Spacecraft microbes

Spacecraft Microbiology

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.

Spacecraft Environments

As stated the type of environment available to microbes is fundamentally determined by the presence or absence of humans on the mission. Increased radiation exposure and microgravity are common challenges faced by microbes in each environment. Early experiments seemed to show no effect of a microgravity on cells smaller than 10 µm in diameter (Pollard et al 1967), 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 (Klaus et al. 2004 and Thevenet 1996). 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 (Horneck 2010). Different strains display varying levels of resistance and threshold lethality to radiation-induced damage (Horneck 2010).

Manned Spacecraft and Space Stations

Hermetically sealed spacecraft designed for human occupancy provide many opportunities for microbial populations. 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 (bioshmars).

The first and probably richest microenvironment inside the craft is the astronauts themselves. The natural human microbiota accompanies them on their journey (bioshmars). 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 (bioshmars).

Surfaces of the craft also provide adequate environments for many bacteria. Microbes that colonize the infrastructure and equipment are termed technofiles and can be a serious threat to the craft's integrity (bioshmars). Bacterial-fungal associations will form on polymers to utilize them as a carbon source and release enzymes and acids that further corrode the polymers (bioshmars). Biodegredation of polymers in this way can also release volatile noxious byproducts that can adversely affect air quality (Novikova 2002). Microbes can also exploit organic deposits on metal surfaces and similarly the metal through release of enzymes and organic acids(bioshmars). Polymer and surface corrosion were both observed on the MIR space station (Novikova 2004) and technophile bacterial strains have been detected on the ISS (Novikova 2006).

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 (bioshmars). 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 nearly every a major biogeochemical process on Earth they will undoubtedly be a part in establishing artificial biospheres in future spaceflight (Roberts et. al 2004).

Unmanned and Robotic Spacecraft

Welcome to MicrobeWiki

Study Microbes * Microbial Biorealm * Viral Biorealm * Microbial Mythology

MicrobeWiki is a free wiki resource on microbes and microbiology, authored by students at many colleges and universities. Curated pages such as those linked to the Taxonomy Index are reviewed and updated by microbiologists at Kenyon College. Student pages authored independently, or for coursework, are not monitored further. Interested readers are encouraged to add information, after registering a free account.

Study Microbes is a new section of study questions and recommended species for students to learn, based on the textbook Microbiology: An Evolving Science by Joan Slonczewski and John Foster (W. W. Norton & Co.)

Educators: You may assign MicrobeWiki page creation and editing as projects for your students. We create a template page for your assignment, which you may edit to meet your needs. See for example the pages created by the following classes:

• BIOL 238 Class Index 2024, Joan L. Slonczewski,Kenyon College
• Microbial Ecology, Dr. Jay Lennon, Indiana University
• SSC111 Soil Microbiology, Kate Scow, University of California, Davis
• Microbial Ecology, Dr. Hidetoshi Urakawa, Florida Gulf Coast University.
• General Microbiology by Students of Jennifer Bhatnagar, Boston University

Your students receive individual passwords. Assessment and grading are up to you; after your class is over, we review pages for our standards. Students of all levels, from first-year to graduate students, have contributed pages to our site.

MicrobeWiki includes these curated pages:
Microbial Biorealm: encylopedia of bacteria, archaea and eukaryotic microbes. See also Taxonomy Index.
Viral Biorealm: encyclopedia of viruses of animals and plants, and bacteriophages. See also Taxonomy Index.
Microbial Mythology: common misconceptions and controversies in microbiology.

Managing Editor

Daniel Barich '05

Kenyon Student Editors

Kristina Buschur, '11, Ryo Tashiro '09, Molly Schlemmer '08, Shrochis Karki '09, Drew Taber³, Allison Whipple '06, Zeva Levine¹, Laura Damon-Moore¹, Ariel Kahrl², Hannah Sacks '08, Michael Stulberg '05, Casey M. Smith '06, and Shana Scogin '07

Advisor: Joan Slonczewski, Biology Dept, Kenyon College
Guest editors from ¹Beloit, ²Oberlin, and ³Columbia Union College.
Funded by HHMI awards to Kenyon College, 2000, 2004.

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