Methanosarcina acetivorans
A Microbial Biorealm page on the genus Methanosarcina acetivorans
Classification
Higher order taxa
Archaea; Euryarchaeota; Methanomicrobia; Methanosarcinales; Methanosarcinaceae; Methanosarcina
Species
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NCBI: Taxonomy |
Methanosarcina acetivorans
Description and significance
Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.
Methanosarcina acetivorans is an acetotrophic marine methane-producing bacterium that was isolated from methane-evolving sediments. These marine sediments were obtained from the Sumner branch of Scripps Canyon located near La Jolla, CA. This species has optimal growth at 35 to 40 degrees celcius, an optimal pH range of 6.5 to 7.0. Additionally, NaCl and Mg2+ were required for growth. Methanosarcina acetivorans was sequenced due to the availability of genetic tools that can modify it and allow it to be used as a model species for methanogens. Methanosarcina acetivorans is a unique methanogen because it uses acetate as a source of carbon and as a source of energy. It does so by breaking down acetate to produce carbon dioxide and methane. This property makes it a possible key player in global warming.
Genome structure
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?
The genome of Methanosarcina acetivorans is the largest known archaeon genome and the third largest fully sequenced prokaryote. It consists of 5,751,492 nucleotides and 4528 protein coding genes. Methanosarcina acetivorans has a linear genome and little is known about the presence of plasmids.
Cell structure and metabolism
Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.
Methanosarcina acetivorans has the greatest number and diversity of surface layer protens than any other archaea species. Although Methanosarcina acetivorans is gram negative, there were thin sections that revealed a monolayer cell wall 10nm thick that is characteristice of marine methanogenic bacteria with a protein cell wall. Motility has not been observed in any Methanosarcina species, but one flagellin (fla) and two complete chemotaxis (che) gene clusters were found which may suggest that motility could be possible under certain situations.
Methanosarcina acetivorans is also capable of methanogenesis (a form of anaerobic respiration). Acetic acid is the terminal electron acceptor in this pathway and methane is evolved.
Ecology
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
Methanosarcina acetivorans interacts with other organisms and affects the environment through its production of methane. Methane is a potent greenhouse gas that reflects heat better than carbon dioxide. Methane is also a potential alternative energy source.
Pathology
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
Enter summaries of the most recent research here--at least three required
References
http://www.genome.org/cgi/reprint/12/4/532 James E. Galagan, et al. The Genome of M. acetivorans Reveals Extensive Metabolic and Physiological Diversity Genome Res., Apr 2002, 12: 532 - 542.
Winstead, Edward R., Key player in global warming: M. acetivorans is sequenced April 26, 2002
Methanosarcina Sequencing Project. Broad Institute of MIT and Harvard (www.broad.mit.edu)
Edited by Paul Molina, student of Rachel Larsen and Kit Pogliano
