Higher order taxa:
Archaea; Euryarchaeota; Methanococci; Methanococcales; Methanocaldococcaceae;
Genus: Methanococcus Species: Maripaludis
Description and significance
The species Methanococcus maripaludis is a member of the kingdom Archaea. More specifically, it is a member of the methanogenic archaea. “Methanogens are obligate anaerobes that carry out the reduction of carbon dioxide to methane using molecular hydrogen as the reductant” (1). This means that this species undergoes anaerobic metabolic processes with the final product being methane, utilizing H2 as an electron donor for CO2 reduction to methane.
Methanococcous maripaludis is a significant microbe because of its excellent laboratory growth behavior. This anaerobic archaea is helpful in “development of methods for growth on solid medium, enriching auxotrophic mutants, efficient transformation, and random insertional inactivation of genes” (2). It is because of these improvements to laboratory techniques that Methanococcus maripaludis is a popular archaebacteria for genetic manipulation.
The genome of Methanococcus maripaludis is similar to the genome of the more common Methanococcus jannaschii, with the difference being that Methanococcus maripaludis lacks inteins. It contains a circular genome of 1.66Mb in length, with no extra-chromosomal elements. . This chromosome also contains 1,722 protein-coding genes and has a 33% Guanine-Cytosine content (GC content) (3).
Cell structure and metabolism
“Methane formation occurs only under strictly anaerobic conditions” (5). Because of this, methanogenesis occurs only in environments that are anoxic, meaning environments that are abnormally low in or lacking oxygen. Methanococcus is commonly found in geothermal habitats such as thermal vents. Methanococcus maripaludis is found in salt-marsh sediment on the southeastern coast of the United States.
1. Dawes, Edwin. Microbial Engergetics. New York: Blackie. 1986
2. Whitman et al. 1997. Development of genetic approaches for the methane-producing areabacterium Methanococcus maripaluis. Biofactors, Volume 6, Number 1: 37-46. http://www.ingentaconnect.com/content/ios/bio/1997/00000006/00000001/bio29;jsessionid=3ko9jad5p7srd.alice?format=print
3. John Leigh Lab. University of Washington Department of Microbiology. http://faculty.washington.edu/leighj/mm.html
4. Moat et al. Microbial Physiology, 4th edition. New York: Wiley-Liss. 2002
5. Brock et al. Biology of Microorganisms, 7th edition. New Jersey. 1994