Kotler, M., and the EuroGeoMars MDRS Team. "Astrobiology and Habitability studies supporting Mars Research and Missions" ''42nd Lunar and Planetary Science Conference'' 2011.<br />
<br />
[16]Z. Martins, M.A. Sephton, B.H. Foing and P. Ehrenfreund. "Extraction of amino acids from soils close to the Mars Desert Research Station (MDRS), Utah." ''International Journal of Astrobiology,'' 2011. Volume 10. p.231-238 <br />
<br />
Edited by Samantha Chavez, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Terraforming&diff=72284Terraforming2012-04-25T06:33:04Z<p>Akent: /* Planetary Engineering */</p>
<hr />
<div>{{Uncurated}}<br />
<br><br />
[[image:46068edaa8c3a0a77d8ae5962027c93a.jpg |thumb||800px||right|]]<br><br />
<br />
==Planetary Engineering==<br />
[[Image:Terraformed_mars_3_stage-We.jpg |thumb|500px|right|Artists rendition of Mars terraformation (galaxyexplorers.org).]]<br />
<br>Terraforming or “Planetary Ecosynthesis” is the process of changing a planet’s atmosphere to resemble that of the Earth’s, with the goal of sustaining terrestrial life. It is predicted that establishment of life will be similar to Earth’s history, starting with basic unicellular microorganisms. The most feasible pioneer to begin life on a new planet would be some kind of photosynthetic microbe.[[#References |[8]]]<br><br />
<br><br />
The strategy of using photosynthesis to engineer a habitable planet for humans through photosynthesis would not be unlike the <b>Great Ogygenation Event</b> that took place on Earth 2.4 billion years ago, sometime after cyanobacteria first evolved (2.7-2.8 billion years ago.) This pivotal event paved the way for evolution of multi-cellular organisms and later, human beings.[[#References |[4]]]<br />
<br><br />
The topic has sprung much speculation as well as the ethical debates surrounding the idea, including the impacts on already exsisting life on Mars.<br />
<br><br><br />
===<u>Candidates for Terraformation</u>===<br />
====[[Mars]]====<br />
[[Mars]] is the preferred planet of interest for terraforming because it contains a lot of CO<sub>2</sub>, nitrogen, and H<sub>2</sub>O.[[#References |[8]]] Currently [[Mars]] is very cold (on average 220 degrees K, roughly -63.7 degrees F.) and its atmosphere is relatively thin and mostly consists of CO<sub>2</sub> (95.3%) with very little O<sub>2</sub> and N<sub>2</sub>. Mars only receives 43% of the light Earth gets from the Sun, yet it is still sufficient enough for photosynthesis.[[#References |[10]]]<br />
<br><br><br />
Proposed Terraformation of [[Mars]] would require:<br><br />
<ul><br />
<li>Warming the planet substantially to 290 K [[#References |[1]]]</li><br><br />
<li>Increase atmospheric pressure from 6 mbar to atleast 61.8 mbar which is required for people to live in, 10 mbar is required for plant life [[#References |[1]]]<br />
</li><br><br />
<li>Adding O<sub>2</sub>, about 240 mbar of oxygen would be comfortable for humans</sub>[[#References |[1]]]<br />
</li><br><br />
<li>Melt water (which Mars has frozen in Ice caps)[[#References |[1]]]<br />
</li><br><br />
====Venus====<br />
Venus has been proposed but it’s problems far surpass Mars in that it has a very thick atmosphere, little water, no hydrogen, and it’s temperatures are much warmer than Earth around 730 K. The removal of atmospheric gas would be very difficult.[[#References |[11]]] Venus also has clouds made of searing sulfuric acid, and one Venus day is equivalent to 127 Earth days.[[#References |[2]]]<br />
<br><br>Proposed Terraformation of Venus would require:<br><br />
<ul><br />
<li>Cooling the planet substantially [[#References |[2]]]<br />
</li><br><br />
<li>Removing CO<sub>2</sub> and other poisonous gases from the atmosphere while replacing it with O<sub>2</sub> [[#References |[2]]]<br />
</li><br><br />
<li>Reduce day length to 24 hours [[#References |[2]]]<br />
</li><br><br />
<li>Provide water [[#References |[2]]]<br />
</li></ul><br />
<br />
==Biological interaction==<br />
The interaction of pioneering microbial species within an alien atmosphere will hopefully pave the way for future organisms such as plants and eventually humans to be able to colonize that planet.<br />
<br><br />
The primary function of photosynthetic pioneers would be to take CO<sub>2</sub> out of the atmosphere while adding O<sub>2</sub> to the atmosphere.[[#References |[10]]]<br><br />
Microbes could also be utilized to add greenhouse gases to the atmosphere through anaerobic respiration, as well as contribute to soil fertility simply by producing (and becoming) organic matter.<br />
<br />
==<b>Niche: A New World</b>==<br />
To lay the foundation of microbial terraforming on Mars, requirments include:<br> <br />
<ul><li>the release of man-made and/or microbial greenhouse gases into the atmosphere, heating the planet substantially, [[#References |[8]]]<br />
</li> <br />
<li>Initial warming will then cause CO<sub>2</sub> evaporation from the planet’s own glaciers and soil, producing further warming. [[#References |[8]]]<br />
</li> <br />
<li>Melting glaciers will produce hydrologic cycles and evaporated H<sub>2</sub>O into the air, creating a denser atmosphere. This suggests a global temperature of at least 0 degrees Celsius. .[[#References |[8]]]<br />
</li> <br />
<li>Water will be stable on the surface and temperatures will be more moderate, but the atmosphere will be mostly CO<sub>2</sub> and have little O<sub>2</sub>. .[[#References |[8]]]<br />
</li><br />
So long as UV radiation remains high, microorganisms will be confined to living in or under rocks.[[#References |[5]]]<br />
<br> <br />
UV radiation screens have been proposed for microbial access to surfaces.[[#References |[8]]]<br />
<br> <br />
<br />
Microbial populations set to colonize Mars can expect extreme cold temperatures, high radiation, little to no moisture, and limited nutrients. [[#References |[8]]]<br />
<br />
[[image:Marsview5.jpg|thumb||500px||right|<sub>http://www.antarcticaedu.com/visions/</sub>]]<br />
[[image:Mars2.jpg|thumb||600px||left|<sub>http://io9.com/5655719/terraforming-earth-pt-4-nowhere-to-go-but-up</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br />
==Microbial processes==<br />
[[Mars]] has no tectonic activity and thus no chemical turnover occurs there. It's thought that biological and photochemical processes can run some kind of biogeochemicalcycles on Mars.[[#References |[10]]]<br />
<br><br />
====Carbon cycling====<br />
Photosynthetic microorganisms remove CO<sub>2</sub> from the atmosphere by photosynthesis:<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br><br />
Eventually heterotrophic microbes will release CO<sub>2</sub> back into the atmosphere through respiration:<br><br />
<b>C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub> --> 6CO<sub>2</sub> + 6H<sub>2</sub>O + energy</b><br><br />
Certain Microorganisms such as <i>Matteia</i> have been proposed to release CO<sub>2</sub> from carbonate rock to complete the cycle in the early stages of colonization, just until enough carbohydrate is available to support heterotrophs.[[#References |[6]]]<br />
<br />
<br><br />
[[Image:1995 Thomas 48 415-418-2-.JPG |thumb||500px||right|Thomas, David J. 1995. "<I>Biological Aspects of the Ecopoesis and Terraformation of Mars: Current Perspectives and Research</I>]]<br />
<br />
====Oxygen====<br />
Cyanobacteria and algae will be used to increase O<sub>2</sub> through photosynthesis.<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br />
<br />
====Nitrogen cycling====<br />
Besides CO<sub>2</sub> and O<sub>2</sub>, a buffer gas is needed to support human life, and nitrogen is necessary for photosynthesis at the start of terraformation.<br />
Currently there is not enough N<sub>2</sub> in Mars' atmosphere for nitrogen fixation and therefore, denitrification is necessary as long as the regolith contains nitrate as is proposed.[[#References |[1]]]<br />
<br><br />
Denitrification:<br><br />
<b>NO<sub>3</sub>− → NO<sub>2</sub>− → NO + N<sub>2</sub>O → N<sub>2</sub> (g)</b><br><br />
Cyanobacteria and other Nitrogen fixers can reduce N<sub>2</sub> to ammonia:<br><br />
<b>N<sub>2</sub> + 8 H+ + 8 e− → 2 NH<sub>3</sub> + H<sub>2</sub></b><br />
<br />
====Methanogenesis====<br />
Methanogenesis is a an anaerobic process. Archaeal [[mathanogens]] can utilize CO<sub>2</sub> for production of methane which is 20x better at trapping heat than CO<sub>2</sub>. Methane gas also has the potential of being a fuel source.[[#References |[14]]]<br />
<br><br />
<b>CO<sub>2</sub> + 4 H<sub>2</sub> → CH<sub>4</sub> + 2H<sub>2</sub>O </b><br />
<br />
====Sulfur cycling====<br />
Most microbes utilize oxidized sulfur for protein synthesis.<br />
<br><br />
<br />
====Phosphorous cycling====<br />
Phosphates are insoluble minerals that are highly conserved in stable environments but through time losses can be a possible issue for terraformation. This may be the case with other non-volatile, minerals such as iron, manganese, and magnesium.[[#References |[10]]]<br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
Microorganisms are the best option for colonization of a new planet because of their wide range of physiologic and metabolic functions, as well as their ability to conduct <b>horizontal gene transfer.</b> Two strategies have been proposed for choosing the best pioneers. One can either choose a generalist extremophile on Earth that inhabits environments similar to the new planet, or genetically modifying a new species with all the best traits required for the job. (Creating a Genetically Engineered Mars Organism "GEMO")[[#References |[9]]]<br />
<br><br />
<b>Proposed traits of the perfect pioneer are:</b><br><ul><br />
<li>Must be photoautotrophs</li><br><br />
<li>Must be anaerobic and respire without O<sub>2</sub></li><br><br />
<li>Osmotic tolerance</li><br><br />
<li>Resistance to UV radiation</li><br><br />
<li>Cold tolerance</li><br><br />
<li>Tolerance for Nutrient limitations</li><br><br />
<li>Tolerance for water limitations</li><br><br />
<li>Resistance to oxides</li><br><br />
<li>Adaptation to lowered intracellular pH due to CO<sub>2</sub> in atmosphere</li><br><br />
<li>Can form Endospores</li><br>[[#References |[9]]]</ul><br />
<br />
===<u>Proposed Photoautotrophs</u>===<br />
====<i>[[Cyanidium caldarium]]</i>====<br />
A unicellular red algae found in diverse extreme environments such as bogs, wet acidic soils, and hot streams.<br />
It has been found to survive with little to no oxygen.[[#References |[12]]]<br />
[[image:Ideyuk 4.jpg |thumb| |300px| |left| Cyandium Caladarium Algae (Shu Suehiro Botanic.jp)]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Cryptoendolith Lichens====<br />
Literally "hiding in rocks" An extremophile found in porous rock in Antarctica where temperatures are normally -89.2°C to -93.4°C. There has been no rain or snowfall in the Antarctic Desert for over 100 years.[[#References |[3]]][[image:Cryptoendolith.jpg|thumb||300px||left|Antarctic sandstone inhabited by cryptoendolithic lichen communities. Photo courtesy of NASA]]<br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====<i>Chroococcidiopsis</i>====<br />
This primitive cyanobacterium has a high range of variability and may be the most desiccant-resistant of its kind. It is found in extreme habitats such as Antarctic rocks, thermal springs, and hypersaline habitats. [[#References |[7]]]<br />
<br />
[[image:45.jpg |thumb||300px||left|Chroococcidiopsis cf. cubana Komárek et Hindák]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
===<u>Proposed Denitrifers</u>===<br />
[[image:Matteia.jpg|thumb||300px||right|http://www.cyanodb.cz]]<br />
<br />
====<i>Matteia</i>====<br />
Matteia sp., a cyanobacterium found on desert rocks, has been proposed to dissolve carbonate rocks both for release of CO<sub>2</sub> and in hopes of creating a Martian carbon cycle.[[#References |[6]]]<br />
<br />
====<i>Psuedomonads</i> and <i>Alcaligenes</i>====<br />
Psuedomonads and [[Alcaligenes]] could be appropriate denitrifiers once enough oxygen and carbonate are present to sustain them.[[#References |[10]]]<br />
<br />
===<u>Proposed GEMOs</u>===<br />
<br />
====<i>Bacillus polymyxa</i>====<br />
Now known as <i>[[Paenibacillus polymyxa]]</i>, A Facultative anaerobe that can form endospores, can fix nitrogen aerobically and anaerobically, and has tolerance to heavy metals. A good start for an eventual GEMO.[[#References |[9]]]<br />
<br />
<br />
[[image:Superbug.jpg|thumb||300px||left|A better GEMO may do the trick <sub>http://www.usc.edu/hsc/info/pr/hmm/04fall/superbug.html</sub>]]<br />
<br><br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br />
==Current Research==<br />
<b>EXPLORING ICELANDIC SUBGLACIAL VOLCANOES AS ANALOGS TO HABITATS ON MARS</b><br><br />
<sub>Gaidos, E., Thorsteinsson, Th., Wade, N., Marteinsson, V., and Stefansson, A.</sub><br><br />
Icelands glacial and volcanic ecosystems are compared to Mars as well as volcanic subglacial lakes. Objectives include studying the microbial populations established there, describe where they get their energy and nutrients, and finally determine biomarkers for integration on Mars.<br />
[[#References |[13]]]<br />
<br><br />
<br><b>ASTROBIOLOGY AND HABITABILITY STUDIES SUPPORTING MARS RESEARCH AND MISSIONS</b><br><br />
<sub>Foing, B.H., Thiel, C., Direito, S., Ehrenfreund, P., Roling, W., Martins, Z., Sephton, M., Stoker, C., Zhavaleta, J.,<br />
Orzechowska, G., Kidd, R., Quinn, R., Kotler, M., and the EuroGeoMars MDRS Team.</sub><br><br />
A scientific protocal is formulated to simulate future scenarios on Mars or the Moon. The desert in Utah is used as a testing ground as it's terrain is similar to that of the targets. Mineralogy, organic compounds, and microbiology were sampled at 10 locations across the desert. Samples were analyzed in situ first followed by ex situ. Further optimizing extraction procedures is the future objective.[[#References |[15]]]<br />
<br><br />
<br><br />
<b>EXTRACTION OF AMINO ACIDS FROM SOILS CLOSE TO THE MARS DESERT RESEARCH STATION (MDRS), UTAH</b><br><br />
<sub>Martinsa Z., Sephtona M.A., Foinga B.H., Ehrenfreund, P.</sub><br><br />
In the search for life exsisting on Mars, the authors suggest amino acid analysis as an option for future exploration. Soil samples were taken in a Utah desert (a Martian analog system,) and amino acid extraction and analysis were performed. Data suggest that mineralogy may play an important role in future life-detection.[[#References |[16]]]<br />
<br><br />
<br><br />
<br />
==References==<br />
<br />
[1]Birch, P. “Terraforming Mars Quickly” ''Journal of the British Interplanetary Society''. 1992. Volume 45. p. 331-340<br />
<br />
[2]Birch, P. “Terraforming Venus Quickly” ''Journal of the British Interplanetary Society''. 1991. Volume 44. p. 157-167<br />
<br />
[3]Blackhurst, R., Verchovsky, A., Jarvis, K., Grady, M.M. “Cryptoendolith communities in Antarctic Dry Valley Region Sanstones: Potential Analogues of Martian Life-Forms” <br>''Lunar and Planetary Science''. 2003. Volume 34.<br />
<br />
[4]Farquhar, J., Bao, H., Thiemens, M. ''Atmospheric Influence of Earth’s Earliest Sulfur Cycle” ''Science''. 2000. Volume 289. P. 756-758<br><br />
<br />
[5][http://www.users.globalnet.co.uk/~mfogg/paper1.htm Fogg, M. J., "Terraforming" ''Society of Automotive Engineers''. 1995. Warrendale, PA] <br />
<br />
[6]Friedmann, EI., Hua, M., Ocampo-Friedmann, R. “Terraforming Mars: dissolution of carbonate rocks by cyanobacteria” ''Journal of Interplanetary Society''. 1993. Volume 46. P. 291-292<br><br />
[7]Friedmann, EI., Ocampo-Friedmann, R. "A Primitive Cyanobacterium as Pioneer Microorganism for Terraforming Mars" ''Adv. Space Res.'' 1994. Volume 15, No. 3. p. 243-246<br />
<br />
[8][http://www.marspapers.org/papers/MAR98089.pdf Graham, J., Graham L. "Chapter 18: Terraforming Mars" 1989.]<br />
<br />
[9]Hiscox, J., Thomas, D. “Genetic Modification and Selection of Microorganisms for Growth on Mars” ''Journal of the British Interplanetary Society.'' 1995 Volume 48. P. 419-426.<br><br />
<br />
[10]Thomas, D. “Biological Aspects of the Ecopoeisis and Terraformation of Mars: Current Perspectives and Research” ''Journal of the British Interplanetary Society''. 1995. Volume 48. P. 415-418<br />
<br />
[11]Sagan, C. "The Planet Venus" ''Science'' 1961. Volume 133. p. 849-858<br><br />
<br />
[12]Seckbach, J., Baker, F.A., Shugarman, P.M. "Algae Thrive in Pure CO<sub>2</sub>" ''Nature''. 1977. Volume 227. p. 774-775<br />
<br />
[13]Gaidos, E., Thorsteinsson, Th., Wade, N., Marteinsson, V., Stefansson, A.<br />
"Exploring Icelandic Subglacial Volcanoes as Analogs to Habitats on Mars" ''42nd Lunar and Planetary Science Conference'' held March 7–11, 2011 at The Woodlands, Texas. LPI Contribution No. 1608. p.1446<br />
<br />
[14]http://www.epa.gov/methane/<br />
<br />
[15]Foing, B.H., Thiel, C., Direito, S., Ehrenfreund, P., Roling, W., Martins, Z., Sephton, M., Stoker, C., Zhavaleta, J.,<br />
Orzechowska, G., Kidd, R., Quinn, R., Kotler, M., and the EuroGeoMars MDRS Team. "Astrobiology and Habitability studies supporting Mars Research and Missions" ''42nd Lunar and Planetary Science Conference'' 2011.<br />
<br />
[16]Z. Martins, M.A. Sephton, B.H. Foing and P. Ehrenfreund. "Extraction of amino acids from soils close to the Mars Desert Research Station (MDRS), Utah." ''International Journal of Astrobiology,'' 2011. Volume 10. p.231-238 <br />
<br />
Edited by Samantha Chavez, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Legume-Rhizobium&diff=72283Legume-Rhizobium2012-04-25T06:20:26Z<p>Akent: /* Improving Symbiotic N Fixation */</p>
<hr />
<div>{{Uncurated}}<br />
<br />
==Introduction==<br />
[http://en.wikipedia.org/wiki/Rhizobia Rhizobia] are symbiotic diazotrophs (prokaryotic organisms that carry out dinitrogen fixation) that form a symbiotic association with legumes. This association is symbiotic in that both the plant and rhizobia benefit. The plant supplies the rhizobia with energy in the form of amino acids and the rhizobia [http://microbewiki.kenyon.edu/index.php/Nitrogen_cycle_including_GHG#Nitrogen_fixation fix nitrogen] from the atmosphere for plant uptake. The reduction of atmospheric dinitrogen into ammonia is the second most important biological process on earth after photosynthesis (Sylvia, 2005). The actual process of dinitrogen fixation can only be carried out by diazotrophs that contain the enzyme dinitrogenase. Nitrogen is the most critical nutrient needed to support plant growth. Unfortunately, atmospheric dinitrogen (78% of air we breathe) is extremely stable due to triple bonds which can only be broken by energy intensive ways. These include electrical N<sub>2</sub> fixation by lightning where oxides of N come to ground with rain, the Haber-Bosch process in industrial fertilizer production, and biological N<sub>2</sub> fixation in legumes by bacterial symbionts such as <i>[[Rhizobium etli]]</i>. Biological fixation of nitrogen was the leading form of annual nitrogen input until the last decade of the 20th century (Russelle, 2008). It is gaining attention once again as sustainability becomes a central focus to feed a world population of over 7 billion people. <br />
[[Image:ZBDYF00Z.jpg |thumb|300px|right|http://www.google.com/imgres?hl=en&biw=1366&bih=624&tbm=isch&tbnid=OjqCIhtC7-xNtM:&imgrefurl=http://www.goldposters.com/item-6014897/nitrogen-fixing-bacteria-rhizobium-nodules-on-soybean-roots-glycine-max.html&docid=7Mg42URN49FyjM&imgurl=http://cache2.artprintimages.com/LRG/38/3817/ZBDYF00Z.jpg&w=400&h=300&ei=FG97T7j5G8qigweytZXvAg&zoom=1&iact=hc&vpx=111&vpy=142&dur=3616&hovh=194&hovw=259&tx=173&ty=135&sig=109319213114400326664&page=1&tbnh=123&tbnw=164&start=0&ndsp=9&ved=1t:429,r:0,s:0]]<br />
<br><br />
<br />
==Biological interaction==<br />
Biological N<sub>2</sub> fixation takes energy which comes at the expense of photosynthate (sucrose). Generally, legumes gain extra nitrogen for plant growth to offset the loss of photosynthate in this mutualistic association. The rhizobia invade plant roots and induce a nodule in which the bacteria reduce atmospheric nitrogen to ammonia and supply the plant with nitrogenous compounds (Young, 1989). The plant gains the ability to grow in nitrogen poor soils, and the bacteria gain a protected niche where they multiply and eventually escape back into the surrounding soil when the nodule senesces (Young, 1989). <br />
Because biological N<sub>2</sub> fixation requires such a large amount of energy, it is important to understand the energy transfer in the process. The stepwise reaction of energy transfer is characterized by the following steps: N<sub>2</sub> yields diamine which yields hydrazine which yields NH<sub>4</sub><sup>+</sup>. Each yield requires 2 e- for a total of 6 electrons needed. Electrons come in via Fe protein and are donated by ferredoxin. ATP is used to reduce N<sub>2</sub> to NH<sub>4</sub><sup>+</sup> whereby ATP hydrolysis takes place and the Fe protein reduces the MoFe protein which reduces the nitrogen (Dixon and Wheeler, 1986). 4 ATPs are used per electron in the N<sub>2</sub> fixation process. N<sub>2</sub> + 6e- + 8H+ yields 2 molecules NH<sub>4</sub><sup>+</sup>. So a total of 24 ATPs would be required to make 2 molecules of NH<sub>4</sub><sup>+</sup> from one molecule of N<sub>2</sub>. <br><br />
<br><br />
<br />
===Nodulation===<br />
The actual process of nodulation is a very coordinated effort between the legume and the <i>Rhizobium</i> bacteria in the soil. Infection typically occurs in root hairs of legumes. Many rhizobia and host plants are highly specific and legumes can either attract rhizobia to root hairs directly by excretory compounds or by induction of [http://microbewiki.kenyon.edu/index.php/Bradyrhizobium#Nodulation <i>nod</i>] gene activity in the bacteria.<br />
<br><br />
<br />
[[Image:CMI 1736 f1.gif |thumb|300px|left|Molecular determinants of host specificity during nitrogen-fixing symbiosis. http://onlinelibrary.wiley.com/doi/10.1111/j.1462-5822.2011.01736.x/pdf.]]<br />
<br />
====Communication between legume and <i>Rhizobium</i>==== <br />
1. Flavonoids are released by the host root. The flavonoid is at the highest concentration at the root and interacts with the product of bacterial <i>nodD</i> gene. The <i>nodD</i> gene produces the protein, <i>nodD</i>, which is the sensor that recognizes chemicals excreted by host plant roots (Russelle, 2008). <br />
<br />
2. Rhizobia colonize the soil in the vicinity of the root hair in response to the flavonoids. This process is autoregulated where favonoids stimulate Nod factor production, which stimulates flavonoid secretion (Russelle, 2008). <br />
<br />
3. Response to Nod factors is extremely rapid and the disruption of cell wall happens very quickly. Disruption of crystallization of cell walls take place, thereby allowing entrance by the rhizobia. At the same time Rhizobia multiply in the rhizosphere. The root hair is then stimulated and curls to the side where the bacteria are attached which stimulates cell division in the root cortex. <br />
<br />
4. A "shepherd's crook" is formed and entraps the rhizobia which then erode the host cell wall and enter near the root hair tip. An infection thread is formed as rhizobia digest the root hair cell wall. Free-living <i>Rhizobium</i> bacteria are converted to bacteroids as the infection elongates by tip growth down root hair and toward epidermal cells.<br />
<br />
5. Infection thread branches and heads toward the cortex and a visibly evident nodule develops on the root as the plant produces cytokinin and cells divide. Nodules can contain one or more rhizobial strains and can be either determinant (lack a persistent meristem and are spherical) or indeterminate (located at the distal end of cylindrically shaped lobes) (Russelle, 2008). Many infections are aborted due to a breakdown in communication between rhizobia and the host plant leaving nodule number strictly regulated by the plant. <br />
<br />
6. Once inside the nodule, rhizobia are released from the infection thread in a droplet of polysaccharide. A plant-derived peribacteroid membrane, which regulates the flow of compounds between the plant and [http://microbewiki.kenyon.edu/index.php/Bradyrhizobium#Cell_Structure_and_Metabolism bacteroid], quickly develops around this droplet via endocytosis. This process keeps the microbes "outside" the plant where the rhizobia are intracellular but [http://en.wiktionary.org/wiki/extracytoplasmic extracytoplasmic] (Russelle, 2008). The loss of the ammonium assimilatory capacity by bacteroids is important for maintaining the symbiotic relationship with legumes.<br />
<br />
<br />
<br />
==Niche==<br />
The amount of N<sub>2</sub> fixed depends on the soil population of bacterial symbionts, soil acidity, and often overlooked soil nitrogen availability. Nodulation will only be initiated when the plant is in low nitrogen status. <i>Rhizobium</i> populations are sensitive to changes in environmental conditions. <br />
<br />
===Favorable Environment===<br />
A balanced pH with high levels of nutrients and good physical properties is favored by rhizobia. A variety of C and N compounds can be utilized by rhizobia. A single rhizobial cell in a favorable environment can infect a root hair and generate 10<sup>10</sup> progeny (Russelle, 2008).<br />
===Unfavorable Environment===<br />
Rhizobia can be reduced in numbers by strong soil acidity which has high hydrogen ion concentration. Plant growth can also be limited by toxic levels of aluminum and manganese. A reduction in rhizobial pools can be due to nutrient limitations including deficiencies in calcium, phosphorus, and molybdenum, low or high soil temperatures (rhizobia are [http://en.wikipedia.org/wiki/Mesophile mesophiles]), and poor soil physical properties that restrict aeration and moisture supply. (Sylvia, 2005). Soil acidity reduces nodulation and overall N<sub>2</sub> fixation. Soil nitrate concentration and phosphorus concentration can also affect rhizobia populations. Furthermore, indegenous rhizobial populations are maintained over time and depend on how often host plants are grown and on competitive ability of different rhiboia strains (Furseth et al., 2012). Hundreds of microbial species can fix nitrogen as most nitrogen fixing prokaryotes are free-living organisms or associate with plants. Unfortunately, the environmental factors have to optimal for many of the aerobic, microaerobic, anaerobic, and even photosynthetic bacteria, and actinomycetes to be reliable sources of nitrogen fixation. <br />
<br><br />
<br><br />
<br />
==Microbial processes==<br />
Estimates of the amount of N<sub>2</sub> fixed range from 57 – 600 kg/ha per year and vary widely. (Evans and Barber, 1977). The rates of N<sub>2</sub> fixation, unfortunatley, cannot be measured accurately (LaRue and Patterson, 1982). Legumes prefer to take up available soil nitrogen from soil solution as fixation by bacteria is expensive to the plant. N<sub>2</sub> fixation is constrained in many agricultural soils where nitrogen levels are high from routine addition of fertilizer. Nitrate in the soil reduces fixation where nitrate reduction uses photosynthate.<br />
===Role of Nitrogenase===<br />
[http://en.wikipedia.org/wiki/Nitrogenase Nitrogenase] is the actual enzyme responsible for conversion of N<sub>2</sub> to ammonium. Nitrogenase exists in three forms that include molybdenum nitrogenase, vanadium nitrogenase, and iron nitrogenase. Mo-containing nitrogenase is the most widely studied and is the enzyme utilized by <i>Rhizobium</i> (Russelle, 2008). This enzyme actually is made up of two enzymes, dinitrogenase and dinitrogenase reductase. Nitrogenase is regulated by N supply and by O<sub>2</sub> which can inhibit nitrogenase. Leghemoglobin, responsible for giving efficitive nodules their pink color, binds oxygen and transfers it to bacterial electron transport chain so that ATP synthesis can occur. Thus, the concentration of free O<sub>2</sub> is lower in the nodule. Unfortunately, high amounts of ATP and oxygen reductant are needed to meet the demands of the enzyme, but at the same time, nitrogenase is oxygen sensitive. This is often refered to as the 'paradox' of symbiotic nitrogen fixation (Schulze, 2004). <br />
<br><br />
<br><br />
<br />
==Key Microorganisms==<br />
There are currently six phylogenetically distinct genera of rhizobia. The taxonomy of these organisms is still in flux due to rapidly advancing analytical techniques.<br />
<br />
[[Image:2nd edition 001.jpg |thumb|300px|right|Sylvia, D.M., Fuhrmann, J.J., Hartel, P.G., and Zuberer, D.A., 2005. Principles and Applications of Soil Microbiology. 2nd Edition. Table 16-2, p. 409.]]<br />
<br />
===<i>Allorhizobium</i>===<br />
<i>Allorhizobium</i> is a monospecific genus. <br />
====<i>Allorhizobium</i> species====<br />
<i>A. undicola</i> produces nodules on <i>Neptunia prostrata</i>. This plant is an aquatic legume indigenous to humid tropics used for both human consumption and green manure (Russelle, 2008).<br />
<br />
<br />
===<i>Azorhizobium</i>===<br />
<i>Azorhizobium</i> produce nodules on the aquatic legume <i>Sesbania rostrata</i>. <i>Azorhizobium</i> are unique in that they have the ability to grow with N<sub>2</sub> as the only nitrogen source. (Russelle, 2008).<br><br />
====<i>Azorhizobium</i> species====<br />
<i>A. caulinodans</i> is the only species for this genus. <br />
<br />
<br />
===<i>[[Bradyrhizobium]]</i>===<br />
<i>[[Bradyrhizobium]]</i> as a genus grows slowly and is widely known for symbiosis with [[soybean]], but other crops such as peanut, lupine, and cowpea can form symbiosis with <i>[[Bradyrhizobium]]</i>. <br />
====<i>[[Bradyrhizobium]]</i> species====<br />
<i>[[Bradyrhizobium japonicum]] and B. elkanii</i> are found in symbiosis with [[soybean]]. <i>B. lupini</i> is a symbiont of lupine. <i>B. spp.</i> nodulate peanut.<br />
<br />
<br />
===<i>Mesorhizobium</i>===<br />
Mesorhizobium grow faster than <i>[[Bradyrhizobium]]</i>, but slower than <i>Rhizobium</i> and <i>Sinorhizobium</i>. They nodulate trefoils, chickpea, and found in the nodules of several legume species in China.<br />
====<i>Mesorhizobium</i> species====<br />
<i>[[Mesorhizobium loti]]</i> nodulates trefoils, <i>M. huakuii</i> nodulates <i>Astragalus</i>, <i>M. ciceri</i> and <i>M. mediteraneum</i> nodulate chickpea, and <i>M. tianshanense</i> are found in symbiosis with several legume species in China (Russelle, 2008). <br><br />
<br />
<br />
===<i>Rhizobium</i>===<br />
<i>Rhizobium</i> form symbiosis with vetches, peas, lentil, clovers, and beans.<br />
====<i>Rhizobium</i> species====<br />
<i>R. leguminosarum</i> nodulates vetch, <i>R. tropici</i> is a symbiont of beans and other hosts, <i>[[Rhizobium etli]]</i> nodulates both alfalfa and beans, <i>R. gallicum</i> can nodulate bean, <i>R. giardinii</i> nodulates leuceana, <i>R. galegae</i> nodulates galega, and <i>R. spp NGR234</i> nodulates 112 genera of legumes and the nonlegume <i>Parasponia andersonii</i>.<br><br />
<br />
<br />
===<i>Sinorhizobium</i>===<br />
Sinorhizobium produce nodules in alfalfa, medics, sweetclover, sesbania. <br />
====<i>Sinorhizobium</i> species====<br />
<i>[[Sinorhizobium meliloti]]</i> nodulates alfalfa, medics, and sweetclover. <i>S. fredii</i> nodulates soybean; <i>S. saheli</i> and <i>S. terangae</i> nodulate roots of <i>Sesbania, Acacia, Leucaena leucocephala, and Neptunia prostrata</I>.<br><br />
<br><br />
<br><br />
<br />
==Current Research==<br />
<br />
===Seed-applied Rhizobia Inoculants===<br />
Biological fixation of nitrogen can contribute large amounts of plant usable nitrogen to the soil nitrogen pool. Only a small percentage of soybean producers use rhizobia inoculants as a seed treatment in an attempt to maximize the biological fixation of atmospheric nitrogen to plant usable forms in the soil. Results of this experiment indicate that the greatest responses of rhizobia inoculation on yield came on soils having low levels of indigenous rhizobial populations. Yield responded positively to inoculation at only 3 out of 18 environments. The investigators linked low response to high levels of rhizobial populations which were maintained by regular crop rotation with soybean, which kept rhizobial levels sufficient for plant nodulation and rhizobium bacteria reproduction. Researchers concluded that soybean growers should only inoculate soybean seed with rhizobia if soybean had not been grown for 5 or more years at a particular tract of land (Furseth et al., 2012).<br />
<br><br />
<br />
[[File:Increase1.gif |thumb|300px|left|Fig. 1. Schematic depicting the process of hydrogen uptake conferred by pHUTFXPAR in 1278K105a. Hydrogen is an obligate product of the nitrogenase reaction. H2 is oxidized to protons and electrons. Through electron transport, ATP is recovered and is available for bacterial and/or plant metabolism. The addition of genes to Rhizobium that provides this hydrogen uptake phenotype results in increased bean production.http://www.plantmanagementnetwork.org/pub/cm/review/2004/yield/]]<br />
<br />
===[http://www.pnas.org/content/104/24/10282.full.pdf+html Pesticides Reduce Rhizobia Efficiency]===<br />
Symbiotic nitrogen fixation (SNF) is noted to reduce the need for excessive synthetic fertilizer additions by replacing man-made nitrogen with a naturally produced form. Utilizing crop rotation with legumes could save millions or billions of dollars currently being spent on synthetic nitrogen forms used extensively in monoculture agriculture, namely continuous corn production. Creating environments that will allow chemical signals to be exchanged between the host plant and rhizobia are extremely important in efficient SNF. Phytochemical signals sent out by host plant roots are only specifically recognized by certain soil bacterium leading to high host specificity by rhizobium. Disrupting this signal is costly and was examined by the investigators. The researchers tested five phytochemicals ranging from natural derived phytochemicals to various insecticides (some of which are no longer used in production agriculture, namely DDT) and found that all chemical treatment groups exhibited significantly lower plant yields, inhibited establishment of symbiosis, reduced SNF, and negatively impacted N fixations and plant biomass production (Fox et al., 2007). <br />
<br />
===[http://www.plantmanagementnetwork.org/pub/cm/review/2004/yield/ Improving Symbiotic N Fixation]===<br />
<br />
Much of the energy consumed in nitrogen fixation is wasted in the production of H<sub>2</sub>. Luckily there are strains, namely the hydrogenase positive Hup+ strains, that can oxidize the H<sub>2</sub> produced during the nitrogenase reaction and recover energy. Using these strains of <i>Bradyrhizobium japonicum</i> as an inoculant could increase soybean yield and increase nitrogen fixation efficiency. Improvement of these strains could lead to a higher amounts of nitrogen fixation ([http://www.tandfonline.com/doi/pdf/10.1080/07352689609701941 Maier, 1996)]. Microbial biologists have taken the first step of identification of genes that can enhance nitrogen fixation and discovery of competition strategies against indegenous bacteria ([http://microbes.nres.uiuc.edu/~files/Kent-1998-Hup%20plasmid.pdf Kent, 1998]). Furthermore, utilization of anti-rhizobial peptides called trifolitoxins to reduce the inability of inoculum strains to compete with native root nodule bacteria for root nodulation would be beneficial. The addition of the plasmid pHUTPFXPAR to a rhizobium population increased nodulation competitiveness and increased efficiency by way of Hup+ had significant yield increase compared to unioculated treatment. Further research is needed to ensure that this type of antibiotic-resistant gene will not affect indeginous rhizobial communities via lateral gene transfer.<br />
<br />
<br><br />
<br><br />
<br />
==References==<br />
Evans, H.J., and Barber, L.E., 1977. "Biological nitrogen fixation for food and fiber production. What are some immediately feasible possibilities"? Science. 197:332-339.<br />
<br />
[http://www.pnas.org/content/104/24/10282.full.pdf+html Fox, J.E., Gulledge, J., Engelhaupt, E., Burow, M.E., and McLachlan, J.A. 2007. "Pesticides reduce symbiotic efficiency of nitrogen-fixing rhizobia and host plants". PNAS. 104(24):10282-10287.] <br />
<br />
Furseth, B.J., Conley, S.P., and Ane, J-M. 2012. "Soybean Response to Soil Rhizobia and Seed-applied Rhizobia Inoculants in Wisconsin". Crop Science. 52:339-344.<br />
<br />
[http://www.plantmanagementnetwork.org/pub/cm/review/2004/yield/ Iniquez, A. L., Robleto, E. A., Kent, A. D., Triplett, E. W. 2004. "Significant yield increase in Phaseolus vulgaris obtained by inoculation with a trifolitoxin-producing, Hup + strain of Rhizobium leguminosarum bv. phaseoli." Crop Management. March:1-5.]<br />
<br />
[http://microbes.nres.uiuc.edu/~files/Kent-1998-Hup%20plasmid.pdf Kent, A.D., M.L. Wojtasiak, E.A. Robleto, and E.W. Triplett. 1998. A transposable partitioning locus used to stabilize plasmid-borne hydrogen oxidation and trifolitoxin production genes in a Sinorhizobium strain. Applied and Environmental Microbiology 64:1657-1662.]]<br />
<br />
[http://www.era.lib.ed.ac.uk/bitstream/1842/469/1/Kiers_etal_03.pdf Kiers, E.T., Rousseau, R.A., West, S.A., Denison, R.F. 2003. "Host sanctions and the legume-rhizobium mutualism". 425:78-81.]<br />
<br />
LaRue, T.A., and Patterson, T.G., 1982. "How much nitrogen do legumes fix"? Adv. Agron. 34:15-38.<br />
<br />
[http://www.tandfonline.com/doi/pdf/10.1080/07352689609701941 Maier, R.J., and E.W. Triplett. 1996. Toward more productive, efficient, and competitive nitrogen-fixing symbiotic bacteria. Crit. Rev. Plant Sci. 15:191-234.]<br />
<br />
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC160880/pdf/070869.pdf Mylona, P., Pawlowski, K. and Bisseling, T., 1995. "Symbiotic Nitrogen Fixation". The Plant Cell. 7:869-885]<br />
<br />
[http://www.annualreviews.org/doi/full/10.1146/annurev-genet-110410-132549 Oldroyd, G.E.D., Murray, J.D., Poole, P.S., Downie, J.A. 2011. "The Rules of Engagement in the Legume-Rhizobial Symbiosis". Annual Review of Genetics. 45:119-144.]<br />
<br />
Russelle, M. P. "Biological Dinitrogen Fixation in Agriculture". Nitrogen in Agricultural Systems. Ed. Schepers, J.S. and Raun W.R. 2008. 281 - 359.<br />
<br />
Schulze, J. 2004. "How are nitrogen fixation rates regulated in legumes?" J. Plant Nutr. Soil Sci. 167:125-137.<br />
<br />
Sylvia, D.M., Fuhrmann, J.J., Hartel, P.G., and Zuberer, D.A., 2005. Principles and Applications of Soil Microbiology. 2nd Edition. 373 - 404.<br />
<br />
Wang, D., Yang, S., Tang, F., Zhu, H., 2012. "Symbiosis specificity in the legume-rhizobial mutualism". Cellular Microbiology: 14(3):334-342.<br />
<br />
[http://ac.els-cdn.com/016953478990089X/1-s2.0-016953478990089X-main.pdf?_tid=534c3b5fb4a5306c18a97bac4b81355c&acdnat=1333582493_cacc88dcf80860fcf8cedf9ecb6e746c Young, J.P.W and Johnston, A.W.B. 1989. "The Evolution of Specificity in the Legume-Rhizobium Symbiosis". Tree. 4:341-349]<br />
<br />
<br><br />
<br />
Edited by Blake Meentemeyer, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Freshwater_Lakes&diff=72282Freshwater Lakes2012-04-25T06:02:34Z<p>Akent: /* Cyanobacteria */</p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
Freshwater lakes are bodies of still, unsalted water surrounded by land. They are usually found in low lying areas and are fed from streams, rivers and runoff from the surrounding area. Freshwater lakes provide a unique habitat for microbes because they differ from other aquatic habitats such as oceans and moving water. This habitat is home to a plethora of microbes such as Proteobacteria, Actinobacteria, Cyanobacteria, and Bacteroidetes. These microbes help sequester inorganic compounds, mineralize nitrogen, and decompose organic matter, as well as other important processes.<br />
<br />
[[Image:lake2.jpg|thumb|300px|right|Common freshwater lake. Home to a plethora of different microbes. From dem.ri.gov.]]<br />
<br />
==Physical environment==<br />
<br />
<br />
===Physical===<br />
Freshwater lakes are formed in a variety of different ways and depending on how a lake was formed, it can affect the microbes that are able to live and survive. Common types of lakes are stream or river fed lakes, glacial lakes, which are created by melting glaciers, and artificial lakes, which can be formed by the addition of a dam from old mines or quarries which have filled in after use. Another more unique lake type is a subglacial lake, which is a lake permanently covered by ice such as in Antarctica. In addition to the formation affecting microbial composition, lake stratification can make a difference throughout a lake. <br />
<br />
====Stratification====<br />
Environmental factors such as pH, dissolved oxygen, nutrient concentrations, and light availability are affected by lake stratification. Thermal differences are what cause a lake to stratify into a warm upper layer, the epilimnion, a lower cool layer, the thermocline, and the deepest coldest layer, the hypolimnion, due to cooler water having a higher density than warm water. These differences cause completely different habitats to exist throughout a lake. The epilimnion has the highest dissolved oxygen, and light availability, but is low on nutrients. Aerobic microbes are most abundant here. The thermocline has less oxygen and light, but more nutrients creating a habitat for facilitative anaerobes. The cold hypolimnion contains almost no oxygen or light, however, it contains abundant nutrients. Anaerobes thrive in these conditions, but because of their metabolisms, they are unable to take full advantage of the nutrients (Ndebele 2010).<br />
<br />
====River Fed====<br />
These lakes have their input and output from rivers. This differs then from other types of lakes because they can receive storm water run off from not only the surrounding area but from all the areas in the basin of the lake and feeding rivers. <br />
====Subglacial====<br />
A subglacial lake is one in which there is flowing water under a glacier, ice cap, or ice sheet. They are found is regions such as Antarctica which are constantly under the freezing point. Only certain types of unique bacteria are able to thrive in such environments. This is also the only type of lake which is known to exist in an extraterrestrial location. Jupiter’s moon Europa’s surface is entirely covered in an ice sheet, and it is believed to be one of the most likely locations for extraterrestrial life.<br />
====Artificial====<br />
These include lakes formed from dams,man-dug, or mines and quarries. <br />
====Dammed====<br />
Dammed lakes are fed by rainwater and inflow of a river, and drain from outflow from drains on the dam. Water quality testing is done often in this type of lake to insure the dam or other inputs are not polluting the water.<br />
====Man-made====<br />
These lakes only receive water run off from the surrounding areas and precipitation. Lakes such as these are often built near roadways and other urban areas and have a higher about of pollutants than more natural lakes.<br />
<br />
====Mines/Quarries====<br />
Old and abandoned mines and quarries often become lakes because most require the use of water control devices to keep ground water from seeping in. Lakes formed this way often have high amounts of contamination due to chemicals and machinery used in the harvesting process.<br />
===Chemical===<br />
Many factors contribute to the chemical environment in which lake microbes live. These include the drainage basin, the amount of water flowing in and out of a lake, the concentrations of nutrients and dissolved oxygen, the pH, and any pollutants and sedimentation in a lake. The overall drainage basin will affect the amount of run off from other sources in the surrounding area, which will, in turn, affect the amount of nutrients available to microbes and will increase pollutants and sedimentation. The lake level, which is regulated by inflow and outflow of a lake, the pH and the dissolved oxygen content in a lake, will also determine what types of microbes can survive because each microbe has its own unique environmental conditions in which it can outcompete the competition (Paul 2008).<br />
<br />
====Stratified Lakes====<br />
Lake stratification also has an affect on chemical characteristics, and the redox reactions microbes are able to perform. In the epilimnion, the abundant oxygen and light allow for anaerobes to use oxygen as their terminal electron acceptor. Aerobic respiration is capable of producing the most amount energy. The thermocline and hypolimnion, have less oxygen and are forced to use anaerobic respiration when lacking oxygen. This includes reduction of sulfur and iron by microbes and does not produce a lot of energy.<br />
<br />
==Microbial communities==<br />
<br />
<br />
The microbial community in freshwater lakes is as diverse as any other ecosystem found on earth. These microbes have found a way to take advantage of the different resources provided from lake habitats oppose to terrestrial soil habitats microbes are usually thought to live. The main players are [[Proteobacteria]], Cyanobacteria, Actinobacteria, and Bacteroidestes. All of these different microbes contribute to important processes carried out in freshwater lakes.<br />
<br />
===[[Proteobacteria]]===<br />
This is the most abundant and commonly found group of microbes in freshwater lakes. Taxa include [[Rickettsia prowazekii]], [[Coxiella burnetti]], and [[Wolinella succinogenes]]. Proteobacteria is broken up into alpha-, beta-, delta-, and gammaproteobacteria, each with their own distinct characteristics (Yannarell 2009). <br />
====Alpha/Gammaproteobacteria====<br />
Alphaproteobacteria and Gammaproteobacteria are mostly commonly found in marine habitats, but still can be found in freshwater water columns. They tend to be phototrophic and contribute to increasing the amount of dissolved oxygen in a lake. Taxa include [[Acetobacter]] and [[Acinetobacter]] for Alphaproteobacteria and Gammaproteobacteria respectively.<br />
<br />
====Betaproteobacteria====<br />
Betaproteobacteria are most common of the proteobacteria in lakes. They consist of Chemolithotrophes and phototrophs, who in some places makes up 60% of the bacterioplankton. They also play an important role in nitrogen fixation and oxidation of ammonium (Wetzel 2000). Taxa include [[Alcaligenes]] and [[Nitrosomonas]]<br />
<br />
====Deltaproteobacteria====<br />
Deltaproteobacteria tend to live in anaerobic conditions such as the bottom of lakes or in sediment and they commonly reduce sulfur as a source of energy. Taxa include [[Desulfovibrio]] and [[Geobacter]].<br />
<br />
===Cyanobacteria===<br />
Cyanobacteria are bacteria that carry out photosynthesis. They tend to be the dominant bacterial phototrophs in open parts of a lake and are important in the carbon cycle, but also the nitrogen cycle because some are capable of nitrogen fixation.<br />
<br />
===Actinobacteria=== <br />
This microbe can be found in a wide range of aquatic conditions. They are decomposers of organic matter and tend to favor conditions with low concentrations of organic carbon because they can be outcompeted when carbon concentration rise.<br />
<br />
===Bacteroidetes===<br />
This microbe is a commonly particle associated in bacterial communities. They are found at the bottom of lakes where they can degrade larger molecules.<br />
<br />
==Microbial processes==<br />
The two main microbial processes that occur in freshwater lake habitats are the nitrogen and carbon cycle. Both these cycles affect the lives of the macro flora and fauna which share this habitat. <br />
<br />
===Carbon cycle===<br />
The carbon cycle allows carbon to be recycled and reused throughout the biospheres and all living organisms. It is essential for new life. Bacteria help breakdown dead and decaying organic matter. During decomposition, these bacteria will release carbon dioxide if oxygen is present, or methane if it is not. While this diagram (fig. 1) shows the carbon cycle in marine habitats, the same is true in freshwater lakes but at a much smaller scale.<br />
[[Image:carboncycle.png|thumb|400px|right|Figure 1: The Carbon Cycle, Source: peswiki.com]]<br />
<br />
===Nitrogen cycle===<br />
The Nitrogen cycle (fig. 2) is the process in which nitrogen is converted into different forms. The majority of nitrogen is found in the atmosphere where it is unusable by plants, but through the processes of microbes, such as nitrification and denitrification, it can be converted into a form plants can consume. Nitrification is performed by [[Nitrospira]] is the oxidation of ammonia into nitrate. Denitrification is performed by [[Flexibacter]] converts nitrate in to nitrogen gas. It is important to note that Nitrospira is a type of Betaproteobacteria, and Flexibacter is a type of Bacteroidetes (Krivtsov 2005).<br />
[[Image:nitrogencycle.gif|thumb|400px|left|Figure 2: The Nitrogen Cycle in aquatic habitats, Source: awesomelibrary.org]]<br />
====Other processes====<br />
Another important process that is carried out in freshwater habitats is decomposition. Decomposition is the breaking down of organic matter into simpler forms. This is preformed by different types of microbes such as actinobacteria and results in the reduction of dead organic matter in the lake, and increased food sources for living flora and fauna. Without decomposition, lakes would be clouded with a layer of dead organic matter and there would be very little sunlight penetration for photosynthesis. Anaerobic respiration is one more important process that occurs in stratified freshwater lakes. This includes the reduction of iron, manganese, and sulfur, all which can affect the bio-availability of these micronutrients (Nealson 1994).<br />
<br />
==Current Research==<br />
===Koschorreck et al.===<br />
<br />
In a study done in 2011 by Koschorreck et al., They looked at how adding whey to an acidic mine pit lake could induce oxygen depletion. They added whey into the water column or the lake and mixed it using a boat motor. By doing this they found it helped neutralize the acidity of the pit and allowed oxygen consumption. This allowed for a wider variety of biota, including microbes, to inhabitant these zones. Even though a small amount of oxygen was produced by primary producers, this still led to anoxic conditions.<br />
<br />
===Verleyen et al.===<br />
<br />
This study done in 2012 looked at polar lakes and how they responded to climate induced environmental changes. They looked at differences in pH, and concentrations of major nutrients between lakes. They found the variability could have been caused by lake origin and evolution, catchment areas, distance of lakes to ice sheets and presence of particular biota.<br />
<br />
===Esteban et al===<br />
<br />
This study done in 2012 looked at water columns of Priest Pot. It is a highly stratified lake and they found that dissolved oxygen content at changing depths was the main factor that determined which microbes lived where. Different microbes can utilize different niches because microbes do not all have the same enzymes and microbes can metabolize different substrates. They also looked at biological activity driven my microbes, and looked at the different species present throughout the water column and sediments.<br />
<br />
==References==<br />
Esteban, G., Finlay,B., and Clarke, K. 2012. "Priest Pot in the English Lake District: a showcase of microbial diversity". ''Freshwater Biology''. 57: 321-330.<br />
<br />
Koschorreck, M., Boehrer, B., Frieses, K., et al. 2011. "Oxygen depletion induced by adding whey to an enclosure in an acidic mine pit lake". ''Ecological Engineering''. 37: 1983-89.<br />
<br />
Krisvtsov, V., Sigee, D. 2005. "Importance of biological and adiotic factors for geochemical cycling in a freshwater eutrophic lake". ''Biogeochemistry''. 74: 205-30.<br />
<br />
Lindstrom, E., Agterveld, M., and Zwart, G. 2005. "Distribution of Typical Freshwater Bacterial Groups Is Associated with pH, Temperature, and Lake Water Retention Time". ''American Society for Microbiology''. 71: 8201-06.<br />
<br />
Ndebele, M., Mzime, R., Musil, C., Charles, F., et al. 2010. "A review of Phytoplankton dynamics in tropical African lakes". ''South African Journal of Science''. 106: 13-18.<br />
<br />
Nealson, K., Saffarini, D. 1994. "Iron and Manganese in Anaerobic Respiration: Environmental Significance, Physiology, and Regulation". ''Annual Review of Microbiology''. 48: 311-43.<br />
<br />
Paul, D., Hebert, N. 2008. "Chemical properties of lakes". [http://www.eoearth.org/article/Chemical_properties_of_lakes Encyclopedia of Earth]. <br />
<br />
<br />
Verleyen, E., Hodgson, D., Gibson,J., Imura, S., et al. 2012. "Chemical limnology in coastal East Antarctic lakes: monitoring future climate change in centres of endemism and biodiversity" ''Antarcitic Science''. 24: 23-33.<br />
<br />
Wetzel, R. 2000. "Freshwater ecology: changes, requirements, and future demands". ''Limnology'', 1: 3-9.<br />
<br />
Yannarell, A., Kent, A. 2009. "Bacteria, Distribution and community Structure". University of Illinois at Urbana-Champaign.<br />
<br />
<br />
Edited by Neal Phelps, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Freshwater_Lakes&diff=72281Freshwater Lakes2012-04-25T05:59:13Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
Freshwater lakes are bodies of still, unsalted water surrounded by land. They are usually found in low lying areas and are fed from streams, rivers and runoff from the surrounding area. Freshwater lakes provide a unique habitat for microbes because they differ from other aquatic habitats such as oceans and moving water. This habitat is home to a plethora of microbes such as Proteobacteria, Actinobacteria, Cyanobacteria, and Bacteroidetes. These microbes help sequester inorganic compounds, mineralize nitrogen, and decompose organic matter, as well as other important processes.<br />
<br />
[[Image:lake2.jpg|thumb|300px|right|Common freshwater lake. Home to a plethora of different microbes. From dem.ri.gov.]]<br />
<br />
==Physical environment==<br />
<br />
<br />
===Physical===<br />
Freshwater lakes are formed in a variety of different ways and depending on how a lake was formed, it can affect the microbes that are able to live and survive. Common types of lakes are stream or river fed lakes, glacial lakes, which are created by melting glaciers, and artificial lakes, which can be formed by the addition of a dam from old mines or quarries which have filled in after use. Another more unique lake type is a subglacial lake, which is a lake permanently covered by ice such as in Antarctica. In addition to the formation affecting microbial composition, lake stratification can make a difference throughout a lake. <br />
<br />
====Stratification====<br />
Environmental factors such as pH, dissolved oxygen, nutrient concentrations, and light availability are affected by lake stratification. Thermal differences are what cause a lake to stratify into a warm upper layer, the epilimnion, a lower cool layer, the thermocline, and the deepest coldest layer, the hypolimnion, due to cooler water having a higher density than warm water. These differences cause completely different habitats to exist throughout a lake. The epilimnion has the highest dissolved oxygen, and light availability, but is low on nutrients. Aerobic microbes are most abundant here. The thermocline has less oxygen and light, but more nutrients creating a habitat for facilitative anaerobes. The cold hypolimnion contains almost no oxygen or light, however, it contains abundant nutrients. Anaerobes thrive in these conditions, but because of their metabolisms, they are unable to take full advantage of the nutrients (Ndebele 2010).<br />
<br />
====River Fed====<br />
These lakes have their input and output from rivers. This differs then from other types of lakes because they can receive storm water run off from not only the surrounding area but from all the areas in the basin of the lake and feeding rivers. <br />
====Subglacial====<br />
A subglacial lake is one in which there is flowing water under a glacier, ice cap, or ice sheet. They are found is regions such as Antarctica which are constantly under the freezing point. Only certain types of unique bacteria are able to thrive in such environments. This is also the only type of lake which is known to exist in an extraterrestrial location. Jupiter’s moon Europa’s surface is entirely covered in an ice sheet, and it is believed to be one of the most likely locations for extraterrestrial life.<br />
====Artificial====<br />
These include lakes formed from dams,man-dug, or mines and quarries. <br />
====Dammed====<br />
Dammed lakes are fed by rainwater and inflow of a river, and drain from outflow from drains on the dam. Water quality testing is done often in this type of lake to insure the dam or other inputs are not polluting the water.<br />
====Man-made====<br />
These lakes only receive water run off from the surrounding areas and precipitation. Lakes such as these are often built near roadways and other urban areas and have a higher about of pollutants than more natural lakes.<br />
<br />
====Mines/Quarries====<br />
Old and abandoned mines and quarries often become lakes because most require the use of water control devices to keep ground water from seeping in. Lakes formed this way often have high amounts of contamination due to chemicals and machinery used in the harvesting process.<br />
===Chemical===<br />
Many factors contribute to the chemical environment in which lake microbes live. These include the drainage basin, the amount of water flowing in and out of a lake, the concentrations of nutrients and dissolved oxygen, the pH, and any pollutants and sedimentation in a lake. The overall drainage basin will affect the amount of run off from other sources in the surrounding area, which will, in turn, affect the amount of nutrients available to microbes and will increase pollutants and sedimentation. The lake level, which is regulated by inflow and outflow of a lake, the pH and the dissolved oxygen content in a lake, will also determine what types of microbes can survive because each microbe has its own unique environmental conditions in which it can outcompete the competition (Paul 2008).<br />
<br />
====Stratified Lakes====<br />
Lake stratification also has an affect on chemical characteristics, and the redox reactions microbes are able to perform. In the epilimnion, the abundant oxygen and light allow for anaerobes to use oxygen as their terminal electron acceptor. Aerobic respiration is capable of producing the most amount energy. The thermocline and hypolimnion, have less oxygen and are forced to use anaerobic respiration when lacking oxygen. This includes reduction of sulfur and iron by microbes and does not produce a lot of energy.<br />
<br />
==Microbial communities==<br />
<br />
<br />
The microbial community in freshwater lakes is as diverse as any other ecosystem found on earth. These microbes have found a way to take advantage of the different resources provided from lake habitats oppose to terrestrial soil habitats microbes are usually thought to live. The main players are [[Proteobacteria]], Cyanobacteria, Actinobacteria, and Bacteroidestes. All of these different microbes contribute to important processes carried out in freshwater lakes.<br />
<br />
===[[Proteobacteria]]===<br />
This is the most abundant and commonly found group of microbes in freshwater lakes. Taxa include [[Rickettsia prowazekii]], [[Coxiella burnetti]], and [[Wolinella succinogenes]]. Proteobacteria is broken up into alpha-, beta-, delta-, and gammaproteobacteria, each with their own distinct characteristics (Yannarell 2009). <br />
====Alpha/Gammaproteobacteria====<br />
Alphaproteobacteria and Gammaproteobacteria are mostly commonly found in marine habitats, but still can be found in freshwater water columns. They tend to be phototrophic and contribute to increasing the amount of dissolved oxygen in a lake. Taxa include [[Acetobacter]] and [[Acinetobacter]] for Alphaproteobacteria and Gammaproteobacteria respectively.<br />
<br />
====Betaproteobacteria====<br />
Betaproteobacteria are most common of the proteobacteria in lakes. They consist of Chemolithotrophes and phototrophs, who in some places makes up 60% of the bacterioplankton. They also play an important role in nitrogen fixation and oxidation of ammonium (Wetzel 2000). Taxa include [[Alcaligenes]] and [[Nitrosomonas]]<br />
<br />
====Deltaproteobacteria====<br />
Deltaproteobacteria tend to live in anaerobic conditions such as the bottom of lakes or in sediment and they commonly reduce sulfur as a source of energy. Taxa include [[Desulfovibrio]] and [[Geobacter]].<br />
<br />
===Cyanobacteria===<br />
Cyanobacteria are other bacteria which preforms photosynthesis. They tend to be the dominant bacterial phototrophs in open parts of a lake and are important in the carbon cycle, but also the nitrogen cycle because some are capable of nitrogen fixation.<br />
===Actinobacteria=== <br />
This microbe can be found in a wide range of aquatic conditions. They are decomposers of organic matter and tend to favor conditions with low concentrations of organic carbon because they can be outcompeted when carbon concentration rise.<br />
<br />
===Bacteroidetes===<br />
This microbe is a commonly particle associated in bacterial communities. They are found at the bottom of lakes where they can degrade larger molecules.<br />
<br />
==Microbial processes==<br />
The two main microbial processes that occur in freshwater lake habitats are the nitrogen and carbon cycle. Both these cycles affect the lives of the macro flora and fauna which share this habitat. <br />
<br />
===Carbon cycle===<br />
The carbon cycle allows carbon to be recycled and reused throughout the biospheres and all living organisms. It is essential for new life. Bacteria help breakdown dead and decaying organic matter. During decomposition, these bacteria will release carbon dioxide if oxygen is present, or methane if it is not. While this diagram (fig. 1) shows the carbon cycle in marine habitats, the same is true in freshwater lakes but at a much smaller scale.<br />
[[Image:carboncycle.png|thumb|400px|right|Figure 1: The Carbon Cycle, Source: peswiki.com]]<br />
<br />
===Nitrogen cycle===<br />
The Nitrogen cycle (fig. 2) is the process in which nitrogen is converted into different forms. The majority of nitrogen is found in the atmosphere where it is unusable by plants, but through the processes of microbes, such as nitrification and denitrification, it can be converted into a form plants can consume. Nitrification is performed by [[Nitrospira]] is the oxidation of ammonia into nitrate. Denitrification is performed by [[Flexibacter]] converts nitrate in to nitrogen gas. It is important to note that Nitrospira is a type of Betaproteobacteria, and Flexibacter is a type of Bacteroidetes (Krivtsov 2005).<br />
[[Image:nitrogencycle.gif|thumb|400px|left|Figure 2: The Nitrogen Cycle in aquatic habitats, Source: awesomelibrary.org]]<br />
====Other processes====<br />
Another important process that is carried out in freshwater habitats is decomposition. Decomposition is the breaking down of organic matter into simpler forms. This is preformed by different types of microbes such as actinobacteria and results in the reduction of dead organic matter in the lake, and increased food sources for living flora and fauna. Without decomposition, lakes would be clouded with a layer of dead organic matter and there would be very little sunlight penetration for photosynthesis. Anaerobic respiration is one more important process that occurs in stratified freshwater lakes. This includes the reduction of iron, manganese, and sulfur, all which can affect the bio-availability of these micronutrients (Nealson 1994).<br />
<br />
==Current Research==<br />
===Koschorreck et al.===<br />
<br />
In a study done in 2011 by Koschorreck et al., They looked at how adding whey to an acidic mine pit lake could induce oxygen depletion. They added whey into the water column or the lake and mixed it using a boat motor. By doing this they found it helped neutralize the acidity of the pit and allowed oxygen consumption. This allowed for a wider variety of biota, including microbes, to inhabitant these zones. Even though a small amount of oxygen was produced by primary producers, this still led to anoxic conditions.<br />
<br />
===Verleyen et al.===<br />
<br />
This study done in 2012 looked at polar lakes and how they responded to climate induced environmental changes. They looked at differences in pH, and concentrations of major nutrients between lakes. They found the variability could have been caused by lake origin and evolution, catchment areas, distance of lakes to ice sheets and presence of particular biota.<br />
<br />
===Esteban et al===<br />
<br />
This study done in 2012 looked at water columns of Priest Pot. It is a highly stratified lake and they found that dissolved oxygen content at changing depths was the main factor that determined which microbes lived where. Different microbes can utilize different niches because microbes do not all have the same enzymes and microbes can metabolize different substrates. They also looked at biological activity driven my microbes, and looked at the different species present throughout the water column and sediments.<br />
<br />
==References==<br />
Esteban, G., Finlay,B., and Clarke, K. 2012. "Priest Pot in the English Lake District: a showcase of microbial diversity". ''Freshwater Biology''. 57: 321-330.<br />
<br />
Koschorreck, M., Boehrer, B., Frieses, K., et al. 2011. "Oxygen depletion induced by adding whey to an enclosure in an acidic mine pit lake". ''Ecological Engineering''. 37: 1983-89.<br />
<br />
Krisvtsov, V., Sigee, D. 2005. "Importance of biological and adiotic factors for geochemical cycling in a freshwater eutrophic lake". ''Biogeochemistry''. 74: 205-30.<br />
<br />
Lindstrom, E., Agterveld, M., and Zwart, G. 2005. "Distribution of Typical Freshwater Bacterial Groups Is Associated with pH, Temperature, and Lake Water Retention Time". ''American Society for Microbiology''. 71: 8201-06.<br />
<br />
Ndebele, M., Mzime, R., Musil, C., Charles, F., et al. 2010. "A review of Phytoplankton dynamics in tropical African lakes". ''South African Journal of Science''. 106: 13-18.<br />
<br />
Nealson, K., Saffarini, D. 1994. "Iron and Manganese in Anaerobic Respiration: Environmental Significance, Physiology, and Regulation". ''Annual Review of Microbiology''. 48: 311-43.<br />
<br />
Paul, D., Hebert, N. 2008. "Chemical properties of lakes". [http://www.eoearth.org/article/Chemical_properties_of_lakes Encyclopedia of Earth]. <br />
<br />
<br />
Verleyen, E., Hodgson, D., Gibson,J., Imura, S., et al. 2012. "Chemical limnology in coastal East Antarctic lakes: monitoring future climate change in centres of endemism and biodiversity" ''Antarcitic Science''. 24: 23-33.<br />
<br />
Wetzel, R. 2000. "Freshwater ecology: changes, requirements, and future demands". ''Limnology'', 1: 3-9.<br />
<br />
Yannarell, A., Kent, A. 2009. "Bacteria, Distribution and community Structure". University of Illinois at Urbana-Champaign.<br />
<br />
<br />
Edited by Neal Phelps, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Bark_Beetles_and_Symbiotic_Fungi&diff=72280Bark Beetles and Symbiotic Fungi2012-04-25T05:47:05Z<p>Akent: /* Elm Trees */</p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
[[Image:Bark_beetle.jpg|thumb|500px|right|Bark Beetle galleries in wood. Photo taken by Deborah Bell, Smithsonian Institution.]]<br />
<br> <br />
A symbiotic relationship is held between [http://en.wikipedia.org/wiki/Bark_beetle bark beetles] and [http://en.wikipedia.org/wiki/Fungi fungi]. This interaction has been known to be devastating to forest stands all over the world. Fungi in this interaction lead to the devastating effects in certain arboreal species. There have been many important studies and research performed in order to understand and perhaps to prevent or contain the spread of certain diseases to valued tree stands. Bark beetles destroy stands of trees every year by having a symbiotic relationship with fungi. These fungi are devastating to the health of the tree. Not only are the bark beetles, fungi, and trees involved but also the microorganisms that break down the organic matter left by the dead trees. This interaction affects humans as well. We spend millions of capital in order to preserve and protect stands of trees we hold dear. For example, [http://denver.cbslocal.com/2011/06/07/bark-beetle-costs-rising/ $10.4 million was spent in 2010] to control the bark beetle outbreak in lodgepole pine stands.<br />
<br />
==Biological Interaction==<br />
<br />
The interaction between bark beetles, fungi, and species of trees a specific interaction. Each species affects another either positively (beetles to fungi) or negatively (beetles and fungi to species of trees).<br />
<br />
===Mutualism===<br />
Mutualism occurs between two organisms when they both mutually benefit from interacting with one another [[#References |[1]]]. Bark beetles transport the fungi to new trees and the symbiotic fungi protect the beetles by preventing the tree from decimating the bark beetle larvae population.<br />
<br />
===Parasitism===<br />
Parasitism happens when one individual harms another in order to benefit from the interaction. The bark beetles and fungi both utilize the protection and resources within the tree without offering anything back except death and destruction.<br />
<br />
===Microbial populations===<br />
The interaction between bark beetles and symbiotic fungi not only affect the host plant they are occupying but also microbial populations. When the bark beetles burrow and reside in the host tree they are increasing surface area where other microbes, pathogens, and insects can have a deleterious effect. The interaction between bark beetles and symbiotic fungi is a harmonious interaction. Furthermore, allowing other organisms access to the inside of the tree is a positive influence to those microbial populations.<br />
<br />
===Ecological effects===<br />
This interaction between the bark beetles and the symbiotic fungi eventually leads to the death of the tree, then the beetles and fungi move on to their next host. There are ecological consequences to an unregulated population of bark beetles and their symbiotic fungi. However, there are some [http://www.fs.fed.us/r3/resources/health/beetle/faq.shtml#10 positive effects]. Ecologically the continued destruction of types of species of trees can affect the surrounding habitats in that there is less water uptake by a diseased tree, when a tree perishes then it provides an available food source for bacteria and fungi in the environment. This cycle aids in the development of younger trees that are then allowed to grow and take the place of the affected trees. <br />
<br><br />
<br />
==Niche==<br />
Bark beetles have been creating mazes in trees for a long while. These bark beetles live in the dead phloem tissues of trees. Most bark beetles live in dead or decaying trees, however some are known to actively penetrate healthy trees, such as the [http://en.wikipedia.org/wiki/Mountain_pine_beetle mountain pine beetle (Dendroctonus ponderosae)]. Female bark beetles burrow into mature trees, signal males, mate, and then deposit their eggs deep within the tree’s tissue. After entering the tree the beetles transport the fungi on structures called [http://en.wikipedia.org/wiki/Mycangium mycangia]. When bark beetles attack trees that are healthy, these trees may produce resin or latex as a defense. <br />
<br />
===Elm Trees=== <br />
<br />
[[Image:Elm_on_UIUC_Quad.jpg|thumb|200px|right|Elm populations were devastated on the University of Illinois Quad in the 1950's. Photo taken by Alumni Association, University of Illinois.]]<br />
<br><br />
<br />
In Elm trees, bark beetles spread the fungi during mating. With this, the fungus spreads and due to a [http://en.wikipedia.org/wiki/Tylose tylotic] response in the xylem, the tree prevents the fungus from spreading. This response, however, also blocks water from moving up and photosynthates from moving down the trunk of the tree. This [http://en.wikipedia.org/wiki/Dutch_elm_disease Dutch Elm Disease] has been spreading across North America killing unresistant elm species. This disease is one of the most talked about issues of shade trees in North America. [http://web.aces.uiuc.edu/vista/pdf_pubs/647.pdf The University of Illinois Extension has information about Dutch Elm Disease]<br />
<br />
===Pine Trees===<br />
[[Image:pinetreebarkbeetles.jpg|thumb|200px|right|Millions of pine trees are wiped out in the western United States each year. Photo taken by Anne Sherwood, New York Times.]]<br />
<br><br />
<br />
In pine trees, bark beetles infest by laying eggs under the bark. Once present in the tree, these beetles inoculate the tree with a blue stain fungus. This specific fungus is injected into the sapwood. This action prevents the tree from controlling or exterminating the beetle larvae with sap. The introduction of this particular fungus blocks water and nutrient transportation within the xylem and phloem of the tree. [[#References |[5]]]<br />
<br />
<br><br />
<br />
==Microbial processes==<br />
The microbial processes within these interactions are multi-leveled and complex. Certain types of fungi in these interactions are relied upon by specific types of bark beetles. For example, the blue stain fungus and also the fungi related to [http://en.wikipedia.org/wiki/Dutch_elm_disease Dutch Elm Disease] can both prevent the tree's xylem and phloem from functioning properly. This defensive response from the tree to slow the spread of the pathogen also slows the spread of water and photosynthate. This process causes the tree to eventually kill itself. After the tree has died, many other microorganisms utilize this new food source and break it down for energy. <br />
<br />
===Ecosystem-level Effects===<br />
Millions of trees perish each year due to this symbiotic relationship between bark beetles and symbiotic fungi. This uncontrolled destruction increases the numbers of fungi and bark beetles infiltrating and devastating stands of trees. This termination of specific types of trees changes the macro ecosystem by decreasing the types of species present. Furthermore, it allows the decomposing microorganism levels to rise because of the abundance of decaying plant matter.<br />
<br />
===Environmental Effects===<br />
This microbial process can cause an environmental effect because of the reduction of susceptible species of trees. Having decreasing amounts of trees reduces the amount of carbon sequestering that trees do each year. A reduction in carbon sequestration increases the level of atmospheric carbon and can add to the effects of global [http://en.wikipedia.org/wiki/Climate_change climate change].<br />
<br><br />
<br />
==Key Microorganisms==<br />
[[Image:Ophiostoma_ulmi.jpg|thumb|400px|right|Close up of Ophiostoma ulmi, the pathogen responsible for Dutch Elm Disease. Photo taken by William Jacobi, Colorado State University.]]<br />
<br />
<br><br />
Fungi are the major microorganisms that are involved with this symbiotic interaction. <br />
<br />
===Ophiostomatales Fungi===<br />
This fungi genus of pathogens is responsible for the Dutch Elm Disease. It is adapted for insects to disperse the spores in order to inoculate trees.[[#References |[6]]]<br />
<br />
====<i>Ophiostoma novo-ulmi</i>====<br />
This fungi species is extremely destructive and it was first described in both Europe and North America in the 1940s and has devastated elm stands in both areas since the late 1960s.<br />
<br />
====<i>Ophiostoma himal-ulmi</i>====<br />
This fungal species is very devastating to elms located in the western Himalaya<br />
<br />
====<i>Ophiostoma ulmi</i>====<br />
This fungal species affected elm stands in Europe around 1910 and was transported to North America in 1928<br />
<br />
===Grosmannia Fungi===<br />
This pathogenic fungi genus is responsible for the destruction by mountain pine beetles.<br />
====<i>Grosmannia clavigera</i>====<br />
This fungal species affects Lodgepole pine, Ponderosa pine, Douglas-fir, and Whitebark pine trees. <br />
<br />
<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Resistant Varieties===<br />
Fungicides are only useful as a protective measure, are not very cost effective. Research has therefore focused on selection of elm varieties that are both resistant to Dutch elm disease and well suited to European environments. Research conducted by INRA and CEMAGREF has shown that European elms are susceptible to Dutch elm disease. Resistant varieties are found in Asian species, but they do not look similar. A project began in 1975 that led to the creation of new varieties through cross-breeding. The Lutèce® variety is a result of this research. It combines resistance to Dutch elm disease, ornamental qualities, and also is adapted to the European climate. Furthermore, other varieties are currently being selected to restore the genetic diversity necessary for the future of the elm. [[#References |[7]]]<br />
<br />
===Solar Treatments===<br />
Experiments were conducted to evaluate the use of solar radiation for reducing survival of mountain pine beetle populations in infested logs. Plastic sheeting, routine turning of the logs, and stacking of logs were utilized in these experiments. All treatments in all experiments caused drastic reductions in brood survival. Also in all experiments brood survival was regularly decreased when the logs were exposed to the sun. High temperatures were consistently greater in the treatments with plastic sheeting, the exposed surfaces of the logs to the sun, and the upper layer of logs in the two-layer treatments. This information suggests that heat is directly responsible for the observed reductions in survival. Solar treatments are an effective alternative for reducing mountain pine beetle survival in infested trees. [[#References |[8]]]<br />
<br />
===Utilizing Cloning Techniques===<br />
An efficient procedure for the conservation of mature American elm trees that have survived the epidemics of Dutch elm disease and are potential sources of disease resistance is reported. This experiment utilizes in vitro propagation of buds from mature trees to clone 100 year old American elm trees. An important factor which is used for the optimization of culture process is auxin metabolism in the source tissue. In this experiment use of blocking antiauxins was utilized so that auxins would not be metabolized. This was important because a high shoot rate was necessary. Plantlets that had roots were easily adapted to the greenhouse with 90 percent surviving. This will aid in making Dutch elm disease resistant clones, and this will also provide an approach to advance preservation of other endangered tree species. [[#References |[4]]]<br />
<br />
<br><br />
<br />
==References==<br />
[1][http://www.cals.ncsu.edu/course/ent591k/symbiosis.html Myer, J. 1998. College of Agriculture and Life Sciences.]<br />
<br />
[2][http://www.springerlink.com/content/u137187u05662102/ Kirisits T. 2004. Fungal associates of European bark beetles with special emphasis on the ophiostomatoid fungi. In: Bark and Wood boring insects in living trees in Europe, a synthesis. (Lieutier F, Day KR, Battisti A, Grégoire JC, Evans HF, eds). Kluwer Academic Press, The Netherlands:181– 235.]<br />
<br />
[3][http://aem.asm.org/content/63/2/621.short Klepzig, K. D. and Wilkens, R. T. 1997. "Competitive Interactions among Symbiotic Fungi of the Southern Pine Beetle." Appl. Environ. Microbiol. vol. 63 no. 2: 621-627.]<br />
<br />
[4][http://www.nrcresearchpress.com/doi/abs/10.1139/x2012-022 Mukund R. Shukla, A. Maxwell P. Jones, J. Alan Sullivan, Chunzhao Liu,* Susan Gosling,† Praveen K. Saxena. 2012. "In vitro conservation of American elm (Ulmus americana): potential role of auxin metabolism in sustained plant proliferation". Department of Plant Agriculture, University of Guelph.]<br />
<br />
[5][http://www.ext.colostate.edu/pubs/Insect/05528.html#top Leatherman, D.A., Aguayo I., Mehall T.M. 2011. "Mountain Pine Beetle". Colorado State University, U.S. Department of Agriculture and Colorado]<br />
<br />
[6][http://www.fabinet.up.ac.za/ophiostomaweb/pdf/Wingfield%20&%20Seifert%20What%20are%20Ophiostomatoid%20fungi.pdf Wingfield, Michael J., Seifert, Keith A. "What are Ophiostomatoid Fungi?". Forestry and Agricultural Research Institute.]<br />
<br />
[7][http://www.international.inra.fr/research/some_examples/lutece_r_a_resistant_variety_brings_elms_back_to_paris Pinon, J. 2006. "Lutèce®, a resistant variety brings elms back to Paris" Forest, Grassland and Freshwater Ecology Department.]<br />
<br />
[8][http://treesearch.fs.fed.us/pubs/4624 Negron, Jose F. et al. 2001. "Solar treatments for reducing survival of mountain pine beetle in infested ponderosa and lodgepole pine logs". Res. Pap. RMRS-RP-30. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 11 p.]<br />
<br />
Edited by Kord Nolte, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=70708University of Illinois2012-04-11T04:33:22Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Acidic hot springs]]<br />
<br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Deep subsurface microbes]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]<br />
<br />
[[Category:Class indexes]]<br />
<br />
<b>Created in 2012</b><br><br />
<br />
[[Aeromicrobiology]]<br />
<br />
[[Aphids and Buchnera]]<br />
<br />
[[Bark Beetles and Symbiotic Fungi]]<br />
<br />
[[Biocontrol]]<br />
<br />
[[Freshwater Lakes]]<br />
<br />
[[Foaming in wastewater treatment plant (WWTP)]]<br />
<br />
[[Legume-Rhizobium]] symbiosis<br />
<br />
[[Meromictic lakes]]<br />
<br />
[[Terraforming]]<br />
<br />
[[White nose syndrome in bats]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=70707University of Illinois2012-04-11T04:32:54Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Acidic hot springs]]<br />
<br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Deep subsurface microbes]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]<br />
<br />
[[Category:Class indexes]]<br />
<br />
<b>Created in 2012</b><br><br />
<br />
[[Aeromicrobiology]]<br />
<br />
[[Aphids and Buchnera]]<br />
<br />
[[Bark Beetles and Symbiotic Fungi]]<br />
<br />
[[Biocontrol]]<br />
<br />
[[Freshwater Lakes]]<br />
<br />
[[Foaming in wastewater treatment plant (WWTP)]]<br />
<br />
[[Legume-Rhizobium]]<br />
<br />
[[Meromictic lakes]]<br />
<br />
[[Terraforming]]<br />
<br />
[[White nose syndrome in bats]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Terraforming&diff=70436Terraforming2012-04-06T14:58:46Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
<br />
<br />
[[image:46068edaa8c3a0a77d8ae5962027c93a.jpg |800px||right|]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
==Planetary Engineering==<br />
[[Image:Terraformed_mars_3_stage-We.jpg |thumb|500px|right|Artists rendition of Mars terraformation (galaxyexplorers.org).]]<br />
<br>Terraforming or “Planetary Ecosynthesis” is the process of changing a planet’s atmosphere to resemble that of the Earth’s, with the goal of sustaining terrestrial life. It is predicted that establishment of life will be similar to Earth’s history, starting with basic unicellular microorganisms. The most pheasible pioneer to begin life on a new planet would be some kind of photosynthetic microbe.[[#References |[8]]]<br><br />
<br><br />
The strategy of using photosynthesis to engineer a habitable planet for humans through photosynthesis would not be unlike the <b>Great Ogygenation Event</b> that took place on Earth 2.4 billion years ago, sometime after cyanobacteria first evolved (2.7-2.8 billion years ago.) This pivotal event paved the way for evolution of multi-cellular organisms and later, human beings.[[#References |[4]]]<br />
<br />
<br><br><br />
The topic has sprung much speculation as well as the ethical debates surrounding the idea.<br />
<br><br><br />
===<u>Candidates for Terraformation</u>===<br />
====Mars: the winner====<br />
Mars is the preferred planet of interest for terraforming because it's history of once being a water planet, and the fact that it still retains much of its CO<sub>2</sub>, nitrogen, and H<sub>2</sub>O.[[#References |[8]]] Currently Mars is very cold and it's atmosphere is relatively thin and mostly consists of CO<sub>2</sub> (95.3%) with very little O<sub>2</sub> and N<sub>2</sub>. Mars only receives 43% of the light Earth gets from the Sun, yet it is still sufficient enough for photosynthesis.[[#References |[10]]]<br />
<br><br><br />
Proposed Terraformation of Mars would require:<br><br />
<ul><br />
<li>Warming the planet substantially</li><br><br />
<li>Increase atmospheric pressure while adding O<sub>2</sub></li><br><br />
<li>Melt water (which Mars has frozen in Ice caps)</li><br />
</ul><br />
[[#References |[1]]]<br />
<br />
====Venus====<br />
Venus has been proposed but it’s problems far surpass Mars in that it has a very thick atmosphere, little water, and it’s temperatures are much warmer than Earth.[[#References |[11]]] Venus also has clouds made of searing sulfuric acid, and one Venus day is equivalent to 127 Earth days.[[#References |[2]]]<br />
<br><br>Proposed Terraformation of Venus would require:<br><br />
<ul><br />
<li>Cooling the planet substantially</li><br><br />
<li>Removing CO<sub>2</sub> and other poisonous gases from the atmosphere while replacing it with O<sub>2</sub></li><br><br />
<li>Reduce day length to 24 hours</li><br><br />
<li>Provide water</li></ul><br />
[[#References |[2]]]<br />
<br />
==Biological interaction==<br />
The interaction of pioneering microbial species within an alien atmosphere will hopefully pave the way for future organisms such as plants and eventually humans to be able to colonize that planet.<br />
<br><br />
The primary function of photosynthetic pioneers would be to take CO<sub>2</sub> out of the atmosphere while adding O<sub>2</sub> to the atmosphere.[[#References |[10]]]<br />
<br />
==<b>Niche: A New World</b>==<br />
To lay the foundation for microbial terraforming, the agreed plan for Mars begins with:<br> <br />
<ul><li>the release of man-made greenhouse gases into the atmosphere, heating the planet substantially,</li> <br />
<li>Initial warming will then cause CO<sub>2</sub> evaporation from the planet’s own glaciers and soil, producing further warming</li> <br />
<li>Melting glaciers will produce hydrologic cycles and evaporated H<sub>2</sub>O into the air, creating a denser atmosphere. This suggests a global temperature of at least 0 degrees Celsius.</li> <br />
<li>Water will be stable on the surface and temperatures will be more moderate, but the atmosphere will be mostly CO<sub>2</sub> and have little O<sub>2</sub>.</li><br />
So long as UV radiation remains high, microorganisms will be confined to living in or under rocks.[[#References |[5]]]<br />
<br> <br />
UV radiation screens have been proposed for microbial access to surfaces.[[#References |[8]]]<br />
<br> <br />
<br />
Microbial populations set to colonize Mars can expect extreme cold temperatures, high radiation, little to no moisture, and limited nutrients.[[#References |[8]]]<br />
<br />
[[image:Marsview5.jpg|thumb||600px||right|<sub>http://www.antarcticaedu.com/visions/</sub>]]<br />
[[image:Mars2.jpg|thumb||700px||left|<sub>http://io9.com/5655719/terraforming-earth-pt-4-nowhere-to-go-but-up</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br />
==Microbial processes==<br />
Mars has no tectonic activity so no biogeochemical cycling occurs there. It's thought that biological and photochemical processes can run the cycles on Mars.[[#References |[10]]]<br />
<br><br />
====Carbon cycling====<br />
Photosynthetic microorganisms remove CO<sub>2</sub> from the atmosphere by photosynthesis:<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br><br />
Eventually heterotrophic microbes will release CO<sub>2</sub> back into the atmosphere through respiration:<br><br />
<b>C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub> --> 6CO<sub>2</sub> + 6H<sub>2</sub>O + energy</b><br><br />
Certain Microorganisms such as <i>Matteia</i> have been proposed to release CO<sub>2</sub> from carbonate rock to complete the cycle in the early stages of colonization, just until enough carbohydrate is available to support heterotrophs.<br />
<br><br />
[[Image:1995 Thomas 48 415-418-2-.JPG |thumb||500px||right|Thomas, David J. 1995. "<I>Biological Aspects of the Ecopoesis and Terraformation of Mars: Current Perspectives and Research</I>]]<br />
<br />
====Oxygen====<br />
Cyanobacteria and algae will be used to increase O<sub>2</sub> through photosynthesis<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br />
<br />
====Nitrogen cycling====<br />
Besides CO<sub>2</sub> and O<sub>2</sub>, a buffer gas is needed to support human life, and nitrogen is necessary for photosynthesis at the start of terraformation.<br />
Currently there is not enough N<sub>2</sub> in Mars' atmosphere for nitrogen fixation and therefore, denitrification is necessary as long as the regolith contains nitrate as is proposed<br><br />
Denitrification:<br><br />
<b>NO<sub>3</sub>− → NO<sub>2</sub>− → NO + N<sub>2</sub>O → N<sub>2</sub> (g)</b><br><br />
Cyanobacteria can reduce N<sub>2</sub> to ammonia:<br><br />
<b>N<sub>2</sub> + 8 H+ + 8 e− → 2 NH<sub>3</sub> + H<sub>2</sub></b><br />
<br />
====Sulfur cycling====<br />
Most microbes utilize oxidized sulfur for protein synthesis.<br />
<br><br />
<br />
====Phosphorous cycling====<br />
Phosphates are insoluble minerals that are highly conserved in stable environments but through time losses can be a possible issue for terraformation. This may be the case with other non-volatile, minerals such as iron, manganese, and magnesium.[[#References |[10]]]<br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
Microorganisms are the best option for colonization of a new planet because of their wide range of physiologic and metabolic functions and are capable of <b>horizontal gene transfer.</b> Two strategies have been proposed for choosing the best pioneers. One can either choose a generalist extremophile on Earth that inhabits environments similar to the new planet, or genetically modifying a new species with all the best traits required for the job. (Creating a Genetically Engineered Mars Organism "GEMO")[[#References |[9]]]<br />
<br><br />
<b>Proposed traits of the perfect pioneer are:</b><br><ul><br />
<li>Must be photoautotrophs</li><br><br />
<li>Must be anaerobic and respire without O<sub>2</sub></li><br><br />
<li>Osmotic tolerance</li><br><br />
<li>Resistance to UV radiation</li><br><br />
<li>Cold tolerance</li><br><br />
<li>Tolerance for Nutrient limitations</li><br><br />
<li>Tolerance for water limitations</li><br><br />
<li>Resistance to oxides</li><br><br />
<li>Adaptation to lowered intracellular pH due to CO<sub>2</sub> in atmosphere</li><br><br />
<li>Can form Endospores</li><br>[[#References |[9]]]</ul><br />
<br />
===<u>Proposed Photoautotrophs</u>===<br />
====Cyanidium caldarium====<br />
A unicellular red algae found in diverse extreme environments such as bogs, wet acidic soils, and hot streams.<br />
It has been found to survive with little to no oxygen.[[#References |[12]]]<br />
[[image:Ideyuk 4.jpg |thumb| |300px| |left| Cyandium Caladarium Algae (Shu Suehiro Botanic.jp)]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Cryptoendolith Lichens====<br />
Literally "hiding in rocks" An extremophile found in porous rock in Antarctica where temperatures are normally -89.2°C to -93.4°C. There has been no rain or snowfall in the Antarctic Desert for over 100 years.[[#References |[3]]][[image:Cryptoendolith.jpg|thumb||300px||left|Antarctic sandstone inhabited by cryptoendolithic lichen communities. Photo courtesy of NASA]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Chroococcidiopsis====<br />
This primitive cyanobacterium has a high range of variability and may be the most desiccant-resistant of it's kind. It is found in extreme habitats such as Antarctic rocks, thermal springs, and hypersaline habitats. [[#References |[7]]]<br />
<br />
[[image:45.jpg |thumb||300px||left|Chroococcidiopsis cf. cubana Komárek et Hindák]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
===<u>Proposed Denitrifers</u>===<br />
[[image:Matteia.jpg|thumb||300px||right|http://www.cyanodb.cz]]<br />
<br />
====Matteia====<br />
Matteia sp., a cyanobacterium found on desert rocks, has been proposed to dissolve carbonate rocks both for release of CO<sub>2</sub> and in hopes of creating a Martian carbon cycle.[[#References |[6]]]<br />
<br />
====Psuedomonads and Alcaligenes====<br />
Psuedomonads and [[Alcaligenes]] could be appropriate denitrifiers once enough oxygen and carbonate are present to sustain them.[[#References |[10]]]<br />
<br />
===<u>Proposed GEMOs</u>===<br />
<br />
====Bacillus Polymyxa====<br />
A Facultative anaerobe that can form endospores, can fix nitrogen aerobically and anaerobically, and has tolerance to heavy metals. A good start for an eventual GEMO.[[#References |[9]]]<br />
<br />
<br><br />
[[image:Superbug.jpg|thumb||500px||center|A better GEMO may do the trick <sub>http://www.usc.edu/hsc/info/pr/hmm/04fall/superbug.html</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
==Current Research==<br />
There is no current research being done on terraforming.<br />
<br><br />
<br />
==References==<br />
<br />
[1]Birch, P. “Terraforming Mars Quickly” ''Journal of the British Interplanetary Society''. 1992. Volume 45. p. 331-340<br />
<br />
[2]Birch, P. “Terraforming Venus Quickly” ''Journal of the British Interplanetary Society''. 1991. Volume 44. p. 157-167<br />
<br />
[3]Blackhurst, R., Verchovsky, A., Jarvis, K., Grady, M.M. “Cryptoendolith communities in Antarctic Dry Valley Region Sanstones: Potential Analogues of Martian Life-Forms” <br>''Lunar and Planetary Science''. 2003. Volume 34.<br />
<br />
[4]Farquhar, J., Bao, H., Thiemens, M. ''Atmospheric Influence of Earth’s Earliest Sulfur Cycle” ''Science''. 2000. Volume 289. P. 756-758<br><br />
<br />
[5][http://www.users.globalnet.co.uk/~mfogg/paper1.htm Fogg, M. J., "Terraforming" ''Society of Automotive Engineers''. 1995. Warrendale, PA] <br />
<br />
[6]Friedmann, EI., Hua, M., Ocampo-Friedmann, R. “Terraforming Mars: dissolution of carbonate rocks by cyanobacteria” ''Journal of Interplanetary Society''. 1993. Volume 46. P. 291-292<br><br />
[7]Friedmann, EI., Ocampo-Friedmann, R. "A Primitive Cyanobacterium as Pioneer Microorganism for Terraforming Mars" ''Adv. Space Res.'' 1994. Volume 15, No. 3. p. 243-246<br />
<br />
[8][http://www.marspapers.org/papers/MAR98089.pdf Graham, J., Graham L. "Chapter 18: Terraforming Mars" 1989.]<br />
<br />
[9]Hiscox, J., Thomas, D. “Genetic Modification and Selection of Microorganisms for Growth on Mars” Journal of the British Interplanetary Society. 1995 Volume 48. P. 419-426.<br><br />
<br />
[10]Thomas, D. “Biological Aspects of the Ecopoeisis and Terraformation of Mars: Current Perspectives and Research” ''Journal of the British Interplanetary Society''. 1995. Volume 48. P. 415-418<br />
<br />
[11]Sagan, C. "The Planet Venus" ''Science'' 1961. Volume 133. p. 849-858<br><br />
<br />
[12]Seckbach, J., Baker, F.A., Shugarman, P.M. "Algae Thrive in Pure CO<sub>2</sub>" ''Nature''. 1977. Volume 227. p. 774-775<br />
<br />
<br />
<br />
Edited by Samantha Chavez, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Terraforming&diff=70435Terraforming2012-04-06T14:58:29Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
<br />
[[image:46068edaa8c3a0a77d8ae5962027c93a.jpg |800px||right|]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
==Planetary Engineering==<br />
[[Image:Terraformed_mars_3_stage-We.jpg |thumb|500px|right|Artists rendition of Mars terraformation (galaxyexplorers.org).]]<br />
<br>Terraforming or “Planetary Ecosynthesis” is the process of changing a planet’s atmosphere to resemble that of the Earth’s, with the goal of sustaining terrestrial life. It is predicted that establishment of life will be similar to Earth’s history, starting with basic unicellular microorganisms. The most pheasible pioneer to begin life on a new planet would be some kind of photosynthetic microbe.[[#References |[8]]]<br><br />
<br><br />
The strategy of using photosynthesis to engineer a habitable planet for humans through photosynthesis would not be unlike the <b>Great Ogygenation Event</b> that took place on Earth 2.4 billion years ago, sometime after cyanobacteria first evolved (2.7-2.8 billion years ago.) This pivotal event paved the way for evolution of multi-cellular organisms and later, human beings.[[#References |[4]]]<br />
<br />
<br><br><br />
The topic has sprung much speculation as well as the ethical debates surrounding the idea.<br />
<br><br><br />
===<u>Candidates for Terraformation</u>===<br />
====Mars: the winner====<br />
Mars is the preferred planet of interest for terraforming because it's history of once being a water planet, and the fact that it still retains much of its CO<sub>2</sub>, nitrogen, and H<sub>2</sub>O.[[#References |[8]]] Currently Mars is very cold and it's atmosphere is relatively thin and mostly consists of CO<sub>2</sub> (95.3%) with very little O<sub>2</sub> and N<sub>2</sub>. Mars only receives 43% of the light Earth gets from the Sun, yet it is still sufficient enough for photosynthesis.[[#References |[10]]]<br />
<br><br><br />
Proposed Terraformation of Mars would require:<br><br />
<ul><br />
<li>Warming the planet substantially</li><br><br />
<li>Increase atmospheric pressure while adding O<sub>2</sub></li><br><br />
<li>Melt water (which Mars has frozen in Ice caps)</li><br />
</ul><br />
[[#References |[1]]]<br />
<br />
====Venus====<br />
Venus has been proposed but it’s problems far surpass Mars in that it has a very thick atmosphere, little water, and it’s temperatures are much warmer than Earth.[[#References |[11]]] Venus also has clouds made of searing sulfuric acid, and one Venus day is equivalent to 127 Earth days.[[#References |[2]]]<br />
<br><br>Proposed Terraformation of Venus would require:<br><br />
<ul><br />
<li>Cooling the planet substantially</li><br><br />
<li>Removing CO<sub>2</sub> and other poisonous gases from the atmosphere while replacing it with O<sub>2</sub></li><br><br />
<li>Reduce day length to 24 hours</li><br><br />
<li>Provide water</li></ul><br />
[[#References |[2]]]<br />
<br />
==Biological interaction==<br />
The interaction of pioneering microbial species within an alien atmosphere will hopefully pave the way for future organisms such as plants and eventually humans to be able to colonize that planet.<br />
<br><br />
The primary function of photosynthetic pioneers would be to take CO<sub>2</sub> out of the atmosphere while adding O<sub>2</sub> to the atmosphere.[[#References |[10]]]<br />
<br />
==<b>Niche: A New World</b>==<br />
To lay the foundation for microbial terraforming, the agreed plan for Mars begins with:<br> <br />
<ul><li>the release of man-made greenhouse gases into the atmosphere, heating the planet substantially,</li> <br />
<li>Initial warming will then cause CO<sub>2</sub> evaporation from the planet’s own glaciers and soil, producing further warming</li> <br />
<li>Melting glaciers will produce hydrologic cycles and evaporated H<sub>2</sub>O into the air, creating a denser atmosphere. This suggests a global temperature of at least 0 degrees Celsius.</li> <br />
<li>Water will be stable on the surface and temperatures will be more moderate, but the atmosphere will be mostly CO<sub>2</sub> and have little O<sub>2</sub>.</li><br />
So long as UV radiation remains high, microorganisms will be confined to living in or under rocks.[[#References |[5]]]<br />
<br> <br />
UV radiation screens have been proposed for microbial access to surfaces.[[#References |[8]]]<br />
<br> <br />
<br />
Microbial populations set to colonize Mars can expect extreme cold temperatures, high radiation, little to no moisture, and limited nutrients.[[#References |[8]]]<br />
<br />
[[image:Marsview5.jpg|thumb||600px||right|<sub>http://www.antarcticaedu.com/visions/</sub>]]<br />
[[image:Mars2.jpg|thumb||700px||left|<sub>http://io9.com/5655719/terraforming-earth-pt-4-nowhere-to-go-but-up</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br />
==Microbial processes==<br />
Mars has no tectonic activity so no biogeochemical cycling occurs there. It's thought that biological and photochemical processes can run the cycles on Mars.[[#References |[10]]]<br />
<br><br />
====Carbon cycling====<br />
Photosynthetic microorganisms remove CO<sub>2</sub> from the atmosphere by photosynthesis:<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br><br />
Eventually heterotrophic microbes will release CO<sub>2</sub> back into the atmosphere through respiration:<br><br />
<b>C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub> --> 6CO<sub>2</sub> + 6H<sub>2</sub>O + energy</b><br><br />
Certain Microorganisms such as <i>Matteia</i> have been proposed to release CO<sub>2</sub> from carbonate rock to complete the cycle in the early stages of colonization, just until enough carbohydrate is available to support heterotrophs.<br />
<br><br />
[[Image:1995 Thomas 48 415-418-2-.JPG |thumb||500px||right|Thomas, David J. 1995. "<I>Biological Aspects of the Ecopoesis and Terraformation of Mars: Current Perspectives and Research</I>]]<br />
<br />
====Oxygen====<br />
Cyanobacteria and algae will be used to increase O<sub>2</sub> through photosynthesis<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br />
<br />
====Nitrogen cycling====<br />
Besides CO<sub>2</sub> and O<sub>2</sub>, a buffer gas is needed to support human life, and nitrogen is necessary for photosynthesis at the start of terraformation.<br />
Currently there is not enough N<sub>2</sub> in Mars' atmosphere for nitrogen fixation and therefore, denitrification is necessary as long as the regolith contains nitrate as is proposed<br><br />
Denitrification:<br><br />
<b>NO<sub>3</sub>− → NO<sub>2</sub>− → NO + N<sub>2</sub>O → N<sub>2</sub> (g)</b><br><br />
Cyanobacteria can reduce N<sub>2</sub> to ammonia:<br><br />
<b>N<sub>2</sub> + 8 H+ + 8 e− → 2 NH<sub>3</sub> + H<sub>2</sub></b><br />
<br />
====Sulfur cycling====<br />
Most microbes utilize oxidized sulfur for protein synthesis.<br />
<br><br />
<br />
====Phosphorous cycling====<br />
Phosphates are insoluble minerals that are highly conserved in stable environments but through time losses can be a possible issue for terraformation. This may be the case with other non-volatile, minerals such as iron, manganese, and magnesium.[[#References |[10]]]<br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
Microorganisms are the best option for colonization of a new planet because of their wide range of physiologic and metabolic functions and are capable of <b>horizontal gene transfer.</b> Two strategies have been proposed for choosing the best pioneers. One can either choose a generalist extremophile on Earth that inhabits environments similar to the new planet, or genetically modifying a new species with all the best traits required for the job. (Creating a Genetically Engineered Mars Organism "GEMO")[[#References |[9]]]<br />
<br><br />
<b>Proposed traits of the perfect pioneer are:</b><br><ul><br />
<li>Must be photoautotrophs</li><br><br />
<li>Must be anaerobic and respire without O<sub>2</sub></li><br><br />
<li>Osmotic tolerance</li><br><br />
<li>Resistance to UV radiation</li><br><br />
<li>Cold tolerance</li><br><br />
<li>Tolerance for Nutrient limitations</li><br><br />
<li>Tolerance for water limitations</li><br><br />
<li>Resistance to oxides</li><br><br />
<li>Adaptation to lowered intracellular pH due to CO<sub>2</sub> in atmosphere</li><br><br />
<li>Can form Endospores</li><br>[[#References |[9]]]</ul><br />
<br />
===<u>Proposed Photoautotrophs</u>===<br />
====Cyanidium caldarium====<br />
A unicellular red algae found in diverse extreme environments such as bogs, wet acidic soils, and hot streams.<br />
It has been found to survive with little to no oxygen.[[#References |[12]]]<br />
[[image:Ideyuk 4.jpg |thumb| |300px| |left| Cyandium Caladarium Algae (Shu Suehiro Botanic.jp)]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Cryptoendolith Lichens====<br />
Literally "hiding in rocks" An extremophile found in porous rock in Antarctica where temperatures are normally -89.2°C to -93.4°C. There has been no rain or snowfall in the Antarctic Desert for over 100 years.[[#References |[3]]][[image:Cryptoendolith.jpg|thumb||300px||left|Antarctic sandstone inhabited by cryptoendolithic lichen communities. Photo courtesy of NASA]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Chroococcidiopsis====<br />
This primitive cyanobacterium has a high range of variability and may be the most desiccant-resistant of it's kind. It is found in extreme habitats such as Antarctic rocks, thermal springs, and hypersaline habitats. [[#References |[7]]]<br />
<br />
[[image:45.jpg |thumb||300px||left|Chroococcidiopsis cf. cubana Komárek et Hindák]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
===<u>Proposed Denitrifers</u>===<br />
[[image:Matteia.jpg|thumb||300px||right|http://www.cyanodb.cz]]<br />
<br />
====Matteia====<br />
Matteia sp., a cyanobacterium found on desert rocks, has been proposed to dissolve carbonate rocks both for release of CO<sub>2</sub> and in hopes of creating a Martian carbon cycle.[[#References |[6]]]<br />
<br />
====Psuedomonads and Alcaligenes====<br />
Psuedomonads and [[Alcaligenes]] could be appropriate denitrifiers once enough oxygen and carbonate are present to sustain them.[[#References |[10]]]<br />
<br />
===<u>Proposed GEMOs</u>===<br />
<br />
====Bacillus Polymyxa====<br />
A Facultative anaerobe that can form endospores, can fix nitrogen aerobically and anaerobically, and has tolerance to heavy metals. A good start for an eventual GEMO.[[#References |[9]]]<br />
<br />
<br><br />
[[image:Superbug.jpg|thumb||500px||center|A better GEMO may do the trick <sub>http://www.usc.edu/hsc/info/pr/hmm/04fall/superbug.html</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
==Current Research==<br />
There is no current research being done on terraforming.<br />
<br><br />
<br />
==References==<br />
<br />
[1]Birch, P. “Terraforming Mars Quickly” ''Journal of the British Interplanetary Society''. 1992. Volume 45. p. 331-340<br />
<br />
[2]Birch, P. “Terraforming Venus Quickly” ''Journal of the British Interplanetary Society''. 1991. Volume 44. p. 157-167<br />
<br />
[3]Blackhurst, R., Verchovsky, A., Jarvis, K., Grady, M.M. “Cryptoendolith communities in Antarctic Dry Valley Region Sanstones: Potential Analogues of Martian Life-Forms” <br>''Lunar and Planetary Science''. 2003. Volume 34.<br />
<br />
[4]Farquhar, J., Bao, H., Thiemens, M. ''Atmospheric Influence of Earth’s Earliest Sulfur Cycle” ''Science''. 2000. Volume 289. P. 756-758<br><br />
<br />
[5][http://www.users.globalnet.co.uk/~mfogg/paper1.htm Fogg, M. J., "Terraforming" ''Society of Automotive Engineers''. 1995. Warrendale, PA] <br />
<br />
[6]Friedmann, EI., Hua, M., Ocampo-Friedmann, R. “Terraforming Mars: dissolution of carbonate rocks by cyanobacteria” ''Journal of Interplanetary Society''. 1993. Volume 46. P. 291-292<br><br />
[7]Friedmann, EI., Ocampo-Friedmann, R. "A Primitive Cyanobacterium as Pioneer Microorganism for Terraforming Mars" ''Adv. Space Res.'' 1994. Volume 15, No. 3. p. 243-246<br />
<br />
[8][http://www.marspapers.org/papers/MAR98089.pdf Graham, J., Graham L. "Chapter 18: Terraforming Mars" 1989.]<br />
<br />
[9]Hiscox, J., Thomas, D. “Genetic Modification and Selection of Microorganisms for Growth on Mars” Journal of the British Interplanetary Society. 1995 Volume 48. P. 419-426.<br><br />
<br />
[10]Thomas, D. “Biological Aspects of the Ecopoeisis and Terraformation of Mars: Current Perspectives and Research” ''Journal of the British Interplanetary Society''. 1995. Volume 48. P. 415-418<br />
<br />
[11]Sagan, C. "The Planet Venus" ''Science'' 1961. Volume 133. p. 849-858<br><br />
<br />
[12]Seckbach, J., Baker, F.A., Shugarman, P.M. "Algae Thrive in Pure CO<sub>2</sub>" ''Nature''. 1977. Volume 227. p. 774-775<br />
<br />
<br />
<br />
Edited by Samantha Chavez, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Terraforming&diff=70434Terraforming2012-04-06T14:58:13Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
[[image:46068edaa8c3a0a77d8ae5962027c93a.jpg |800px||right|]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
==Planetary Engineering==<br />
[[Image:Terraformed_mars_3_stage-We.jpg |thumb|500px|right|Artists rendition of Mars terraformation (galaxyexplorers.org).]]<br />
<br>Terraforming or “Planetary Ecosynthesis” is the process of changing a planet’s atmosphere to resemble that of the Earth’s, with the goal of sustaining terrestrial life. It is predicted that establishment of life will be similar to Earth’s history, starting with basic unicellular microorganisms. The most pheasible pioneer to begin life on a new planet would be some kind of photosynthetic microbe.[[#References |[8]]]<br><br />
<br><br />
The strategy of using photosynthesis to engineer a habitable planet for humans through photosynthesis would not be unlike the <b>Great Ogygenation Event</b> that took place on Earth 2.4 billion years ago, sometime after cyanobacteria first evolved (2.7-2.8 billion years ago.) This pivotal event paved the way for evolution of multi-cellular organisms and later, human beings.[[#References |[4]]]<br />
<br />
<br><br><br />
The topic has sprung much speculation as well as the ethical debates surrounding the idea.<br />
<br><br><br />
===<u>Candidates for Terraformation</u>===<br />
====Mars: the winner====<br />
Mars is the preferred planet of interest for terraforming because it's history of once being a water planet, and the fact that it still retains much of its CO<sub>2</sub>, nitrogen, and H<sub>2</sub>O.[[#References |[8]]] Currently Mars is very cold and it's atmosphere is relatively thin and mostly consists of CO<sub>2</sub> (95.3%) with very little O<sub>2</sub> and N<sub>2</sub>. Mars only receives 43% of the light Earth gets from the Sun, yet it is still sufficient enough for photosynthesis.[[#References |[10]]]<br />
<br><br><br />
Proposed Terraformation of Mars would require:<br><br />
<ul><br />
<li>Warming the planet substantially</li><br><br />
<li>Increase atmospheric pressure while adding O<sub>2</sub></li><br><br />
<li>Melt water (which Mars has frozen in Ice caps)</li><br />
</ul><br />
[[#References |[1]]]<br />
<br />
====Venus====<br />
Venus has been proposed but it’s problems far surpass Mars in that it has a very thick atmosphere, little water, and it’s temperatures are much warmer than Earth.[[#References |[11]]] Venus also has clouds made of searing sulfuric acid, and one Venus day is equivalent to 127 Earth days.[[#References |[2]]]<br />
<br><br>Proposed Terraformation of Venus would require:<br><br />
<ul><br />
<li>Cooling the planet substantially</li><br><br />
<li>Removing CO<sub>2</sub> and other poisonous gases from the atmosphere while replacing it with O<sub>2</sub></li><br><br />
<li>Reduce day length to 24 hours</li><br><br />
<li>Provide water</li></ul><br />
[[#References |[2]]]<br />
<br />
==Biological interaction==<br />
The interaction of pioneering microbial species within an alien atmosphere will hopefully pave the way for future organisms such as plants and eventually humans to be able to colonize that planet.<br />
<br><br />
The primary function of photosynthetic pioneers would be to take CO<sub>2</sub> out of the atmosphere while adding O<sub>2</sub> to the atmosphere.[[#References |[10]]]<br />
<br />
==<b>Niche: A New World</b>==<br />
To lay the foundation for microbial terraforming, the agreed plan for Mars begins with:<br> <br />
<ul><li>the release of man-made greenhouse gases into the atmosphere, heating the planet substantially,</li> <br />
<li>Initial warming will then cause CO<sub>2</sub> evaporation from the planet’s own glaciers and soil, producing further warming</li> <br />
<li>Melting glaciers will produce hydrologic cycles and evaporated H<sub>2</sub>O into the air, creating a denser atmosphere. This suggests a global temperature of at least 0 degrees Celsius.</li> <br />
<li>Water will be stable on the surface and temperatures will be more moderate, but the atmosphere will be mostly CO<sub>2</sub> and have little O<sub>2</sub>.</li><br />
So long as UV radiation remains high, microorganisms will be confined to living in or under rocks.[[#References |[5]]]<br />
<br> <br />
UV radiation screens have been proposed for microbial access to surfaces.[[#References |[8]]]<br />
<br> <br />
<br />
Microbial populations set to colonize Mars can expect extreme cold temperatures, high radiation, little to no moisture, and limited nutrients.[[#References |[8]]]<br />
<br />
[[image:Marsview5.jpg|thumb||600px||right|<sub>http://www.antarcticaedu.com/visions/</sub>]]<br />
[[image:Mars2.jpg|thumb||700px||left|<sub>http://io9.com/5655719/terraforming-earth-pt-4-nowhere-to-go-but-up</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br />
==Microbial processes==<br />
Mars has no tectonic activity so no biogeochemical cycling occurs there. It's thought that biological and photochemical processes can run the cycles on Mars.[[#References |[10]]]<br />
<br><br />
====Carbon cycling====<br />
Photosynthetic microorganisms remove CO<sub>2</sub> from the atmosphere by photosynthesis:<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br><br />
Eventually heterotrophic microbes will release CO<sub>2</sub> back into the atmosphere through respiration:<br><br />
<b>C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub> --> 6CO<sub>2</sub> + 6H<sub>2</sub>O + energy</b><br><br />
Certain Microorganisms such as <i>Matteia</i> have been proposed to release CO<sub>2</sub> from carbonate rock to complete the cycle in the early stages of colonization, just until enough carbohydrate is available to support heterotrophs.<br />
<br><br />
[[Image:1995 Thomas 48 415-418-2-.JPG |thumb||500px||right|Thomas, David J. 1995. "<I>Biological Aspects of the Ecopoesis and Terraformation of Mars: Current Perspectives and Research</I>]]<br />
<br />
====Oxygen====<br />
Cyanobacteria and algae will be used to increase O<sub>2</sub> through photosynthesis<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br />
<br />
====Nitrogen cycling====<br />
Besides CO<sub>2</sub> and O<sub>2</sub>, a buffer gas is needed to support human life, and nitrogen is necessary for photosynthesis at the start of terraformation.<br />
Currently there is not enough N<sub>2</sub> in Mars' atmosphere for nitrogen fixation and therefore, denitrification is necessary as long as the regolith contains nitrate as is proposed<br><br />
Denitrification:<br><br />
<b>NO<sub>3</sub>− → NO<sub>2</sub>− → NO + N<sub>2</sub>O → N<sub>2</sub> (g)</b><br><br />
Cyanobacteria can reduce N<sub>2</sub> to ammonia:<br><br />
<b>N<sub>2</sub> + 8 H+ + 8 e− → 2 NH<sub>3</sub> + H<sub>2</sub></b><br />
<br />
====Sulfur cycling====<br />
Most microbes utilize oxidized sulfur for protein synthesis.<br />
<br><br />
<br />
====Phosphorous cycling====<br />
Phosphates are insoluble minerals that are highly conserved in stable environments but through time losses can be a possible issue for terraformation. This may be the case with other non-volatile, minerals such as iron, manganese, and magnesium.[[#References |[10]]]<br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
Microorganisms are the best option for colonization of a new planet because of their wide range of physiologic and metabolic functions and are capable of <b>horizontal gene transfer.</b> Two strategies have been proposed for choosing the best pioneers. One can either choose a generalist extremophile on Earth that inhabits environments similar to the new planet, or genetically modifying a new species with all the best traits required for the job. (Creating a Genetically Engineered Mars Organism "GEMO")[[#References |[9]]]<br />
<br><br />
<b>Proposed traits of the perfect pioneer are:</b><br><ul><br />
<li>Must be photoautotrophs</li><br><br />
<li>Must be anaerobic and respire without O<sub>2</sub></li><br><br />
<li>Osmotic tolerance</li><br><br />
<li>Resistance to UV radiation</li><br><br />
<li>Cold tolerance</li><br><br />
<li>Tolerance for Nutrient limitations</li><br><br />
<li>Tolerance for water limitations</li><br><br />
<li>Resistance to oxides</li><br><br />
<li>Adaptation to lowered intracellular pH due to CO<sub>2</sub> in atmosphere</li><br><br />
<li>Can form Endospores</li><br>[[#References |[9]]]</ul><br />
<br />
===<u>Proposed Photoautotrophs</u>===<br />
====Cyanidium caldarium====<br />
A unicellular red algae found in diverse extreme environments such as bogs, wet acidic soils, and hot streams.<br />
It has been found to survive with little to no oxygen.[[#References |[12]]]<br />
[[image:Ideyuk 4.jpg |thumb| |300px| |left| Cyandium Caladarium Algae (Shu Suehiro Botanic.jp)]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Cryptoendolith Lichens====<br />
Literally "hiding in rocks" An extremophile found in porous rock in Antarctica where temperatures are normally -89.2°C to -93.4°C. There has been no rain or snowfall in the Antarctic Desert for over 100 years.[[#References |[3]]][[image:Cryptoendolith.jpg|thumb||300px||left|Antarctic sandstone inhabited by cryptoendolithic lichen communities. Photo courtesy of NASA]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Chroococcidiopsis====<br />
This primitive cyanobacterium has a high range of variability and may be the most desiccant-resistant of it's kind. It is found in extreme habitats such as Antarctic rocks, thermal springs, and hypersaline habitats. [[#References |[7]]]<br />
<br />
[[image:45.jpg |thumb||300px||left|Chroococcidiopsis cf. cubana Komárek et Hindák]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
===<u>Proposed Denitrifers</u>===<br />
[[image:Matteia.jpg|thumb||300px||right|http://www.cyanodb.cz]]<br />
<br />
====Matteia====<br />
Matteia sp., a cyanobacterium found on desert rocks, has been proposed to dissolve carbonate rocks both for release of CO<sub>2</sub> and in hopes of creating a Martian carbon cycle.[[#References |[6]]]<br />
<br />
====Psuedomonads and Alcaligenes====<br />
Psuedomonads and [[Alcaligenes]] could be appropriate denitrifiers once enough oxygen and carbonate are present to sustain them.[[#References |[10]]]<br />
<br />
===<u>Proposed GEMOs</u>===<br />
<br />
====Bacillus Polymyxa====<br />
A Facultative anaerobe that can form endospores, can fix nitrogen aerobically and anaerobically, and has tolerance to heavy metals. A good start for an eventual GEMO.[[#References |[9]]]<br />
<br />
<br><br />
[[image:Superbug.jpg|thumb||500px||center|A better GEMO may do the trick <sub>http://www.usc.edu/hsc/info/pr/hmm/04fall/superbug.html</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
==Current Research==<br />
There is no current research being done on terraforming.<br />
<br><br />
<br />
==References==<br />
<br />
[1]Birch, P. “Terraforming Mars Quickly” ''Journal of the British Interplanetary Society''. 1992. Volume 45. p. 331-340<br />
<br />
[2]Birch, P. “Terraforming Venus Quickly” ''Journal of the British Interplanetary Society''. 1991. Volume 44. p. 157-167<br />
<br />
[3]Blackhurst, R., Verchovsky, A., Jarvis, K., Grady, M.M. “Cryptoendolith communities in Antarctic Dry Valley Region Sanstones: Potential Analogues of Martian Life-Forms” <br>''Lunar and Planetary Science''. 2003. Volume 34.<br />
<br />
[4]Farquhar, J., Bao, H., Thiemens, M. ''Atmospheric Influence of Earth’s Earliest Sulfur Cycle” ''Science''. 2000. Volume 289. P. 756-758<br><br />
<br />
[5][http://www.users.globalnet.co.uk/~mfogg/paper1.htm Fogg, M. J., "Terraforming" ''Society of Automotive Engineers''. 1995. Warrendale, PA] <br />
<br />
[6]Friedmann, EI., Hua, M., Ocampo-Friedmann, R. “Terraforming Mars: dissolution of carbonate rocks by cyanobacteria” ''Journal of Interplanetary Society''. 1993. Volume 46. P. 291-292<br><br />
[7]Friedmann, EI., Ocampo-Friedmann, R. "A Primitive Cyanobacterium as Pioneer Microorganism for Terraforming Mars" ''Adv. Space Res.'' 1994. Volume 15, No. 3. p. 243-246<br />
<br />
[8][http://www.marspapers.org/papers/MAR98089.pdf Graham, J., Graham L. "Chapter 18: Terraforming Mars" 1989.]<br />
<br />
[9]Hiscox, J., Thomas, D. “Genetic Modification and Selection of Microorganisms for Growth on Mars” Journal of the British Interplanetary Society. 1995 Volume 48. P. 419-426.<br><br />
<br />
[10]Thomas, D. “Biological Aspects of the Ecopoeisis and Terraformation of Mars: Current Perspectives and Research” ''Journal of the British Interplanetary Society''. 1995. Volume 48. P. 415-418<br />
<br />
[11]Sagan, C. "The Planet Venus" ''Science'' 1961. Volume 133. p. 849-858<br><br />
<br />
[12]Seckbach, J., Baker, F.A., Shugarman, P.M. "Algae Thrive in Pure CO<sub>2</sub>" ''Nature''. 1977. Volume 227. p. 774-775<br />
<br />
<br />
<br />
Edited by Samantha Chavez, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Terraforming&diff=70433Terraforming2012-04-06T14:57:45Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br><br />
<br><br />
<br><br />
<br />
[[image:46068edaa8c3a0a77d8ae5962027c93a.jpg |500px||right|]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
==Planetary Engineering==<br />
[[Image:Terraformed_mars_3_stage-We.jpg |thumb|500px|right|Artists rendition of Mars terraformation (galaxyexplorers.org).]]<br />
<br>Terraforming or “Planetary Ecosynthesis” is the process of changing a planet’s atmosphere to resemble that of the Earth’s, with the goal of sustaining terrestrial life. It is predicted that establishment of life will be similar to Earth’s history, starting with basic unicellular microorganisms. The most pheasible pioneer to begin life on a new planet would be some kind of photosynthetic microbe.[[#References |[8]]]<br><br />
<br><br />
The strategy of using photosynthesis to engineer a habitable planet for humans through photosynthesis would not be unlike the <b>Great Ogygenation Event</b> that took place on Earth 2.4 billion years ago, sometime after cyanobacteria first evolved (2.7-2.8 billion years ago.) This pivotal event paved the way for evolution of multi-cellular organisms and later, human beings.[[#References |[4]]]<br />
<br />
<br><br><br />
The topic has sprung much speculation as well as the ethical debates surrounding the idea.<br />
<br><br><br />
===<u>Candidates for Terraformation</u>===<br />
====Mars: the winner====<br />
Mars is the preferred planet of interest for terraforming because it's history of once being a water planet, and the fact that it still retains much of its CO<sub>2</sub>, nitrogen, and H<sub>2</sub>O.[[#References |[8]]] Currently Mars is very cold and it's atmosphere is relatively thin and mostly consists of CO<sub>2</sub> (95.3%) with very little O<sub>2</sub> and N<sub>2</sub>. Mars only receives 43% of the light Earth gets from the Sun, yet it is still sufficient enough for photosynthesis.[[#References |[10]]]<br />
<br><br><br />
Proposed Terraformation of Mars would require:<br><br />
<ul><br />
<li>Warming the planet substantially</li><br><br />
<li>Increase atmospheric pressure while adding O<sub>2</sub></li><br><br />
<li>Melt water (which Mars has frozen in Ice caps)</li><br />
</ul><br />
[[#References |[1]]]<br />
<br />
====Venus====<br />
Venus has been proposed but it’s problems far surpass Mars in that it has a very thick atmosphere, little water, and it’s temperatures are much warmer than Earth.[[#References |[11]]] Venus also has clouds made of searing sulfuric acid, and one Venus day is equivalent to 127 Earth days.[[#References |[2]]]<br />
<br><br>Proposed Terraformation of Venus would require:<br><br />
<ul><br />
<li>Cooling the planet substantially</li><br><br />
<li>Removing CO<sub>2</sub> and other poisonous gases from the atmosphere while replacing it with O<sub>2</sub></li><br><br />
<li>Reduce day length to 24 hours</li><br><br />
<li>Provide water</li></ul><br />
[[#References |[2]]]<br />
<br />
==Biological interaction==<br />
The interaction of pioneering microbial species within an alien atmosphere will hopefully pave the way for future organisms such as plants and eventually humans to be able to colonize that planet.<br />
<br><br />
The primary function of photosynthetic pioneers would be to take CO<sub>2</sub> out of the atmosphere while adding O<sub>2</sub> to the atmosphere.[[#References |[10]]]<br />
<br />
==<b>Niche: A New World</b>==<br />
To lay the foundation for microbial terraforming, the agreed plan for Mars begins with:<br> <br />
<ul><li>the release of man-made greenhouse gases into the atmosphere, heating the planet substantially,</li> <br />
<li>Initial warming will then cause CO<sub>2</sub> evaporation from the planet’s own glaciers and soil, producing further warming</li> <br />
<li>Melting glaciers will produce hydrologic cycles and evaporated H<sub>2</sub>O into the air, creating a denser atmosphere. This suggests a global temperature of at least 0 degrees Celsius.</li> <br />
<li>Water will be stable on the surface and temperatures will be more moderate, but the atmosphere will be mostly CO<sub>2</sub> and have little O<sub>2</sub>.</li><br />
So long as UV radiation remains high, microorganisms will be confined to living in or under rocks.[[#References |[5]]]<br />
<br> <br />
UV radiation screens have been proposed for microbial access to surfaces.[[#References |[8]]]<br />
<br> <br />
<br />
Microbial populations set to colonize Mars can expect extreme cold temperatures, high radiation, little to no moisture, and limited nutrients.[[#References |[8]]]<br />
<br />
[[image:Marsview5.jpg|thumb||600px||right|<sub>http://www.antarcticaedu.com/visions/</sub>]]<br />
[[image:Mars2.jpg|thumb||700px||left|<sub>http://io9.com/5655719/terraforming-earth-pt-4-nowhere-to-go-but-up</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br />
==Microbial processes==<br />
Mars has no tectonic activity so no biogeochemical cycling occurs there. It's thought that biological and photochemical processes can run the cycles on Mars.[[#References |[10]]]<br />
<br><br />
====Carbon cycling====<br />
Photosynthetic microorganisms remove CO<sub>2</sub> from the atmosphere by photosynthesis:<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br><br />
Eventually heterotrophic microbes will release CO<sub>2</sub> back into the atmosphere through respiration:<br><br />
<b>C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub> --> 6CO<sub>2</sub> + 6H<sub>2</sub>O + energy</b><br><br />
Certain Microorganisms such as <i>Matteia</i> have been proposed to release CO<sub>2</sub> from carbonate rock to complete the cycle in the early stages of colonization, just until enough carbohydrate is available to support heterotrophs.<br />
<br><br />
[[Image:1995 Thomas 48 415-418-2-.JPG |thumb||500px||right|Thomas, David J. 1995. "<I>Biological Aspects of the Ecopoesis and Terraformation of Mars: Current Perspectives and Research</I>]]<br />
<br />
====Oxygen====<br />
Cyanobacteria and algae will be used to increase O<sub>2</sub> through photosynthesis<br><br />
<b>6CO<sub>2</sub> + 12H<sub>2</sub>O + Light -> C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6O<sub>2</sub>+ 6H<sub>2</sub>O</b><br />
<br />
====Nitrogen cycling====<br />
Besides CO<sub>2</sub> and O<sub>2</sub>, a buffer gas is needed to support human life, and nitrogen is necessary for photosynthesis at the start of terraformation.<br />
Currently there is not enough N<sub>2</sub> in Mars' atmosphere for nitrogen fixation and therefore, denitrification is necessary as long as the regolith contains nitrate as is proposed<br><br />
Denitrification:<br><br />
<b>NO<sub>3</sub>− → NO<sub>2</sub>− → NO + N<sub>2</sub>O → N<sub>2</sub> (g)</b><br><br />
Cyanobacteria can reduce N<sub>2</sub> to ammonia:<br><br />
<b>N<sub>2</sub> + 8 H+ + 8 e− → 2 NH<sub>3</sub> + H<sub>2</sub></b><br />
<br />
====Sulfur cycling====<br />
Most microbes utilize oxidized sulfur for protein synthesis.<br />
<br><br />
<br />
====Phosphorous cycling====<br />
Phosphates are insoluble minerals that are highly conserved in stable environments but through time losses can be a possible issue for terraformation. This may be the case with other non-volatile, minerals such as iron, manganese, and magnesium.[[#References |[10]]]<br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
Microorganisms are the best option for colonization of a new planet because of their wide range of physiologic and metabolic functions and are capable of <b>horizontal gene transfer.</b> Two strategies have been proposed for choosing the best pioneers. One can either choose a generalist extremophile on Earth that inhabits environments similar to the new planet, or genetically modifying a new species with all the best traits required for the job. (Creating a Genetically Engineered Mars Organism "GEMO")[[#References |[9]]]<br />
<br><br />
<b>Proposed traits of the perfect pioneer are:</b><br><ul><br />
<li>Must be photoautotrophs</li><br><br />
<li>Must be anaerobic and respire without O<sub>2</sub></li><br><br />
<li>Osmotic tolerance</li><br><br />
<li>Resistance to UV radiation</li><br><br />
<li>Cold tolerance</li><br><br />
<li>Tolerance for Nutrient limitations</li><br><br />
<li>Tolerance for water limitations</li><br><br />
<li>Resistance to oxides</li><br><br />
<li>Adaptation to lowered intracellular pH due to CO<sub>2</sub> in atmosphere</li><br><br />
<li>Can form Endospores</li><br>[[#References |[9]]]</ul><br />
<br />
===<u>Proposed Photoautotrophs</u>===<br />
====Cyanidium caldarium====<br />
A unicellular red algae found in diverse extreme environments such as bogs, wet acidic soils, and hot streams.<br />
It has been found to survive with little to no oxygen.[[#References |[12]]]<br />
[[image:Ideyuk 4.jpg |thumb| |300px| |left| Cyandium Caladarium Algae (Shu Suehiro Botanic.jp)]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Cryptoendolith Lichens====<br />
Literally "hiding in rocks" An extremophile found in porous rock in Antarctica where temperatures are normally -89.2°C to -93.4°C. There has been no rain or snowfall in the Antarctic Desert for over 100 years.[[#References |[3]]][[image:Cryptoendolith.jpg|thumb||300px||left|Antarctic sandstone inhabited by cryptoendolithic lichen communities. Photo courtesy of NASA]]<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br><br />
<br><br />
<br><br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
====Chroococcidiopsis====<br />
This primitive cyanobacterium has a high range of variability and may be the most desiccant-resistant of it's kind. It is found in extreme habitats such as Antarctic rocks, thermal springs, and hypersaline habitats. [[#References |[7]]]<br />
<br />
[[image:45.jpg |thumb||300px||left|Chroococcidiopsis cf. cubana Komárek et Hindák]]<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
===<u>Proposed Denitrifers</u>===<br />
[[image:Matteia.jpg|thumb||300px||right|http://www.cyanodb.cz]]<br />
<br />
====Matteia====<br />
Matteia sp., a cyanobacterium found on desert rocks, has been proposed to dissolve carbonate rocks both for release of CO<sub>2</sub> and in hopes of creating a Martian carbon cycle.[[#References |[6]]]<br />
<br />
====Psuedomonads and Alcaligenes====<br />
Psuedomonads and [[Alcaligenes]] could be appropriate denitrifiers once enough oxygen and carbonate are present to sustain them.[[#References |[10]]]<br />
<br />
===<u>Proposed GEMOs</u>===<br />
<br />
====Bacillus Polymyxa====<br />
A Facultative anaerobe that can form endospores, can fix nitrogen aerobically and anaerobically, and has tolerance to heavy metals. A good start for an eventual GEMO.[[#References |[9]]]<br />
<br />
<br><br />
[[image:Superbug.jpg|thumb||500px||center|A better GEMO may do the trick <sub>http://www.usc.edu/hsc/info/pr/hmm/04fall/superbug.html</sub>]]<br />
<br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br><br />
<br />
==Current Research==<br />
There is no current research being done on terraforming.<br />
<br><br />
<br />
==References==<br />
<br />
[1]Birch, P. “Terraforming Mars Quickly” ''Journal of the British Interplanetary Society''. 1992. Volume 45. p. 331-340<br />
<br />
[2]Birch, P. “Terraforming Venus Quickly” ''Journal of the British Interplanetary Society''. 1991. Volume 44. p. 157-167<br />
<br />
[3]Blackhurst, R., Verchovsky, A., Jarvis, K., Grady, M.M. “Cryptoendolith communities in Antarctic Dry Valley Region Sanstones: Potential Analogues of Martian Life-Forms” <br>''Lunar and Planetary Science''. 2003. Volume 34.<br />
<br />
[4]Farquhar, J., Bao, H., Thiemens, M. ''Atmospheric Influence of Earth’s Earliest Sulfur Cycle” ''Science''. 2000. Volume 289. P. 756-758<br><br />
<br />
[5][http://www.users.globalnet.co.uk/~mfogg/paper1.htm Fogg, M. J., "Terraforming" ''Society of Automotive Engineers''. 1995. Warrendale, PA] <br />
<br />
[6]Friedmann, EI., Hua, M., Ocampo-Friedmann, R. “Terraforming Mars: dissolution of carbonate rocks by cyanobacteria” ''Journal of Interplanetary Society''. 1993. Volume 46. P. 291-292<br><br />
[7]Friedmann, EI., Ocampo-Friedmann, R. "A Primitive Cyanobacterium as Pioneer Microorganism for Terraforming Mars" ''Adv. Space Res.'' 1994. Volume 15, No. 3. p. 243-246<br />
<br />
[8][http://www.marspapers.org/papers/MAR98089.pdf Graham, J., Graham L. "Chapter 18: Terraforming Mars" 1989.]<br />
<br />
[9]Hiscox, J., Thomas, D. “Genetic Modification and Selection of Microorganisms for Growth on Mars” Journal of the British Interplanetary Society. 1995 Volume 48. P. 419-426.<br><br />
<br />
[10]Thomas, D. “Biological Aspects of the Ecopoeisis and Terraformation of Mars: Current Perspectives and Research” ''Journal of the British Interplanetary Society''. 1995. Volume 48. P. 415-418<br />
<br />
[11]Sagan, C. "The Planet Venus" ''Science'' 1961. Volume 133. p. 849-858<br><br />
<br />
[12]Seckbach, J., Baker, F.A., Shugarman, P.M. "Algae Thrive in Pure CO<sub>2</sub>" ''Nature''. 1977. Volume 227. p. 774-775<br />
<br />
<br />
<br />
Edited by Samantha Chavez, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Wetlands&diff=65056Wetlands2011-07-22T20:54:50Z<p>Akent: /* Wetland Loss */</p>
<hr />
<div>{{Uncurated}}<br />
[[Image:wetlands.jpg|thumb|300px|right|Sample picture of a freshwater wetland ecosystem.]]<br />
==Introduction==<br />
[[Image:How-wetlands-work.jpg|thumb|300px|right|General hydrology and function of a typical inland wetland.]]<br />
Wetland ecosystems are extraordinarily useful communities (National Resource Counsel 1992). They perform vital environmental functions ([http://en.wikipedia.org/wiki/Denitrification denitrification], water purification, flood control, etc) and provide more services per hectare than any other ecosystem (Craig et al. 2008, Richardson 2008). Along with these natural benefits, wetlands also have the ability to reduce the effects of anthropogenic pollution, such as wastewater treatment and excessive fertilizer removal (Keeny 1973, Lee et al. 1969, Nichols 1983). One of the most important functions that wetlands perform is their role in the transformation of nitrogen. Fertilizers generate high nitrate loads and wetlands have the ability to transform this into less harmful forms of nitrogen. <br />
<br />
Denitrification is an especially important function carried out by wetland communities (Smith and Ogram 2008, Forshay and Stanley 2005, Craig et al. 2008) as excessive nitrate in the water can contribute to [http://en.wikipedia.org/wiki/Eutrophication eutrophication]. Left unchecked, eutrophication can lead to extensive algal blooms, [http://en.wikipedia.org/wiki/Hypoxia_(environmental) hypoxia] following decomposition of algal biomass, and an abrupt change in the makeup of the overall ecosystem. This phenomenon has been observed in both the Gulf of Mexico and Chesapeake Bay, and is mostly caused by the excessive amounts of fertilizer that end up in the waterways from extensive farming (Hey, 2002) along the Mississippi and Potomac rivers respectively (Galeone et al. 2006, Howarth et al. 1996, Malakoff 1998). Natural wetlands remove nitrate from the water and can be used to alleviate eutrophication. However, because of extensive habitat loss, nitrification of waterways increased drastically during the 20th century (Malakoff 1998, Walter and Merritts 2008).<br />
<br />
Wetlands are vital communities, and provide a multitude of services to ecosystem function. They are incredibly diverse ecosystems and have large roles in primary production and floodwater retention. Perhaps one of the most important functions of a wetland is the habitats ability to purify water. Wetlands have the ability to aid in pollutant removal, and microorganisms present in the saturated soils of these wetlands play a large role in performing that function.<br />
<br />
==Main classes of Wetlands==<br />
While wetlands can be found in a variety of regional and topographical locations, there are two general categories of wetlands recognized: coastal/tidal wetlands and inland/non-tidal wetlands. <br />
<br />
===Coastal Wetlands===<br />
These ecosystems are closely linked with [http://microbewiki.kenyon.edu/index.php/Estuaries estuary] and [http://microbewiki.kenyon.edu/index.php/Salt_Marsh salt marsh] systems in that fresh water and salt water combine to form a wide array of salinities. In this environment, the constantly fluctuating water levels (from tidal action) and salt concentrations combine to form a difficult habitat. Certain plants have adapted to these variable conditions to form unique communities capable of flourishing in the extreme environment. These include [http://microbewiki.kenyon.edu/index.php/Mangroves mangroves], certain grasses, and other salt-tolerant trees and shrubs. <br />
<br />
===Inland Wetlands===<br />
Unlike coastal wetlands, salinity is not as big a contributing factor for inland wetland systems. While salinity is important for various plant and microbial communities, wild fluctuations in the salt concentration are not seen as frequently as in estuarine habitats. Inland wetlands are most common on floodplains along rivers and streams (riparian wetlands), but can also be found in land depressions, surrounding lakes and ponds, and anywhere else where the soil environment is under constant, or near constant, saturation (vernal pools and bogs) (USEPA). Riparian wetlands are unique because they allow the water to percolate through the system slowly as opposed to rushing down a stream channel. Because the water is spread out over a large surface floodplain, the hydric soil microbial communities, along with the plants present are able to filter out nutrients and other pollutants to help purify the water. Because inland wetlands cover a wide range of environmental conditions, classification is broken down further into [http://www.epa.gov/owow/wetlands/vital/what.html types of wetlands based on region].<br />
<br />
==Physical Environment==<br />
[[Image:Wetland-upland_diagram.gif|thumb|300px|right|Diagrammatic representation of typical wetland environments as the distance from the source of water increases.]]<br />
Wetlands are classified as a transition between aquatic and terrestrial environments (Casey, 2001). Water hydrology (wetlands are usually saturated) generally determines the structure of the soil environment and the types of plant, animal, and microbial communities can inhabit the ecosystem. Because of the continual presence of water, conditions are created that support the growth of specially adapted plants and the formation of characteristic wetland soil – [http://soils.usda.gov/use/hydric/intro.html hydric soils]. Wetlands are unique in that they actively support both aquatic and terrestrial species throughout the year (USEPA).<br />
===Hydrology===<br />
Water availability plays a huge role in determining the processes that can be performed by a wetland. In general, more saturated environments (aquatic wetlands and flooded riparian wetlands) experience higher rates of [http://en.wikipedia.org/wiki/Anaerobic_respiration anaerobic respiration] - like dentrification, [http://en.wikipedia.org/wiki/Methanogenesis methanogenesis], iron reduction, and sulfate reduction, and depressed rates of aerobic processes - like nitrification. Constant saturation causes oxygen to be depleted quickly, causing microorganisms to turn to other substrates for energy (Balser, 2006). Microorganisms are quite adept at using other available substrates for [http://en.wikipedia.org/wiki/Microbial_metabolism energy]. Environments that experience wetting and drying cycles tend to be able to perform both aerobic and anaerobic functions depending on the conditions experienced. During wet cycles, anaerobic pathways can be used for energy (dentrification, etc) while in dry cycles, oxygen is present allowing for aerobic cycles to present themselves again. <br />
===Soil Structure===<br />
[[Image:Hydric_soils.jpg|thumb|200px|left|Vertical representation of soil structure as depth increases. Light brown signifies topsoil while the grey shows the hydric soils lying beneath. The striped gray at the bottom represents gravel and bedrock found below the water table.]]<br />
The layout of wetland soil plays a significant role in the processes performed by the community. The main identifying feature of a wetland is the presence of hydric soils – basically soils that function in strict anaerobic conditions under increased redox potential (USDA, 2004). In riparian wetlands, topsoil is generally found sitting on the surface, and is capable of performing aerobic functions because of the proximity to oxygen. Below the water line lie the hydric soils, gravel, and bedrock as you descend. The main factor influencing the structure and formation of hydric soils is the hydrology of the ecosystem. Communities that are constantly flooded (ie aquatic and some riparian wetlands) have constantly saturated hydric soils. These soils also act like sponges, helping alleviate flooding potential. The structure of the soil allows water to percolate through slowly, so when increased volume is added to the system, the soil itself can absorb some of the floodwater, mitigating some of the problems. <br />
<br />
==Biological interactions==<br />
===Plants===<br />
[[Image:Wetland_food_web.gif|thumb|300px|right|Diagram showing the diversity and complexity of the wetland food web.]]<br />
Wetlands are characterized by a wide variety of plants that can inhabit the saturated environment. The most common of these are cattails, bulrushes, sedges, water lilies (known as emergent vegetation) and pondweed and waterweed (known as submergent vegetation). These plants play a vital role in ecosystem function in that they help in various biogeochemical cycles. As the most productive ecosystem on earth, wetlands provide an enormous amount of dissolved organic matter through the process of [http://en.wikipedia.org/wiki/Photosynthesis photosynthesis] and subsequent death and decomposition. The wide variety of plant life and subsequent pool of dissolved organic matter is vital in creating vibrant wetland communities and accounts for the wide diversity of organisms seen in marsh environments. Plants are not the only organisms capable of photosynthesis. Wetland communities have large populations of [http://en.wikipedia.org/wiki/Cyanobacteria cyanobacteria] and [http://en.wikipedia.org/wiki/Algae algae] – capable of also fixing carbon dioxide into a useful substrate. This is important because it provides the foundation of the extensive food web found in wetland communities.<br />
===Animals===<br />
A variety of insect and animal species can inhabit wetland environments. The availability of standing water makes the habitat an ideal breeding ground for a host of insect species including mosquitoes and gnats. The overabundance of algae and photosynthetic bacteria also provides the insect populations with an easy source of food. Wetlands are particularly important habitats for amphibians and reptiles because of the proximity of open water to vegetated areas. Also, because of the wide array of insects inhabiting the ecosystem, a plentiful source of food is available for the amphibians and reptiles. Larger mammals and birds also are plentiful in marshy environments, again because of the abundance of food found. Overall, the food web found in wetland conditions is often the most complex and involved simply because of the abundance and diversity of life found in the area.<br />
===Microorganisms===<br />
Microorganisms play vital roles in the food web, functioning as primary producers and decomposers. Some microorganisms are primary producers – [http://en.wikipedia.org/wiki/Phototroph photoautotrophic] organisms who glean energy from light. These are fundamental in ensuring the strong food web observed because they provide the essential energy needed to higher trophic levels. When these higher trophic organisms die, microbes decompose the plant or animal to gain back valuable energy and reintroduce it into the system as dissolved organic carbon. This overall process is known as the [http://en.wikipedia.org/wiki/Microbial_loop microbial loop]. <br />
<br />
==Microbial processes==<br />
Wetlands microbes mediate many of the vital biogeochemical processes needed in the environment. The carbon, nitrogen, phosphorus, sulfur, and iron cycles all have some role in wetland communities and the bacteria present in the anoxic hydric soils are often responsible for the various oxidations and reductions that occur.<br />
===Carbon Cycle===<br />
Microbes are very important in the carbon cycle. Many photoautotrophs are responsible for the initial fixing of carbon dioxide into useful sugars that can be used for energy. Aside from primary production, decomposition is also a function of microbial communities in wetland soils. Because of anaerobic conditions, decomposition rates are slow, but overall [http://en.wikipedia.org/wiki/Organic_matter soil organic matter (SOM)] is quite high. Microbial communities in hypoxic conditions have the ability to transform this organic matter into usable forms of mineralized dissolved organic carbon. This process allows plants and other organisms to use these substrates once again for energy. If mineralization did not occur, then carbon would stay in an organic form and be unusable to plants. Microbial communities in the soil can mineralize the SOM into inorganic forms of carbon, like carbon dioxide, that plants can then use for photosynthesis once again.<br />
<br />
Under extremely reduced conditions, where no good terminal electron accepters are available, microbes can use carbon dioxide. These methanogenic bacteria use the CO<sub>2</sub> as a TEA resulting in the production of methane (CH<sub>4</sub>) also known as swamp gas. Another group of bacteria, known as methanotrophs, use the methane as their energy source and oxidize it to CO<sub>2</sub>. In general, methanotrophs are obligate aerobes, meaning that in hydric soils, they will be active right above the aerobic/anaerobic dividing line. Methane is a major greenhouse gas, but because of the placement of methanotrophs, up to 90% CH<sub>4</sub> generated in hydric soils can be consumed before it reaches the atmosphere ([http://www.docstoc.com/docs/7882653/Guide-to-Hydric-Soils-in-the--Mid-Atlantic-Region-(PDF) USDA], 2004). <br />
===Nitrogen Cycle===<br />
[[Image:Wetland_nitrogen_cycle.gif|thumb|300px|right|Diagrammatic representation of the wetland nitrogen cycle. Almost all of the transformations seen here are mediated by microbial communities.]]<br />
The nitrogen cycle is perhaps the cycle that feels the greatest influence from microbial activities. One of the most importance processes carried out by soil microbes is bacterial denitrification – the process of converting nitrate (NO<sub>3</sub><sup>-</sup>) to gaseous nitrogen compounds (N<sub>2</sub>, N<sub>2</sub>O, NO). This process is used by facultative anaerobic bacteria as a means to use nitrate a terminal electron acceptor (TEA). Normally, the most energetically favorable TEA is oxygen, but because hydric soils operate in hypoxic conditions, microbes must turn to other compounds to complete the phosphorylation pathway. This process is the primary removal mechanism of dissolved N in wetland communities. This is an extremely important process because of the excessive amounts of fertilizers used for agricultural purposes. Without denitrifying populations of bacteria, the excess nitrate would remain in the aquatic system causing an explosive growth of algae. Ultimately this process would lead to the creation of a [http://en.wikipedia.org/wiki/Dead_zone_(ecology) dead zone] and cause extensive ecological and economic damage.<br />
<br />
A similar process to this is dissimilatory nitrate reduction in which bacteria convert nitrate all the way to ammonium, which is then released by the cell. This process is favored by a high ratio of available C to NO<sub>3</sub><sup>-</sup>. This is because the microbes need useable forms of nitrogen, and the conversion all the way to ammonium creates and inorganic form of nitrogen usable to both microbes and plants. Also, a select few groups of chemoautotrophic bacteria can get energy from oxidizing ammonia to nitrite (NO<sub>2</sub><sup>-</sup>) and subsequently nitrate. <br />
<br />
Other organisms are capable of nitrification (the process of converting N<sub>2</sub?> to ammonia), but this process is not as prevalent a pathway as denitrification. Nitrification requires an extensive energy input to convert nitrogen gas to ammonia, and the process is usually only done under conditions of low nitrogen availability. In general, wetlands have high concentrations of available nitrogen (in the form of NO<sub>3</sub><sup>-</sup> and NH<sub>3</sub>), so the nitrification pathway is not readily used. <br />
<br />
===Iron and Manganese===<br />
When nitrate and oxygen are not readily available as TEA’s, microbes must turn to other oxidized compounds in an effort to gain energy. Both Fe<sup>3+</sup> and Mn<sup>4+</sup> have the ability to be reduced by bacteria and fungi under strict anaerobic conditions as TEA’s, resulting in the formation of Fe<sup>3+</sup> and Mn<sup>3+</sup>. While they will not yield as much energy for the organism, it will still allow anaerobic respiration to continue. However, this process is controlled largely by oxygen availability and redox conditions. When oxygen is present, that will be used as the TEA and chemoautotrophic bacteria will oxidize the reduced forms of iron and manganese back to the original +3 and +4 oxidation states respectively.<br />
<br />
===Sulfur===<br />
Another possible compound that can be used by bacteria as a TEA is sulfate (SO<sub>4</sub><sup>2-</sup>). In the reduction process, sulfate is converted to either elemental sulfur or hydrogen sulfide (H<sub>2</sub>S), which gives off the characteristic smell of rotting eggs. Sulfur-oxidizing bacteria, on the other hand, have the ability to oxidize the sulfides and elemental sulfer back to sulfate, or some other partially oxidized form of sulfur. While this is a useful process, bacteria often will use any available oxidized substrate before sulfate as a TEA. The reduction of sulfate will give the organism energy, but it will be nowhere near the amount gained as if the organism had used oxygen, nitrate, iron, or manganese.<br />
<br />
==Key Microorganisms==<br />
===Bacteria===<br />
Bacteria are present in high diversity in wetland environments. The largest group of wetland bacteria is proteobacteria – capable of a number of important functions ranging from nitrogen fixation, to denitrification, to iron and sulfate reducers. These are chemotrophs – gaining their energy from chemical sources as opposed to light (or photosynthetic) energy. Other chemotrophic bacteria are actinomycetes and firmicutes. Both of these are found in lower abundance in wetland communities due to low decomposition rates, but they are present in small amounts. Some examples include:<br />
*[http://microbewiki.kenyon.edu/index.php/Proteobacteria Proteobacteria]<br />
**[http://en.wikipedia.org/wiki/Betaproteobacteria β-Proteobacteria]<br />
***[http://microbewiki.kenyon.edu/index.php/Nitrospira Nitrospira] (nitrate reductions – denitrification)<br />
***[http://microbewiki.kenyon.edu/index.php/Nitrosomonas Nitrosomonas] (ammonia oxidations)<br />
**[http://en.wikipedia.org/wiki/Gammaproteobacteria γ-Proteobacteria]<br />
***[http://microbewiki.kenyon.edu/index.php/Pseudomonas Pseudomonas] (capable of degrading contaminants – naphthalene, toluene, etc.)<br />
**[http://en.wikipedia.org/wiki/Deltaproteobacteria δ-Proteobacteria]<br />
***[http://microbewiki.kenyon.edu/index.php/Desulfovibrio Desulfovibrio] (sulfate reducers)<br />
***[http://microbewiki.kenyon.edu/index.php/Geobacter Geobactor] (Iron reducers)<br />
*[http://en.wikipedia.org/wiki/Actinomycetes Actinomycetes] – resemble fungi with filamentous growth form<br />
**[http://microbewiki.kenyon.edu/index.php/Streptomyces Streptomyces] – most common actinomycetes group (degrade resistant substrates)<br />
**[http://microbewiki.kenyon.edu/index.php/Arthrobacter Arthrobacter] (degrade toxic compounds)<br />
*[http://en.wikipedia.org/wiki/Firmicutes Firmicutes]<br />
**[http://microbewiki.kenyon.edu/index.php/Bacillus Bacillus] (falcultative aerobes)<br />
**[http://microbewiki.kenyon.edu/index.php/Clostridium Clostridium] (anaerobic bacteria capable of using various TEAs) <br />
<br />
There are also photosynthetic bacteria present in wetlands. The primary photosynthetic bacteria group is [http://en.wikipedia.org/wiki/Cyanobacteria cyanobacteria]. Often time, these will form symbiotic relationships with plants, because of their capability to fix nitrogen into a useful inorganic form (ammonium). <br />
<br />
===Archaea===<br />
[http://en.wikipedia.org/wiki/Archaea Archaea] are the organisms responsible for the sulfate reductions that occur in wetlands, along with a good portion of the ammonia reductions. These lithotrophic organisms are almost exclusively anaerobic in wetland environments and are classified as nitrifiers, methanogens, and anaerobic methane oxidizers. Some of the common organisms found in this domain include:<br />
**[http://en.wikipedia.org/wiki/Euryarchaeota Euryarchaeota]<br />
***[http://en.wikipedia.org/wiki/Methanobacteria Methanobacteria] (methanogenesis)<br />
***[http://microbewiki.kenyon.edu/index.php/Methanosarcina Methanosarcina]<br />
**[http://en.wikipedia.org/wiki/Crenarchaeota Crenarchaeota]<br />
<br />
===Eukaryotes===<br />
[http://en.wikipedia.org/wiki/Algae Algae], classified as eukaryotes, also undergo photosynthesis to obtain energy and are a primary source of food for higher trophic levels. Other higher organisms, like plankton, daphnia, and ciliates are also integral parts of wetland communities, but are generally higher up in the trophic level, making them heterotrophs, and thus reliant on lower trophic levels for energy. As far as wetland function goes, bacteria and archaea are the primary drivers in biogeochemical cycling.<br />
<br />
One eukaryotic organism that is relatively important to nutrient cycling is [http://microbewiki.kenyon.edu/index.php/Rhizosphere:_environment_and_mycorrhizal_fungi fungi]. Normally an important decomposer, fungi are present in relatively low amounts in wetland communities because of the constant saturation and anoxic conditions. Because of the anoxic conditions, decomposition rates are low, limiting the importance of fungi in the environment. <br />
<br />
==Wetland Loss==<br />
[[Image:Wetlands_loss.jpg|thumb|300px|right|Rendering of the extensive wetland acreage in the Mississippi delta region of Louisiana.]]<br />
Land changes, mostly brought about by human industrialization, have significantly reduced the acreage of this vital habitat, as wetlands were once considered useless features of the landscape (Vitousek et al. 1997). However, this view has been reversed, and land developers have recognized the importance of having these ecosystems around. In the United States, the government instituted a “no net loss” policy, dictating that the total acreage of wetlands must not decrease any further. This law gained new importance after the tragic loss of life in the New Orleans area after hurricane Katrina. In February of 2005, a report was published by National Geographic documenting how devastating a hurricane could be to the region because of the significant loss of wetlands in the region (Handwerk 2005). These lost wetlands could have significantly reduced the storm surge and prevented the loss of hundreds of lives (Handwerk 2005). Because wetland soils are porous, water from floods or storm surges are effectively dampened when they pass through the marshy terrain (Middleton 1999). By recreating these habitats along rivers, spring flood damage can be lessened by the buffering effect of wetlands. <br />
<br />
There are some factors working in favor of recreating proper ecosystem function. In many cases, wetland soils were buried during land use changes and not completely uprooted or destroyed. Because microbes are so resilient, it is possible that once these remnant wetland soils are uncovered and restored, the microbes that have lain dormant for decades can return to normal function if appropriate environmental conditions are established (Orr et al. 2007).<br />
<br />
==Current Research==<br />
===Monitoring denitrification rates at restored wetlands===<br />
One large area of ongoing research has focused on individual wetland restoration/mitigation projects, usually at the site of a former or currently degraded wetland. While many of these projects have been successful at producing a wetland, they have often focused on restoring the floodplain and macro-ecology rather than the microbial ecology necessary for biogeochemical cycling (Orr et al. 2007, Richardson 2008). Even wetlands that are classified as “successful” may fail to deliver microbially-mediated ecosystem services like denitrification. In the Orr et al. paper (2007), a floodplain was reconnected to the Baraboo River system by removing a series of levees. The area was restored and it was expected that the reconnected floodplain would allow for rapid denitrification of the river. Following restoration, however, it was found that while the potential for denitrification was present, the improved floodplain did not noticeably improve denitrification rates (Orr et al. 2007). Even though the macro-ecology was accurately reproduced, the restoration effort did not achieve its overall goal of significantly enhancing denitrification rates.<br />
===Temporal microbial community shift during wetlands restoration===<br />
Because of the role played by microbial communities during biogeochemical cycling, a huge effort has been made to ensure that microbial community composition of restored wetlands mimics that of natural, unharmed wetlands (Bossio, 2006; Peralta et al., 2007). This can be done in one of two ways. The first method often used is high throughput, genotypic techniques. In general, these methods attempt to determine if the structure of the restored wetland appears similar to that of the natural wetland. Lab procedures like BIOLOG assays, PLFAs, PCR techniques, and others determine if the function of the two communities are similar. Using genes, substrate utilization, or other indicators, it can be determined if the two communities, even if phylogenetically different, have the ability to do the same function (denitrification, nitrification, etc.) The second method involves culturing the microbes found on site in an effort to determine phylogenetically what inhabits a given site. The problem with this method is that less than 1% of bacteria are able to be cultured. So while this technique may give some phylogenetic data, the overall diversity is grossly underestimated. These techniques allow for monitoring of the community over time to see if the restoration has any affect on the makeup of the microorganisms inhabiting the soil. <br />
===Wetlands as waste treatment plants===<br />
Water purification is an important function of wetland ecosystems. As mentioned above, microbes have the ability to remove excessive amounts of nutrient runoff from agricultural/human sources. One big area of recent research has been the area of wastewater treatment. The extensive diversity of plant, animal, and microbial life allows wetlands to remove pollutants and purify water at an extremely high rate (USEPA, 1993). It has been repeatedly observed that suspended solids and oxidized nutrients are readily used by wetland organisms. As the water percolates through the system, these substrates are removed from the aquatic environment either through adsorption to the soil (phosphates and large organic compounds), microbially mediated removal (biochemical reactions), or uptake into plants (heavy metals, and some organic compounds). The resulting output of water is substantially cleaner than the inflow, showing how effective wetlands can be at water purification. <br />
<br />
==Resources==<br />
[http://www.docstoc.com/docs/7882653/Guide-to-Hydric-Soils-in-the--Mid-Atlantic-Region-(PDF) Mid-Atlantic guide to hydric soils and microbial processes]<br />
<br />
[http://www.epa.gov/owow/wetlands/pdf/ConstructedWetlands-Complete.pdf Wetland Wastewater Treatment studies]<br />
<br />
==References==<br />
<br />
Balser, T., K. McMahon, D. Bart, D. Bronson, D.R. Coyle, N. Craig, M. Flores-Mangual, K. Forshay, S. Jones, A. Kent, A. Shade. 2006. Bridging the gap between micro- and macro-scale perspectives on the role of microbial communities in global change ecology. Plant and Soil 289:59-70.<br />
<br />
Bossio et al., 2006. Alteration of soil microbial communities and water quality in restored wetlands. Soil Biology & Biochemistry 38 (2006) pp. 1223-1233.<br />
<br />
Casey, R. E., Klaine, S. J., Nutrient Attenuation by a Riparian Wetland during Natural and Artificial Runoff Events. J. Environ. Qual. 30:1720–1731 (2001).<br />
<br />
Craig, LS, MA Palmer, DC Richardson, S Filoso, ES Bernhardt, BP Bledsoe, MW Doyle, PM Groffman, BA Hassett, SS Kaushal, PM Mayer, SM Smith, and PR Wilcock. Stream restoration strategies for reducing river nitrogen loads. 2008. Frontiers in Ecology and the Environment 6:529-538.<br />
<br />
Forshay KJ, Stanley EH. 2005. Rapid nitrate loss and denitrification in a temperate river floodplain. Biogeochemistry 75: 43–64.<br />
<br />
Galeone DG, Brightbill RA, Low DJ, O’Brien DL. 2006. Effects of streambank fencing of pastureland on benthic macroinvertebrates and the quality of surface water and shallow ground water in the Big Spring Run basin of Mill Creek watershed, Lancaster County, Pennsylvania, 1993-2001: Scientific Investigations Report 2006-5141, 183 p.<br />
<br />
Handwerk, B.2005. Louisiana coast threatened by wetlands loss. National Geographic. Feb. 2005.<br />
<br />
Howarth RW, Billen G, Swaney D, Townsend A, Jaworski N, Lajtha K, Downing JA, Elmgren R, Caraco N, Jordan T. 1996. Regional nitrogen budgets and riverine N & P fluxes for the drainages to the North Atlantic Ocean: Natural and human influences. Biogeochemistry 35: 75-139.<br />
<br />
Keeny, D.R. 1973. The Nitrogen Cycle in Sediment-Water Systems. Journal Environ. Quality 2(1):15-29.<br />
<br />
Lee, G, E., Bentley and R. Amundson. 1969. Effect of Marshes on Water Quality. University of Wisconsin, Madison.<br />
<br />
Malakoff, D. 1998. Death by Suffocation in the Gulf of Mexico. Science 281:190-193.<br />
<br />
Middleton, B. 1999. Wetland restoration: flood pulsing and disturbance dynamics. John Wiley and Sons, New York.<br />
<br />
National Research Council. 1992. Restoration of aquatic ecosystems: science, technology, public policy. National Academy Press, Washington, D.C.<br />
<br />
Nichols, D. 1983. Capacity of Natural Wetlands to Remove Nutrients from Wastewater. Jour. Of Water Poll. Control Fed. 55(5):495.<br />
<br />
Orr et al., 2007. Effects of restoration and reflooding on soil denitrification in a leveed Midwestern floodplain. Ecological Applications 17(8), 2007, pp. 2365-2376.<br />
<br />
Peralta, A.L., J.W. Matthews, D.N. Flanagan, and A.D. Kent. 2007. Microbial community structure and function in restored floodplain forest wetlands. Proceedings of the International Symposium on Soil Biodiversity and Ecology. Taipei, Taiwan.<br />
<br />
Richardson CJ (2008) The Everglades Experiments: Lessons for Ecosystem Restoration (Springer, New York) p 698.<br />
<br />
Smith, J. M., and A. Ogram. 2008. Genetic and functional variation in denitrifier populations along a short-term restoration chronosequence. Applied and Environmental Microbiology. 74(18):5615-5620.<br />
<br />
Vitousek, P. M., H. A. Mooney, J. Lubchenco, and J. Melillo. 1997. Human domination of Earth’s ecosystems. Science 277:494–499.<br />
<br />
Walter RC and Merritts DJ. 2008. Natural streams and the legacy of water-powered mills. Science 319:299-304<br />
<br />
[http://www.epa.gov/owow/wetlands/vital/what.html USEPA wetlands definitions]<br />
<br />
[http://www.epa.gov/owow/wetlands/pdf/ConstructedWetlands-Complete.pdf USEPA wetland wastewater treatment]<br />
<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=64880University of Illinois2011-05-13T16:08:48Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Acidic hot springs]]<br />
<br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Deep subsurface microbes]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Leafcutter_ants,_fungi,_and_bacteria&diff=60930Leafcutter ants, fungi, and bacteria2011-04-21T19:26:56Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br />
<br />
==Introduction== <br />
[[Image:leafcolony.jpg|thumb|653px|right|foraging ants carry back cuts of leaves.]]Microorganisms often require a symbiotic relationship with other organisms in order to reproduce and survive. This symbiotic relationship is shown through the relationship between leafcutter ants, fungi, and bacteria. Sometimes refered to as the "First Agriculture," this relationship can be compared to farmer (the ants) cultivating its crops (the fungus). Up until recently, the fungal colonies seemed to be free of any pests or parasites. This was thought to be because the ants were so diligent in caring for the fungus that they did not allow any parasites to enter and take hold. Cameron Currie was the first to look at why the nests were pest free. He concluded that the ants carried a white powdery bacteria on their abdomens that had antimicrobial properties. Without the ants, the parasitic mold could take over the fungus in the colony in a matter of days.<br />
<br><br />
<br />
Picture taken from: http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4<br />
<br />
==Symbiotic Processes==<br />
<br />
[[Image:fungus.jpg|thumb|200px|right|A worker ant harvesting the fungus. http://scienceblogs.com/notrocketscience/2009/11/leafcutter_ants_rely_on_bacteria_to_fertilise_their_fungus_g.php]]<br />
<br />
===Main Functions===<br />
The fungus and the ants depend on each other for survival. The ants cultivate the fungus in its colonies from chewed up leaves and at the same time the fungus acts as the main food source for the ants. One symbiotic partner can not survive without the other.<br />
====Fungi Growth====<br />
The leaves in the rain forest have toxic qualities in them which is supposed to deter herbivory. But the harvesting ants cut the leaves without ingesting any of the toxins and are able to bring the leaves back to the nest. There the leaves are given to worker ants which chew up the leaves in their mouths into a paste which becomes the food source for the fungus. The plant material is broken down through enzymes that break down the proteins and starches. Depending on the colony, the enzymes can slightly different between complete plant break down and those that focus mainly on plant wall digestion. Because of the symbiotic relationship, the toxins in the leaves are broken down by the fungi into needed sugars and proteins safe for the ant to consume. <br />
<br><br />
<br />
===Bacterial resistance to fungal parasites===<br />
To maintain a clean and healthy fungus colony, the ants have a bacteria on their exoskeleton which they use when cultivating the fungus. Some ants have this on their underbelly while ants that are in constant contact with the fungus are almost completely covered with the bacteria. The ants are able to use this bacter, with the antibiotic qualities, to fight against any invasive molds or fungi. This bacteria is similar to the bacterium which is produces half the antibiotics made today. The antibiotic qualities allow it to specifically work with the fungus to inhibit the parasitic mold.<br />
<br><br />
<br><br />
Unlike the ant, fungi, and bacteria symbiosis, present day antibiotics often produce resistant types of pathogens. It is thought that the ant colonies do not produce antibiotic resistant molds because of the high diversity of the bacteria and as the two evolve together the parasitic mold will not evolve a resistance.<br />
<br><br />
<br><br />
Another method to cultivate only its native strain of Pseudonocardia is that the ant's feces contain incompatibility chemicals which select only for its resident fungus. There are also behavior cues which suggest that the ants physically pick out other types of fungus.<br />
<br />
==Environmental Implications==<br />
The millions of ants in the forests have a huge effect on the ecosystem. They consume 15-20% of fresh vegetation and up to 240 kg of dry leaves per year. They make up 86% of the total anthropod biomass. For such a small organism, it has a huge effect.<br />
<br><br />
===Nitrogen Fixation===<br />
<br />
Like any other garden, the ant's fungus garden needs nitrogen. Because of the low nitrogen ratio in leaves, there are nitrogen fixing bacteria in the colonies that help to introduce usable nitrogen into the system. The n-fixing bacteria fixes enough nitrogen for the fungus and the ants and also leaves a large amount in the refuse of the colony. This nitrogen can be worked back into the surrounding system replenishing the nutrient poor tropical environment with an essential limiting nutrient (Pinto-Tomas, 2009).<br />
<br><br />
<br />
===Decomposition===<br />
<br />
==Niche==<br />
<br />
[[Image:Colonies.jpg|thumb|259px|right|An underground chamber where the fungus and the queen is housed. http://laanitarainforestranch.com/pages/leafcutterants.htm]]<br />
<br />
===<b>Habitat</b>===<br />
The ant's nests are subterranean and can be found in mostly tropical areas including Costa Rica, Panama, and Argentina.<br />
<br><br />
===<b>Nest Characteristics</b>=== <br />
Nests begin when a queen ant leaves one nest with a small amount of the fungus in her mouth and moves to a different area to start her own colony. Once a nest becomes established, the colonies can grow to have millions of ants in them. <br />
<br><br />
These subterranean nests vary in sizes. They can be small with a single fungus growing "room" or can be multiple feet below ground with many different rooms and complex tunnels. Ants are also known as organized and clean insects. They have certain refuse dumps where the worker ants take the garbage and seclude it from the rest of the colony to decrease contamination. <br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
<br />
===<b>Ants</b>=== <br />
The group of ants that are LeafCutters belong to the tribe <i>attini</i> and their genera is <i>Atta</i> and <i>acromyrmex</i> These ants have been around for the better part of 50 million years. Interestingly, these ants are consume the largest amount of primary producers in the tropical rainforest areas which is not surprising considering their biomass is four times the amount of other invertebrates. World wide, these insects take up a third of the total insect biomass.<br />
<br />
===Fungi=== <br />
Playing the role of both a decomposer and the primary food source for the Leafcutters, the fungi from the family <i>Lepiotaceae</i> is grown underground in the nests chambers by the worker ants. <br />
<br />
====Parasites====<br />
Battling against the ant's seemingly clean fungis' agriculture are parasites that would quickly take over the colony's fungus growth if not carefully weeded against. These can be competing molds or funguses that would come along and compete with the fungi for the delicious broken down vegetation. The ant's fungi cant survive against the invaders. Some of these parasites are refered to as <i>escovopsis</i>, and would feed on the fungus (Reynolds,2004).<br />
<br />
===Black Yeasts=== <br />
One of the most interesting and only recently discovered partners is the antibiotic producing bacteria <i>pseudonocardia</i><br />
<br><br />
There has recently been research conducted on a fourth bacterial partner. This is a black yeast that can be found on the cuticle of the ant and is used in a similar fashion in discouraging parasitic growth. This yeast has evolved with the ant-fungi symbiotic relationship and according to Little et al, the research into this partner shows how complicated and sophisticated this symbiotic partnership can be (Little, 2007).<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Coevolution between attine ants and actinomycete bacteria===<br />
It has been the thought that the close relationship between the ant and the bacteria has caused the two to evolve together. But the study looks at if that is truly so. It concluded that the ant has probably evolved with the bacteria, but the bacteria has evolved independently. The study states that more research needs to be done on the reciprocality of the evolving partners.<br />
<br />
===Enzyme activity activity in different ant colonies===<br />
Ants have evolved into different sister clades. This research shows how the enzyme activity between lower and higher evolved colonies has changed. The study shows that higher evolved colonies contain more protein and starch digesting enzymes while those of lower clades have enzymes that just focus on <i>partial</i> degradation of the plant material.<br />
<br />
===Ant Genome===<br />
The complete ant genome has recently been mapped out. With that, their are multiple studies going on about the evolution of the ants with its symbiotic partners and other attributes of the ant. Especial focus is put on the antimicrobial properties of the bacteria.<br />
<br />
===Evolution and Competition===<br />
There are studies conducted to how the ant and its partners have evolved together and how they originally came to work together. This has led to studies on how the partners work to discourage different types of fungus and bacteria in interfering. This interference could lead to an instability within the network. Resistant pathogenic molds are also a source of research to see why they have not evolved over the years to take over the fungus.<br />
<br />
==References==<br />
Ask Nature, A project of the Biomimicry Institute. <http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4><br />
<br />
Dash, D., Mueller, U., Rabeling, C.,Rodrigues, A., 2008. "COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION." Evolution 62. 11:2894-2912. Academic Search Premier. EBSCO. Web. 5 Apr. 2011.<br />
<br />
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G., & Boomsma, J. J. (2010). EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS. Evolution, 64(7), 2055-2069. <br />
<br />
Little, A., Currie, C. 2007. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant-microbe symbiosis." PubMed.gov. 3(5):501-504<br />
<br />
Reynolds, H. Currie, C. "Pathogenicity of Escovopsis weberi: The parasite of the attine ant-microbe symbiosis directly consumes the ant-cultivated fungus." 2004. Mycologia. 96(5): 955-959<br />
<br />
Pinto-Tomas, A., Anderson, M., Suen, G., Stevensen, D., Chu, F., Cleland, W., Weimer, P., Currie, C. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants.” Science. 326: 1120-1123.<br />
<br />
Ulrich, M., Schultz, T., Currie, C., Adams, R., Malloch, D. 2001. "The origin of the attin ant-fungus mutualism." 76:169-197 <br />
<br />
Edited by Katie Yi, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Leafcutter_ants,_fungi,_and_bacteria&diff=60929Leafcutter ants, fungi, and bacteria2011-04-21T19:26:15Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br />
<br />
==Introduction== <br />
[[Image:leafcolony.jpg|Thumb|653px|right|foraging ants carry back cuts of leaves.]]Microorganisms often require a symbiotic relationship with other organisms in order to reproduce and survive. This symbiotic relationship is shown through the relationship between leafcutter ants, fungi, and bacteria. Sometimes refered to as the "First Agriculture," this relationship can be compared to farmer (the ants) cultivating its crops (the fungus). Up until recently, the fungal colonies seemed to be free of any pests or parasites. This was thought to be because the ants were so diligent in caring for the fungus that they did not allow any parasites to enter and take hold. Cameron Currie was the first to look at why the nests were pest free. He concluded that the ants carried a white powdery bacteria on their abdomens that had antimicrobial properties. Without the ants, the parasitic mold could take over the fungus in the colony in a matter of days.<br />
<br><br />
<br />
Picture taken from: http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4<br />
<br />
==Symbiotic Processes==<br />
<br />
[[Image:fungus.jpg|thumb|200px|right|A worker ant harvesting the fungus. http://scienceblogs.com/notrocketscience/2009/11/leafcutter_ants_rely_on_bacteria_to_fertilise_their_fungus_g.php]]<br />
<br />
===Main Functions===<br />
The fungus and the ants depend on each other for survival. The ants cultivate the fungus in its colonies from chewed up leaves and at the same time the fungus acts as the main food source for the ants. One symbiotic partner can not survive without the other.<br />
====Fungi Growth====<br />
The leaves in the rain forest have toxic qualities in them which is supposed to deter herbivory. But the harvesting ants cut the leaves without ingesting any of the toxins and are able to bring the leaves back to the nest. There the leaves are given to worker ants which chew up the leaves in their mouths into a paste which becomes the food source for the fungus. The plant material is broken down through enzymes that break down the proteins and starches. Depending on the colony, the enzymes can slightly different between complete plant break down and those that focus mainly on plant wall digestion. Because of the symbiotic relationship, the toxins in the leaves are broken down by the fungi into needed sugars and proteins safe for the ant to consume. <br />
<br><br />
<br />
===Bacterial resistance to fungal parasites===<br />
To maintain a clean and healthy fungus colony, the ants have a bacteria on their exoskeleton which they use when cultivating the fungus. Some ants have this on their underbelly while ants that are in constant contact with the fungus are almost completely covered with the bacteria. The ants are able to use this bacter, with the antibiotic qualities, to fight against any invasive molds or fungi. This bacteria is similar to the bacterium which is produces half the antibiotics made today. The antibiotic qualities allow it to specifically work with the fungus to inhibit the parasitic mold.<br />
<br><br />
<br><br />
Unlike the ant, fungi, and bacteria symbiosis, present day antibiotics often produce resistant types of pathogens. It is thought that the ant colonies do not produce antibiotic resistant molds because of the high diversity of the bacteria and as the two evolve together the parasitic mold will not evolve a resistance.<br />
<br><br />
<br><br />
Another method to cultivate only its native strain of Pseudonocardia is that the ant's feces contain incompatibility chemicals which select only for its resident fungus. There are also behavior cues which suggest that the ants physically pick out other types of fungus.<br />
<br />
==Environmental Implications==<br />
The millions of ants in the forests have a huge effect on the ecosystem. They consume 15-20% of fresh vegetation and up to 240 kg of dry leaves per year. They make up 86% of the total anthropod biomass. For such a small organism, it has a huge effect.<br />
<br><br />
===Nitrogen Fixation===<br />
<br />
Like any other garden, the ant's fungus garden needs nitrogen. Because of the low nitrogen ratio in leaves, there are nitrogen fixing bacteria in the colonies that help to introduce usable nitrogen into the system. The n-fixing bacteria fixes enough nitrogen for the fungus and the ants and also leaves a large amount in the refuse of the colony. This nitrogen can be worked back into the surrounding system replenishing the nutrient poor tropical environment with an essential limiting nutrient (Pinto-Tomas, 2009).<br />
<br><br />
<br />
===Decomposition===<br />
<br />
==Niche==<br />
<br />
[[Image:Colonies.jpg|Thumb|259px|right|An underground chamber where the fungus and the queen is housed. http://laanitarainforestranch.com/pages/leafcutterants.htm]]<br />
<br />
===<b>Habitat</b>===<br />
The ant's nests are subterranean and can be found in mostly tropical areas including Costa Rica, Panama, and Argentina.<br />
<br><br />
===<b>Nest Characteristics</b>=== <br />
Nests begin when a queen ant leaves one nest with a small amount of the fungus in her mouth and moves to a different area to start her own colony. Once a nest becomes established, the colonies can grow to have millions of ants in them. <br />
<br><br />
These subterranean nests vary in sizes. They can be small with a single fungus growing "room" or can be multiple feet below ground with many different rooms and complex tunnels. Ants are also known as organized and clean insects. They have certain refuse dumps where the worker ants take the garbage and seclude it from the rest of the colony to decrease contamination. <br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
<br />
===<b>Ants</b>=== <br />
The group of ants that are LeafCutters belong to the tribe <i>attini</i> and their genera is <i>Atta</i> and <i>acromyrmex</i> These ants have been around for the better part of 50 million years. Interestingly, these ants are consume the largest amount of primary producers in the tropical rainforest areas which is not surprising considering their biomass is four times the amount of other invertebrates. World wide, these insects take up a third of the total insect biomass.<br />
<br />
===Fungi=== <br />
Playing the role of both a decomposer and the primary food source for the Leafcutters, the fungi from the family <i>Lepiotaceae</i> is grown underground in the nests chambers by the worker ants. <br />
<br />
====Parasites====<br />
Battling against the ant's seemingly clean fungis' agriculture are parasites that would quickly take over the colony's fungus growth if not carefully weeded against. These can be competing molds or funguses that would come along and compete with the fungi for the delicious broken down vegetation. The ant's fungi cant survive against the invaders. Some of these parasites are refered to as <i>escovopsis</i>, and would feed on the fungus (Reynolds,2004).<br />
<br />
===Black Yeasts=== <br />
One of the most interesting and only recently discovered partners is the antibiotic producing bacteria <i>pseudonocardia</i><br />
<br><br />
There has recently been research conducted on a fourth bacterial partner. This is a black yeast that can be found on the cuticle of the ant and is used in a similar fashion in discouraging parasitic growth. This yeast has evolved with the ant-fungi symbiotic relationship and according to Little et al, the research into this partner shows how complicated and sophisticated this symbiotic partnership can be (Little, 2007).<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Coevolution between attine ants and actinomycete bacteria===<br />
It has been the thought that the close relationship between the ant and the bacteria has caused the two to evolve together. But the study looks at if that is truly so. It concluded that the ant has probably evolved with the bacteria, but the bacteria has evolved independently. The study states that more research needs to be done on the reciprocality of the evolving partners.<br />
<br />
===Enzyme activity activity in different ant colonies===<br />
Ants have evolved into different sister clades. This research shows how the enzyme activity between lower and higher evolved colonies has changed. The study shows that higher evolved colonies contain more protein and starch digesting enzymes while those of lower clades have enzymes that just focus on <i>partial</i> degradation of the plant material.<br />
<br />
===Ant Genome===<br />
The complete ant genome has recently been mapped out. With that, their are multiple studies going on about the evolution of the ants with its symbiotic partners and other attributes of the ant. Especial focus is put on the antimicrobial properties of the bacteria.<br />
<br />
===Evolution and Competition===<br />
There are studies conducted to how the ant and its partners have evolved together and how they originally came to work together. This has led to studies on how the partners work to discourage different types of fungus and bacteria in interfering. This interference could lead to an instability within the network. Resistant pathogenic molds are also a source of research to see why they have not evolved over the years to take over the fungus.<br />
<br />
==References==<br />
Ask Nature, A project of the Biomimicry Institute. <http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4><br />
<br />
Dash, D., Mueller, U., Rabeling, C.,Rodrigues, A., 2008. "COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION." Evolution 62. 11:2894-2912. Academic Search Premier. EBSCO. Web. 5 Apr. 2011.<br />
<br />
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G., & Boomsma, J. J. (2010). EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS. Evolution, 64(7), 2055-2069. <br />
<br />
Little, A., Currie, C. 2007. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant-microbe symbiosis." PubMed.gov. 3(5):501-504<br />
<br />
Reynolds, H. Currie, C. "Pathogenicity of Escovopsis weberi: The parasite of the attine ant-microbe symbiosis directly consumes the ant-cultivated fungus." 2004. Mycologia. 96(5): 955-959<br />
<br />
Pinto-Tomas, A., Anderson, M., Suen, G., Stevensen, D., Chu, F., Cleland, W., Weimer, P., Currie, C. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants.” Science. 326: 1120-1123.<br />
<br />
Ulrich, M., Schultz, T., Currie, C., Adams, R., Malloch, D. 2001. "The origin of the attin ant-fungus mutualism." 76:169-197 <br />
<br />
Edited by Katie Yi, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Leafcutter_ants,_fungi,_and_bacteria&diff=60928Leafcutter ants, fungi, and bacteria2011-04-21T19:25:02Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br />
<br />
==Introduction== <br />
[[Image:leafcolony.jpg|Thumb|653px|right|foraging ants carry back cuts of leaves.]]Microorganisms often require a symbiotic relationship with other organisms in order to reproduce and survive. This symbiotic relationship is shown through the relationship between leafcutter ants, fungi, and bacteria. Sometimes refered to as the "First Agriculture," this relationship can be compared to farmer (the ants) cultivating its crops (the fungus). Up until recently, the fungal colonies seemed to be free of any pests or parasites. This was thought to be because the ants were so diligent in caring for the fungus that they did not allow any parasites to enter and take hold. Cameron Currie was the first to look at why the nests were pest free. He concluded that the ants carried a white powdery bacteria on their abdomens that had antimicrobial properties. Without the ants, the parasitic mold could take over the fungus in the colony in a matter of days.<br />
<br><br />
<br />
Picture taken from: http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4<br />
<br />
==Symbiotic Processes==<br />
<br />
[[Image:fungus.jpg|Thumb|200px|right|A worker ant harvesting the fungus.]]<br />
<br />
===Main Functions===<br />
The fungus and the ants depend on each other for survival. The ants cultivate the fungus in its colonies from chewed up leaves and at the same time the fungus acts as the main food source for the ants. One symbiotic partner can not survive without the other.<br />
====Fungi Growth====<br />
The leaves in the rain forest have toxic qualities in them which is supposed to deter herbivory. But the harvesting ants cut the leaves without ingesting any of the toxins and are able to bring the leaves back to the nest. There the leaves are given to worker ants which chew up the leaves in their mouths into a paste which becomes the food source for the fungus. The plant material is broken down through enzymes that break down the proteins and starches. Depending on the colony, the enzymes can slightly different between complete plant break down and those that focus mainly on plant wall digestion. Because of the symbiotic relationship, the toxins in the leaves are broken down by the fungi into needed sugars and proteins safe for the ant to consume. <br />
<br><br />
<br />
===Bacterial resistance to fungal parasites===<br />
To maintain a clean and healthy fungus colony, the ants have a bacteria on their exoskeleton which they use when cultivating the fungus. Some ants have this on their underbelly while ants that are in constant contact with the fungus are almost completely covered with the bacteria. The ants are able to use this bacter, with the antibiotic qualities, to fight against any invasive molds or fungi. This bacteria is similar to the bacterium which is produces half the antibiotics made today. The antibiotic qualities allow it to specifically work with the fungus to inhibit the parasitic mold.<br />
<br><br />
<br><br />
Unlike the ant, fungi, and bacteria symbiosis, present day antibiotics often produce resistant types of pathogens. It is thought that the ant colonies do not produce antibiotic resistant molds because of the high diversity of the bacteria and as the two evolve together the parasitic mold will not evolve a resistance.<br />
<br><br />
<br><br />
Another method to cultivate only its native strain of Pseudonocardia is that the ant's feces contain incompatibility chemicals which select only for its resident fungus. There are also behavior cues which suggest that the ants physically pick out other types of fungus.<br />
<br />
==Environmental Implications==<br />
The millions of ants in the forests have a huge effect on the ecosystem. They consume 15-20% of fresh vegetation and up to 240 kg of dry leaves per year. They make up 86% of the total anthropod biomass. For such a small organism, it has a huge effect.<br />
<br><br />
===Nitrogen Fixation===<br />
<br />
Like any other garden, the ant's fungus garden needs nitrogen. Because of the low nitrogen ratio in leaves, there are nitrogen fixing bacteria in the colonies that help to introduce usable nitrogen into the system. The n-fixing bacteria fixes enough nitrogen for the fungus and the ants and also leaves a large amount in the refuse of the colony. This nitrogen can be worked back into the surrounding system replenishing the nutrient poor tropical environment with an essential limiting nutrient (Pinto-Tomas, 2009).<br />
<br><br />
<br />
===Decomposition===<br />
<br />
==Niche==<br />
<br />
[[Image:Colonies.jpg|Thumb|259px|right|An underground chamber where the fungus and the queen is housed. http://laanitarainforestranch.com/pages/leafcutterants.htm]]<br />
<br />
===<b>Habitat</b>===<br />
The ant's nests are subterranean and can be found in mostly tropical areas including Costa Rica, Panama, and Argentina.<br />
<br><br />
===<b>Nest Characteristics</b>=== <br />
Nests begin when a queen ant leaves one nest with a small amount of the fungus in her mouth and moves to a different area to start her own colony. Once a nest becomes established, the colonies can grow to have millions of ants in them. <br />
<br><br />
These subterranean nests vary in sizes. They can be small with a single fungus growing "room" or can be multiple feet below ground with many different rooms and complex tunnels. Ants are also known as organized and clean insects. They have certain refuse dumps where the worker ants take the garbage and seclude it from the rest of the colony to decrease contamination. <br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
<br />
===<b>Ants</b>=== <br />
The group of ants that are LeafCutters belong to the tribe <i>attini</i> and their genera is <i>Atta</i> and <i>acromyrmex</i> These ants have been around for the better part of 50 million years. Interestingly, these ants are consume the largest amount of primary producers in the tropical rainforest areas which is not surprising considering their biomass is four times the amount of other invertebrates. World wide, these insects take up a third of the total insect biomass.<br />
<br />
===Fungi=== <br />
Playing the role of both a decomposer and the primary food source for the Leafcutters, the fungi from the family <i>Lepiotaceae</i> is grown underground in the nests chambers by the worker ants. <br />
<br />
====Parasites====<br />
Battling against the ant's seemingly clean fungis' agriculture are parasites that would quickly take over the colony's fungus growth if not carefully weeded against. These can be competing molds or funguses that would come along and compete with the fungi for the delicious broken down vegetation. The ant's fungi cant survive against the invaders. Some of these parasites are refered to as <i>escovopsis</i>, and would feed on the fungus (Reynolds,2004).<br />
<br />
===Black Yeasts=== <br />
One of the most interesting and only recently discovered partners is the antibiotic producing bacteria <i>pseudonocardia</i><br />
<br><br />
There has recently been research conducted on a fourth bacterial partner. This is a black yeast that can be found on the cuticle of the ant and is used in a similar fashion in discouraging parasitic growth. This yeast has evolved with the ant-fungi symbiotic relationship and according to Little et al, the research into this partner shows how complicated and sophisticated this symbiotic partnership can be (Little, 2007).<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Coevolution between attine ants and actinomycete bacteria===<br />
It has been the thought that the close relationship between the ant and the bacteria has caused the two to evolve together. But the study looks at if that is truly so. It concluded that the ant has probably evolved with the bacteria, but the bacteria has evolved independently. The study states that more research needs to be done on the reciprocality of the evolving partners.<br />
<br />
===Enzyme activity activity in different ant colonies===<br />
Ants have evolved into different sister clades. This research shows how the enzyme activity between lower and higher evolved colonies has changed. The study shows that higher evolved colonies contain more protein and starch digesting enzymes while those of lower clades have enzymes that just focus on <i>partial</i> degradation of the plant material.<br />
<br />
===Ant Genome===<br />
The complete ant genome has recently been mapped out. With that, their are multiple studies going on about the evolution of the ants with its symbiotic partners and other attributes of the ant. Especial focus is put on the antimicrobial properties of the bacteria.<br />
<br />
===Evolution and Competition===<br />
There are studies conducted to how the ant and its partners have evolved together and how they originally came to work together. This has led to studies on how the partners work to discourage different types of fungus and bacteria in interfering. This interference could lead to an instability within the network. Resistant pathogenic molds are also a source of research to see why they have not evolved over the years to take over the fungus.<br />
<br />
==References==<br />
Ask Nature, A project of the Biomimicry Institute. <http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4><br />
<br />
Dash, D., Mueller, U., Rabeling, C.,Rodrigues, A., 2008. "COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION." Evolution 62. 11:2894-2912. Academic Search Premier. EBSCO. Web. 5 Apr. 2011.<br />
<br />
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G., & Boomsma, J. J. (2010). EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS. Evolution, 64(7), 2055-2069. <br />
<br />
Little, A., Currie, C. 2007. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant-microbe symbiosis." PubMed.gov. 3(5):501-504<br />
<br />
Reynolds, H. Currie, C. "Pathogenicity of Escovopsis weberi: The parasite of the attine ant-microbe symbiosis directly consumes the ant-cultivated fungus." 2004. Mycologia. 96(5): 955-959<br />
<br />
Pinto-Tomas, A., Anderson, M., Suen, G., Stevensen, D., Chu, F., Cleland, W., Weimer, P., Currie, C. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants.” Science. 326: 1120-1123.<br />
<br />
Ulrich, M., Schultz, T., Currie, C., Adams, R., Malloch, D. 2001. "The origin of the attin ant-fungus mutualism." 76:169-197 <br />
<br />
Edited by Katie Yi, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Deep_subsurface_microbes&diff=60443Deep subsurface microbes2011-04-19T16:34:43Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
[[Image:B_infernus-1.jpg|thumb|300px|right|Bacillus infernus. Extracted in 1995 at Taylorsville Triassic Basin in Virginia from a depth of 2,700 meters (1.6777 miles). Copyright: Henry Aldrich (Friedman, Roberta “Extreme Life.” Astrobiology Magazine 2 June 2002)[6]]]<br />
<br />
With such a surprising diversity of organisms in such an extreme environment, the deep subsurface has been the subject of many studies in the recent years. They carry out processes that alter the chemical makeup of minerals, degrade pollutants, and alter the mineral content of ground water. Many of them can also break down petroleum substances, which has been utilized in cleaning up oil spills and other accidents of that nature. Studies are being done to search for deep subsurface microbes that produce antibiotics and heat stable enzymes, and for those that assist in the degradation of toxic substances.<br />
<br />
Microbes have found a way to exist in every corner of the planet, and humans have found ways to utilize their incredible diversity for thousands of years. From fermenting cheese and wine, to the production of pharmaceuticals, microbes have been utilized for a myriad of reasons. It was not until the late 1920's however, that scientists thought to look deep within the body of our earth itself for a new source of potential biodiversity. Due to the massive amount of habitable area, and the surprising density with which these microbes live, it is now believed that subsurface microbes are responsible for over half of the biomass on the planet [2]. <br />
<br />
==<b>History</b>==<br />
Deep subsurface microbes first came into question when the American geologist Edson S. Bastin questioned why samples of water extracted from oil fields contained hydrogen sulfide and bicarbonates. Armed with the knowledge that certain species of bacteria can derive energy from reducing sulfur compounds in the absence of oxygen, he concluded that there must be populations of these bacteria living in the underground oil reserves, degrading the organic components of oil as a carbon source, and reducing sulfur compounds for energy. By 1926, Bastin and his colleague, Frank E. Greer has cultured sulfur reducing bacteria from samples taken from the groundwater of an oil deposit several hundred meters below the surface. Bastin and Greer's initial deduction was that the bacteria were the ancestors of those buried up to 300 million years ago when the organic materials constituting the oil deposit were buried [1]. <br />
<br />
Perhaps the most incredible thing about the microbes found in the deep subsurface, is that the majority of the populations can thrive indefinitely without any input from the earth's surface[1]. That being said, they are effectively 100% disconnected from the rest of life as we know it.<br />
<br />
==<b>Physical environment</b>==<br />
The deep subsurface ecosystem begins at about 50m below the surface of earths crust, and extends variably downward, up to 2.8km (1.7mi)[1]. The organisms live within the flooded pore space within the rocks and live by reducing inorganic compounds found in the rock. Intense pressures, high temperatures, limited livable space, and limited nutrient availability are all factors that microbes living in this environment must adapt to. It seems that the largest limitation to microbial life in this habitat is temperature, which increases with depth. The highest temperature generally accepted as the livable range for microorganisms in this habitat is 110 degrees C [1] In oceanic crusts, the temperature of the subsurface increases at a rate of about 15 degrees C per kilometer of depth, giving a maximum livable depth of about 7 kilometers. In the continental crusts the rock warms at a significantly faster rate, about 25 degrees C per kilometer, resulting in a maximum livable depth of approximately 4 kilometers [1]. Microbes in these environments can only exist where water fills the pore spaces of rocks. In the marine subsurface, this is rarely an issue, but in continental subsurface, there tends to be a bit more variability in groundwater dispersion. <br />
<br />
===<i>Hydrothermal Waters</i>===<br />
Hydrothermal waters are generally located at tectonically active regions on the ocean floor. Spreading centers and hot spots bring magma relatively close to the surface, which heats the surrounding sediments and rock layers to extremely high temperatures. Hydrothermal subsurface ecosystems are characterized by extreme heat and the presence of sediments comprising both organic and inorganic compounds. The water located in the pore spaces of these deep hydrothermal systems more closely resembles axial hydrothermal vent fluid than typical seawater [2]. Because of this, the microbes inhabiting these ecosystems are almost exclusively thermophilic archea, with a few genera of thermophilic bacteria as well [2].<br />
<br />
===<i>Sedimentary Basins/Oil Reservoirs</i>===<br />
In sedimentary basins and oil reservoirs, it is thought that the microbial communities are remnants from when their ancestors were buried underneath the sediment or organic matter. The nutrients contained within these ecosystems is typically organic matter produced by plants existing at the time when the layers were exposed at the surface. Energy is derived from the reduction of organic compounds in oil or sediments, as well as from inorganic compounds such as sulfur, iron, and manganese [3]. As depth increases, available pore space and nutrient availability decreases, so the metabolic rate of the communities slows down significantly. As the rock becomes increasingly compacted, the colonizable areas become increasingly patchy and isolated, resulting in a plethora of microcommunities surrounding the available sources of nutrients[1].<br />
<br />
===<i>Crystalline Metamorphic and Igneous Rocks</i>===<br />
Igneous rocks are perhaps the most hostile environment in which deep subsurface microbes exist. Due to the processes needed to create igneous rocks, i.e. extreme temperature and pressure, these habitats are effectively sterilized at their creation. Microbes can only colonize the rocks when they have been removed from the hostile surroundings, usually by tectonic processes. Once the rocks cool to below the temperature threshold for microbial life (as far as we know it) the microbes must be transported there by the infiltration of groundwater from above. The groundwater penetrates microscopic fissures and spaces between the crystals and the microbes begin to take hold. [[Image:geofig2.jpg|thumb|300px|left|Scanning electron microscope image of bacterial cells attached to muscovite flakes within quartzite. This sample was collected from a depth of 2km in South Africa. (Photo is courtesy of M. Davidson, Princeton University, and G. Southam, University of Western Ontario.) [4]]]<br />
<br />
Due to the lack of organic materials in these igneous rocks, the microbial communities are comprised primarily of autotrophs. Their primary source of energy is hydrogen gas, which is produced by reducing iron and sulfur in the presence of oxygen poor water, and gather carbon from carbon dioxide. These microbes, termed "acetogens", excrete organic compounds that can then be utilized by other microbes[1]. These environments are often referred to as "SLiMEs", which stands for subsurface lithoautotrophic microbial ecosystems [1]. These ecosystems can exist indefinitely without any input from the surface.<br />
<br />
==<b>Microbial communities</b>==<br />
Microbial communities are surprisingly diverse in the deep subsurface. Communities consist mainly of bacterial and archeal species that specialize in inorganic substrate reduction, with iron and sulfur reduction the two main energy sources. Thermophilic metal reducers proliferate throughout the range of deep subsurface microbes [3]. In communities colonizing sedimentary deposits or oil reservoirs, anaerobic heterotrophs utilize the abundant organic matter deposited when the formation was created. <br />
Microbes exist in a vast range of densities in these ecosystems, from a single cell permanently isolated from all other life, up to 100 million individuals per gram of rock [1]. Densities are a limited by substrate availability and pore space, which sometimes can be so small that only a single cell may fill the void at any given time. <br />
The life cycles of these microbes is impressively slow, with cell division occurring up to once per decade, or even once per century [1]. This is in stark contrast to surface microbes, which typically reproduce in a matter of minutes, or months at most. <br />
<br />
===Key Organisms=== <br />
====<i>Lithotrophs</i>====<br />
Lithotrophs obtain energy from the reduction of soluble inorganic compounds. These organisms are considered primary producers and constitute the largest portion of biomass in the deep subsurface biosphere. <br />
====<i>Thermophiles</i>====<br />
Thermophiles are microbes that have adapted to living in extremely hot environments. These environments occur deep in the rocks near the magma layer, or within the hydrothermal waters deep under the ocean floor. As far as we know, the hottest temperatures in which the most extreme thermophiles can sustain life is around 110 degrees C [1]. <br />
===Adaptations===<br />
====<i>Nutrient Limitations</i>====<br />
Most species inhabiting these depths have evolved the ability to reduce inorganic compounds contained within the rocks. These organisms typically use the inorganic compounds, such as iron and sulfur (ex. Desulfotomaculum, Thermodesulforhabdus,<br />
and Desulfacinum [3]), in conjunction with water to produce the hydrogen gas from which they get their energy. Some microbes (ex. Thermincola ferriacetica) have evolved the ability to survive with molecular hydrogen as the only energy substrate, iron compounds as terminal electron acceptors, and carbon dioxide as a carbon source [3]. There are some heterotrophic species that exist in these ecosystems as well. They feed on the organic waste products produced by the lithoautotrophs, as well as dead cells. Some can degrade petroleum substances heterotrophically and have been found to be quite useful because of it. <br />
<br />
Microorganisms living under these conditions have developed an extraordinary ability to limit their metabolism to a level that is best measured in geologic time. Most have the ability to remain viable at minuscule to negligible metabolic cost [1]. It is because of this that the lines between life and death begin to blur. Some microbes remain metabolically dormant for such extended periods of time, that is impossible to tell whether a cell is dead or just dormant. Many individuals tend to lose the ability to reproduce after significant periods of dormancy as well [1]. It is because of these two facts that the classification of "living" or "dead" becomes a relative term when referring to deep subsurface microbes. <br />
====<i>Dessication Resistance</i>====<br />
As the microbes in this ecosystem use up their water reserves and have no way of replenishing, they will shrink their body size to under 1/1000 of the original volume. These dwarfed microbes are effectively termed "ultramicro-bacteria". Periods of dormancy may persist seemingly indefinitely in these stages [1].<br />
====<i>Radiation Resistance</i>====<br />
Some organisms from deep subsurface ecosystem have been shown to be extremely radiation resistant. There is speculation that higher levels of radiation in some subsurface environments provides a renewable source of energy for the microbial communities [4]. It is possible that the radiation resistance results from the improved DNA repair mechanisms that also characterize the organisms in these communities. <br />
====<i>DNA Repair Mechanisms</i>====<br />
Due to the long lifetimes of these organisms, coupled with periods of extreme stress and possibly radiation, DNA damage is rampant. There is considerable strain on DNA repair mechanisms to keep up with the damages provided by the environment. Over millenia, this pressure has selected for those individuals with exceptionally effective and efficient DNA repair mechanisms [5].<br />
<br />
==<b>Microbial processes</b>==<br />
===Anaerobic Respiration===<br />
Due to lack of oxygen the deep subsurface, the only way for life to carry on is to engage in anaerobic respiration. Anaerobic respiration is characterized by the use of alternative compounds as terminal electron acceptors, <br />
====<i>Lithotrophy</i>====<br />
Microbes use inorganic substances, such as iron, sulfur, or magnesium from which to derive the chemical energy necessary to conduct biosynthesis. <br />
====<i>Methanogenesis</i>====<br />
Methanogenesis is the production of methane by microbes via anaerobic respiration. [[Methanogens]] as they are effectively named, have only been identified within the kingdom [[Archaea]]. Deep subsurface archaea are known to metabolize available organic carbon sources and are responsible for the production of large pockets of methane trapped within the earths crust. [[Image:hydrocarbon degredation.jpg|thumb|300px|left|Metabolic pathway of anaerobic hydrocarbon biodegradation in deep subsurface oil reservoirs. Copyright: Aitken, C.M., Jones, D.M., Larter, S.R., 2004. Anaerobic hydrocarbon biodegradation in deep subsurface oil reservoirs, Nature 431, p. 291-294]]<br />
====<i>Hydrocarbon Degredation</i>====<br />
<br />
Metabolic activity in areas rich in hydrocarbon substances support large numbers of anaerobic heterotrophic microorganisms. These microbes metabolize the hydrocarbons as both an energy source as well as for a carbon source. These organisms have special relevance in today's day and age, as petroleum products become increasingly more and more prevalent. These organisms facilitate the breakdown of these substances, and have been used to clean up oil spills and to help degrade other petroleum distillates [4].<br />
<br />
==Current Research==<br />
===The Dark Energy Biosphere Institute (DEBI)===<br />
DEBI is focused on bringing together scientists from diverse fields such as microbiology, biogeochemistry, and observatory science to try and create and expand ways to study and conceptualize life as we know it. DEBI is designated as a research coordination network, which, as an organization will provide opportunities and plan expeditions to study deep subsurface life [4].<br />
<br />
[[Image:DEBI.jpg|thumb|300px|right|a.)This diagram shows the mine shaft that the DEBI project is set to be constructed within.<i>(Image courtesy of Dr. Z. Hladysz of SDSMT.)</i> b.) The yellow lines in this image show potential coring opportunities for future microbiology experiments. The purple shaded area denotes the area of the ground that has contributed to groundwater seepage into the mine. [4]]]<br />
===Deep Underground Science and Engineering Laboratory (DUSEL)===<br />
This facility takes advantage of the largest and deepest underground mine in the United States. Located in the Black Hills of South Dakota, this old gold mine will provide microbiologists with a drilling platform from which to study deep subsurface microbiology. Though the facility is mainly being developed for the study of quantum physics, it will serve as a station to study the ecological habits and interactions of deep subsurface microbes [4].<br />
<br />
===International Continental Drilling Program and the Integrated Ocean Drilling Program (IODP)===<br />
Almost all knowledge gained about deep subsurface microbiology has been gained through the cooperation of biologists and unrelated drilling operations. By "piggybacking" on exploratory drilling operations, biologists have been able to test otherwise inaccessible areas. The IODP is a cooperative program that aims to continue to give biologists and other scientists alike the ability to incorporate scientific study of deep subsurface microbes with current unrelated drilling plans.<br />
<br />
==References==<br />
<br />
[1]http://wvlc.uwaterloo.ca/biology447/modules/module6/Scientific_American_Article_Microbes.htm Fredrickson, J., Onstott, T. "Microbes Deep Inside the Earth." "Scientific American". 1996. <br />
<br />
[2]Amend, J. P., & Teske, A. (2005). Expanding frontiers in deep subsurface microbiology. Palaeogeography, Palaeoclimatology, Palaeoecology, 219(1-2), 131-155. Elsevier. Retrieved from http://linkinghub.elsevier.com/retrieve/pii/S0031018204005954<br />
<br />
[3] http://www.episodes.co.in/www/backissues/303/202.pdf Dong, H., Yu, B., "Geomicrobiological processes in extreme<br />
environments: A review" ''Episodes: Journal of International Geosciences''. 2007. Volume 30. p. 202-216.<br />
<br />
[4] http://www.microbemagazine.org/index.php/11-2009-home/1045-new-horizons-for-deep-subsurface-microbiology T. C. Onstott, F. S. Colwell, T. L. Kieft, L. Murdoch, and T. J. Phelps, "New Horizons for Deep Subsurface Microbiology". ''Microbe Magazine''. 2009.<br />
<br />
[5] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC182496/pdf/aem00040-0041.pdf Arrage, A., Phelps, T., Benoit, R., White, D., "Survival of Subsurface Microorganisms Exposed to UV Radiation and Hydrogen Peroxide". ''Applied and Environmental Microbiology''. 1993. Volume 59 . p. 3545-3550.<br />
<br />
[6] http://web.mst.edu/~microbio/BIO221_2010/B_infernus.html Image: Copyright: Henry Aldrich (Friedman, Roberta “Extreme Life.” Astrobiology Magazine 2 June 2002)<br />
<br />
Edited by Craig Mack, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Alliaria_Petiolata_and_Mycorrhiza&diff=60429Alliaria Petiolata and Mycorrhiza2011-04-19T16:07:52Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
[[Image:Gm.jpg|thumb|300px|right|Alliaria petiolata]]<br />
<br />
<br />
There is strong evidence that plant–soil community feedback play a major role in plant species coexistence [1]. Soil microbial communities have been shown to rapidly change in response to plant identity [2;3;4]. These microbial community compositions can have strong direct effects on the outcome of plant–plant interactions [5,6]. <br />
The invasive plant, <i>Alliaria petiolata</i> (Bieb.) Cavara & Grande, has been shown to effect microbial communities through exuding allelopathic compound and thus effect plant to plant interactions.<br />
<br />
==<i>Alliaria petiolata</i>==<br />
<br />
[[Image:garlic_mustard_plantillinoiexgthumb.jpeg|300px|left|Alliaria petiolata. University of Illinois Extension]]<br />
<br />
<br />
<br />
For at least two decades, garlic mustard, <i>Alliaria petiolata</i>, (Bieb.) Cavara & Grande) a European biennial herb, has been a serious invader of natural areas and woodland communities of North America [20; 21]. Garlic mustard seeds germinate in early spring, and remain as an evergreen basal rosette during the first year; densities of up to up to 5,080 seedlings per square meter have been recorded [22; 23) During the second year, rosettes bolt between mid-April and mid-May and may occur in densities as high as 303 plants per square meter [22]. The flowers begin anthesis in early spring, set seed in June, and senesce by mid-late July [22; 23). Seeds germinate after a period of at least 14 weeks of cold stratification at temperatures from 1 degree Celsius (°C) to 10°C [24]. In the first spring following production, 70% of seeds germinate but may remain viable for up to 10 years [24; 25].<br />
<br />
===An Invasive Plant===<br />
<br />
Invasive species can and do effect soil microbial communities. These interactions in areas of low diversity can be classified as competitive dominance, inhibition and positive feedback [1]. Monotypical stands formed by invasive species sometimes have symbiotic relationships novel to the invaded areas. These novel mutualisms could increase the competitiveness and niche-space of invasive species [7], a form of the ‘empty niche’ hypothesis [8]. The ‘degraded mutualist hypothesis’ proposes that some invasive plants will inhibit native symbiotic communities, indirectly reducing native plant fitness [9; 10]. <i>Alliaria</I> petiolata is a nonmycorrhizal species and may follow the 'degraded mutualist hypothesis.'<br />
<br />
===Allelopathy===<br />
<br />
[[Image:allelopathygm.jpg|300px|center|Alliaria petiolata. University of Illinois Extension]]<br />
Allelopathy is the suppression of germination or growth of neighboring plants by the release of toxic secondary chemical compounds. These secondary metabolites are leached, exuded or volatilized into the environment from the plant [11] and may act as act as novel weapons to suppress mycorrhizal fungi [12; 13; 14; 15], inhibit germination [16;17; 18; 19] and decrease survival of native mycorrhizal plants [13].<br />
<br />
===Microbial Species===<br />
<br />
At least 80% of the world's plants form mycorrhizal assocations [32]. Arbuscular mycorrhizal fungi (AMF), phylum Glomermycota and ectomycorrhizal fungi (EMF), phylums Basidiomycota, Ascomycota, Zygomycota are soil mutualists with resident plant roots acting as an extension of the root system. Mycorrhizal associations lead to protection of the plant from soil pathogens [33] and an enhanced tolerance to drought [34].<br />
<br />
===<i>Alliaria petiolata</i> Allelopathy===<br />
<br />
<i>Alliaria petiolata</i> has been shown to inhibit plant growth and mycorrizal fungi. This effect is most likely due to secondary metabolities exudated by this plant. Glucosinolates, alliarinosides, flavoinoid glycosides and cyanide all have been shown to be part of the suite of chemicals produced by this plant, with glucosinolates being more present in belowground tissues [17; 26; 27]. Interestingly, compounds from glucosinolates predominately degrade to the secondary metabolites, allyl isothiocyanate and benzl isothiocyanate, both shown to be inhibitory to fungi [28].<br />
<br />
==Effects on Mycorrhiza==<br />
<br />
There is growing interest in invasion ecology as to the effect of invasive plants species on mycorrhizae in soil and how these invasive plants can affect native plants and diversity of mycorrhiza [29]. Native tree species <i>Acer saccharum, Acer rubra</i> and <i>Fraxinus americana</i> all showed less colonization of roots by AMF in soil and slower growth in soil with a history of Alliaria petiolata suggesting the methods of suppression is microbially-mediated [10]. Extracts inhibited the growth of EMF and led to changes in EMF communities in invaded soils, with strongest inhibition within 10 cm of patches [14]. Other studies have shown while no effect was seen on total root length colonization on herbaceous plants with <i>Alliaria petiolata</i> presence, there was some effect of <i>Alliaria</i> presence on mycorrizal community structure with the plant <i>Maianthemum racemosum</i> (29). Overall mycorrhizal inoculum potential of soil (MIP) was tested in another study and found a significant negative correlation between the density of <i>Alliaria petiolata</i> in dm2 quadrats and MIP (35). Understanding if and how the mycorrhizal association influences plant invasion may be a key aspect of the ecology and management of invasive plant species, as well as the conservation biology of native habitats [30]. Further study of volatiles released by this plant and the effect on mycorrhizal associations is needed [17]. <br />
<br><br />
<br />
==Current Research==<br />
<br />
Recently, research to understand long term effects of <i>Alliaria petiolata</i> on microbial communities, including AMF communities, has shown over time an increase in operational taxonomic units as <i>Alliaria petiolata</i> evolves to produce less allelopathic exudates [31]. This suggest impacts of particular invasive species may change over time because of changes both in the invader and the invaded community which will implications for how invasive species are studied and managed.<br />
<br />
Another area of research has shown exudates inhibit the germination in the North American species <i>Geum laciniatum</i> [19] and inhibited germination of <i>Impatiens pallida</i> was seen when seeds were exposed to levels of extract expected in the field [18]. This suggests the strongest allelopathic effects occur during seed and spore germination and presymbiosis growth [18]. <br />
The affect of garlic mustard exudates on native plant seed germination is needed to understand how recruitment of native species composition is being altered by this presymbiosis exposure and is currently being researched.<br />
<br />
Finally, community feedbacks vary within as well as between species, and a variation could help the spread and impact of which should help prioritize management efforts. Research is needed for these species specific and broad associations are needed [31,36].<br />
<br />
<br />
<br><br />
<br />
==References==<br />
<br />
1. Bever J.D. 2010. “Rooting theories of plant community ecology in microbial interactions” Trends in Ecology and Evoluation 25 : 46-478<br />
<br />
2. Mills, K.E. and Bever, J.D. (1998) Maintenance of diversity within plant communities: soil pathogens as agents of negative feedback. Ecology 79, 1595–1601<br />
<br />
3. Bever J.D 2002. “Negative feedback within a mutualism: host-specific growth of mycorrrhizal fungi reduces plant benefit”. Proceeding of the Royal Society of London Series B-Biolgical Sciences.1509:2595-2601 <br />
<br />
4. Mitchell, R.J. et al. 2010. “The ecological engineering impact of a single tree species on the soil microbial community”. J. Ecol. 98, 50–61<br />
<br />
5. vanderHeijden,M.G.A. 2006. Symbiotic bacteria as a determinant of plant community structure and plant productivity in dune grassland. Microbiol. Ecol. 56. 178–187 <br />
<br />
6. Vogelsang,K.M.et al. 2006 “Mycorrhizal fungal identity and richness determine the diversity and productivity of a tallgrass prairie system”. New Phytol. 172, 554–562<br />
<br />
7. Richardson, D.M. et al. 2000. “Plant invasions - the role of mutualisms”. Biol. Rev. 75:65-93<br />
<br />
8. Mitchell, C.E. et al. 2006. “Biotic interactions and plant invasions”. Ecol. Lett. 9, 726–740<br />
<br />
9. Vogelsang, K.M. and Bever, J.D. 2009. “Mycorrhizal densities decline in association with nonnative plants and contribute to plant invasion”. Ecology 90, 399–407<br />
<br />
10. Stinson, K. et al. 2006. “Invasive plant suppresses the growth of native tree seedlings by disrupting belowground mutualisms”. PLOS Biol. 4(5) 727-731<br />
<br />
11. Rice EL (1984) Allelopathy, 3rd edn. Academic Press, London<br />
<br />
12. Callaway, R. M., and W. M. Ridenour. 2004. Novel weapons: invasive success and the evolution of increased competitive ability. Frontiers in Ecology and the Environment 2 :436-443<br />
<br />
13. Callaway, R.M., Cipollini, D., Barto, K., Thelen, G.C., Hallett, S.G., Prati, D., Stinson, K. and Klironomos, J. 2008. “Novel weapons: invasive plant suppresses fungal mutualists in America but not in its native Europe”. Ecology, 89, 1043–1055<br />
<br />
14. Wolfe, BE, Rodgers, VL, Stinson, KA & Pringle, A. 2008. “The invasive plant Alliaria petiolata (garlic mustard) inhibits ectomycorrhizal fungi in its introduced range”. Journal of Ecology, 96, 777-83<br />
<br />
15. Barto EK, Cipollini D. 2009. “Half lives and field soil con- centrations of Alliaria petiolata secondary metabolites”. Chemosphere 76(1):71–75<br />
<br />
16. Roberts KJ & Anderson RC. 2001. “Effect of garlic mustard [Alliaria petiolata (Beib. Cavara & Grande)] extracts on plants and arbuscular mycorrhizal (AM) fungi”. American Midland Naturalist. 146:146-52<br />
<br />
17. Vaughn, S & Berhow, MA. 1999. “Allelochemicals isolated from tissues of the invasive weed garlic mustard (Alliaria petiolata)”. Journal of Chemical Ecology, 25, 2495-04<br />
<br />
18. Barto, EK, Friese, C & Cipollini, D. 2010. “Arbuscular mycorrhizal fungi protect a native plant from allelopathic effects of an invader. Journal of Chemical Ecology, DOI 10.1007/s10886-010-9768-4.<br />
<br />
19. Prati, D & Bossdorf, P. 2004. “Allelopathic inhibition of germination by Alliaria petiolata (Brassicaceae)”. American Journal of Botany. 91:285-88<br />
<br />
20. Nuzzo VA. 1991. “Experimental Control of Garlic mustard [Alliaria petiolata (Bieb.) Cavara and Grande] in Northern Illinois Using Fire, Herbicide and Cutting”. Natural Areas Journal, 11, 158-167<br />
<br />
21. Nuzzo, V. A. 1994a. “Element stewardship abstract for Alliaria petiolata (Alliaria officinalis) garlic mustard”. The Nature Conservancy. Arlington V A. 20 p.<br />
<br />
22. Anderson, R. C., T. C. Kelley, and S. S. Dhillion. 1996. “Aspects of the ecology of an invasive plant, garlic mustard (Alliaria petiolata), in central Illinois”. Restoration Ecology 4:181-191.<br />
<br />
23. Cavers, P. B., M. I. Heagy, and R. F. Kokron. 1979. “The biology of Canadian weeds. 35. Alliaria petiolata (M. Bieb.) Cavara and Grande”. Canadian Journal of Plant Science 59: 217-229.<br />
<br />
24. Baskin, J. M. and C. C. Baskin. 1992. Seed germination biology of the weedy biennial Alliaria petiolata. Natural Areas Journal 12:191-197.<br />
<br />
25. Rodgers, VL, Stinson, KA & Finzi, AC (2008) Ready or not, garlic mustard is moving in: Alliaria petiolata as a member of eastern North American forests. BioScience, 58, 426-36.<br />
<br />
26. Cipollini D, B Gruner 2007. “Cyanide in the chemical arsenal of garlic mustard, Alliaria petiolata”. J Chem Ecol 33:85–94.<br />
<br />
27. Haribal, M. and J. A. A. Renwick. 1998. Isovitexin 6"-O-B-D-glucopyranoside: a feeding deterrent to Pieris napi oleracea from Alliaria petiolata. Phytochemistry 47: 1237-1240.<br />
<br />
28. Gamliel, A. and J.J. Stapleton. 1993a. Characterization of antifungal volatile compounds evolved from solarized soil amended with cabbage residues. Phytopathology 83:899-905.<br />
<br />
29. Burke, DJ 2008. “Effects of Alliaria petiolata (garlic mustard; Brassicaceae) on mycorrhizal colonization and community structure in three herbaceous plants in a mixed deciduous forest”. American Journal of Botany. 95:1416-1425.<br />
<br />
30. Pringle A, Bever JD, Gardes M, Parrent JL, Rillig MC, Klironomos JN. 2009. Mycorrhizal Symbioses and Plant Invasions. Annual Reveiow of Ecology Evolution and Systematic Volume. 40: 699-715<br />
<br />
31. Lankau R. A. 2011. “Intraspecific variation in allelochemistry determines an invasive species’ impact on soil microbial communities”. Oecologia. 165:453-463.<br />
<br />
32. PA McGee. 1986. "Mycorrhizal associations of plant species in a semi-arid community”. Australian Journal of Botany, 34: 585-593<br />
<br />
33. Borowicz, VA. 2001. “Do arbuscular mycorrhizal fungi alter plant-pathogen relations?” Ecology. 82, 3057-68.<br />
<br />
34. Auge, RM. 2004. “Arbuscular mycorrhizae and soil/plant water relations”. Canadian Journal of Soil Science, 84, 373-81.<br />
<br />
35. Roberts KJ. 2001. "Effect of garlic mustard [Alliaria petiolata (Beib. Cavara & Grande)] extracts on plants and arbuscular mycorrhizal (AM) fungi American Midland Naturalist 146 : 146 <br />
<br />
36. Stinson, K.A., Kaufman, S.R, Durbin*, L.M., and Lowenstein, F. 2007. "Responses of a New England Forest community to increasing levels of invasion by garlic mustard (Alliaria petiolata)." Northeastern Naturalist 14:73-88.<br />
<br />
Edited by <Scott Rose>, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Acidic_hot_springs&diff=60428Acidic hot springs2011-04-19T15:50:56Z<p>Akent: </p>
<hr />
<div>[[Image:Islande_source_Deildartunguhver.jpg|thumb|300px|right|[http://en.wikipedia.org/wiki/Deildartunguhver A hot spring in iceland called Deildartunguhver that is the highest flow hot spring in Europe. The heat is used to heat the towns Borgarnes and Akranes]]] <br />
<br />
==Introduction:==<br />
Hot springs can be found all around the world and while there are many specific definitions, they can be generally be described as any spring that is heated geothermally<sup>1</sup>. Not only are these environment considered extreme in terms of temperature, but they can also be very extreme in regard to pH. This may seem like a habitat that is unfit for life, but there are many microbes that are able to utilize acidic hot springs in order to survive. <br />
<br />
==Physical environment==<br />
As mentioned before, acidic hot springs are a very extreme environment, home to thermophilic and acidophilic microbes. Thermophile means attraction to heat, so thermophilic microbes prosper in very high temperatures. Acidophile means attraction to acids, therefore acidophilic microbes need an acidic environment. <br />
<br />
===<b>Acidity</b>===<br />
On a pH scale of 1 to 14, 1 being the most acidic and 14 being the most basic, hot springs can reach pH as low as 1.5, like in Pozzuoli, Italy<sup>2</sup>. In most springs, the acidity is the result of sulfide being oxidized by microbes<sup>3</sup>.[[Image:Sulphur_Springs.jpg|thumb|300px|right|Acidic sulphur springs near Redondo Peak in New Mexico. The water comes from snow melting and in the dry season the pools become boiling mud or dry fumaroles<sup>3</sup>]] <br />
<br />
===<b>Temperature</b>===<br />
Hot springs vary in temperature, some are at a temperature comfortable enough to be used as a sort of hot tub for both humans and animals while other reach temperatures of up to 100 °C (212 °F)<sup>4</sup>. The fact that these springs are heated can be extremely beneficial because it serves both as a tourist attraction and as a natural energy source. <br />
<br />
====<b>Tourism</b>====<br />
Some of the most visited acidic hot springs are be found in [[Yellowstone Hot Springs]]. While these springs are visited frequently, they are visited for aesthetic reasons rather than recreational purposes. However, other hot springs are highly valued for their therapeutic usefulness. <br />
For example, the Tabacon Hot Springs in Costa Rica are a very popular tourist spot. The hot springs are used as a natural hot tub that can have a lot of benefits. They help relax muscles and increase the body’s absorption of minerals<sup>5</sup>. <br />
<br />
====<b>Energy</b>====<br />
The energy released from hot springs can be used to heat swimming pools, greenhouses and even homes. The springs, paired with a geothermal power plant, can also provide electricity. This method of creating electricity is limited to only certain springs due to issues with size, location and water temperature<sup>6</sup>. <br />
<br />
<br />
<br />
<br />
==Microbial Communities==<br />
Microbes found in acidic hot springs are typically thermoacidophilic archaea and bacteria. However, viruses that infect archaea have also been discovered in some acidic hot spring<sup>2</sup>. <br />
<br />
===<b>Viruses</b>===<br />
There are many new virus families that have been discovered in hot springs, some of these are <i>Fuselloviridae, Lipothrixviridae, Rudiviridae, Guttaviridae, and Globuloviridae</i>. These viruses all have unique morphologies and genomic qualities that have yet to be observed outside of the hot springs, and therefore were assigned to new families. <br />
One of these viruses, called <i>Acidianus</i> bottle-shaped virus, uses it’s shape to funnel it’s double stranded DNA into the archaeal genus <i>Acidianus</i>. While it is not clear what the exact virus-host relationship is in this example further studies are being conducted. This study strongly supports the idea that there are many morphologically different viruses that we have yet to discover, and that many may be surviving in extreme environments<sup>2</sup>. <br />
[[Image:Acidianus_bottle-shaped_virus.gif|thumb|300px|right|Electron micrographs of the <i>Acidianus</i> bottle-shaped virus. A- Particles are pointed toward the membrane of the host. B- Particles are attached to each other with thin filaments<sup>2</sup>.]] <br />
<br />
===<b>Archaea</b>===<br />
The microbes most commonly found in acidic hot springs come from the domain archaea. They are some of the oldest known organisms in existence and can survive in some of the most extreme environments on the planet<sup>7</sup>. The archaea that oxidize sulfur belong to the order <i>Sulfolobales</i><sup>8</sup>. Some specific examples of those archaea that have been found in acidic hot springs are [[Sulfolobus]] and [[Sulfurisphaera]]. <br />
<br />
===<b>Bacteria</b>===<br />
Sulfur can be oxidized by some bacteria that can be defined as either aerobic lithotrophs or anaerobic phototrophs<sup>8</sup>. One particular genus of bacteria that is known to oxidize sulfur to sulfuric acid is [[Thiobacillus]]. <br />
<br />
==Microbial processes==<br />
Sulfur is an element that is frequently found in hot springs; it is dissolved into the springs through the surrounding rocks and soil<sup>3</sup>. The most important microbial process that occurs in hot springs is the oxidation of sulfur, producing sulfuric acid. <br />
<br />
===<b>Oxidation</b>===<br />
When an element is oxidized, this means that it is losing electrons<sup>9</sup>. These electrons can then be used by the microbe to generate ATP, which is the energy that allows cells to grow and reproduce. <br />
<br />
==Current Research==<br />
One recent study was investigating potential antimicrobial effects of acidic hot spring water on the species <i>Staphylococcus aureus</i>. These strains of <i>S. Aureus</i> were collected from patients with atopic dermatitis, more commonly known by the name eczema. The results showed significant decreases in the amount of <i>S. Aureus</i> cells that were able to survive in the acidic hot spring water. The conclusions reached was that some of the present ions and the low pH conditions allowed the water to act as a bactericidal agent<sup>10</sup>. <br />
In New Zealand, stromatolites were found developing in several acidic hot springs. Small spicular, columnar and blade-shaped stromatolites are something frequently found in hot springs and geysers, however, they are most commonly found in neutral and alkaline springs. Recently stromatolites have been discovered forming in the acid-sulfate springs of Lake Rotokawa. When the mineral structure and biota found in these stromatolites was compared to those of neutral and alkaline waters there were many differences. This analysis can help us better describe ancient thermal deposits based on their mineralogy<sup>11</sup>. <br />
More research done in a different area of New Zealand found microbes other than <i>Sulfolobus</i> in the acidic hot springs of Waiotapu for the first time. Some rod shaped, spherical and filamentous cells were observed in addition to <i>Sulfolobus</i> spheres. However, the attempts to culture the microbes were unsuccessful. Several analyses of the microbes determined a few known species and several unknown bacteria in the pools<sup>12</sup>. <br />
<br />
==References==<br />
<br />
1. [http://encarta.msn.com/encnet/features/dictionary/DictionaryResults.aspx?refid=1861692101 2009. “Hot Spring”. Encarta World English Dictionary. Microsoft Corportation.]<br />
<br />
2. [http://jvi.asm.org/cgi/content/full/79/15/9904?view=long&pmid=16014951 Monika Häring, Reinhard Rachel, Xu Peng, Roger A. Garrett, and David Prangishvili. 2005. “Viral Diversity in Hot Springs of Pozzuoli, Italy, and Characterization of a Unique Archaeal Virus, Acidianus Bottle-Shaped Virus, from a New Family, the Ampullaviridae”. Journal of Virology. 79:9904-9911.] <br />
<br />
3. [http://www.lpi.usra.edu/science/treiman/greatdesert/workshop/sulphursprings/index.html Treiman, Allan. “Sulphur Springs”. Lunar and Planetary Institute. 2003.]<br />
<br />
4. [http://www.husafell.is/ensku_sidurnar/e_nagrenni/e_deildartunguhver/e_deildartunguhver.htm “Deildartunguhver”. Ferðaþjónustan Húsafelli.]<br />
<br />
5. [http://www.tabacon.com/costa-rica-resort-thermal-springs-1.html “The Tabacon Hot Springs”. Tabacon: Grand Spa, Thermal Resort.]<br />
<br />
6. [http://www.energyquest.ca.gov/story/chapter11.html “Geothermal Energy”. California Energy Commision. 2011.]<br />
<br />
7. [http://www.ucmp.berkeley.edu/archaea/archaea.html Speer, Brian. “Introduction to the Archaea: Life’s extremists...” Univeristy of California Museum of Paleontology. 2001.]<br />
<br />
8. [http://aem.asm.org/cgi/content/full/67/7/2873 Cornelius G. Friedrich, Dagmar Rother, Frank Bardischewsky, Armin Quentmeier, and Jörg Fischer. 2001. “Oxidation of Reduced Inorganic Sulfur Compounds by Bacteria: Emergence of a Common Mechanism?”. American Society for Microbiology. 67:2873-2882.] <br />
<br />
9. [http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch9/redox.php “Oxidation and Reduction”. The Bodner Group: Purdue Department of Chemistry.]<br />
<br />
10. [http://www.ncbi.nlm.nih.gov/pubmed/11064246 Akiyama H., Yamasaki O., Tada J., Kubota K., Arata J. 2000. “Microbial effects of acidic hot-spring water of Satphylococcus aureus strains isolated from atopic dermatitis patients”. Journal of Dermatological Science 24:112-118.] <br />
<br />
11. [http://www.jstor.org/pss/3515515 Jones B., Renaut R.W., Rosen M.R. 2000 “Stromatolites Forming in Acidic Hot-Spring Waters, North Island, New Zealand”. Palaios. 15:450.] <br />
<br />
12. [http://docs.google.com/viewer?a=v&q=cache:-Wt3FNAmxZEJ:www.bio.sdsu.edu/faculty/kelley/19.pdf+acidic+hot+springs&hl=en&gl=us&pid=bl&srcid=ADGEESh3IYG7XE-o9D0rJwAURAGl26cgtzcM9F8PPJ1Fic5_pFGLFIO1eBIf-bGKcevFSrzdJXL7gqg4gA3OOFz-8OZsTcvoBFBmxC6DJ_zQSuA45H3YvCZYJGUb5R5m9LgLpJY3gvRu&sig=AHIEtbR1PzB8jn_YmTC-4_IcWDD8ntCe7Q Ellis D.G., Weiss Bizzoco R.L., Maezato Y., Baggett J.N., Kelley S.T. 2005. “Microscopic examination of acidic hot springs of Waiotapu, North Island, New Zealand”. New Zealand Journal of Marine and Freshwater Research. 39:1001-1011.]<br />
<br />
Edited by Maureen Barr, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Microbes_and_invasive_plants&diff=60427Microbes and invasive plants2011-04-19T15:44:56Z<p>Akent: /* Reference */</p>
<hr />
<div> [[Image:target_invasive_plants.jpg|thumb|400px|right| Morphology of several common invasive plants]]<br />
==<b>Introduction</b>==<br />
<br />
'''Interaction between microbes and invasive plants''' indicates two aspect: 1)invasive plants influence microbial community composition and its ecological functions as '''consequences''' of plant invasion; 2)changed or original microbial community influences the process of invasive plants as '''drivers''' of invasion process. Three key interactions are involved: plant-pathogen, plant-symbiont and plant-decomposer interaction. <br />
<br><br />
<br />
<br />
==<b>Key Microorganisms</b>==<br />
'''Key Microorganisms''' involved in the interaction of invasive plants and microbes include three main categories: '''parasites or pathogens, mutualists or symbionts, and saprotrophs or decomposers'''.<br />
<br />
<br />
====<b>Parasites or Pathogens and Invasive Plants</b>====<br />
<br />
<br />
Evidence of plant species-specific pathogens have been found in rhizosphere of plants<sup>[[#References|[1]]]</sup>, which lead to the application of enemy release hypothesis in pathogens in driving plant invasion. Theoretically after invasive plants occupy a new habitat, these newly established plant species tend to have less specialistic pathogens, thus they can outcompete other native plant species. However, the probability still exists that shifts of pathogens from native plants to their phylogenetic close non-native plants may confound the effects of enemy release<sup>[[#References|[2]]]</sup>. <br />
[[Image:Chromolaena_odorata.jpg|thumb|400px|right| Distribution of invaded area of Chromolaena <i>odorata</i>]]<br />
<br />
<br><br />
There are some invasive plants that are able to accumulate generalist pathogens in their rhizosphere, which will in turn inhibit native vegetation grown in the habitat<sup>[[#References|[3]]]</sup>. Empirical evidence has been found in a study about invasion success of Chromolaena <i>odorata</i> which suppress native plants by accumulating high concentration of pathogens in its rhizosphere, since native plants are more sensitive to these pathogens than newly established plants.<sup>[[#References|[4]]]</sup>.<br />
<br />
<br />
<br />
====<b>Mutualists or Symbionts Invasive Plants</b>====<br />
<br />
[[Image:AMF.jpg|thumb|300px|left| Association with AMF influences plant growth]]<br />
[[Image:Nitrogen fixers.jpg|thumb|200px|center| Root nodules]] <br><br />
Two main mutualists in the soil that have a close relationship with plant invasion success:[http://microbewiki.kenyon.edu/index.php/Mycorrhizae myccorhizas] and [http://microbewiki.kenyon.edu/index.php/Nitrogen_cycle_including_GHG nitrogen fixers]. There are two ways that these microbes can facilitate plant invasion. One way is that invasive plants benefit from association with native mutualists, such as AMF(arbuscular myccorhizal fungi) and nitrogen fixers, to outcompete native plant species and change the soil properties of newly established habitat, which in turn influences native plant community. For those mutualist-dependent exotic plants, whether they will become a successful invader largely depends on whether they can find their mutualists in the invasive range<sup>[[#References|[5]]]</sup>. <br />
[[Image:alliaria_petiolata_garlic_mustard_group_large.jpg|thumb|300px|right| Alliaria <i>petiolata</i>]]<br />
<br><br />
<br />
The other way is that invasive plants disrupt the mutualism systems of native plants by exuding toxic chemicals to their mutualists, thus suppress native species. A typical example of this case is Alliaria <i>petiolata</i>, a invasive plant that inhibits AMF and ectomycorrhizal fungal colonization on which native plants depend on<sup>[[#References|[6]]]</sup>.<br />
<br />
<br />
<br />
====<b>Saprotrophs or Decomposers and Invasive Plants</b>====<br />
<br />
<br />
<br><br />
If invasive plants occupy a new range where native plants tend to have different life strategy from invasive plants, in most cases, invasive plants have acquisitive traits such as fast-growth, short-lived poorly defended tissues, and high nutrient concentrations while native plants have conservative traits such as slow growth, long-lived well-defended tissues, and low nutrient concentration, invasive plants tend to have greater influences on native decomposers by adding exotic nutrient resources to affect native saprophytic microbial community, native decomposition, native soil process, therefore influence native plant community<sup>[[#References|[1]]]</sup>.<br />
<br />
<br />
<br><br />
==<b>Interaction Mechanisms</b>==<br />
<br />
<br><br />
There are three main categories about how interaction of microbes and invasive plants drive their invasion success. First, invasive plants suffer less negative soil feedback than native species, or even have neutral or positive feedback<sup>[[#References|[7]]]</sup>, also known as '''Enemy Release hypothesis'''. Second, invasive plants are able to disturb newly established habitat by enhancing pathogen levels or destructing symbionts systems, thus suppress native plants while invaders suffer less from this, which involves '''Accumulation of Local Pathogens hypothesis'''<sup>[[#References|[3]]]</sup>. Third, allelochemicals can play an important role in helping exotic plants establishing invaded habitats. These chemicals hard to be detoxified by local microbial community can easily reach toxic level therefore harm native plant species, also known as '''Novel Weapons hypothesis'''<sup>[[#References|[8]]]</sup>.<br />
<br />
[[Image:major_mechanisms.jpg|thumb|700px|center| Major mechanisms<sup>[[#References|[10]]]</sup>]]<br />
Natural systems usually tend to be more complex than the models we use to test those hypothesis above, it is unlikely to explain the mechanism of invasion only by one factor. Thus interactions between different factors should be taken into account when addressing the mechanisms of plant invasion<sup>[[#References|[5]]]</sup>. In addition, abiotic factors might also influence the invasion process.<br />
<br />
==<b>Recent Research</b>==<br />
<br />
Interaction between microbes and invasive plants has been specifically studied only for just decades, although it has been long that plant invasion has drawn attention from ecologists<sup>[[#References|[5]]]</sup>. Up to date, enormous literatures from the last decades show that invasive plants have a dramatic effect on microbial community in their newly established habitats and those microorganisms have a feedback effect on plant community<sup>[[#References|[5]]]</sup>. However, some theories are better understood theoretically than others and only a few studies actually provide sufficient evidences for these well-understood mechanisms<sup>[[#References|[2]]]</sup>. Especially plant-soil feedback has been treated as a black box, little is known about the role of particular microbes in functioning plant invasion due to methodological difficulties<sup>[[#References|[1]]]</sup>. Furthermore, to better understand the whole system, interaction of different factors should be examined<sup>[[#References|[2]]]</sup>. What is more, additional studies involving more invasive plant species in more systems should be studied in a biogeographical context<sup>[[#References|[9]]]</sup>, since there is not necessarily a consistency among different systems or different species. Here are some specific examples of recent research.<br><br />
1) Batten found that two invasive plant change microbial community composition in the rhizosphere by the method PLFA (phospholipid fatty acid analysis) using corresponding analysis. The longer invaded the dissimilarity it is from the original soil. <sup>[[#References|[11]]]</sup><br />
2) Stinson studied <i>Alliaria petiolata</i> and found that they can disrupt native mutualists, AMF, thus affect native AMF associated plants and facilitate themselves to establish.<sup>[[#References|[12]]]</sup><br />
<br />
==<b>References</b>==<br />
<br />
[1] [http://microbes.nres.uiuc.edu/~files/NRES512/VanDerPuten-2007-biological%20invasions.pdf Van der putten, 2007, Microbial ecology and biological invasions.<i> International Society for Microbial Ecology </i> 1, 28-37.]<br />
<br />
<br><br />
[2][http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2006.01715.x/abstract Reinhart, 2006, Soil biota and invasive plants. <i> New Phytologist</i> 170,445-457.]<br />
<br />
<br><br />
[3][http://onlinelibrary.wiley.com/doi/10.1111/j.2006.0030-1299.14625.x/abstract Eppinga, 2006, Accumulation of local pathogens: a new hypothesis to explain exotic plant invasions. <i>Plant Physiology</i> 404,278-281.]<br />
<br />
<br><br />
[4][http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2745.2007.01312.x/abstract Mangla, 2008, Exotic invasive plant accumulates native soil pathogen which inhibit native plants. <i> Journal of Ecology</i> 96,58-67. ]<br />
<br />
<br><br />
[5][http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2006.00908.x/abstract Mitchell,2006, Biotic interactions and plant invasions. <i>Ecology Letters</i> 9,726-740.]<br />
<br />
<br><br />
[6][http://www.jstor.org/stable/27651643 Callaway, 2008, Novel weapons: invasive plant suppresses fungal mutualists in America but not in its native Europe. <i>Ecology</i> 89,1043-1055.]<br />
<br />
<br><br />
[7][http://www.life.illinois.edu/ib/453/klironomos.pdf Klironomos,2002, Feedback with soil biota contributes to plant rarity and invasiveness in communities. <i>Nature</i> 417,67-70.]<br />
<br />
<br><br />
[8][http://web.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=03d52cde-2886-4485-8ead-e94b7ca7b0f7%40sessionmgr13&vid=2&hid=8 Thorpe, 2009, Root exudate is allelopathic in invaded community but not in native community: field evidence for the novel weapons hypothesis. <i> Journal of Ecology</i> 97,641-645.]<br />
<br />
<br><br />
[9][http://dbs.umt.edu/research_labs/maronlab/docs/Hierro%20Maron%20and%20Callaway%202005.pdf Hierro,2005, A biogeographical approach to plant invasions: the importance of studying exotics in their introduced and native range. <i>Journal of Ecology</i> 93,5-15.]<br />
<br />
<br><br />
[10][http://www.jstor.org/stable/3658994 Inderjit, 2010, Impacts of soil microbial communities on exotic plant invasions.<i> Trends in Ecology and Evolution </i> 25, 512-519.]<br />
<br />
<br><br />
[11][http://www.des.ucdavis.edu/faculty/Harrison/people/sue/papers/batten_etal_2006.pdf, Two invasive plants alter soil microbial community composition in serpentine grasslands.<i> Biological Invasions </i> 8: 217–230.]<br />
<br />
<br><br />
[12][http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0040140. Invasive Plant Suppresses the Growth of Native Tree Seedlings by Disrupting Belowground Mutualisms. <i>PLoS Biology</i> 4(5): e140.]<br />
<br />
<br><br />
Edited by Lingzi Hu, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Anchialine_pools_and_cenotes&diff=60383Anchialine pools and cenotes2011-04-19T04:41:34Z<p>Akent: /* Methanogenesis */</p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
[[Image:Anchialine_pool.jpg|thumb|300px|right|[http://www.aquaculturehub.org/photo/anchialine-pools?context=user Brackish anchialine pool.]]]<br />
<br />
[[Image:cenote.jpg|thumb|300px|right|[http://www.tulumtoday.com/index.php/Area/Cenotes_The_Sacred_Waters_of_the_Riviera_Maya.html Amazing photo of Yax Mul cenote on the Yucatan Peninsula, Mexico.]]]<br />
<br />
[[Image:blue hole.jpg|thumb|300px|right|[http://ambergriscaye.com/pages/town/greatbluehole.html The Great Blue Hole at Lighthouse Reef in Belize.]]]<br />
<br />
[http://en.wikipedia.org/wiki/Anchialine_pool Anchialine pools], also known as [http://en.wikipedia.org/wiki/Cenotes Cenotes] in the Yucatan Peninsula region, are subterranean bodies of water that have a connection to the surface, some with connections to the ocean. Anchialine pools are circular and cliffed sinkholes that contain watertable lakes (Webb et al. 2009). They are filled with brackish water. They contain large passage ways which make them desirable for cave explorations. They are very common globally, with the most popular located in the [http://en.wikipedia.org/wiki/Hawaiian_Islands Hawaiian Islands] and the [http://en.wikipedia.org/wiki/Yucatan_peninsula Yucatan Peninsula, Mexico]. They are also located in the Florida peninsula, southeastern South Australia, South Africa, Turkey on the Anatolian Plateau, and the Bahamas Banks. In the Bahamas Banks, they occur onshore and offshore, where they occur as drowned anchialine pools called [http://en.wikipedia.org/wiki/Blue_hole Blue Holes] (Donachie et al. 2004). Sistema Zacaton, Mexico, is the world's largest known cenote that is over 300 meters deep.<br />
<br />
Anchialine pools serve as the main source of water for humans and animals in regions like the Yucatan Peninsula. They are home to many endemic flora and fauna, like crustaceans and fishes. Since the water in these lakes is so clear, they are prime places for scuba diving and cave diving. Both of these activities also have the potential to harm the ecosystems that occur in cenotes. Anchialine pools are threatened by nitrate contamination from untreated animal wastes, leaching of fertilizers, vegetation removal and invasive species.<br />
<br />
==Chemical Environment==<br />
Anchialine pools have many different parameters. Some of these parameters include temperature, pH, and total organic carbon. Cenotes contain many different anions: PO <sub>4</sub><sup>3-</sup>, Cl<sup>-</sup>, NO<sub>3</sub><sup>-</sup>, Br, HCO<sub>3</sub><sup>-</sup>, and SO<sub>4</sub><sup>2-</sup>. Cations that exist in cenotes are Ca, K, Mg, Na, Si, and Sr. Trace elements are Zn, Mo, As, and Cd. They also include NH<sub>4</sub><sup>+</sup>, H<sub>2</sub>S, and S (Sahl et al. 2011). <br />
Cenotes have a high sulfur content and lack sunlight or dissolved oxygen. Sulfate-reducing bacteria, like ''Desulfovibrio'' spp., reduce sulfate (SO<sub>4</sub><sup>2-</sup> into sulfide gas (H<sub>2</sub>S).<br />
<br />
==Physical environment==<br />
===Vegetation===<br />
There are many plant species that are endemic to anchialine pools. Characteristic heterogeneous vegetation, including tall evergreen trees like ''Ficus'' species, surrounds the opening of the pools. Floating [http://en.wikipedia.org/wiki/Macrophyte macrophytes] inhabit part of the surface water in oligotrophic anchialine pools. Removal of vegetation by large herbivores is threatening the ecosystems that reside in the anchialine pools. Threats to anchialine pools include sedimentation, altered hydrologic processes, and nutrient filtering when vegetation is removed.<br />
<br />
===Formation===<br />
Anchialine pools are formed by the dissolution of limestone by carbonic acid in [http://microbewiki.kenyon.edu/index.php/Karst_Springs karst] landforms. Underlying these landforms is calcerous rock. As the rock breaks off and falls into the pool, it is further dissolved. In the Hawaiian Islands, these pools occur in highly porous substrates like recent lava flows or limestone that are near the ocean.<br />
<br />
===Hydrology===<br />
Anchialine pools experience tidal fluctations and lack surface connections that are near the ocean. They contain very clear water and large channels. The anchialine pools of the Yucatan Peninsula in Mexico are the only known underground aquatic system located there. They are stratified, with brackish water on the top layer. They experience a salinity gradient throughout the water column. Salinity decreases as depth increases.<br />
<br />
===Topography===<br />
Anchialine pools are common on coastal karst plains with low topography. Karst topography forms when rock is dissolved, causing small cracks in the geologic structure. Typically karst landscapes are limestone, dolomite, or gypsum. The cracks eventually create anchialine pools, or sinkholes, in the surface as the rock further weathers.<br />
<br />
==Microbial communities==<br />
Anchialine pools contain a high concentrations of chlorophyll which consists of chlorophyceans, cyanobacteria, diatoms, and dinoflagellates. The hypolimnion and sediment have high amounts of organic matter in which anaerobic bacteria and archaea thrive. Anchialine pools are considered heterotrophic systems because they contain such high amounts of organic matter input and production and low water flow.<br />
Anchialine pools are home to different types of grazers. Thick and intricate [http://en.wikipedia.org/wiki/Microbial_mat microbial mats] also form in these areas due to nutrients provided by hydrothermal inputs. The microbes in the microbial mats undergo anaerobic respiration. Microbial processes that occur here include: methanogenesis, sulfur reduction, and anaerobic ammonia oxidation.<br />
<br />
===[http://en.wikipedia.org/wiki/Microbial_mat Microbial Mats]===<br />
Microbial mats cover the upper part of anchialine pool walls. These mats form stratified, complex communities comprised mostly of bacteria and archaea. The mats can range in size from a few millimeters to a few centimeters. Microbial mats have distinct layering of different microbial populations.<br />
Some common microbes found in anchialine pools in Mexico include ''Epsilonproteobacteria'', ''Betaproteobacteria'',''Chlorobi'', and ''Chlorophycea''. Microbial communities change throughout the water column. There is a phylogenetic distribution shift between shallow and deep water-column areas. Surface samples were dominated by ''Gammaproteobacteria'', ''Rhodocyclales'', and ''Neisserales''. As water depth increases, ''Bacteroidetes'' can be observed, as well as ''Gammaproteobacteria''. ''Deltaproteobacteria'', ''Nitrospirae'' and ''Chloroflexi'' can be observed at depth within microbial mats.<br />
Archaea are found in microbial mats in cenotes including methanogens (''Methanomicrobia'') and anaerobic methan oxidizers (ANME-1). <br />
Cyanobacteria can also be found at shallow depths in cenotes (Sahl et al. 2011).<br />
Cenotes in Hawaii have a somewhat different composition: marine green sulfur bacteria ''Chlorobium vibrioforme'' and ''Prosthecochloris aestuarii'', iron-oxidizing bacteria ''Leptothrix cholodnii'', ''Marinobacter sp.'' (a deep-sea iron-oxidizer''. Other microbes included: ''Deinococci'', ''Planctomycetes'', ''Fibrobacter/Acidobacter'', ''Verrucomicrobia'', ''Cyanobacteria'', and ''Euryarchaeota'' (Donachie et al. 2004).<br />
<br />
====Calothrix Mat====<br />
This is the most common type of microbial mat. It is made of upward tapered filaments of the rivulariacean cyanobactera ''Calothrix''. The mat forms shores at low angles. The filaments of ''Calothrix'' are branched to form upward diverging bushs that give the stromatolite interior of the cenote. This type of microbe forms heterocysts. ''Calothrix'' mats have the widest distribution in the lake. Other bacteria associated with this mat include ''Schizothrix'', ''Scytonema'', ''Entophysalis'', and ''Gloeothece'' (Gischler et al. 2011). <br />
<br />
====Scytonema Mat====<br />
These microbial mats form around habitats with strong currents. These mats are almost always entire populations of ''Scytonema'' sp. Structures are dome-shaped and covered by a biofilm with calcified sheaths. Filaments are curved and intertwined but are nto oriented upwards. <br />
<br />
====Leptolyngbya Mat====<br />
These mats are bright orange in color and grow on top of microbialite heads. They are very close to the surface of the water and are partially exposed to the atmosphere. There are produced by cyanobacteria with narrow trichomes known as ''Leptolyngbya''. they consist of unbranched cellular trichomes surrounded by a thin sheath. The orange color the the mats reflect high concentrations of carotenoids in the cells, this protects microbes underneath the mat from UV radiation. Underneath this protection layer, the mat is blue-green in color.<br />
<br />
===[[Methanogens]]===<br />
Methanogens (''Methanomicrobia'') are a type of microbe that belongs to the domain [http://en.wikipedia.org/wiki/Archaea Archaea]. They undergo a type of anaerobic respiration called methanogenesis.<br />
<br />
===Sulfate reducing bacteria===<br />
Sulfate reducing bacteria are obligate anaerobes that convert sulfate (SO<sub>4</sub><sup>2-</sup>) to hydrogen sulfide gas (H<sub>2</sub>S) <br />
Specific bacteria that reduce sulfur include''Desulfovibrio'' spp., ''Desulfomonas'' spp., and ''Desulfotomaculum'' spp. These species of bacteria use end products of other fermentations like lactate, malate, and ethonal as electron donors.<br />
<br />
===Ammonium oxidizing bacteria===<br />
Ammonium oxidizers are anaerobic microbes that undergo ammonium oxidation. Nitrifying microorganisms include both bacteria and archaea. There include microbes that oxidize ammonia (NH<sub>3</sub>) and those that oxidize nitrite (NO<sub>2</sub><sup>-</sup>) directly into dinitrogen gas. Ammonia (NH<sub>3</sub>) oxidizers include members from the [http://en.wikipedia.org/wiki/Betaproteobacteria betaproteobacteria] group (''Nitrosomonas'' spp., and ''Nitrosospira'' spp.) and from the [http://en.wikipedia.org/wiki/Gammaproteobacteria gammaproteobacteria] group (''Nitrosococcus'' spp.). Nitrite (NO<sub>2</sub><sup>-</sup>) oxidizers include members from the [http://en.wikipedia.org/wiki/Alphaproteobacteria alphaproteobacteria] group (''Nitrobacter'' spp.), gammaproteobacteria group (''Nitrococcus'' spp.), [http://en.wikipedia.org/wiki/Deltaproteobacteria deltaproteobacteria] group (''Nitrospina'' spp.), and ''Nitrospira'' spp.<br />
<br />
==Microbial processes==<br />
===[http://en.wikipedia.org/wiki/Anaerobic_respiration Anaerobic respiration]===<br />
Anaerobic respiration occurs when microbes use other terminal electron acceptors other than oxygen. In environments, like anchialine pools and cenotes, microbes use terminal electron acceptors like sulfate (SO<sub>4</sub><sup>-2</sup>), nitrate (NO<sub>3</sub><sup>-</sup>), sulfur (S), and carbon dioxide (CO<sub>2</sub>). This type of respiration occurs in the absence of oxygen. Although these terminal electron acceptors produce energy, they release less energy than oxygen. Therefore, anaerobic respiration produces less energy than aerobic respiration.<br />
====[http://en.wikipedia.org/wiki/Methanogenesis Methanogenesis]====<br />
Methanogenesis is the formation of methane by microbes. Methanogens, a type of Archaea, specifically carry out this process. This is a type of anaerobic respiration that uses carbon dioxide (CO<sub>2</sub>) and acetic acid as the terminal electron acceptors.<br />
<br />
CO<sub>2</sub> + H<sub>2</sub> → CH<sub>4</sub> + 2H<sub></sub><br />
<br />
CH<sub>3</sub>COOH → CH<sub>4</sub> + 2H<sub></sub><br />
<br />
====Sulfate reduction====<br />
Sulfate (SO<sub>4</sub><sup>2-</sup>) is part of the [http://en.wikipedia.org/wiki/Sulfur_cycle sulfur cycle]. Sulfate reduction occurs when sulfate is reduced to sulfide (S<sup>-</sup>). Sulfur-reducing microbes use sulfate as the terminal electron acceptor in the anaerobic conditions that occur in anchialine pools. This is especially important in the water-logged sediments in the benthos of these pools.<br />
<br />
====Sulfide oxidation====<br />
Sulfide oxidation occurs when microbes oxidize sulfide (S<sup>2-</sup>) or hydrogen sulfide gas (H<sub>2</sub>S) and producing sulfate (SO<sub>4</sub><sup>2-</sup>). Microbes produce electrons and make ATP (Sylvia et al. 2005).<br />
<br />
====Fermentation====<br />
Fermentation occurs in cenotes where oxygen is not available. Iron-iron hydrogenase sequences associated with fermentation in bacteria have been amplified from shallow water samples of cenotes (Sahl et al. 2011).<br />
<br />
====Ammonia oxidation====<br />
Ammonia (NH<sub>3</sub>) oxidation occurs when ammonia is oxidized into nitrite (NO<sub>2</sub><sup>-</sup>). There are three different ammonia oxidizers groups: ''Nitrosomonas'', ''Nitrosospira'', and ''Nitrosococcus''. This is an endergonic reaction and requires a small amount of energy. Ammonia monooxygenase facilitates this reaction. Ammonia oxidation produces nitrous oxide (N<sub>2</sub>O) and acidity. Ammonia oxidation can cause acidity in anchialine pools (Sylvia et al. 2005).<br />
<br />
====Nitrite oxidation====<br />
Nitrite oxidation is the final step in ammonia oxidation. ''Nitrobacter'' spp. and ''Nitrospira'' spp. can oxidize nitrite (NO<sub>2</sub><sup>-</sup>) into nitrate (NO<sub>3</sub><sup>-</sup>). Nitrite oxidoreductase facilitates this reaction (Sylvia et al. 2005).<br />
<br />
===Lithotrophic Processes===<br />
====[http://en.wikipedia.org/wiki/Anammox Anaerobic ammonia oxidation]====<br />
Aerobic ammonium oxidation is part of the [http://en.wikipedia.org/wiki/Nitrogen_cycle nitrogen cycle]. Ammonium-oxidizing bacteria convert nitrite (NO<sub>2</sub><sup>-</sup>) and ammonium (NH<sub>4</sub><sup>+</sup>) directly to nitrous oxide ((N<sub>2</sub>O). All ammonia oxidizers contain nitrite reductase which can reduce nitrite directly into nitrous oxide. Production of nitrous oxide occurs more often hen oxygen availability decreases because nitrite is being used as a terminal electron acceptor (Sylvia et al. 2005). <br />
<br />
NH<sub>4</sub><sup>+</sup> + NO<sub>2</sub><sup>-</sup> → N<sub>2</sub> + 2H<sub>2</sub>O<br />
<br />
==Current Research==<br />
<br />
====[http://onlinelibrary.wiley.com.proxy2.library.illinois.edu/doi/10.1111/j.1462-2920.2010.02324.x/pdf "''A Comparative Molecular analysis of Water-filled Limestone Sinkholes in North-eastern Mexico''"]====<br />
<br />
Researchers are using new methods to study cenotes in Sistema Zacaton in north-eastern Mexico. Microbial mat communities were studied using comparative analysis of small-subunit 16S rRNA gene sequences. Genes associated with methanogenesis, sulfate reduction and anaerobic ammonium oxidation were also identified and studied.<br />
<br />
====[http://ijr.sagepub.com.proxy2.library.illinois.edu/content/29/6/748.full.pdf+html "''Autonomous Exploration and Mapping of Flooded Sinkholes''"]====<br />
[[Image: page0001.jpg|thumb|300px|right|Sonar image of four cenotes in the Sistema Zacaton]]<br />
<br />
NASA conducted an experiment in which flooded cenotes were mapped using the DEPTHX )Deep Phreatic Thermal Explorer) autonomous vehicle in Sistema Zacaton in Mexico. Three-dimensional maps of cenotes were constructed and environmental data, imagery, water samples, and core samples were taken from the cenotes in this region. Four different cenotes were studied and mapped: La Pilita, Zacaton, Verde, and Caracol.<br />
<br />
====[http://www.sciencedirect.com.proxy2.library.illinois.edu/science?_ob=MImg&_imagekey=B6V93-4YH4PS4-2-R&_cdi=5887&_user=571676&_pii=S0169555X1000084X&_origin=gateway&_coverDate=06%2F15%2F2010&_sk=998809998&view=c&wchp=dGLbVlb-zSkzS&md5=1bb4ce8b4bf1190e5a4ee1a7e66c4ec4&ie=/sdarticle.pdf "''Volcanogenic origin of cenotes near Mt Gambier, southeastern Australia''"]====<br />
<br />
Researchers studied the origin of cenotes in southeastern Australia. Caves had collapsed to form the Mt Gambier cenotes. Acidified groundwater containing significant amounts of volcanogenic carbon dioxide that has ascended up cracks from the magma chambers formed the cenotes in this area, as opposed to how most cenotes are formed by freshwater/seawater mixing. This research shows that there are different ways that cenotes form and further investigation needs to occur to fully understand the formation of these sinkholes.<br />
<br />
==References==<br />
<br />
[http://onlinelibrary.wiley.com.proxy2.library.illinois.edu/doi/10.1002/iroh.19980830107/pdf Brock, R.E. and Bailey-Brock, J.H. "''An Unique Anchialine Pool in the Hawaiian Islands''". ''International Review of Hydrobiology''. 1998. Volume 83. p. 65-75.]<br />
<br />
[http://scholarspace.manoa.hawaii.edu/bitstream/handle/10125/1034/v41-200-208.pdf;jsessionid=00CC01D3A8C22C981629F8E319502348?sequence=1 Brock, R.E., Norris, J.E., Ziemann, D.A., and Lee, M.T. "''Characteristics of Water Quality in Anchialine Ponds of the Kona, Hawaii, Coast''". ''Pacific Science''. 1987. Volume 41. p. 200-208.]<br />
<br />
[http://www.jstor.org.proxy2.library.illinois.edu/openurl?volume=48&date=2004&spage=509&issn=00953628&issue=4& Donachie, S.P., Hou, S., Lee, K.S., Riley, C.W., Pikina, A., Belisle, C., Kempe, S., Gregory, T.S., Bossuyt, A., Boerema, J., Liu, J., Freitas, T.A., Malahoff, A., and Alam, M. "''The Hawaiian Archipelago: A Microbial Diversity Hotspot''". ''Microbial Ecology''. 2004. Volume 48. p. 509-520.]<br />
<br />
Gischler, E., Golubic, S., Gibson, M.A., Oschmann, W., and hudson, J.H. "''Microbial mats and microbialites in the freshwater Laguna Bacalar, Yucatan Peninsula, Mexico''". ''Advances in Stromatolite Geobiology''. 2011. Volume 131. p. 187-205. <br />
<br />
[http://ijr.sagepub.com.proxy2.library.illinois.edu/content/29/6/748.full.pdf+html Fairfield, N., Kantor, G., Jonak, D., Wettergreen, D. "''Autonomous Exploration and Mapping of Flooded Sinkholes''". ''The International Journal of Robotics Research''. 2010. Volume 29. p. 748-774.]<br />
<br />
[http://www.sciencedirect.com.proxy2.library.illinois.edu/science?_ob=MImg&_imagekey=B6V5X-4N5KY2X-1-7&_cdi=5798&_user=571676&_pii=S0006320707000274&_origin=gateway&_coverDate=05%2F31%2F2007&_sk=998639995&view=c&wchp=dGLbVzW-zSkzS&md5=7eb89f8aaed913f9845c511f0d502bb0&ie=/sdarticle.pdf MacSwiney G., M.C., Vilchis L., P., Clarke, F.M., and Racey, P.A. "''The Importance of Cenotes in Conserving Bat Assemblages in the Yucatan, Mexico''". ''Biological Conservation''. 2007. Volume 136. p. 499-509.]<br />
<br />
[http://www.caves.org/pub/journal/PDF/v69/cave-69-02-250.pdf Mejia-Ortiz, L.M., Yanez, G., Lopez-Mejia, M., Zarza-Gonzalez, E. "''Cenotes (Anchialine Caves) on Cozumel Island, Quintana Roo, Mexico''". ''Journal of Cave and Karst Studies''. 2007. Volume 69. p. 250-255.]<br />
<br />
[http://onlinelibrary.wiley.com.proxy2.library.illinois.edu/doi/10.1111/j.1462-2920.2010.02324.x/pdf Sahl, J.W., Gary, M.O., Harris, J.K., and Spear, J.R. "''A Comparative Molecular Analysis of Water-filled Limestone Sinkholes in North-eastern Mexico''". ''Environmental Microbiology''. 2011. Volume 13. p. 226-240.]<br />
<br />
[http://www.springerlink.com.proxy2.library.illinois.edu/content/32dq5wtv0mk7bnpr/ Schmitter-Soto, J.J., Comín, F.A., Escobar-Briones, E., Herrera-Silveira, J., Alcocer, J., Suárez-Morales, E., Elías-Gutiérrez, M., Díaz-Arce, V., Marín, L.E., and Steinich, B. "''Hydrogeochemical and Biological Characteristics of Cenotes in the Yucatan Peninsula (SE Mexico)''". ''Hydrobiologia''. 2002. Volume 467. p. 215-228.] <br />
<br />
Sylvia, D.M. Fuhrmann, J.J., Hartel, P.G., and Zuberer D.A. ''Principles and Applications of Soil Microbiology 2nd Edition''. New Jersey: Pearson Prentice Hall, 2005. Print.<br />
<br />
[http://www.sciencedirect.com.proxy2.library.illinois.edu/science?_ob=MImg&_imagekey=B6V93-4YH4PS4-2-R&_cdi=5887&_user=571676&_pii=S0169555X1000084X&_origin=gateway&_coverDate=06%2F15%2F2010&_sk=998809998&view=c&wchp=dGLbVlz-zSkzV&md5=1bb4ce8b4bf1190e5a4ee1a7e66c4ec4&ie=/sdarticle.pdf Webb, J.A., Grimes, K.G., Lewis, I.D. "''Volcanogenic Origin of Cenotes Near Mt Gambier , Southeastern Australia''". ''Geomorphology''. 2010. Volume 119. p. 23-35.]<br />
<br />
<br />
<br />
Edited by Lauren Behnke, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Anchialine_pools_and_cenotes&diff=60350Anchialine pools and cenotes2011-04-19T04:13:56Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
[[Image:Anchialine_pool.jpg|thumb|300px|right|[http://www.aquaculturehub.org/photo/anchialine-pools?context=user Brackish anchialine pool.]]]<br />
<br />
[[Image:cenote.jpg|thumb|300px|right|[http://www.tulumtoday.com/index.php/Area/Cenotes_The_Sacred_Waters_of_the_Riviera_Maya.html Amazing photo of Yax Mul cenote on the Yucatan Peninsula, Mexico.]]]<br />
<br />
[[Image:blue hole.jpg|thumb|300px|right|[http://ambergriscaye.com/pages/town/greatbluehole.html The Great Blue Hole at Lighthouse Reef in Belize.]]]<br />
<br />
[http://en.wikipedia.org/wiki/Anchialine_pool Anchialine pools], also known as [http://en.wikipedia.org/wiki/Cenotes Cenotes] in the Yucatan Peninsula region, are subterranean bodies of water that have a connection to the surface, some with connections to the ocean. Anchialine pools are circular and cliffed sinkholes that contain watertable lakes (Webb et al. 2009). They are filled with brackish water. They contain large passage ways which make them desirable for cave explorations. They are very common globally, with the most popular located in the [http://en.wikipedia.org/wiki/Hawaiian_Islands Hawaiian Islands] and the [http://en.wikipedia.org/wiki/Yucatan_peninsula Yucatan Peninsula, Mexico]. They are also located in the Florida peninsula, southeastern South Australia, South Africa, Turkey on the Anatolian Plateau, and the Bahamas Banks. In the Bahamas Banks, they occur onshore and offshore, where they occur as drowned anchialine pools called [http://en.wikipedia.org/wiki/Blue_hole Blue Holes] (Donachie et al. 2004). Sistema Zacaton, Mexico, is the world's largest known cenote that is over 300 meters deep.<br />
<br />
Anchialine pools serve as the main source of water for humans and animals in regions like the Yucatan Peninsula. They are home to many endemic flora and fauna, like crustaceans and fishes. Since the water in these lakes is so clear, they are prime places for scuba diving and cave diving. Both of these activities also have the potential to harm the ecosystems that occur in cenotes. Anchialine pools are threatened by nitrate contamination from untreated animal wastes, leaching of fertilizers, vegetation removal and invasive species.<br />
<br />
==Chemical Environment==<br />
Anchialine pools have many different parameters. Some of these parameters include temperature, pH, and total organic carbon. Cenotes contain many different anions: PO <sub>4</sub><sup>3-</sup>, CL<sup>-</sup>, NO<sub>3</sub><sup>-</sup>, Br, HCO<sub>3</sub><sup>-</sup>, and SO<sub>4</sub><sup>2-</sup>. Cations that exist in cenotes are Ca, K, Mg, Na, Si, and Sr. Trace elements are Zn, Mo, As, and Cd. They also include NH<sub>4</sub><sup>+</sup>, H<sub>2</sub>S, and S (Sahl et al. 2011). <br />
Cenotes have a high sulfur content and lack sunlight or dissolved oxygen. Sulfate-reducing bacteria, like ''Desulfovibrio'' spp., reduce sulfate (SO<sub>4</sub><sup>2-</sup> into sulfide gas (H<sub>2</sub>S).<br />
<br />
==Physical environment==<br />
===Vegetation===<br />
There are many plant species that are endemic to anchialine pools. Characteristic heterogeneous vegetation, including tall evergreen trees like ''Ficus'' species, surrounds the opening of the pools. Floating [http://en.wikipedia.org/wiki/Macrophyte macrophytes] inhabit part of the surface water in oligotrophic anchialine pools. Removal of vegetation by large herbivores is threatening the ecosystems that reside in the anchialine pools. Threats to anchialine pools include sedimentation, altered hydrologic processes, and nutrient filtering when vegetation is removed.<br />
<br />
===Formation===<br />
Anchialine pools are formed by the dissolution of limestone by carbonic acid in [http://microbewiki.kenyon.edu/index.php/Karst_Springs karst] landforms. Underlying these landforms is calcerous rock. As the rock breaks off and falls into the pool, it is further dissolved. In the Hawaiian Islands, these pools occur in highly porous substrates like recent lava flows or limestone that are near the ocean.<br />
<br />
===Hydrology===<br />
Anchialine pools experience tidal fluctations and lack surface connections that are near the ocean. They contain very clear water and large channels. The anchialine pools of the Yucatan Peninsula in Mexico are the only known underground aquatic system located there. They are stratified, with brackish water on the top layer. They experience a salinity gradient throughout the water column. Salinity decreases as depth increases.<br />
<br />
===Topography===<br />
Anchialine pools are common on coastal karst plains with low topography. Karst topography forms when rock is dissolved, causing small cracks in the geologic structure. Typically karst landscapes are limestone, dolomite, or gypsum. The cracks eventually create anchialine pools, or sinkholes, in the surface as the rock further weathers.<br />
<br />
==Microbial communities==<br />
Anchialine pools contain a high concentrations of chlorophyll which consists of chlorophyceans, cyanobacteria, diatoms, and dinoflagellates. The hypolimnion and sediment have high amounts of organic matter in which anaerobic bacteria and archaea thrive. Anchialine pools are considered heterotrophic systems because they contain such high amounts of organic matter input and production and low water flow.<br />
Anchialine pools are home to different types of grazers. Thick and intricate [http://en.wikipedia.org/wiki/Microbial_mat microbial mats] also form in these areas due to nutrients provided by hydrothermal inputs. The microbes in the microbial mats undergo anaerobic respiration. Microbial processes that occur here include: methanogenesis, sulfur reduction, and anaerobic ammonia oxidation.<br />
<br />
<br />
===[http://en.wikipedia.org/wiki/Microbial_mat Microbial Mats]===<br />
Microbial mats cover the upper part of anchialine pool walls. These mats form stratified, complex communities comprised mostly of bacteria and archaea. The mats can range in size from a few millimeters to a few centimeters. Microbial mats have distinct layering of different microbial populations.<br />
Some common microbes found in anchialine pools in Mexico include ''Epsilonproteobacteria'', ''Betaproteobacteria'',''Chlorobi'', and ''Chlorophycea''. Microbial communities change throughout the water column. There is a phylogenetic distribution shift between shallow and deep water-column areas. Surface samples were dominated by ''Gammaproteobacteria'', ''Rhodocyclales'', and ''Neisserales''. As water depth increases, ''Bacteroidetes'' can be observed, as well as ''Gammaproteobacteria''. ''Deltaproteobacteria'', ''Nitrospirae'' and ''Chloroflexi'' can be observed at depth within microbial mats.<br />
Archaea are found in microbial mats in cenotes including methanogens (''Methanomicrobia'') and anaerobic methan oxidizers (ANME-1). <br />
Cyanobacteria can also be found at shallow depths in cenotes (Sahl et al. 2011).<br />
Cenotes in Hawaii have a somewhat different composition: marine green sulfur bacteria ''Chlorobium vibrioforme'' and ''Prosthecochloris aestuarii'', iron-oxidizing bacteria ''Leptothrix cholodnii'', ''Marinobacter sp.'' (a deep-sea iron-oxidizer''. Other microbes included: ''Deinococci'', ''Planctomycetes'', ''Fibrobacter/Acidobacter'', ''Verrucomicrobia'', ''Cyanobacteria'', and ''Euryarchaeota'' (Donachie et al. 2004).<br />
<br />
====Calothrix Mat====<br />
This is the most common type of microbial mat. It is made of upward tapered filaments of the rivulariacean cyanobactera ''Calothrix''. The mat forms shores at low angles. The filaments of ''Calothrix'' are branched to form upward diverging bushs that give the stromatolite interior of the cenote. This type of microbe forms heterocysts. ''Calothrix'' mats have the widest distribution in the lake. Other bacteria associated with this mat include ''Schizothrix'', ''Scytonema'', ''Entophysalis'', and ''Gloeothece'' (Gischler et al. 2011). <br />
<br />
====Scytonema Mat====<br />
These microbial mats form around habitats with strong currents. These mats are almost always entire populations of ''Scytonema'' sp. Structures are dome-shaped and covered by a biofilm with calcified sheaths. Filaments are curved and intertwined but are nto oriented upwards. <br />
<br />
====Leptolyngbya Mat====<br />
These mats are bright orange in color and grow on top of microbialite heads. They are very close to the surface of the water and are partially exposed to the atmosphere. There are produced by cyanobacteria with narrow trichomes known as ''Leptolyngbya''. they consist of unbranched cellular trichomes surrounded by a thin sheath. The orange color the the mats reflect high concentrations of carotenoids in the cells, this protects microbes underneath the mat from UV radiation. Underneath this protection layer, the mat is blue-green in color.<br />
<br />
===[[Methanogens]]===<br />
Methanogens (''Methanomicrobia'') are a type of microbe that belongs to the domain [http://en.wikipedia.org/wiki/Archaea Archaea]. They undergo a type of anaerobic respiration called methanogenesis.<br />
<br />
===Sulfate reducing bacteria===<br />
Sulfate reducing bacteria are obligate anaerobes that convert sulfate (SO<sub>4</sub><sup>2-</sup>) to hydrogen sulfide gas (H<sub>2</sub>S) <br />
Specific bacteria that reduce sulfur include''Desulfovibrio'' spp., ''Desulfomonas'' spp., and ''Desulfotomaculum'' spp. These species of bacteria use end products of other fermentations like lactate, malate, and ethonal as electron donors.<br />
<br />
===Ammonium oxidizing bacteria===<br />
Ammonium oxidizers are anaerobic microbes that undergo ammonium oxidation. Nitrifying microorganisms include both bacteria and archaea. There include microbes that oxidize ammonia (NH<sub>3</sub>) and those that oxidize nitrite (NO<sub>2</sub><sup>-</sup>) directly into dinitrogen gas. Ammonia (NH<sub>3</sub>) oxidizers include members from the [http://en.wikipedia.org/wiki/Betaproteobacteria betaproteobacteria] group (''Nitrosomonas'' spp., and ''Nitrosospira'' spp.) and from the [http://en.wikipedia.org/wiki/Gammaproteobacteria gammaproteobacteria] group (''Nitrosococcus'' spp.). Nitrite (NO<sub>2</sub><sup>-</sup>) oxidizers include members from the [http://en.wikipedia.org/wiki/Alphaproteobacteria alphaproteobacteria] group (''Nitrobacter'' spp.), gammaproteobacteria group (''Nitrococcus'' spp.), [http://en.wikipedia.org/wiki/Deltaproteobacteria deltaproteobacteria] group (''Nitrospina'' spp.), and ''Nitrospira'' spp.<br />
<br />
==Microbial processes==<br />
===[http://en.wikipedia.org/wiki/Anaerobic_respiration Anaerobic respiration]===<br />
Anaerobic respiration occurs when microbes use other terminal electron acceptors other than oxygen. In environments, like anchialine pools and cenotes, microbes use terminal electron acceptors like sulfate (SO<sub>4</sub><sup>-2</sup>), nitrate (NO<sub>3</sub><sup>-</sup>), sulfur (S), and carbon dioxide (CO<sub>2</sub>). This type of respiration occurs in the absence of oxygen. Although these terminal electron acceptors produce energy, they release less energy than oxygen. Therefore, anaerobic respiration produces less energy than aerobic respiration.<br />
====[http://en.wikipedia.org/wiki/Methanogenesis Methanogenesis]====<br />
Methanogenesis is the formation of methane by microbes. Methanogens, a type of Archaea, specifically carry out this process. This is a type of anaerobic respiration that uses carbon dioxide (CO<sub>2</sub>) and acetic acid as the terminal electron acceptors.<br />
<br />
CO<sub>2</sub> 4 H<sub>2</sub> → CH<sub>4</sub> + 2H<sub></sub><br />
<br />
CH<sub>3</sub>COOH → CH<sub>4</sub> + 2H<sub></sub><br />
<br />
====Sulfate reduction====<br />
Sulfate (SO<sub>4</sub><sup>2-</sup>) is part of the [http://en.wikipedia.org/wiki/Sulfur_cycle sulfur cycle]. Sulfate reduction occurs when sulfate is reduced to sulfide (S<sup>-</sup>). Sulfur-reducing microbes use sulfate as the terminal electron acceptor in the anaerobic conditions that occur in anchialine pools. This is especially important in the water-logged sediments in the benthos of these pools.<br />
<br />
====Sulfide oxidation====<br />
Sulfide oxidation occurs when microbes oxidize sulfide (S<sup>2-</sup>) or hydrogen sulfide gas (H<sub>2</sub>S) and producing sulfate (SO<sub>4</sub><sup>2-</sup>). Microbes produce electrons and make ATP.<br />
<br />
====Fermentation====<br />
Fermentation occurs in cenotes where oxygen is not available. Iron-iron hydrogenase sequences associated with fermentation in bacteria have been amplified from shallow water samples of cenotes (Sahl et al. 2011).<br />
<br />
====Ammonia oxidation====<br />
<br />
===Lithotrophic Processes===<br />
====[http://en.wikipedia.org/wiki/Anammox Anaerobic ammonia oxidation]====<br />
Anaerobic ammonium oxidation is part of the [http://en.wikipedia.org/wiki/Nitrogen_cycle nitrogen cycle]. Ammonium-oxidizing bacteria convert nitrite (NO<sub>2</sub><sup>-</sup>) and ammonium (NH<sub>4</sub><sup>+</sup>) directly to nitrous oxide ((N<sub>2</sub>O). <br />
<br />
NH<sub>4</sub><sup>+</sup> + NO<sub>2</sub><sup>-</sup> → N<sub>2</sub> + 2H<sub>2</sub>O<br />
<br />
==Current Research==<br />
<br />
====[http://onlinelibrary.wiley.com.proxy2.library.illinois.edu/doi/10.1111/j.1462-2920.2010.02324.x/pdf "''A Comparative Molecular analysis of Water-filled Limestone Sinkholes in North-eastern Mexico''"]====<br />
<br />
Researchers are using new methods to study cenotes in Sistema Zacaton in north-eastern Mexico. Microbial mat communities were studied using comparative analysis of small-subunit 16S rRNA gene sequences. Genes associated with methanogenesis, sulfate reduction and anaerobic ammonium oxidation were also identified and studied.<br />
<br />
====[http://ijr.sagepub.com.proxy2.library.illinois.edu/content/29/6/748.full.pdf+html "''Autonomous Exploration and Mapping of Flooded Sinkholes''"]====<br />
[[Image: page0001.jpg|thumb|300px|right|[Sonar image of four cenotes in the Sistema Zacaton]]<br />
<br />
NASA conducted an experiment in which flooded cenotes were mapped using the DEPTHX )Deep Phreatic Thermal Explorer) autonomous vehicle in Sistema Zacaton in Mexico. Three-dimensional maps of cenotes were constructed and environmental data, imagery, water samples, and core samples were taken from the cenotes in this region. Four different cenotes were studied and mapped: La Pilita, Zacaton, Verde, and Caracol.<br />
<br />
====[http://www.sciencedirect.com.proxy2.library.illinois.edu/science?_ob=MImg&_imagekey=B6V93-4YH4PS4-2-R&_cdi=5887&_user=571676&_pii=S0169555X1000084X&_origin=gateway&_coverDate=06%2F15%2F2010&_sk=998809998&view=c&wchp=dGLbVlb-zSkzS&md5=1bb4ce8b4bf1190e5a4ee1a7e66c4ec4&ie=/sdarticle.pdf "''Volcanogenic origin of cenotes near Mt Gambier, southeastern Australia''"]====<br />
<br />
Researchers studied the origin of cenotes in southeastern Australia. Caves had collapsed to form the Mt Gambier cenotes. Acidified groundwater containing significant amounts of volcanogenic carbon dioxide that has ascended up cracks from the magma chambers formed the cenotes in this area, as opposed to how most cenotes are formed by freshwater/seawater mixing. This research shows that there are different ways that cenotes form and further investigation needs to occur to fully understand the formation of these sinkholes.<br />
<br />
==References==<br />
<br />
[http://onlinelibrary.wiley.com.proxy2.library.illinois.edu/doi/10.1002/iroh.19980830107/pdf Brock, R.E. and Bailey-Brock, J.H. "''An Unique Anchialine Pool in the Hawaiian Islands''". ''International Review of Hydrobiology''. 1998. Volume 83. p. 65-75.]<br />
<br />
[http://scholarspace.manoa.hawaii.edu/bitstream/handle/10125/1034/v41-200-208.pdf;jsessionid=00CC01D3A8C22C981629F8E319502348?sequence=1 Brock, R.E., Norris, J.E., Ziemann, D.A., and Lee, M.T. "''Characteristics of Water Quality in Anchialine Ponds of the Kona, Hawaii, Coast''". ''Pacific Science''. 1987. Volume 41. p. 200-208.]<br />
<br />
[http://www.jstor.org.proxy2.library.illinois.edu/openurl?volume=48&date=2004&spage=509&issn=00953628&issue=4& Donachie, S.P., Hou, S., Lee, K.S., Riley, C.W., Pikina, A., Belisle, C., Kempe, S., Gregory, T.S., Bossuyt, A., Boerema, J., Liu, J., Freitas, T.A., Malahoff, A., and Alam, M. "''The Hawaiian Archipelago: A Microbial Diversity Hotspot''". ''Microbial Ecology''. 2004. Volume 48. p. 509-520.]<br />
<br />
Gischler, E., Golubic, S., Gibson, M.A., Oschmann, W., and hudson, J.H. "''Microbial mats and microbialites in the freshwater Laguna Bacalar, Yucatan Peninsula, Mexico''". ''Advances in Stromatolite Geobiology''. 2011. Volume 131. p. 187-205. <br />
<br />
[http://ijr.sagepub.com.proxy2.library.illinois.edu/content/29/6/748.full.pdf+html Fairfield, N., Kantor, G., Jonak, D., Wettergreen, D. "''Autonomous Exploration and Mapping of Flooded Sinkholes''". ''The International Journal of Robotics Research''. 2010. Volume 29. p. 748-774.]<br />
<br />
[http://www.sciencedirect.com.proxy2.library.illinois.edu/science?_ob=MImg&_imagekey=B6V5X-4N5KY2X-1-7&_cdi=5798&_user=571676&_pii=S0006320707000274&_origin=gateway&_coverDate=05%2F31%2F2007&_sk=998639995&view=c&wchp=dGLbVzW-zSkzS&md5=7eb89f8aaed913f9845c511f0d502bb0&ie=/sdarticle.pdf MacSwiney G., M.C., Vilchis L., P., Clarke, F.M., and Racey, P.A. "''The Importance of Cenotes in Conserving Bat Assemblages in the Yucatan, Mexico''". ''Biological Conservation''. 2007. Volume 136. p. 499-509.]<br />
<br />
[http://www.caves.org/pub/journal/PDF/v69/cave-69-02-250.pdf Mejia-Ortiz, L.M., Yanez, G., Lopez-Mejia, M., Zarza-Gonzalez, E. "''Cenotes (Anchialine Caves) on Cozumel Island, Quintana Roo, Mexico''". ''Journal of Cave and Karst Studies''. 2007. Volume 69. p. 250-255.]<br />
<br />
[http://onlinelibrary.wiley.com.proxy2.library.illinois.edu/doi/10.1111/j.1462-2920.2010.02324.x/pdf Sahl, J.W., Gary, M.O., Harris, J.K., and Spear, J.R. "''A Comparative Molecular Analysis of Water-filled Limestone Sinkholes in North-eastern Mexico''". ''Environmental Microbiology''. 2011. Volume 13. p. 226-240.]<br />
<br />
[http://www.springerlink.com.proxy2.library.illinois.edu/content/32dq5wtv0mk7bnpr/ Schmitter-Soto, J.J., Comín, F.A., Escobar-Briones, E., Herrera-Silveira, J., Alcocer, J., Suárez-Morales, E., Elías-Gutiérrez, M., Díaz-Arce, V., Marín, L.E., and Steinich, B. "''Hydrogeochemical and Biological Characteristics of Cenotes in the Yucatan Peninsula (SE Mexico)''". ''Hydrobiologia''. 2002. Volume 467. p. 215-228.] <br />
<br />
Sylvia, D.M. Fuhrmann, J.J., Hartel, P.G., and Zuberer D.A. ''Principles and Applications of Soil Microbiology 2nd Edition''. New Jersey: Pearson Prentice Hall, 2005. Print.<br />
<br />
[http://www.sciencedirect.com.proxy2.library.illinois.edu/science?_ob=MImg&_imagekey=B6V93-4YH4PS4-2-R&_cdi=5887&_user=571676&_pii=S0169555X1000084X&_origin=gateway&_coverDate=06%2F15%2F2010&_sk=998809998&view=c&wchp=dGLbVlz-zSkzV&md5=1bb4ce8b4bf1190e5a4ee1a7e66c4ec4&ie=/sdarticle.pdf Webb, J.A., Grimes, K.G., Lewis, I.D. "''Volcanogenic Origin of Cenotes Near Mt Gambier , Southeastern Australia''". ''Geomorphology''. 2010. Volume 119. p. 23-35.]<br />
<br />
<br />
<br />
Edited by Lauren Behnke, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Mycorrhizae&diff=59865Mycorrhizae2011-04-13T04:58:58Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
<br />
[[Image:withandwithout.jpg|thumb|500px|right|This picture shows the increase in root growth of a redwood seeding with a mycorrhizal relationship (right) compared to a redwood seeding without this symbiotic relationship (left). Photo credit: Mike Amaranthus, USDA (Amaranthus).]]<br />
<br />
<br />
Mycorrhizae can be described as a [http://en.wikipedia.org/wiki/Symbiotic symbiotic] relationship between a [[http://en.wikipedia.org/wiki/Fungus fungus]] and a plant (Sylvia). Due to the fact that this is a symbiotic relationship, both the fungus and the plant benefit from this interaction. Since the plants are aboveground, it is often easier to see the benefits of this association for the plant, but the fungus also takes advantage of this partnership. The mycorrhizae aid the plant with growth, yield, improved fitness, increase the root absorption area of nutrients, while the fungus receives carbon from the associated plant (Sylvia). This is an important interaction due to the benefits that the plants receive. Improved plant growth and yield can aid in the production of crops and therefore produce more plants per area. Although mycorrhizae produce the same overall effects, there are two main types of this fungus. Endomycorrhizae and ectomycorrhizae are the two main types of mycorrhizae that produce the same overall results, but with different fungal characteristics (Allen). Below, more will be explained about the interaction between the fungus and plant, the niches that they are able to occupy, descriptions of the types of mycorrhizae, and the microbial processes that occur.<br />
<br />
==Biological interaction==<br />
As stated above, mycorrhizae create a symbiotic relationship between a plant and a fungus where both organisms benefit from the interaction. Although both the plant and fungi benefit from the partnership, they benefit in different ways. <br />
<br />
===Benefits for Plants===<br />
Mycorrhizae are able to create a vast connection between the roots of a plant and with the soil around them, which allows for the fungus to uptake nutrients such as [[http://en.wikipedia.org/wiki/Nitrogen nitrogen]] and phosphorus for the plant and increase the surface area of the roots (Sylvia). With this increased surface area, it is obvious that the plant will have many benefits. This increase in area within the soil will increase the availability of nutrients and water for the plants consumption. Since nutrients and water are needed in order for plant growth, this mycorrhizal interaction can lead to an increase in the growth of the plant.<br />
<br />
This increase in nutrient availability for the plant leads to even more advantages. A plant with a mycorrhizae interaction will be able to increase its nutrient and water uptake, while a plant without this partnership will just have to rely on its roots for the uptake of materials. If a plant with this symbiosis is in an area with plants who do not have a mycorrhizae partnership, the fungi and plant partnership can give the plant the ability to out compete other plants. Overall, this means that mycorrhizae interactions can lead to changes in the plant composition of an area.<br />
<br />
===Benefits for the [http://en.wikipedia.org/wiki/Fungi Fungi]===<br />
Since this is a symbiotic relationship, the fungus benefits from the partnership as well. While aiding plants in the uptake of nutrients and water, the plants will give ten to twenty percent of the carbon they obtain from [[http://en.wikipedia.org/wiki/Photosynthesis photosynthesis]] to the fungus (Allen). Overall, this is a small price for the plant to pay given that the fungus is providing nutrients and water that will allow it to prosper in its given environment.<br />
<br />
==[[http://en.wikipedia.org/wiki/Ecological_niche Niche]]==<br />
Overall, the relationship between plants and mycorrhizal fungi depend mainly on the availability of [[http://en.wikipedia.org/wiki/Nitrogen nitrogen]], [[http://en.wikipedia.org/wiki/Phosphorus phosphorus]], [[http://en.wikipedia.org/wiki/Carbon carbon]], and [[http://en.wikipedia.org/wiki/Water water]] (Allen). Since areas within the environment vary in nutrient and water availability, this can have a major effect on whether or not a mycorrhizal relationship can form between a plant and the fungus.<br />
<br />
===Environment suitable for mycorrhizae===<br />
With this said, if an environment's soil does not contain much nitrogen and phosphorus, it is likely that a mycorrhizal relationship will occur and a plant is more likely to allocate its carbon to the roots (Kleczewski). This is because the plant needs nitrogen and phosphorus in order to prosper. This can also be true in areas where water is not easily accessible. As noted earlier, mycorrhizae expand the surface area of roots and therefore aid in the uptake of water. If an environment is lacking in moisture available to plants, it is likely that a mycorrhizal symbiosis will occur to aid in the uptake of water.<br />
<br />
===Environment not suitable for mycorrhizae===<br />
On the other hand, if an area contains large amounts of nitrogen, phosphorus, or water, it is not likely that a plant will allocate its carbon to its roots and therefore it is not likely that a symbiotic relationship with mycorrhizae will occur (Kleczewski). This is because the benefit to the fungus would be greater than that for the plant. Since the plant already has enough availability to nutrients and water, there would be no reason for them to give up their carbon for this relationship.<br />
<br />
==Key [[http://en.wikipedia.org/wiki/Microorganisms Microorganisms]]==<br />
<br />
<br />
[[Image:endoandecto.jpg|thumb|500px|right|This picture compares the structures of endomycorrhizae (left) to ectomycorrhizae (right) ("Mycorrhizal Fungi.").]]<br />
<br />
As stated earlier, there are two main types of mycorrhizae. These include the endomycorrhizae and the ectomycorrhizae.<br />
<br />
===Endomycorrhizae===<br />
<br />
This type of mycorrhizae differs in its structure from the ectomycorrhizae. The endomycorrhizae grows in between the cells of a plant root but also forms arbuscules, which are structures that allow the fungus to penetrate the actual cells in the plant root (Sylvia). With this said, this type of mycorrhizae is more invasive than that of the ectomycorrhizae.<br />
<br />
====Ericaceous Mycorrhizae====<br />
<br />
Ericaceous mycorrhizae are a type of endomycorrhizae that penetrate the root cells without creating arbuscules and this relationship is found on vegetation within the order of [[http://en.wikipedia.org/wiki/Ericales Ericales]] (Sylvia).<br />
<br />
====Orchidaceous Mycorrhizae====<br />
<br />
This is another type of endomycorrhizae association, but is needed to supply carbon and other nutrients to plants within the [[http://en.wikipedia.org/wiki/Orchidaceae Orchidaceae]] order by penetrating the root cells and creating hyphal coils (Sylvia).<br />
<br />
===Ectomycorrhizae===<br />
<br />
Ectomycorrhizae differs from endomycorrhizae in its structure. This fungus produces a system of [[http://en.wikipedia.org/wiki/Hyphae hyphae]], called the [[http://en.wikipedia.org/wiki/Hartig_net hartig net]], in between the cells in the root of a plant (Sylvia). With this said, the mycorrhizae is within the plant root, but does not enter the actual cells of the roots and instead travels between the root cells. This fungus also forms a mantle around the outside of the roots of plants and increases the surface area of the roots (Sylvia). With this sheath, the endomycorrhizae are able to increase the plant's ability to obtain nutrients and water.<br />
<br />
==Microbial processes==<br />
<br />
This relationship between the fungus and a plant can obviously have a great impact on the environment. In areas where drought is prevalent, the plants that are able to use mychorrhizae to increase root surface area and obtain water will have an advantage over those without this symbiotic relationship. The same can be said about environments that are low in nutrients such as nitrogen and phosphorus. The plants that can have this association with mycorrhizal fungi will have a greater chance in inhabiting this area.<br />
<br />
===Agriculture===<br />
<br />
Since mycorrhizal relationships can help to increase plant growth and therefore yield, they can be beneficial in agricultural fields. An increase in yield for farmers also means an increase in income. With this said, this symbiotic relationship in agricultural fields would increase crop production and therefore food output. <br />
<br />
The mycorrhizal fungi also aids in soil aggregation, which can increase water [[http://en.wikipedia.org/wiki/Filtration filtration]] and gas exchange within the soil (Sylvia). With an increase in gas exchange, the mycorrhizal fungi can aid in the aeration of agricultural fields. This, along with the other benefits of mycorrhizae, can increase the crop yield.<br />
<br />
===Restoration===<br />
<br />
This symbiotic relationship can also be helpful in restoration areas. Since the fungus allows certain plants to be greater competitors and can allow them to prosper in areas low in nutrients and water, they would be very useful in restoration efforts. Not only could this partnership increase a plant's ability to colonize an area, they would also have a greater capacity to out compete invasive species.<br />
<br />
==Current Research==<br />
<br />
Since mycorrhizae can form beneficial relationships with plants, many experiments have been performed to research the extent of these advantages.<br />
<br />
==="Influence of Arbuscular Mycorrhizae on the Root System of Maize Plants under Salt Stress"===<br />
<br />
This experiment aimed at discovering the effect of [[http://en.wikipedia.org/wiki/Salinity salinity]] on corn with mycorrhizal relationships. The effect of salinity was tested because of its ability to reduce growth and yield of crops. On the other hand, arbuscular mycorrhizae (endomycorrhizae) is known for its ability to increase the growth and yields of plants. In order to conduct this experiment, corn was planted in soil with five different salinity levels for a total of fifty-five days. Half the corn in each different salinity level had a mycorrhizal partnership while the other half of the corn did not. After the days were up, the plants were then removed and their root biomass, root morphology, and root activity. The compiled data showed that the corn associated with the arbuscular mycorrhizae had a larger root biomass, root [[http://en.wikipedia.org/wiki/Morphology_%28biology%29 morphology]], and root activity in all of the salinity levels compared with the corn without the symbiotic association. All in all, this research showed that the corn with the arbuscular mycorrhizae was able to alleviate some of the stress caused by high salinity levels.<br />
<br />
==="Contribution of Mycorrhizae to Early Growth and Phosphorus Uptake by a Neotropical Palm"===<br />
<br />
In this experiment, the association between <i>[[http://en.wikipedia.org/wiki/Desmoncus_orthacanthos Desmoncus orthacanthos]]</i> and arbuscular mycorrhizae was tested. <i>Desmoncus orthacanthos</i> is known for its large roots that do not branch and do not have many hairs. Due to this, research was done to test the ability of the mycorrhizae to increase phosphorus uptake and to increase the growth of the plant seedlings. Seedlings were planted in soil with three different levels of phosphorus for a total of one hundred and sixty days. Half of the seedlings had a partnership with the arbuscular mycorrhizae while the other half did not have an association with this fungus. After the experiment was over, the growth of each seedling was measured. Overall, the concentration of phosphorus in the seedlings increased with the mycorrhizae association as well as with the increased phosphorus in the soil. This experiment revealed that it is very beneficial for <i>Desmoncus orthacanthos</i> seedlings to have a partnership with arbuscular mycorrhizae especially when they are in soil with low levels of phosphorus.<br />
<br />
==="Arbuscular Mycorrhizae Improves Low Temperature Stress in Maize via Alterations in Host Water Status and Photosynthesis"===<br />
<br />
This experiment tested the effect of low temperatures on the growth of corn. Low temperatures are an [[http://en.wikipedia.org/wiki/Abiotic abiotic]] factor that can greatly reduce and limit the growth of plants. With this said, this experiment tested the ability of arbuscular mycorrhizae on the water uptake, growth, and [[http://en.wikipedia.org/wiki/Chlorophyll chlorophyll]] concentration in corn. In order to carry out this research, corn with and without arbuscular mycorrhizae associations were planted in soil for seven weeks in a temperature of twenty-five degrees Celsius. Next, the plants were introduced to temperatures of five degrees Celsius, fifteen degrees Celsius, and twenty-five degrees Celsius for a week. After the results were compiled, it was shown that as the temperature decreased, so did the concentration of arbuscular mycorrhizae on the roots of the corn that had this symbiotic relationship. Although the concentration of the fungi did decrease with temperature, the corn with the mycorrhizal association showed a higher plant growth, dry root weight, water uptake, chlorophyll concentration, and photosynthesis rate than the corn without this partnership. Overall, this experiment came to the conclusion that with arbuscular mycorrhizae, corn has the ability to improving its water uptake and photosynthesis rate when exposed to low temperatures.<br />
<br />
==References==<br />
Allen, M, et al. "Ecology of Mycorrhizae: A Conceptual Framework for Complex Interactions Among Plants and Fungi." Phytopathology 41 (Sept. 2003): 271-300. Annual Reviews. Web. 28 March 2011. <http://www.annualreviews.org/doi/full/10.1146/annurev.phyto.41.052002.095518>. <br />
<br />
<br />
Amaranthus, Mike. "Mycorrhizal Fungi Benefits." Heart Spring. N.p., 11 Jan. 2011. Web. 5 Apr. 2011. <http://heartspring.net<br />
/mycorrhizal_fungi_benefits.html>.<br />
<br />
<br />
Min Sheng, et al."Influence of arbuscular mycorrhizae on the root system of maize plants under salt stress". Canadian Journal of Microbiology, <br />
Jul2009, Vol. 55 Issue 7, p879-886.<br />
<br />
<br />
"Mycorrhizal Fungi." Soil Biological Communities. N.p., n.d. Web. 4 Apr. 2011. <http://www.blm.gov/nstc/soil/fungi/index.html>. <br />
<br />
<br />
Kleczewski, Nathan M, et al. "Effects of soil type, fertilization and drought on carbon allocation to root growth and partitioning between secondary <br />
metabolism and ectomycorrhizae of Betula papyrifera." Tree Physiology, July 2010, Vol. 30 Issue 7, 807-817.<br />
<br />
<br />
Ramos-Zapata, Jose, et al. "Contribution of Mycorrhizae to Early Growth and Phosphorus Uptake by a Neotropical Palm". Journal of Plant Nutrition, May <br />
2009, Vol. 32 Issue 5, 855-866.<br />
<br />
<br />
Sylvia, David, et al. Principles and Applications of Soil Microbiology. Upper Saddle River, NJ: Pearson, 2005.<br />
<br />
<br />
Xian-Can, Zhu, et al."Arbuscular mycorrhizae improves low temperature stress in maize via alterations in host water status and photosynthesis". Plant <br />
& Soil, Jun2010, Vol. 331 Issue 1-2, p129-137.<br />
<br />
<br />
Edited by Lisa Reger, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=59156University of Illinois2011-04-07T20:59:41Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Acidic hot springs]]<br />
<br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Deep subsurface microbes]]<br />
<br />
[[Forest soils]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=59155University of Illinois2011-04-07T20:57:16Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Acidic hot springs]]<br />
<br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Forest soils]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=University_of_Illinois&diff=59154University of Illinois2011-04-07T20:56:28Z<p>Akent: </p>
<hr />
<div>Index to pages authored by students of Angela Kent at the University of Illinois<br />
<br />
<b>Created in 2010</b><br><br />
[[Acid mine drainage]]<br />
<br />
[[Agricultural field]]<br />
<br />
[[Alaskan tundra]]<br />
<br />
[[Biofilms on food preparation surfaces]]<br />
<br />
[[Blood Falls, Antarctica]]<br />
<br />
[[Cave]]<br />
<br />
[[Estuaries]]<br />
<br />
[[Karst Springs]]<br />
<br />
[[Lichens]]<br />
<br />
[[Mangroves]]<br />
<br />
[[Phyllosphere]]<br />
<br />
[[Plant endophyte]]<br />
<br />
[[Rio Tinto (Spain)]]<br />
<br />
[[Salt Marsh]]<br />
<br />
[[Soil Crust]]<br />
<br />
[[Stream biofilm]]<br />
<br />
[[Tropical Rainforest]]<br />
<br />
[[Volcano Fields]]<br />
<br />
[[Wetlands]]<br />
<br />
<b>Created in 2011</b><br><br />
[[Alkaline hot springs]]<br />
<br />
[[Alliaria Petiolata and Mycorrhiza]]<br />
<br />
[[Anchialine pools and cenotes]]<br />
<br />
[[Aquifer]]<br />
<br />
[[Arctic habitats]]<br />
<br />
[[Forest soils]]<br />
<br />
[[Fungiculture]]<br />
<br />
[[Grasses and endophytic fungi]]<br />
<br />
[[Groundwater]]<br />
<br />
[[Leafcutter ants, fungi, and bacteria]]<br />
<br />
[[Microbes and invasive plants]]<br />
<br />
[[Microbial loop]]<br />
<br />
[[Mycoheterotrophy]]<br />
<br />
[[Mycorrhizae]]<br />
<br />
[[Oil spills]]<br />
<br />
[[Prairie Soils]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Mycorrhizae&diff=59153Mycorrhizae2011-04-07T20:53:51Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
==Introduction==<br />
<br />
[[Image:withandwithout.jpg|thumb|500px|right|This picture shows the increase in root growth of a redwood seeding with a mycorrhizal relationship (right) compared to a redwood seeding without this symbiotic relationship (left). Photo credit: Mike Amaranthus, USDA (Amaranthus).]]<br />
<br />
<br />
Mycorrhizae can be described as a [[http://en.wikipedia.org/wiki/Symbiotic symbiotic]] relationship between a [[http://en.wikipedia.org/wiki/Fungus fungus]] and a plant (Sylvia). Due to the fact that this is a symbiotic relationship, both the fungus and the plant benefit from this interaction. Since the plants are aboveground, it is often easier to see the benefits of this association for the plant, but the fungus also takes advantage of this partnership. The mycorrhizae aid the plant with growth, yield, improved fitness, increase the root absorption area of nutrients, while the fungus receives carbon from the associated plant (Sylvia). This is an important interaction due to the benefits that the plants receive. Improved plant growth and yield can aid in the production of crops and therefore produce more plants per area. Although mycorrhizae produce the same overall effects, there are two main types of this fungus. Endomycorrhizae and ectomycorrhizae are the two main types of mycorrhizae that produce the same overall results, but with different fungal characteristics (Allen). Below, more will be explained about the interaction between the fungus and plant, the niches that they are able to occupy, descriptions of the types of mycorrhizae, and the microbial processes that occur.<br />
<br />
==Biological interaction==<br />
As stated above, mycorrhizae create a symbiotic relationship between a plant and a fungus where both organisms benefit from the interaction. Although both the plant and fungi benefit from the partnership, they benefit in different ways. <br />
<br />
===Benefits for Plants===<br />
Mycorrhizae are able to create a vast connection between the roots of a plant and with the soil around them, which allows for the fungus to uptake nutrients such as [[http://en.wikipedia.org/wiki/Nitrogen nitrogen]] and phosphorus for the plant and increase the surface area of the roots (Sylvia). With this increased surface area, it is obvious that the plant will have many benefits. This increase in area within the soil will increase the availability of nutrients and water for the plants consumption. Since nutrients and water are needed in order for plant growth, this mycorrhizal interaction can lead to an increase in the growth of the plant.<br />
<br />
This increase in nutrient availability for the plant leads to even more advantages. A plant with a mycorrhizae interaction will be able to increase its nutrient and water uptake, while a plant without this partnership will just have to rely on its roots for the uptake of materials. If a plant with this symbiosis is in an area with plants who do not have a mycorrhizae partnership, the fungi and plant partnership can give the plant the ability to out compete other plants. Overall, this means that mycorrhizae interactions can lead to changes in the plant composition of an area.<br />
<br />
===Benefits for the [http://en.wikipedia.org/wiki/Fungi Fungi]===<br />
Since this is a symbiotic relationship, the fungus benefits from the partnership as well. While aiding plants in the uptake of nutrients and water, the plants will give ten to twenty percent of the carbon they obtain from [[http://en.wikipedia.org/wiki/Photosynthesis photosynthesis]] to the fungus (Allen). Overall, this is a small price for the plant to pay given that the fungus is providing nutrients and water that will allow it to prosper in its given environment.<br />
<br />
==[[http://en.wikipedia.org/wiki/Ecological_niche Niche]]==<br />
Overall, the relationship between plants and mycorrhizal fungi depend mainly on the availability of [[http://en.wikipedia.org/wiki/Nitrogen nitrogen]], [[http://en.wikipedia.org/wiki/Phosphorus phosphorus]], [[http://en.wikipedia.org/wiki/Carbon carbon]], and [[http://en.wikipedia.org/wiki/Water water]] (Allen). Since areas within the environment vary in nutrient and water availability, this can have a major effect on whether or not a mycorrhizal relationship can form between a plant and the fungus.<br />
<br />
===Environment suitable for mycorrhizae===<br />
With this said, if an environment's soil does not contain much nitrogen and phosphorus, it is likely that a mycorrhizal relationship will occur and a plant is more likely to allocate its carbon to the roots (Kleczewski). This is because the plant needs nitrogen and phosphorus in order to prosper. This can also be true in areas where water is not easily accessible. As noted earlier, mycorrhizae expand the surface area of roots and therefore aid in the uptake of water. If an environment is lacking in moisture available to plants, it is likely that a mycorrhizal symbiosis will occur to aid in the uptake of water.<br />
<br />
===Environment not suitable for mycorrhizae===<br />
On the other hand, if an area contains large amounts of nitrogen, phosphorus, or water, it is not likely that a plant will allocate its carbon to its roots and therefore it is not likely that a symbiotic relationship with mycorrhizae will occur (Kleczewski). This is because the benefit to the fungus would be greater than that for the plant. Since the plant already has enough availability to nutrients and water, there would be no reason for them to give up their carbon for this relationship.<br />
<br />
==Key [[http://en.wikipedia.org/wiki/Microorganisms Microorganisms]]==<br />
<br />
<br />
[[Image:endoandecto.jpg|thumb|500px|right|This picture compares the structures of endomycorrhizae (left) to ectomycorrhizae (right) ("Mycorrhizal Fungi.").]]<br />
<br />
As stated earlier, there are two main types of mycorrhizae. These include the endomycorrhizae and the ectomycorrhizae.<br />
<br />
===Endomycorrhizae===<br />
<br />
This type of mycorrhizae differs in its structure from the ectomycorrhizae. The endomycorrhizae grows in between the cells of a plant root but also forms arbuscules, which are structures that allow the fungus to penetrate the actual cells in the plant root (Sylvia). With this said, this type of mycorrhizae is more invasive than that of the ectomycorrhizae.<br />
<br />
====Ericaceous Mycorrhizae====<br />
<br />
Ericaceous mycorrhizae are a type of endomycorrhizae that penetrate the root cells without creating arbuscules and this relationship is found on vegetation within the order of [[http://en.wikipedia.org/wiki/Ericales Ericales]] (Sylvia).<br />
<br />
====Orchidaceous Mycorrhizae====<br />
<br />
This is another type of endomycorrhizae association, but is needed to supply carbon and other nutrients to plants within the [[http://en.wikipedia.org/wiki/Orchidaceae Orchidaceae]] order by penetrating the root cells and creating hyphal coils (Sylvia).<br />
<br />
===Ectomycorrhizae===<br />
<br />
Ectomycorrhizae differs from endomycorrhizae in its structure. This fungus produces a system of [[http://en.wikipedia.org/wiki/Hyphae hyphae]], called the [[http://en.wikipedia.org/wiki/Hartig_net hartig net]], in between the cells in the root of a plant (Sylvia). With this said, the mycorrhizae is within the plant root, but does not enter the actual cells of the roots and instead travels between the root cells. This fungus also forms a mantle around the outside of the roots of plants and increases the surface area of the roots (Sylvia). With this sheath, the endomycorrhizae are able to increase the plant's ability to obtain nutrients and water.<br />
<br />
==Microbial processes==<br />
<br />
This relationship between the fungus and a plant can obviously have a great impact on the environment. In areas where drought is prevalent, the plants that are able to use mychorrhizae to increase root surface area and obtain water will have an advantage over those without this symbiotic relationship. The same can be said about environments that are low in nutrients such as nitrogen and phosphorus. The plants that can have this association with mycorrhizal fungi will have a greater chance in inhabiting this area.<br />
<br />
===Agriculture===<br />
<br />
Since mycorrhizal relationships can help to increase plant growth and therefore yield, they can be beneficial in agricultural fields. An increase in yield for farmers also means an increase in income. With this said, this symbiotic relationship in agricultural fields would increase crop production and therefore food output. <br />
<br />
The mycorrhizal fungi also aids in soil aggregation, which can increase water [[http://en.wikipedia.org/wiki/Filtration filtration]] and gas exchange within the soil (Sylvia). With an increase in gas exchange, the mycorrhizal fungi can aid in the aeration of agricultural fields. This, along with the other benefits of mycorrhizae, can increase the crop yield.<br />
<br />
===Restoration===<br />
<br />
This symbiotic relationship can also be helpful in restoration areas. Since the fungus allows certain plants to be greater competitors and can allow them to prosper in areas low in nutrients and water, they would be very useful in restoration efforts. Not only could this partnership increase a plant's ability to colonize an area, they would also have a greater capacity to out compete invasive species.<br />
<br />
==Current Research==<br />
<br />
Since mycorrhizae can form beneficial relationships with plants, many experiments have been performed to research the extent of these advantages.<br />
<br />
==="Influence of Arbuscular Mycorrhizae on the Root System of Maize Plants under Salt Stress"===<br />
<br />
This experiment aimed at discovering the effect of [[http://en.wikipedia.org/wiki/Salinity salinity]] on corn with mycorrhizal relationships. The effect of salinity was tested because of its ability to reduce growth and yield of crops. On the other hand, arbuscular mycorrhizae (endomycorrhizae) is known for its ability to increase the growth and yields of plants. In order to conduct this experiment, corn was planted in soil with five different salinity levels for a total of fifty-five days. Half the corn in each different salinity level had a mycorrhizal partnership while the other half of the corn did not. After the days were up, the plants were then removed and their root biomass, root morphology, and root activity. The compiled data showed that the corn associated with the arbuscular mycorrhizae had a larger root biomass, root [[http://en.wikipedia.org/wiki/Morphology_%28biology%29 morphology]], and root activity in all of the salinity levels compared with the corn without the symbiotic association. All in all, this research showed that the corn with the arbuscular mycorrhizae was able to alleviate some of the stress caused by high salinity levels.<br />
<br />
==="Contribution of Mycorrhizae to Early Growth and Phosphorus Uptake by a Neotropical Palm"===<br />
<br />
In this experiment, the association between <i>[[http://en.wikipedia.org/wiki/Desmoncus_orthacanthos Desmoncus orthacanthos]]</i> and arbuscular mycorrhizae was tested. <i>Desmoncus orthacanthos</i> is known for its large roots that do not branch and do not have many hairs. Due to this, research was done to test the ability of the mycorrhizae to increase phosphorus uptake and to increase the growth of the plant seedlings. Seedlings were planted in soil with three different levels of phosphorus for a total of one hundred and sixty days. Half of the seedlings had a partnership with the arbuscular mycorrhizae while the other half did not have an association with this fungus. After the experiment was over, the growth of each seedling was measured. Overall, the concentration of phosphorus in the seedlings increased with the mycorrhizae association as well as with the increased phosphorus in the soil. This experiment revealed that it is very beneficial for <i>Desmoncus orthacanthos</i> seedlings to have a partnership with arbuscular mycorrhizae especially when they are in soil with low levels of phosphorus.<br />
<br />
==="Arbuscular Mycorrhizae Improves Low Temperature Stress in Maize via Alterations in Host Water Status and Photosynthesis"===<br />
<br />
This experiment tested the effect of low temperatures on the growth of corn. Low temperatures are an [[http://en.wikipedia.org/wiki/Abiotic abiotic]] factor that can greatly reduce and limit the growth of plants. With this said, this experiment tested the ability of arbuscular mycorrhizae on the water uptake, growth, and [[http://en.wikipedia.org/wiki/Chlorophyll chlorophyll]] concentration in corn. In order to carry out this research, corn with and without arbuscular mycorrhizae associations were planted in soil for seven weeks in a temperature of twenty-five degrees Celsius. Next, the plants were introduced to temperatures of five degrees Celsius, fifteen degrees Celsius, and twenty-five degrees Celsius for a week. After the results were compiled, it was shown that as the temperature decreased, so did the concentration of arbuscular mycorrhizae on the roots of the corn that had this symbiotic relationship. Although the concentration of the fungi did decrease with temperature, the corn with the mycorrhizal association showed a higher plant growth, dry root weight, water uptake, chlorophyll concentration, and photosynthesis rate than the corn without this partnership. Overall, this experiment came to the conclusion that with arbuscular mycorrhizae, corn has the ability to improving its water uptake and photosynthesis rate when exposed to low temperatures.<br />
<br />
==References==<br />
Allen, M, et al. "Ecology of Mycorrhizae: A Conceptual Framework for Complex Interactions Among Plants and Fungi." Phytopathology 41 (Sept. 2003): 271-300. Annual Reviews. Web. 28 March 2011. <http://www.annualreviews.org/doi/full/10.1146/annurev.phyto.41.052002.095518>. <br />
<br />
<br />
Amaranthus, Mike. "Mycorrhizal Fungi Benefits." Heart Spring. N.p., 11 Jan. 2011. Web. 5 Apr. 2011. <http://heartspring.net<br />
/mycorrhizal_fungi_benefits.html>.<br />
<br />
<br />
Min Sheng, et al."Influence of arbuscular mycorrhizae on the root system of maize plants under salt stress". Canadian Journal of Microbiology, <br />
Jul2009, Vol. 55 Issue 7, p879-886.<br />
<br />
<br />
"Mycorrhizal Fungi." Soil Biological Communities. N.p., n.d. Web. 4 Apr. 2011. <http://www.blm.gov/nstc/soil/fungi/index.html>. <br />
<br />
<br />
Kleczewski, Nathan M, et al. "Effects of soil type, fertilization and drought on carbon allocation to root growth and partitioning between secondary <br />
metabolism and ectomycorrhizae of Betula papyrifera." Tree Physiology, July 2010, Vol. 30 Issue 7, 807-817.<br />
<br />
<br />
Ramos-Zapata, Jose, et al. "Contribution of Mycorrhizae to Early Growth and Phosphorus Uptake by a Neotropical Palm". Journal of Plant Nutrition, May <br />
2009, Vol. 32 Issue 5, 855-866.<br />
<br />
<br />
Sylvia, David, et al. Principles and Applications of Soil Microbiology. Upper Saddle River, NJ: Pearson, 2005.<br />
<br />
<br />
Xian-Can, Zhu, et al."Arbuscular mycorrhizae improves low temperature stress in maize via alterations in host water status and photosynthesis". Plant <br />
& Soil, Jun2010, Vol. 331 Issue 1-2, p129-137.<br />
<br />
<br />
Edited by Lisa Reger, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Leafcutter_ants,_fungi,_and_bacteria&diff=59016Leafcutter ants, fungi, and bacteria2011-04-06T15:14:01Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br />
<br />
==Introduction== <br />
[[Image:leafcolony.jpg|Thumb|653px|right|foraging ants carry back cuts of leaves.]]Microorganisms often require a symbiotic relationship with other organisms in order to reproduce and survive. This symbiotic relationship is shown through the relationship between leafcutter ants, fungi, and bacteria. Sometimes refered to as the "First Agriculture," this relationship can be compared to farmer (the ants) cultivating its crops (the fungus). Up until recently, the fungal colonies seemed to be free of any pests or parasites. This was thought to be because the ants were so diligent in caring for the fungus that they did not allow any parasites to enter and take hold. Cameron Currie was the first to look at why the nests were pest free. He concluded that the ants carried a white powdery bacteria on their abdomens that had antimicrobial properties. Without the ants, the parasitic mold could take over the fungus in the colony in a matter of days.<br />
<br />
==Symbiotic Processes==<br />
<br />
[[Image:fungus.jpg|Thumb|200px|right|A worker ant harvesting the fungus. http://scienceblogs.com/notrocketscience/2009/11/leafcutter_ants_rely_on_bacteria_to_fertilise_their_fungus_g.php]]<br />
<br />
===Main Functions===<br />
The fungus and the ants depend on each other for survival. The ants cultivate the fungus in its colonies from chewed up leaves and at the same time the fungus acts as the main food source for the ants. One symbiotic partner can not survive without the other.<br />
====Fungi Growth====<br />
The leaves in the rain forest have toxic qualities in them which is supposed to deter herbivory. But the harvesting ants cut the leaves without ingesting any of the toxins and are able to bring the leaves back to the nest. There the leaves are given to worker ants which chew up the leaves in their mouths into a paste which becomes the food source for the fungus. The plant material is broken down through enzymes that break down the proteins and starches. Depending on the colony, the enzymes can slightly different between complete plant break down and those that focus mainly on plant wall digestion. Because of the symbiotic relationship, the toxins in the leaves are broken down by the fungi into needed sugars and proteins safe for the ant to consume. <br />
<br><br />
<br />
===Bacterial resistance to fungal parasites===<br />
To maintain a clean and healthy fungus colony, the ants have a bacteria on their exoskeleton which they use when cultivating the fungus. Some ants have this on their underbelly while ants that are in constant contact with the fungus are almost completely covered with the bacteria. This bacteria is similar to the bacterium which is produces half the antibiotics made today. The antibiotic qualities allow it to specifically work with the fungus to inhibit the parasitic mold.<br />
<br><br />
<br><br />
Unlike the ant, fungi, and bacteria symbiosis, present day antibiotics often produce resistant types of pathogens. It is thought that the ant colonies do not produce antibiotic resistant molds because of the high diversity of the bacteria and as the two evolve together the parasitic mold will not evolve a resistance.<br />
<br><br />
<br><br />
Another method to cultivate only its native strain of Pseudonocardia is that the ant's feces contain incompatibility chemicals which select only for its resident fungus. There are also behavior cues which suggest that the ants physically pick out other types of fungus.<br />
<br />
==Environmental Implications==<br />
The millions of ants in the forests have a huge effect on the ecosystem. They consume 15-20% of fresh vegetation and up to 240 kg of dry leaves per year. They make up 86% of the total anthropod biomass. For such a small organism, it has a huge effect.<br />
<br><br />
===Nitrogen Fixation===<br />
<br />
Like any other garden, the ant's fungus garden needs nitrogen. Because of the low nitrogen ratio in leaves, there are nitrogen fixing bacteria in the colonies that help to introduce usable nitrogen into the system. The n-fixing bacteria fixes enough nitrogen for the fungus and the ants and also leaves a large amount in the refuse of the colony. This nitrogen can be worked back into the surrounding system replenishing the nutrient poor tropical environment with an essential limiting nutrient.<br />
<br><br />
<br />
==Niche==<br />
<br />
[[Image:Colonies.jpg|Thumb|259px|right|An underground chamber where the fungus and the queen is housed. http://laanitarainforestranch.com/pages/leafcutterants.htm]]<br />
<br />
===<b>Habitat</b>===<br />
The ant's nests are subterranean and can be found in mostly tropical areas including Costa Rica, Panama, and Argentina.<br />
<br><br />
===<b>Nest Characteristics</b>=== <br />
Nests begin when a queen ant leaves one nest with a small amount of the fungus in her mouth and moves to a different area to start her own colony. Once a nest becomes established, the colonies can grow to have millions of ants in them. <br />
<br><br />
These subterranean nests vary in sizes. They can be small with a single fungus growing "room" or can be multiple feet below ground with many different rooms and complex tunnels. Ants are also known as organized and clean insects. They have certain refuse dumps where the worker ants take the garbage and seclude it from the rest of the colony to decrease contamination. <br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
<br />
===<b>Ants</b>=== <br />
The group of ants that are LeafCutters belong to the tribe <i>attini</i> and their genera is <i>Atta</i> and <i>acromyrmex</i> These ants have been around for the better part of 50 million years. Interestingly, these ants are consume the largest amount of primary producers in the tropical rainforest areas which is not surprising considering their biomass is four times the amount of other invertebrates. World wide, these insects take up a third of the total insect biomass.<br />
<br />
===Fungi=== <br />
Playing the role of both a decomposer and the primary food source for the Leafcutters, the fungi from the family <i>Lepiotaceae</i> is grown underground in the nests chambers by the worker ants. <br />
<br />
====Parasites====<br />
Battling against the ant's seemingly clean fungis' agriculture are parasites that would quickly take over the colony's fungus growth if not carefully weeded against. These parasites are refered to as <i>escovopsis</i> would feed on the fungus.<br />
===Bacteria=== <br />
One of the most interesting and only recently discovered partners is the antibiotic producing bacteria <i>pseudonocardia</i><br />
<br><br />
There has recently been research conducted on a fourth bacterial partner. This is a black mold that can be found on the cuticle of the ant and is used in a similar fashion in discouraging parasitic growth. This mold works like other fungis cultivating symbiots and helps to discourage the growth of parasites on the fungus.<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Coevolution between attine ants and actinomycete bacteria===<br />
It has been the thought that the close relationship between the ant and the bacteria has caused the two to evolve together. But the study looks at if that is truly so. It concluded that the ant has probably evolved with the bacteria, but the bacteria has evolved independently. The study states that more research needs to be done on the reciprocality of the evolving partners.<br />
<br />
===Enzyme activity activity in different ant colonies===<br />
Ants have evolved into different sister clades. This research shows how the enzyme activity between lower and higher evolved colonies has changed. The study shows that higher evolved colonies contain more protein and starch digesting enzymes while those of lower clades have enzymes that just focus on <i>partial</i> degradation of the plant material.<br />
<br />
===Ant Genome===<br />
The complete ant genome has recently been mapped out. With that, their are multiple studies going on about the evolution of the ants with its symbiotic partners and other attributes of the ant. Especial focus is put on the antimicrobial properties of the bacteria.<br />
<br />
===Evolution and Competition===<br />
There are studies conducted to how the ant and its partners have evolved together and how they originally came to work together. This has led to studies on how the partners work to discourage different types of fungus and bacteria in interfering. This interference could lead to an instability within the network. Resistant pathogenic molds are also a source of research to see why they have not evolved over the years to take over the fungus.<br />
<br />
==References==<br />
Ask Nature, A project of the Biomimicry Institute. <http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4><br />
<br />
Dash, D., Mueller, U., Rabeling, C.,Rodrigues, A., 2008. "COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION." Evolution 62. 11:2894-2912. Academic Search Premier. EBSCO. Web. 5 Apr. 2011.<br />
<br />
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G., & Boomsma, J. J. (2010). EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS. Evolution, 64(7), 2055-2069. <br />
<br />
Little, A., Currie, C. 2007. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant-microbe symbiosis." PubMed.gov. 3(5):501-504<br />
<br />
Pinto-Tomas, A., Anderson, M., Suen, G., Stevensen, D., Chu, F., Cleland, W., Weimer, P., Currie, C. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants.” Science. 326: 1120-1123.<br />
<br />
Ulrich, M., Schultz, T., Currie, C., Adams, R., Malloch, D. 2001. "The origin of the attin ant-fungus mutualism." 76:169-197 <br />
<br />
Edited by <Katie Yi>, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Leafcutter_ants,_fungi,_and_bacteria&diff=59015Leafcutter ants, fungi, and bacteria2011-04-06T15:13:41Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br />
<br />
==Introduction== <br />
[[Image:leafcolony.jpg|Thumb|653px|right|foraging ants carry back cuts of leaves.]]<br />
<br />
<br />
<br />
<br />
<br />
Microorganisms often require a symbiotic relationship with other organisms in order to reproduce and survive. This symbiotic relationship is shown through the relationship between leafcutter ants, fungi, and bacteria. Sometimes refered to as the "First Agriculture," this relationship can be compared to farmer (the ants) cultivating its crops (the fungus). Up until recently, the fungal colonies seemed to be free of any pests or parasites. This was thought to be because the ants were so diligent in caring for the fungus that they did not allow any parasites to enter and take hold. Cameron Currie was the first to look at why the nests were pest free. He concluded that the ants carried a white powdery bacteria on their abdomens that had antimicrobial properties. Without the ants, the parasitic mold could take over the fungus in the colony in a matter of days.<br />
<br />
==Symbiotic Processes==<br />
<br />
[[Image:fungus.jpg|Thumb|200px|right|A worker ant harvesting the fungus. http://scienceblogs.com/notrocketscience/2009/11/leafcutter_ants_rely_on_bacteria_to_fertilise_their_fungus_g.php]]<br />
<br />
===Main Functions===<br />
The fungus and the ants depend on each other for survival. The ants cultivate the fungus in its colonies from chewed up leaves and at the same time the fungus acts as the main food source for the ants. One symbiotic partner can not survive without the other.<br />
====Fungi Growth====<br />
The leaves in the rain forest have toxic qualities in them which is supposed to deter herbivory. But the harvesting ants cut the leaves without ingesting any of the toxins and are able to bring the leaves back to the nest. There the leaves are given to worker ants which chew up the leaves in their mouths into a paste which becomes the food source for the fungus. The plant material is broken down through enzymes that break down the proteins and starches. Depending on the colony, the enzymes can slightly different between complete plant break down and those that focus mainly on plant wall digestion. Because of the symbiotic relationship, the toxins in the leaves are broken down by the fungi into needed sugars and proteins safe for the ant to consume. <br />
<br><br />
<br />
===Bacterial resistance to fungal parasites===<br />
To maintain a clean and healthy fungus colony, the ants have a bacteria on their exoskeleton which they use when cultivating the fungus. Some ants have this on their underbelly while ants that are in constant contact with the fungus are almost completely covered with the bacteria. This bacteria is similar to the bacterium which is produces half the antibiotics made today. The antibiotic qualities allow it to specifically work with the fungus to inhibit the parasitic mold.<br />
<br><br />
<br><br />
Unlike the ant, fungi, and bacteria symbiosis, present day antibiotics often produce resistant types of pathogens. It is thought that the ant colonies do not produce antibiotic resistant molds because of the high diversity of the bacteria and as the two evolve together the parasitic mold will not evolve a resistance.<br />
<br><br />
<br><br />
Another method to cultivate only its native strain of Pseudonocardia is that the ant's feces contain incompatibility chemicals which select only for its resident fungus. There are also behavior cues which suggest that the ants physically pick out other types of fungus.<br />
<br />
==Environmental Implications==<br />
The millions of ants in the forests have a huge effect on the ecosystem. They consume 15-20% of fresh vegetation and up to 240 kg of dry leaves per year. They make up 86% of the total anthropod biomass. For such a small organism, it has a huge effect.<br />
<br><br />
===Nitrogen Fixation===<br />
<br />
Like any other garden, the ant's fungus garden needs nitrogen. Because of the low nitrogen ratio in leaves, there are nitrogen fixing bacteria in the colonies that help to introduce usable nitrogen into the system. The n-fixing bacteria fixes enough nitrogen for the fungus and the ants and also leaves a large amount in the refuse of the colony. This nitrogen can be worked back into the surrounding system replenishing the nutrient poor tropical environment with an essential limiting nutrient.<br />
<br><br />
<br />
==Niche==<br />
<br />
[[Image:Colonies.jpg|Thumb|259px|right|An underground chamber where the fungus and the queen is housed. http://laanitarainforestranch.com/pages/leafcutterants.htm]]<br />
<br />
===<b>Habitat</b>===<br />
The ant's nests are subterranean and can be found in mostly tropical areas including Costa Rica, Panama, and Argentina.<br />
<br><br />
===<b>Nest Characteristics</b>=== <br />
Nests begin when a queen ant leaves one nest with a small amount of the fungus in her mouth and moves to a different area to start her own colony. Once a nest becomes established, the colonies can grow to have millions of ants in them. <br />
<br><br />
These subterranean nests vary in sizes. They can be small with a single fungus growing "room" or can be multiple feet below ground with many different rooms and complex tunnels. Ants are also known as organized and clean insects. They have certain refuse dumps where the worker ants take the garbage and seclude it from the rest of the colony to decrease contamination. <br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
<br />
===<b>Ants</b>=== <br />
The group of ants that are LeafCutters belong to the tribe <i>attini</i> and their genera is <i>Atta</i> and <i>acromyrmex</i> These ants have been around for the better part of 50 million years. Interestingly, these ants are consume the largest amount of primary producers in the tropical rainforest areas which is not surprising considering their biomass is four times the amount of other invertebrates. World wide, these insects take up a third of the total insect biomass.<br />
<br />
===Fungi=== <br />
Playing the role of both a decomposer and the primary food source for the Leafcutters, the fungi from the family <i>Lepiotaceae</i> is grown underground in the nests chambers by the worker ants. <br />
<br />
====Parasites====<br />
Battling against the ant's seemingly clean fungis' agriculture are parasites that would quickly take over the colony's fungus growth if not carefully weeded against. These parasites are refered to as <i>escovopsis</i> would feed on the fungus.<br />
===Bacteria=== <br />
One of the most interesting and only recently discovered partners is the antibiotic producing bacteria <i>pseudonocardia</i><br />
<br><br />
There has recently been research conducted on a fourth bacterial partner. This is a black mold that can be found on the cuticle of the ant and is used in a similar fashion in discouraging parasitic growth. This mold works like other fungis cultivating symbiots and helps to discourage the growth of parasites on the fungus.<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Coevolution between attine ants and actinomycete bacteria===<br />
It has been the thought that the close relationship between the ant and the bacteria has caused the two to evolve together. But the study looks at if that is truly so. It concluded that the ant has probably evolved with the bacteria, but the bacteria has evolved independently. The study states that more research needs to be done on the reciprocality of the evolving partners.<br />
<br />
===Enzyme activity activity in different ant colonies===<br />
Ants have evolved into different sister clades. This research shows how the enzyme activity between lower and higher evolved colonies has changed. The study shows that higher evolved colonies contain more protein and starch digesting enzymes while those of lower clades have enzymes that just focus on <i>partial</i> degradation of the plant material.<br />
<br />
===Ant Genome===<br />
The complete ant genome has recently been mapped out. With that, their are multiple studies going on about the evolution of the ants with its symbiotic partners and other attributes of the ant. Especial focus is put on the antimicrobial properties of the bacteria.<br />
<br />
===Evolution and Competition===<br />
There are studies conducted to how the ant and its partners have evolved together and how they originally came to work together. This has led to studies on how the partners work to discourage different types of fungus and bacteria in interfering. This interference could lead to an instability within the network. Resistant pathogenic molds are also a source of research to see why they have not evolved over the years to take over the fungus.<br />
<br />
==References==<br />
Ask Nature, A project of the Biomimicry Institute. <http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4><br />
<br />
Dash, D., Mueller, U., Rabeling, C.,Rodrigues, A., 2008. "COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION." Evolution 62. 11:2894-2912. Academic Search Premier. EBSCO. Web. 5 Apr. 2011.<br />
<br />
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G., & Boomsma, J. J. (2010). EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS. Evolution, 64(7), 2055-2069. <br />
<br />
Little, A., Currie, C. 2007. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant-microbe symbiosis." PubMed.gov. 3(5):501-504<br />
<br />
Pinto-Tomas, A., Anderson, M., Suen, G., Stevensen, D., Chu, F., Cleland, W., Weimer, P., Currie, C. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants.” Science. 326: 1120-1123.<br />
<br />
Ulrich, M., Schultz, T., Currie, C., Adams, R., Malloch, D. 2001. "The origin of the attin ant-fungus mutualism." 76:169-197 <br />
<br />
Edited by <Katie Yi>, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Leafcutter_ants,_fungi,_and_bacteria&diff=59014Leafcutter ants, fungi, and bacteria2011-04-06T15:13:33Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br />
<br />
==Introduction== [[Image:leafcolony.jpg|Thumb|653px|right|foraging ants carry back cuts of leaves.]]<br />
<br />
<br />
<br />
<br />
<br />
Microorganisms often require a symbiotic relationship with other organisms in order to reproduce and survive. This symbiotic relationship is shown through the relationship between leafcutter ants, fungi, and bacteria. Sometimes refered to as the "First Agriculture," this relationship can be compared to farmer (the ants) cultivating its crops (the fungus). Up until recently, the fungal colonies seemed to be free of any pests or parasites. This was thought to be because the ants were so diligent in caring for the fungus that they did not allow any parasites to enter and take hold. Cameron Currie was the first to look at why the nests were pest free. He concluded that the ants carried a white powdery bacteria on their abdomens that had antimicrobial properties. Without the ants, the parasitic mold could take over the fungus in the colony in a matter of days.<br />
<br />
==Symbiotic Processes==<br />
<br />
[[Image:fungus.jpg|Thumb|200px|right|A worker ant harvesting the fungus. http://scienceblogs.com/notrocketscience/2009/11/leafcutter_ants_rely_on_bacteria_to_fertilise_their_fungus_g.php]]<br />
<br />
===Main Functions===<br />
The fungus and the ants depend on each other for survival. The ants cultivate the fungus in its colonies from chewed up leaves and at the same time the fungus acts as the main food source for the ants. One symbiotic partner can not survive without the other.<br />
====Fungi Growth====<br />
The leaves in the rain forest have toxic qualities in them which is supposed to deter herbivory. But the harvesting ants cut the leaves without ingesting any of the toxins and are able to bring the leaves back to the nest. There the leaves are given to worker ants which chew up the leaves in their mouths into a paste which becomes the food source for the fungus. The plant material is broken down through enzymes that break down the proteins and starches. Depending on the colony, the enzymes can slightly different between complete plant break down and those that focus mainly on plant wall digestion. Because of the symbiotic relationship, the toxins in the leaves are broken down by the fungi into needed sugars and proteins safe for the ant to consume. <br />
<br><br />
<br />
===Bacterial resistance to fungal parasites===<br />
To maintain a clean and healthy fungus colony, the ants have a bacteria on their exoskeleton which they use when cultivating the fungus. Some ants have this on their underbelly while ants that are in constant contact with the fungus are almost completely covered with the bacteria. This bacteria is similar to the bacterium which is produces half the antibiotics made today. The antibiotic qualities allow it to specifically work with the fungus to inhibit the parasitic mold.<br />
<br><br />
<br><br />
Unlike the ant, fungi, and bacteria symbiosis, present day antibiotics often produce resistant types of pathogens. It is thought that the ant colonies do not produce antibiotic resistant molds because of the high diversity of the bacteria and as the two evolve together the parasitic mold will not evolve a resistance.<br />
<br><br />
<br><br />
Another method to cultivate only its native strain of Pseudonocardia is that the ant's feces contain incompatibility chemicals which select only for its resident fungus. There are also behavior cues which suggest that the ants physically pick out other types of fungus.<br />
<br />
==Environmental Implications==<br />
The millions of ants in the forests have a huge effect on the ecosystem. They consume 15-20% of fresh vegetation and up to 240 kg of dry leaves per year. They make up 86% of the total anthropod biomass. For such a small organism, it has a huge effect.<br />
<br><br />
===Nitrogen Fixation===<br />
<br />
Like any other garden, the ant's fungus garden needs nitrogen. Because of the low nitrogen ratio in leaves, there are nitrogen fixing bacteria in the colonies that help to introduce usable nitrogen into the system. The n-fixing bacteria fixes enough nitrogen for the fungus and the ants and also leaves a large amount in the refuse of the colony. This nitrogen can be worked back into the surrounding system replenishing the nutrient poor tropical environment with an essential limiting nutrient.<br />
<br><br />
<br />
==Niche==<br />
<br />
[[Image:Colonies.jpg|Thumb|259px|right|An underground chamber where the fungus and the queen is housed. http://laanitarainforestranch.com/pages/leafcutterants.htm]]<br />
<br />
===<b>Habitat</b>===<br />
The ant's nests are subterranean and can be found in mostly tropical areas including Costa Rica, Panama, and Argentina.<br />
<br><br />
===<b>Nest Characteristics</b>=== <br />
Nests begin when a queen ant leaves one nest with a small amount of the fungus in her mouth and moves to a different area to start her own colony. Once a nest becomes established, the colonies can grow to have millions of ants in them. <br />
<br><br />
These subterranean nests vary in sizes. They can be small with a single fungus growing "room" or can be multiple feet below ground with many different rooms and complex tunnels. Ants are also known as organized and clean insects. They have certain refuse dumps where the worker ants take the garbage and seclude it from the rest of the colony to decrease contamination. <br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
<br />
===<b>Ants</b>=== <br />
The group of ants that are LeafCutters belong to the tribe <i>attini</i> and their genera is <i>Atta</i> and <i>acromyrmex</i> These ants have been around for the better part of 50 million years. Interestingly, these ants are consume the largest amount of primary producers in the tropical rainforest areas which is not surprising considering their biomass is four times the amount of other invertebrates. World wide, these insects take up a third of the total insect biomass.<br />
<br />
===Fungi=== <br />
Playing the role of both a decomposer and the primary food source for the Leafcutters, the fungi from the family <i>Lepiotaceae</i> is grown underground in the nests chambers by the worker ants. <br />
<br />
====Parasites====<br />
Battling against the ant's seemingly clean fungis' agriculture are parasites that would quickly take over the colony's fungus growth if not carefully weeded against. These parasites are refered to as <i>escovopsis</i> would feed on the fungus.<br />
===Bacteria=== <br />
One of the most interesting and only recently discovered partners is the antibiotic producing bacteria <i>pseudonocardia</i><br />
<br><br />
There has recently been research conducted on a fourth bacterial partner. This is a black mold that can be found on the cuticle of the ant and is used in a similar fashion in discouraging parasitic growth. This mold works like other fungis cultivating symbiots and helps to discourage the growth of parasites on the fungus.<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Coevolution between attine ants and actinomycete bacteria===<br />
It has been the thought that the close relationship between the ant and the bacteria has caused the two to evolve together. But the study looks at if that is truly so. It concluded that the ant has probably evolved with the bacteria, but the bacteria has evolved independently. The study states that more research needs to be done on the reciprocality of the evolving partners.<br />
<br />
===Enzyme activity activity in different ant colonies===<br />
Ants have evolved into different sister clades. This research shows how the enzyme activity between lower and higher evolved colonies has changed. The study shows that higher evolved colonies contain more protein and starch digesting enzymes while those of lower clades have enzymes that just focus on <i>partial</i> degradation of the plant material.<br />
<br />
===Ant Genome===<br />
The complete ant genome has recently been mapped out. With that, their are multiple studies going on about the evolution of the ants with its symbiotic partners and other attributes of the ant. Especial focus is put on the antimicrobial properties of the bacteria.<br />
<br />
===Evolution and Competition===<br />
There are studies conducted to how the ant and its partners have evolved together and how they originally came to work together. This has led to studies on how the partners work to discourage different types of fungus and bacteria in interfering. This interference could lead to an instability within the network. Resistant pathogenic molds are also a source of research to see why they have not evolved over the years to take over the fungus.<br />
<br />
==References==<br />
Ask Nature, A project of the Biomimicry Institute. <http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4><br />
<br />
Dash, D., Mueller, U., Rabeling, C.,Rodrigues, A., 2008. "COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION." Evolution 62. 11:2894-2912. Academic Search Premier. EBSCO. Web. 5 Apr. 2011.<br />
<br />
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G., & Boomsma, J. J. (2010). EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS. Evolution, 64(7), 2055-2069. <br />
<br />
Little, A., Currie, C. 2007. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant-microbe symbiosis." PubMed.gov. 3(5):501-504<br />
<br />
Pinto-Tomas, A., Anderson, M., Suen, G., Stevensen, D., Chu, F., Cleland, W., Weimer, P., Currie, C. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants.” Science. 326: 1120-1123.<br />
<br />
Ulrich, M., Schultz, T., Currie, C., Adams, R., Malloch, D. 2001. "The origin of the attin ant-fungus mutualism." 76:169-197 <br />
<br />
Edited by <Katie Yi>, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Leafcutter_ants,_fungi,_and_bacteria&diff=59013Leafcutter ants, fungi, and bacteria2011-04-06T15:13:16Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br />
<br />
==Introduction==[[Image:leafcolony.jpg|Thumb|653px|right|foraging ants carry back cuts of leaves.]]<br />
<br />
<br />
<br />
<br />
<br />
Microorganisms often require a symbiotic relationship with other organisms in order to reproduce and survive. This symbiotic relationship is shown through the relationship between leafcutter ants, fungi, and bacteria. Sometimes refered to as the "First Agriculture," this relationship can be compared to farmer (the ants) cultivating its crops (the fungus). Up until recently, the fungal colonies seemed to be free of any pests or parasites. This was thought to be because the ants were so diligent in caring for the fungus that they did not allow any parasites to enter and take hold. Cameron Currie was the first to look at why the nests were pest free. He concluded that the ants carried a white powdery bacteria on their abdomens that had antimicrobial properties. Without the ants, the parasitic mold could take over the fungus in the colony in a matter of days.<br />
<br />
==Symbiotic Processes==<br />
<br />
[[Image:fungus.jpg|Thumb|200px|right|A worker ant harvesting the fungus. http://scienceblogs.com/notrocketscience/2009/11/leafcutter_ants_rely_on_bacteria_to_fertilise_their_fungus_g.php]]<br />
<br />
===Main Functions===<br />
The fungus and the ants depend on each other for survival. The ants cultivate the fungus in its colonies from chewed up leaves and at the same time the fungus acts as the main food source for the ants. One symbiotic partner can not survive without the other.<br />
====Fungi Growth====<br />
The leaves in the rain forest have toxic qualities in them which is supposed to deter herbivory. But the harvesting ants cut the leaves without ingesting any of the toxins and are able to bring the leaves back to the nest. There the leaves are given to worker ants which chew up the leaves in their mouths into a paste which becomes the food source for the fungus. The plant material is broken down through enzymes that break down the proteins and starches. Depending on the colony, the enzymes can slightly different between complete plant break down and those that focus mainly on plant wall digestion. Because of the symbiotic relationship, the toxins in the leaves are broken down by the fungi into needed sugars and proteins safe for the ant to consume. <br />
<br><br />
<br />
===Bacterial resistance to fungal parasites===<br />
To maintain a clean and healthy fungus colony, the ants have a bacteria on their exoskeleton which they use when cultivating the fungus. Some ants have this on their underbelly while ants that are in constant contact with the fungus are almost completely covered with the bacteria. This bacteria is similar to the bacterium which is produces half the antibiotics made today. The antibiotic qualities allow it to specifically work with the fungus to inhibit the parasitic mold.<br />
<br><br />
<br><br />
Unlike the ant, fungi, and bacteria symbiosis, present day antibiotics often produce resistant types of pathogens. It is thought that the ant colonies do not produce antibiotic resistant molds because of the high diversity of the bacteria and as the two evolve together the parasitic mold will not evolve a resistance.<br />
<br><br />
<br><br />
Another method to cultivate only its native strain of Pseudonocardia is that the ant's feces contain incompatibility chemicals which select only for its resident fungus. There are also behavior cues which suggest that the ants physically pick out other types of fungus.<br />
<br />
==Environmental Implications==<br />
The millions of ants in the forests have a huge effect on the ecosystem. They consume 15-20% of fresh vegetation and up to 240 kg of dry leaves per year. They make up 86% of the total anthropod biomass. For such a small organism, it has a huge effect.<br />
<br><br />
===Nitrogen Fixation===<br />
<br />
Like any other garden, the ant's fungus garden needs nitrogen. Because of the low nitrogen ratio in leaves, there are nitrogen fixing bacteria in the colonies that help to introduce usable nitrogen into the system. The n-fixing bacteria fixes enough nitrogen for the fungus and the ants and also leaves a large amount in the refuse of the colony. This nitrogen can be worked back into the surrounding system replenishing the nutrient poor tropical environment with an essential limiting nutrient.<br />
<br><br />
<br />
==Niche==<br />
<br />
[[Image:Colonies.jpg|Thumb|259px|right|An underground chamber where the fungus and the queen is housed. http://laanitarainforestranch.com/pages/leafcutterants.htm]]<br />
<br />
===<b>Habitat</b>===<br />
The ant's nests are subterranean and can be found in mostly tropical areas including Costa Rica, Panama, and Argentina.<br />
<br><br />
===<b>Nest Characteristics</b>=== <br />
Nests begin when a queen ant leaves one nest with a small amount of the fungus in her mouth and moves to a different area to start her own colony. Once a nest becomes established, the colonies can grow to have millions of ants in them. <br />
<br><br />
These subterranean nests vary in sizes. They can be small with a single fungus growing "room" or can be multiple feet below ground with many different rooms and complex tunnels. Ants are also known as organized and clean insects. They have certain refuse dumps where the worker ants take the garbage and seclude it from the rest of the colony to decrease contamination. <br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
<br />
===<b>Ants</b>=== <br />
The group of ants that are LeafCutters belong to the tribe <i>attini</i> and their genera is <i>Atta</i> and <i>acromyrmex</i> These ants have been around for the better part of 50 million years. Interestingly, these ants are consume the largest amount of primary producers in the tropical rainforest areas which is not surprising considering their biomass is four times the amount of other invertebrates. World wide, these insects take up a third of the total insect biomass.<br />
<br />
===Fungi=== <br />
Playing the role of both a decomposer and the primary food source for the Leafcutters, the fungi from the family <i>Lepiotaceae</i> is grown underground in the nests chambers by the worker ants. <br />
<br />
====Parasites====<br />
Battling against the ant's seemingly clean fungis' agriculture are parasites that would quickly take over the colony's fungus growth if not carefully weeded against. These parasites are refered to as <i>escovopsis</i> would feed on the fungus.<br />
===Bacteria=== <br />
One of the most interesting and only recently discovered partners is the antibiotic producing bacteria <i>pseudonocardia</i><br />
<br><br />
There has recently been research conducted on a fourth bacterial partner. This is a black mold that can be found on the cuticle of the ant and is used in a similar fashion in discouraging parasitic growth. This mold works like other fungis cultivating symbiots and helps to discourage the growth of parasites on the fungus.<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Coevolution between attine ants and actinomycete bacteria===<br />
It has been the thought that the close relationship between the ant and the bacteria has caused the two to evolve together. But the study looks at if that is truly so. It concluded that the ant has probably evolved with the bacteria, but the bacteria has evolved independently. The study states that more research needs to be done on the reciprocality of the evolving partners.<br />
<br />
===Enzyme activity activity in different ant colonies===<br />
Ants have evolved into different sister clades. This research shows how the enzyme activity between lower and higher evolved colonies has changed. The study shows that higher evolved colonies contain more protein and starch digesting enzymes while those of lower clades have enzymes that just focus on <i>partial</i> degradation of the plant material.<br />
<br />
===Ant Genome===<br />
The complete ant genome has recently been mapped out. With that, their are multiple studies going on about the evolution of the ants with its symbiotic partners and other attributes of the ant. Especial focus is put on the antimicrobial properties of the bacteria.<br />
<br />
===Evolution and Competition===<br />
There are studies conducted to how the ant and its partners have evolved together and how they originally came to work together. This has led to studies on how the partners work to discourage different types of fungus and bacteria in interfering. This interference could lead to an instability within the network. Resistant pathogenic molds are also a source of research to see why they have not evolved over the years to take over the fungus.<br />
<br />
==References==<br />
Ask Nature, A project of the Biomimicry Institute. <http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4><br />
<br />
Dash, D., Mueller, U., Rabeling, C.,Rodrigues, A., 2008. "COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION." Evolution 62. 11:2894-2912. Academic Search Premier. EBSCO. Web. 5 Apr. 2011.<br />
<br />
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G., & Boomsma, J. J. (2010). EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS. Evolution, 64(7), 2055-2069. <br />
<br />
Little, A., Currie, C. 2007. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant-microbe symbiosis." PubMed.gov. 3(5):501-504<br />
<br />
Pinto-Tomas, A., Anderson, M., Suen, G., Stevensen, D., Chu, F., Cleland, W., Weimer, P., Currie, C. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants.” Science. 326: 1120-1123.<br />
<br />
Ulrich, M., Schultz, T., Currie, C., Adams, R., Malloch, D. 2001. "The origin of the attin ant-fungus mutualism." 76:169-197 <br />
<br />
Edited by <Katie Yi>, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akenthttps://microbewiki.kenyon.edu/index.php?title=Leafcutter_ants,_fungi,_and_bacteria&diff=59011Leafcutter ants, fungi, and bacteria2011-04-06T15:12:46Z<p>Akent: </p>
<hr />
<div>{{Uncurated}}<br />
<br />
<br />
==Introduction==<br />
<br />
<br />
<br />
<br />
<br />
[[Image:leafcolony.jpg|Thumb|653px|right|foraging ants carry back cuts of leaves.]]Microorganisms often require a symbiotic relationship with other organisms in order to reproduce and survive. This symbiotic relationship is shown through the relationship between leafcutter ants, fungi, and bacteria. Sometimes refered to as the "First Agriculture," this relationship can be compared to farmer (the ants) cultivating its crops (the fungus). Up until recently, the fungal colonies seemed to be free of any pests or parasites. This was thought to be because the ants were so diligent in caring for the fungus that they did not allow any parasites to enter and take hold. Cameron Currie was the first to look at why the nests were pest free. He concluded that the ants carried a white powdery bacteria on their abdomens that had antimicrobial properties. Without the ants, the parasitic mold could take over the fungus in the colony in a matter of days.<br />
<br />
==Symbiotic Processes==<br />
<br />
[[Image:fungus.jpg|Thumb|200px|right|A worker ant harvesting the fungus. http://scienceblogs.com/notrocketscience/2009/11/leafcutter_ants_rely_on_bacteria_to_fertilise_their_fungus_g.php]]<br />
<br />
===Main Functions===<br />
The fungus and the ants depend on each other for survival. The ants cultivate the fungus in its colonies from chewed up leaves and at the same time the fungus acts as the main food source for the ants. One symbiotic partner can not survive without the other.<br />
====Fungi Growth====<br />
The leaves in the rain forest have toxic qualities in them which is supposed to deter herbivory. But the harvesting ants cut the leaves without ingesting any of the toxins and are able to bring the leaves back to the nest. There the leaves are given to worker ants which chew up the leaves in their mouths into a paste which becomes the food source for the fungus. The plant material is broken down through enzymes that break down the proteins and starches. Depending on the colony, the enzymes can slightly different between complete plant break down and those that focus mainly on plant wall digestion. Because of the symbiotic relationship, the toxins in the leaves are broken down by the fungi into needed sugars and proteins safe for the ant to consume. <br />
<br><br />
<br />
===Bacterial resistance to fungal parasites===<br />
To maintain a clean and healthy fungus colony, the ants have a bacteria on their exoskeleton which they use when cultivating the fungus. Some ants have this on their underbelly while ants that are in constant contact with the fungus are almost completely covered with the bacteria. This bacteria is similar to the bacterium which is produces half the antibiotics made today. The antibiotic qualities allow it to specifically work with the fungus to inhibit the parasitic mold.<br />
<br><br />
<br><br />
Unlike the ant, fungi, and bacteria symbiosis, present day antibiotics often produce resistant types of pathogens. It is thought that the ant colonies do not produce antibiotic resistant molds because of the high diversity of the bacteria and as the two evolve together the parasitic mold will not evolve a resistance.<br />
<br><br />
<br><br />
Another method to cultivate only its native strain of Pseudonocardia is that the ant's feces contain incompatibility chemicals which select only for its resident fungus. There are also behavior cues which suggest that the ants physically pick out other types of fungus.<br />
<br />
==Environmental Implications==<br />
The millions of ants in the forests have a huge effect on the ecosystem. They consume 15-20% of fresh vegetation and up to 240 kg of dry leaves per year. They make up 86% of the total anthropod biomass. For such a small organism, it has a huge effect.<br />
<br><br />
===Nitrogen Fixation===<br />
<br />
Like any other garden, the ant's fungus garden needs nitrogen. Because of the low nitrogen ratio in leaves, there are nitrogen fixing bacteria in the colonies that help to introduce usable nitrogen into the system. The n-fixing bacteria fixes enough nitrogen for the fungus and the ants and also leaves a large amount in the refuse of the colony. This nitrogen can be worked back into the surrounding system replenishing the nutrient poor tropical environment with an essential limiting nutrient.<br />
<br><br />
<br />
==Niche==<br />
<br />
[[Image:Colonies.jpg|Thumb|259px|right|An underground chamber where the fungus and the queen is housed. http://laanitarainforestranch.com/pages/leafcutterants.htm]]<br />
<br />
===<b>Habitat</b>===<br />
The ant's nests are subterranean and can be found in mostly tropical areas including Costa Rica, Panama, and Argentina.<br />
<br><br />
===<b>Nest Characteristics</b>=== <br />
Nests begin when a queen ant leaves one nest with a small amount of the fungus in her mouth and moves to a different area to start her own colony. Once a nest becomes established, the colonies can grow to have millions of ants in them. <br />
<br><br />
These subterranean nests vary in sizes. They can be small with a single fungus growing "room" or can be multiple feet below ground with many different rooms and complex tunnels. Ants are also known as organized and clean insects. They have certain refuse dumps where the worker ants take the garbage and seclude it from the rest of the colony to decrease contamination. <br />
<br />
<br />
<br><br />
<br />
==Key Microorganisms==<br />
<br />
===<b>Ants</b>=== <br />
The group of ants that are LeafCutters belong to the tribe <i>attini</i> and their genera is <i>Atta</i> and <i>acromyrmex</i> These ants have been around for the better part of 50 million years. Interestingly, these ants are consume the largest amount of primary producers in the tropical rainforest areas which is not surprising considering their biomass is four times the amount of other invertebrates. World wide, these insects take up a third of the total insect biomass.<br />
<br />
===Fungi=== <br />
Playing the role of both a decomposer and the primary food source for the Leafcutters, the fungi from the family <i>Lepiotaceae</i> is grown underground in the nests chambers by the worker ants. <br />
<br />
====Parasites====<br />
Battling against the ant's seemingly clean fungis' agriculture are parasites that would quickly take over the colony's fungus growth if not carefully weeded against. These parasites are refered to as <i>escovopsis</i> would feed on the fungus.<br />
===Bacteria=== <br />
One of the most interesting and only recently discovered partners is the antibiotic producing bacteria <i>pseudonocardia</i><br />
<br><br />
There has recently been research conducted on a fourth bacterial partner. This is a black mold that can be found on the cuticle of the ant and is used in a similar fashion in discouraging parasitic growth. This mold works like other fungis cultivating symbiots and helps to discourage the growth of parasites on the fungus.<br />
<br><br />
<br />
==Current Research==<br />
<br />
===Coevolution between attine ants and actinomycete bacteria===<br />
It has been the thought that the close relationship between the ant and the bacteria has caused the two to evolve together. But the study looks at if that is truly so. It concluded that the ant has probably evolved with the bacteria, but the bacteria has evolved independently. The study states that more research needs to be done on the reciprocality of the evolving partners.<br />
<br />
===Enzyme activity activity in different ant colonies===<br />
Ants have evolved into different sister clades. This research shows how the enzyme activity between lower and higher evolved colonies has changed. The study shows that higher evolved colonies contain more protein and starch digesting enzymes while those of lower clades have enzymes that just focus on <i>partial</i> degradation of the plant material.<br />
<br />
===Ant Genome===<br />
The complete ant genome has recently been mapped out. With that, their are multiple studies going on about the evolution of the ants with its symbiotic partners and other attributes of the ant. Especial focus is put on the antimicrobial properties of the bacteria.<br />
<br />
===Evolution and Competition===<br />
There are studies conducted to how the ant and its partners have evolved together and how they originally came to work together. This has led to studies on how the partners work to discourage different types of fungus and bacteria in interfering. This interference could lead to an instability within the network. Resistant pathogenic molds are also a source of research to see why they have not evolved over the years to take over the fungus.<br />
<br />
==References==<br />
Ask Nature, A project of the Biomimicry Institute. <http://www.asknature.org/strategy/6392180f395ab3f04ee8dd8b3ce632c4><br />
<br />
Dash, D., Mueller, U., Rabeling, C.,Rodrigues, A., 2008. "COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION." Evolution 62. 11:2894-2912. Academic Search Premier. EBSCO. Web. 5 Apr. 2011.<br />
<br />
De Fine Licht, H. H., Schiøtt, M., Mueller, U. G., & Boomsma, J. J. (2010). EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS. Evolution, 64(7), 2055-2069. <br />
<br />
Little, A., Currie, C. 2007. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant-microbe symbiosis." PubMed.gov. 3(5):501-504<br />
<br />
Pinto-Tomas, A., Anderson, M., Suen, G., Stevensen, D., Chu, F., Cleland, W., Weimer, P., Currie, C. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants.” Science. 326: 1120-1123.<br />
<br />
Ulrich, M., Schultz, T., Currie, C., Adams, R., Malloch, D. 2001. "The origin of the attin ant-fungus mutualism." 76:169-197 <br />
<br />
Edited by <Katie Yi>, a student of Angela Kent at the University of Illinois at Urbana-Champaign.<br />
<br />
<!-- Do not edit or remove this line -->[[Category:Pages edited by students of Angela Kent at the University of Illinois at Urbana-Champaign]]</div>Akent