Predation by Myxococcus xanthus: Difference between revisions

From MicrobeWiki, the student-edited microbiology resource
 
(19 intermediate revisions by the same user not shown)
Line 1: Line 1:
{{Uncurated}}
{{Uncurated}}
=Introduction=
=Introduction=
Myxococcus xanthus is a gram-negative, rod-shaped bacterium (see Figure 1), prevalent in soil environments, that exhibits extensive social behaviour [[#References|[1]]]. When nutrients are scarce, bacteria aggregate into fruiting bodies that form spores. When adequate food is present in the environment, however, M. xanthus cells collectively swarm and prey upon other organisms. This mechanism of predation is a highly organized system involving sensing, moving towards, and lysing prey [[#References|[2]]].  
Myxococcus xanthus is a gram-negative, rod-shaped bacterium, prevalent in soil environments, that exhibits extensive social behaviour [[#References|[1]]]. When nutrients are scarce, bacteria aggregate into fruiting bodies that form spores. When adequate food is present in the environment, however, M. xanthus cells collectively swarm and prey upon other organisms. This mechanism of predation is a highly organized system involving sensing, moving towards, and lysing prey [[#References|[2]]].  




[[File:Mxanthus1.png|200px|thumb|right| Myxococcus xanthus cells.]]
[[File:Mxanthus1.png|200px|thumb|right| Myxococcus xanthus cells.]]


=Current Species=
=Sensing Prey=


There are three officially recognized ''Ignicoccus''  species: ''Ignicoccus hospitalis'' , '' Ignicoccus pacificus '' and '' Ignicoccus islandicus'' . The three species were initially identified by 16S rRNA gene analysis from the hydrothermal vent samples obtained from Kolbeinsey Ridge and the coast of Mexico[[#References|[1]]] . All three species have been characterized as hyperthermophiles that are also [http://en.wikipedia.org/wiki/Obligate_anaerobe obligate anaerobes] which explains the presence of ''Ignicoccus'' species near hydrothermal vents[[#References|[1]]] . None of the members of the ''Ignicoccus''  genus have been found to be [http://en.wikipedia.org/wiki/Pathogenic] pathogenic to humans.
==Signal Transduction==


=Morphology=
Myxococcus xanthus uses a frz [http://en.wikipedia.org/wiki/Signal_transduction signal transduction] system to control its directed movement towards prey [[#References|[3]]]. This frz system is similar to the Che [http://en.wikipedia.org/wiki/Chemotaxis chemotaxis] system in E. coli, and frz gene mutants exhibit similar characteristics to well-known che gene mutants in the E. coli system. In M. xanthus, however, chemotactic activity is controlled by reversing direction of gliding motility, rather than by switching direction of [http://en.wikipedia.org/wiki/Flagellum flagellar rotation] [[#References|[4]]].


The members of the ''Ignicoccus''  genus are motile irregular coccoid cells that range in diameter from 1 to 3 µm. The motility observed is due to the presence of flagella, but unfortunately the polarity of the flagella is not yet fully elucidated. They are known to have an outer-membrane but no [http://en.wikipedia.org/wiki/S-layer S-layer]. This is a novel characteristic for these [http://en.wikipedia.org/wiki/Archaea Archaea] because''Ignicoccus'' are the only known Archaea that have been shown to possess an outer-membrane[[#References|[2]]] [[#References|[10]]] .
==Direct Contact==


[[File:Huber-abb2.jpg|300px|thumb|left| Ultrathin section of an ''Ignicoccus hospitalis'' cell.]]
M. xanthus cells cannot sense prey [http://en.wikipedia.org/wiki/Colony_(biology) colonies] until direct cell-cell contact is made. There is no recognition of prey cells even at very short distances, but when contact is made, the M. xanthus cells began to alter their behaviour. The frz signal transduction system is also responsible for keeping the M. xanthus cells in the vicinity of their prey after contact has been made and feeding is underway. When cells start moving away from the source, the frz system senses this and induces a reverse in direction to keep them in contact with the prey colony [[#References|[3]]].


=Motility During Predation=


==Outer-Membrane==
M. xanthus uses what is referred to as the “wolf pack” approach to predation [[#References|[5]]]. Cells usually exist as [http://en.wikipedia.org/wiki/Biofilm biofilms] consisting of a layered arrangement. Once prey is sensed, the cells cluster into organized groups known as swarms, which then invade prey colonies [[#References|[2]]].


The outer-membrane of ''Ignicoccus''  species was found to be composed of various derivatives of the typical lipid [http://en.wikipedia.org/wiki/Archaeol archaeol], including the derivative known as [http://en.wikipedia.org/wiki/Caldarchaeol caldarchaeol] [[#References|[5]]] . The outer-membrane is dominated by a pore composed of the Imp1227 protein (''Ignicoccus''  outer membrane protein 1227). The Imp1227 protein forms a large nonamer ring with a predicted pore size of 2nm[[#References|[7]]] .
[[File:Mxanthus3.gif|300px|thumb|left| A swarm of Myxococcus xanthus cells (upper)engaged in predation of a prey colony of E. coli (lower). M.xanthus cells are engaged in predatory rippling as they move through prey colony. Image courtesy of James E. Berleman and John R. Kirby [10].]]


=Metabolism=


''Ignicoccus'' species are [http://en.wikipedia.org/wiki/Chemolithoautotroph chemolithoautotrophs] that use molecular hydrogen as the inorganic electron donor and elemental sulphur as the inorganic terminal electron acceptor[[#References|[1]]] . The reduction of the elemental sulphur results in the production of hydrogen sulphide gas.
==Predatory Rippling==


''Ignicoccus'' are autotrophs in that they fix their own carbon dioxide into organic molecules. The carbon dioxide fixation process they use is a novel process called [http://www.pnas.org/content/105/22/7851.full a dicarboxylate/4-hydroxybutyrate autotrophic carbon assimilation cycle] that involves 14 different enzymes[[#References|[8]]] .  
Myxococcus xanthus swarms utilise a behaviour known as rippling during predation. It is induced when M. xanthus makes contact with prey or other food sources. Rippling is also observed during fruiting body formation, but research by Berleman et al. [[#References|[6]]] demonstrates that it is generally a predatory mechanism and is necessary for efficient predation. During rippling, cells accumulate in aggregates containing ridges and troughs, and move in a manner similar to water-like ripples [[#References|[7]]]. These ripples were coined “accordion waves” because they reflect off each other when they collide, causing each wave crest to oscillate with no net displacement. This is due to intercellular signalling during wave collision that causes changes in direction in all the cells of the swarm. [[#References|[8]]]. Rippling behaviour has physiological benefits during predation because it retains M. xanthus cells in the area of their prey for a longer time, by decreasing random drift and increasing organized alignment [[#References|[9]]].


Members of the ''Ignicoccus''  genus are able to use ammonium as a nitrogen source.
==Reversal Rate==


==Growth Conditions==
Directed movement of Myxococcus xanthus relies on the reversal of direction. M. xanthus  cells reverse direction on average every 7 minutes. Net movement results when the intervals between the reversals vary [[#References|[4]]]. During predatory rippling, this allows the swarm of cells to increase its expansion in the direction of prey, because more of their potential [http://en.wikipedia.org/wiki/Velocity velocity] is oriented towards the prey as the reversal frequency decreases. [[#References|[10]]]. Varying reversal rate of individual cells and therefore of the swarm is critical for movement in a particular direction.


Because members of the ''Ignicoccus''  genus are [http://en.wikipedia.org/wiki/Hyperthermophile hyperthermophiles] and obligate anaerobes, it is not surprising that their growth conditions are very complex. They are grown in a liquid medium known as ½ SME ''Ignicoccus''  which is a solution of synthetic sea water which is then made anaerobic.
=Killing and Digestion of Prey=


Grown in this media at their optimal growth temperature of 90C, the members of the ''Ignicoccus''  genus typically reach a cell density of ~4x107cells/mL[[#References|[1]]] .  
During predation, Myxococcus xanthus feeds by causing [http://en.wikipedia.org/wiki/Cell_lysis lysis] of prey cell [http://en.wikipedia.org/wiki/Cell_envelope envelopes], and then extracting cytoplasmic contents to digest for carbon, nitrogen, and energy [11]. It is capable of killing prey organisms by collectively secreting both antibiotics and lytic enzymes. The lytic enzymes produced include cell wall cleaving enzymes such as proteases, peptidases, nucleases, and lipases [[#References|[12]]]. Some of the antibiotics produced are [http://en.wikipedia.org/wiki/Bactericide bactericidal], and some only halt growth of prey organisms making them easier to lyse using other compounds [[#References|[13]]].


The addition of [http://en.wikipedia.org/wiki/Yeast_extract yeast extract] to the ½ SME media has been shown to stimulate the growth and increase maximum cell density achieved. The mechanism by which this is achieved is not known[[#References|[1]]] .
[[File:Mxanthus2.png|300px|thumb|right|  Myxococcus xanthus social behaviour in the presence of sufficient (A) and scarce (B) .nutrients. Image adapted from Zusman et al. [2]]]


=Ecology and Predatory Efficiency=


=Symbiosis=
Predation by M. xanthus  is affected by many variables in the environment, such as surface solidity, and density and species of prey colonies to name a few. Higher density of prey colonies greatly increases the number of patches encountered and attacked by M. xanthus. Physical structure of the environment also affects predation, making it easier or harder for predators to move; increased surface solidity was found to increase M. xanthus predatory efficiency. M. xanthus was also shown to have different predation rates for different prey types, which may be due to different mechanisms of lysis and movement used for different species, as well as the ability of some prey species to secrete inhibitory chemicals. However, although ecological variables affect rates of encounter and attack of prey, rates of killing of prey cells once patches were encountered are largely independent of these variables [[#References|[14]]].


''Ignicoccus hospitalis''  is the only member of the genus ''Ignicoccus'' that has been shown to have an extensive [http://en.wikipedia.org/wiki/Symbiosis symbiotic relationship] with another organism.


''Ignicoccus hospitalis''  has been shown to engage in symbiosis with ''Nanoarchaeum equitans'' . ''Nanoarchaeum equitans''  is a very small coccoid species with a cell diameter of 0.4 µm[[#References|[9]]] . Genome analysis has provided much of the known information about this species.
=Further Research=


To further complicate the symbiotic relationship between both species, it’s been observed that the presence of ''Nanoarchaeum equitans''  on the surface of ''Ignicoccus hospitalis'' somehow inhibits the cell replication of ''Ignicoccus hospitalis'' . How or why this occurs has not yet been elucidated[[#References|[3]]] .  
The predatory behaviour of Myxococcus xanthus is potentially beneficial to medical and pharmaceutical advances. Some of the antibiotics produced by M. xanthus to kill their prey have the possibility to be useful as antibiotics for therapeutic use, and this may be an interesting field for further research [[#References|[15]]].


[[File:Urzwerg.jpg|300px|thumb|right| ''Ignicoccus hospitalis'' with two attached  ''Nanoarchaeum equitans'' cells.]]
=References=


[[File:IhNeRelationship2 jpeg.jpg|250px|thumb|left| Epifluoroscence micrographs of an ''Ignicoccus hospitalis''and ''Nanoarchaeum equitans'' coculture stained with BacLight at various time points. Living cells stain green while dead cells stain red. (A) Exponential growth phase 3.25 hours after inoculation. (B) Transition into the stationary phase 7.5 hours after inoculation. (C) Stationary phase 10 hours after inoculation. (D) Stationary phase 23 hours after inoculation.]]
(1) Reichenbach H. 1999. The ecology of myxobacteria. Environmental Microbiology. 1: 15-20.


(2) Zusman DR, Scott AE, Zhaomin Y, Kirby JR. 2007. Chemosensory pathways, motility, and development in Myxococcus xanthus. Nature Reviews. 5:862-872.


==''Nanoarchaeum equitans''==
(3) McBride MJ, Zusman DR. 1996.  Behavioural analysis of single cells of Myxococcus xanthus in response to prey cells of Eschericiea coli. FEMS Microbiology Letters. 137: 227-231.
 
''Nanoarchaeum equitans'' has the smallest non-viral genome ever sequenced at 491kb[[#References|[9]]] . Analysis of the genome sequence indicates that 95% of the predicted proteins and stable RNA molecules are somehow involved in repair and replication of the cell and its genome[[#References|[3]]] .
 
Analysis of the genome also showed that ''Nanoarchaeum equitans''  lacks nearly all genes known to be required in amino acid, nucleotide, cofactor and lipid metabolism. This is partially supported by the evidence that ''Nanoarchaeum equitans''  has been shown to derive its cell membrane from its host ''Ignicoccus hospitalis''  cell membrane. The direct contact observed between ''Nanoarchaeum equitans'' and ''Ignicoccus hospitalis''  is hypothesized to form a pore between the two organisms in order to exchange metabolites or substrates (likely from ''Ignicoccus hospitalis'' towards ''Nanoarchaeum equitans'' due to the parasitic relationship). The exchange of periplasmic vesicles is not thought to be involved in metabolite or substrate exchange despite the presence of vesicles in the periplasm of ''Ignicoccus hospitalis'' .


These analyses of the ''Nanoarchaeum equitans'' genome support the fact of the extensive symbiotic relationship between ''Nanoarchaeum equitans'' and ''Ignicoccus hospitalis''. However, it has not yet been proven that it is a strictly parasitic relationship and further research may prove that there is a commensal relationship between the two species.  
(4) Blackhart BD, Zusman DR.  1985. “Frizzy” genes of Myxococcus xanthus are involved in control of frequency of reversal and gliding motility. Proceedings of the National Academy of Science USA. 82: 8767-8770.  


(5) Martin M. 2002. Predatory Prokaryotes: An Emerging Research Opportunity. Journal of Molecular Microbiology and Biotechnology. 4: 467-477.
=References=


(1) Reichenbach H. 1999. The ecology of myxobacteria. Environmental Microbiology. 1: 15-20.
(6) Berleman JE, Chumley T, Cheung P, Kirby JR. 2006. Rippling is a Predatory Behaviour in Myxococcus xanthus. Journal of Bacteriology. 188: 5888-5895.


(2) Zusman DR, Scott AE, Zhaomin Y, Kirby JR. 2007. Chemosensory pathways, motility, and development in Myxococcus xanthus. Nature Reviews. 5:862-872.
(7) Shimkets JL, Kaiser D. 1982. Induction of coordinated movement of Mycococcus xanthus cells. Journal of Bacteriology. 152: 451-461.


(3) Giannone R.J., Heimerl T., Hettich R.L., Huber H., Karpinets T., Keller M., Kueper U., Podar M. and Rachel R. “Proteomic Characterization of Cellular and Molecular Processes that Enable the Nanoarchaeum equitans- Ignicoccus hospitalis Relationship.” PLoS ONE, 2011, Volume 6, Issue 8.
(8) Sliusarenko O, Neu J, Zusman DR, Oster G. 2006. Accordian Waves in Myxococcus xanthus. Proceedings of the National Academy of Science USA. 103: 1534-1539.


(4) Eisenreich W., Gallenberger M., Huber H., Jahn U., Junglas B., Paper W., Rachel R. and Stetter K.O. “Nanoarchaeum equitans and Ignicoccus hospitalis: New Insights into a Unique, Intimate Association of Two Archaea.” Journal of Bacteriology, 2008, DOI: 10.1128/JB.01731-07.
(9) Zhang H, Vaksman Z, Litwin D, Shi P, Kaplan H, Ogoshin O. 2012. The Mechanistic Basis of Myxococcus xanthus Rippling Behaviour and its Physiological Role During Predation. Computational Biology. 8: 1-13.


(5) Grosjean E., Huber H., Jahn U., Sturt H, and Summons R. “Composition of the lipids of Nanoarchaeum equitans and their origin from its host Ignicoccus sp. strain KIN4/I.” Arch Microbiol, 2004, DOI: 10.1007/s00203-004-0725-x.
(10) Berleman JE, Scott J, Chumley T, Kirby JR. 2008. Predataxis behaviour by Myxococcus xanthus. Proceedings of the National Academy of Science USA. 105: 17127-17132.


(6) Briegel A., Burghardt T., Huber H., Junglas B., Rachel R., Walther P. and Wirth R. “Ignicoccus hospitalis and Nanoarchaeum equitans: ultrastructure, cell–cell interaction, and 3D reconstruction from serial sections of freeze-substituted cells and by electron cryotomography.”  Arch Microbiol, 2008, DOI 10.1007/s00203-008-0402-6.
(11) Kaiser D, Robinson M, Kroos L. 2010. Myxobacteria, Polarity, and Multicellular Morphogenesis. Cold Spring Harbor Perspectives in Biology. 2:a000380


(7) Burghardt T., Huber H., Junglas B., Naether D.J. and Rachel R. “The dominating outer membrane protein of the hyperthermophilic Archaeum Ignicoccus hospitalis: a novel pore-forming complex.” Molecular Microbiology, 2007, Volume 63.
(12) Rosenberg E, Varon M. 1984. Antibiotics and Lytic Enzymes, p.109-125. In Rosenberg E (ed), Myxobacteria. Springer, New York, NY.


(8) Berg I.A., Eisenreich W., Eylert E., Fuchs G., Gallenberger M., Huber H.,Jahn U. and Kockelkorn D. “A dicarboxylate/4-hydroxybutyrate autotrophic carbon assimilation cycle in the hyperthermophilic Archaeum Ignicoccus hospitalis.” PNAS, 2008, Volume 105, issue 22.
(13) Reichenbach H, Hofle G. 1993. Biologically Active Secondary Metabolites From Myxobacteria. Biotech. Adv. 11: 219-277.


(9) Brochier C., Gribaldo S.,  Zivanovic Y.,  Confalonieri F. and Forterre P. “Nanoarchaea: representatives of a novel archaeal phylum or a fast-evolving euryarchaeal lineage related to Thermococcales?” Genome Biology 2005, DOI:10.1186/gb-2005-6-5-r42.
(14) Hillesland KL, Lenski RE, Velicer GJ. 2007. Ecological Variables Affecting Predatory Success of Myxococcus xanthus. Microbial Ecology. 53: 571-578.


(10) Huber H., Rachel R., Riehl S. and Wyschkony I. “The ultrastructure of Ignicoccus: Evidence for a novel outer membrane and for intracellular vesicle budding in an archaeon.” Archaea, 2002, Volume 1.
(15) Rosenberg E, Vaks B, Zuckerberg A. 1973. Bactericidal Action of an Antibiotic Produced by Myxococcus xanthus. Antimicrobial Agents and Chemotherapy. 4: 507-513.

Latest revision as of 23:19, 27 November 2013

This student page has not been curated.

Introduction

Myxococcus xanthus is a gram-negative, rod-shaped bacterium, prevalent in soil environments, that exhibits extensive social behaviour [1]. When nutrients are scarce, bacteria aggregate into fruiting bodies that form spores. When adequate food is present in the environment, however, M. xanthus cells collectively swarm and prey upon other organisms. This mechanism of predation is a highly organized system involving sensing, moving towards, and lysing prey [2].


Myxococcus xanthus cells.

Sensing Prey

Signal Transduction

Myxococcus xanthus uses a frz signal transduction system to control its directed movement towards prey [3]. This frz system is similar to the Che chemotaxis system in E. coli, and frz gene mutants exhibit similar characteristics to well-known che gene mutants in the E. coli system. In M. xanthus, however, chemotactic activity is controlled by reversing direction of gliding motility, rather than by switching direction of flagellar rotation [4].

Direct Contact

M. xanthus cells cannot sense prey colonies until direct cell-cell contact is made. There is no recognition of prey cells even at very short distances, but when contact is made, the M. xanthus cells began to alter their behaviour. The frz signal transduction system is also responsible for keeping the M. xanthus cells in the vicinity of their prey after contact has been made and feeding is underway. When cells start moving away from the source, the frz system senses this and induces a reverse in direction to keep them in contact with the prey colony [3].

Motility During Predation

M. xanthus uses what is referred to as the “wolf pack” approach to predation [5]. Cells usually exist as biofilms consisting of a layered arrangement. Once prey is sensed, the cells cluster into organized groups known as swarms, which then invade prey colonies [2].

A swarm of Myxococcus xanthus cells (upper)engaged in predation of a prey colony of E. coli (lower). M.xanthus cells are engaged in predatory rippling as they move through prey colony. Image courtesy of James E. Berleman and John R. Kirby [10].


Predatory Rippling

Myxococcus xanthus swarms utilise a behaviour known as rippling during predation. It is induced when M. xanthus makes contact with prey or other food sources. Rippling is also observed during fruiting body formation, but research by Berleman et al. [6] demonstrates that it is generally a predatory mechanism and is necessary for efficient predation. During rippling, cells accumulate in aggregates containing ridges and troughs, and move in a manner similar to water-like ripples [7]. These ripples were coined “accordion waves” because they reflect off each other when they collide, causing each wave crest to oscillate with no net displacement. This is due to intercellular signalling during wave collision that causes changes in direction in all the cells of the swarm. [8]. Rippling behaviour has physiological benefits during predation because it retains M. xanthus cells in the area of their prey for a longer time, by decreasing random drift and increasing organized alignment [9].

Reversal Rate

Directed movement of Myxococcus xanthus relies on the reversal of direction. M. xanthus cells reverse direction on average every 7 minutes. Net movement results when the intervals between the reversals vary [4]. During predatory rippling, this allows the swarm of cells to increase its expansion in the direction of prey, because more of their potential velocity is oriented towards the prey as the reversal frequency decreases. [10]. Varying reversal rate of individual cells and therefore of the swarm is critical for movement in a particular direction.

Killing and Digestion of Prey

During predation, Myxococcus xanthus feeds by causing lysis of prey cell envelopes, and then extracting cytoplasmic contents to digest for carbon, nitrogen, and energy [11]. It is capable of killing prey organisms by collectively secreting both antibiotics and lytic enzymes. The lytic enzymes produced include cell wall cleaving enzymes such as proteases, peptidases, nucleases, and lipases [12]. Some of the antibiotics produced are bactericidal, and some only halt growth of prey organisms making them easier to lyse using other compounds [13].

Myxococcus xanthus social behaviour in the presence of sufficient (A) and scarce (B) .nutrients. Image adapted from Zusman et al. [2]

Ecology and Predatory Efficiency

Predation by M. xanthus is affected by many variables in the environment, such as surface solidity, and density and species of prey colonies to name a few. Higher density of prey colonies greatly increases the number of patches encountered and attacked by M. xanthus. Physical structure of the environment also affects predation, making it easier or harder for predators to move; increased surface solidity was found to increase M. xanthus predatory efficiency. M. xanthus was also shown to have different predation rates for different prey types, which may be due to different mechanisms of lysis and movement used for different species, as well as the ability of some prey species to secrete inhibitory chemicals. However, although ecological variables affect rates of encounter and attack of prey, rates of killing of prey cells once patches were encountered are largely independent of these variables [14].


Further Research

The predatory behaviour of Myxococcus xanthus is potentially beneficial to medical and pharmaceutical advances. Some of the antibiotics produced by M. xanthus to kill their prey have the possibility to be useful as antibiotics for therapeutic use, and this may be an interesting field for further research [15].

References

(1) Reichenbach H. 1999. The ecology of myxobacteria. Environmental Microbiology. 1: 15-20.

(2) Zusman DR, Scott AE, Zhaomin Y, Kirby JR. 2007. Chemosensory pathways, motility, and development in Myxococcus xanthus. Nature Reviews. 5:862-872.

(3) McBride MJ, Zusman DR. 1996. Behavioural analysis of single cells of Myxococcus xanthus in response to prey cells of Eschericiea coli. FEMS Microbiology Letters. 137: 227-231.

(4) Blackhart BD, Zusman DR. 1985. “Frizzy” genes of Myxococcus xanthus are involved in control of frequency of reversal and gliding motility. Proceedings of the National Academy of Science USA. 82: 8767-8770.

(5) Martin M. 2002. Predatory Prokaryotes: An Emerging Research Opportunity. Journal of Molecular Microbiology and Biotechnology. 4: 467-477.

(6) Berleman JE, Chumley T, Cheung P, Kirby JR. 2006. Rippling is a Predatory Behaviour in Myxococcus xanthus. Journal of Bacteriology. 188: 5888-5895.

(7) Shimkets JL, Kaiser D. 1982. Induction of coordinated movement of Mycococcus xanthus cells. Journal of Bacteriology. 152: 451-461.

(8) Sliusarenko O, Neu J, Zusman DR, Oster G. 2006. Accordian Waves in Myxococcus xanthus. Proceedings of the National Academy of Science USA. 103: 1534-1539.

(9) Zhang H, Vaksman Z, Litwin D, Shi P, Kaplan H, Ogoshin O. 2012. The Mechanistic Basis of Myxococcus xanthus Rippling Behaviour and its Physiological Role During Predation. Computational Biology. 8: 1-13.

(10) Berleman JE, Scott J, Chumley T, Kirby JR. 2008. Predataxis behaviour by Myxococcus xanthus. Proceedings of the National Academy of Science USA. 105: 17127-17132.

(11) Kaiser D, Robinson M, Kroos L. 2010. Myxobacteria, Polarity, and Multicellular Morphogenesis. Cold Spring Harbor Perspectives in Biology. 2:a000380

(12) Rosenberg E, Varon M. 1984. Antibiotics and Lytic Enzymes, p.109-125. In Rosenberg E (ed), Myxobacteria. Springer, New York, NY.

(13) Reichenbach H, Hofle G. 1993. Biologically Active Secondary Metabolites From Myxobacteria. Biotech. Adv. 11: 219-277.

(14) Hillesland KL, Lenski RE, Velicer GJ. 2007. Ecological Variables Affecting Predatory Success of Myxococcus xanthus. Microbial Ecology. 53: 571-578.

(15) Rosenberg E, Vaks B, Zuckerberg A. 1973. Bactericidal Action of an Antibiotic Produced by Myxococcus xanthus. Antimicrobial Agents and Chemotherapy. 4: 507-513.

Retrieved from "https://microbewiki.kenyon.edu/index.php?title=Predation_by_Myxococcus_xanthus&oldid=93296"