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In the taxonomy of microorganisms, the Methanothrix is a genus of methanogenic archaea within the Euryarchaeota.[1][2] Methanothrix cells were first isolated from a mesophilic sewage digester but have since been found in many anaerobic and aerobic environments.[3][4] Methanothrix were originally understood to be obligate anaerobes that can survive exposure to high concentrations of oxygen,[5][6] but recent studies have shown at least one Candidatus operational taxonomic unit proposed to be in the Methanothrix genus not only survives but remains active in oxic soils.[4] This proposed species, Ca. Methanothrix paradoxum, is frequently found in methane-releasing ecosystems and is the dominant methanogen in oxic soils.
Methanothrix | |
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Genus: | Methanothrix Huser, Wuhrmann & Zehnder 1983 nom. nov.
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Type species | |
Methanothrix soehngenii Huser, Wuhrmann & Zehnder 1983
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Methanothrix are non-motile rod-shaped cells which connect together to form long filaments.[5][7] These filaments are enclosed in a proteinaceous sheath.[6] Methanothrix species, like their close relative Methanosarcina barkeri, have membranes entirely composed of diphytanylglycerol diethers.[6][8][9]
Phylogeny
edit16S rRNA based LTP_06_2022[10][11][12] | 53 marker proteins based GTDB 08-RS214[13][14][15] | |||||||||||||||
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Metabolism
editMethanothrix species use acetate[16][17] and carbon dioxide[3][18] as carbon substrates.
When using acetate, Methanothrix species use an incomplete citric acid cycle in the oxidative direction.[6][8] After formation of acetyl-CoA, the carbon-carbon bond of acetate is cleaved by a carbon monoxide dehydrogenase/acetyl-CoA synthase enzyme. The methyl moiety is transferred through multiple complexes until it is finally reduced to methane by a methyl-CoM reductase.[17]
Methanothrix species have been observed receiving electrons to reduce carbon dioxide to methane through direct interspecies electron transfer (DIET) with Geobacter species.[3][18][19] Geobacter sulfurreducens transfers electrons into Methanothrix cells using electrically conductive pili.[20]
Microbial Ecology
editCompared to the acetotrophic Methanosarcina species, Methanothrix species have lower Monod Equation parameters. Methanothrix have slower maximum growth rates and smaller half-saturation coefficients due to differences in the genera's aceticlastic pathways.[17][21] Consequently, when acetate concentrations are high, Methanothrix species are likely to be outcompeted by Methanosarcina, which can utilize the available substrate faster. However, in low acetate environments, Methanothrix species will dominate due to their lower minimum threshold for acetate. This expectation is consistent with observations of abundant Methanothrix in low-acetate ecosystems across the world.[8][16][22][23]
Because Methanothrix species are well adapted to survive exposure to oxygen and thrive using either acetate or carbon dioxide as a carbon substrate, they are thought to be one of the largest microbial contributors to methanogenesis on Earth.[19][24]
See also
editReferences
edit- ^ See the NCBI webpage on Methanothrix. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. Retrieved 2007-03-19.
- ^ J.P. Euzéby. "Methanothrix". List of Prokaryotic names with Standing in Nomenclature (LPSN). Retrieved 2021-11-17.
- ^ a b c Holmes, Dawn E.; Shrestha, Pravin M.; Walker, David J. F.; Dang, Yan; Nevin, Kelly P.; Woodard, Trevor L.; Lovley, Derek R. (2017). Schloss, Patrick D. (ed.). "Metatranscriptomic Evidence for Direct Interspecies Electron Transfer between Geobacter and Methanothrix Species in Methanogenic Rice Paddy Soils". Applied and Environmental Microbiology. 83 (9). doi:10.1128/AEM.00223-17. ISSN 0099-2240. PMC 5394310. PMID 28258137.
- ^ a b Angle, Jordan C.; Morin, Timothy H.; Solden, Lindsey M.; Narrowe, Adrienne B.; Smith, Garrett J.; Borton, Mikayla A.; Rey-Sanchez, Camilo; Daly, Rebecca A.; Mirfenderesgi, Golnazalsdat; Hoyt, David W.; Riley, William J.; Miller, Christopher S.; Bohrer, Gil; Wrighton, Kelly C. (2017-11-16). "Methanogenesis in oxygenated soils is a substantial fraction of wetland methane emissions". Nature Communications. 8 (1): 1567. doi:10.1038/s41467-017-01753-4. ISSN 2041-1723. PMC 5691036. PMID 29146959.
- ^ a b Huser, Beat A.; Wuhrmann, Karl; Zehnder, Alexander J. B. (1982-07-01). "Methanothrix soehngenii gen. nov. sp. nov., a new acetotrophic non-hydrogen-oxidizing methane bacterium". Archives of Microbiology. 132 (1): 1–9. doi:10.1007/BF00690808. ISSN 1432-072X.
- ^ a b c d PATEL, GIRISHCHANDRA B.; SPROTT, G. DENNIS (1990). "Methanosaeta concilii gen. nov., sp. nov. ("Methanothrix concilii") and Methanosaeta thermoacetophila nom. rev., comb. nov.†". International Journal of Systematic and Evolutionary Microbiology. 40 (1): 79–82. doi:10.1099/00207713-40-1-79. ISSN 1466-5034.
- ^ Koga, Y; Nishihara, M; Morii, H; Akagawa-Matsushita, M (1993). "Ether polar lipids of methanogenic bacteria: structures, comparative aspects, and biosyntheses". Microbiological Reviews. 57 (1): 164–182. doi:10.1128/mr.57.1.164-182.1993. ISSN 0146-0749. PMC 372904. PMID 8464404.
- ^ a b c Ekiel, I; Sprott, G D; Patel, G B (1985). "Acetate and CO2 assimilation by Methanothrix concilii". Journal of Bacteriology. 162 (3): 905–908. doi:10.1128/jb.162.3.905-908.1985. ISSN 0021-9193. PMC 215861. PMID 3922956.
- ^ Langworthy, T. A.; Tornabene, T. G.; Holzer, G. (1982-05-01). "Lipids of Archaebacteria". Zentralblatt für Bakteriologie Mikrobiologie und Hygiene: I. Abt. Originale C: Allgemeine, angewandte und ökologische Mikrobiologie. 3 (2): 228–244. doi:10.1016/S0721-9571(82)80036-7. ISSN 0721-9571.
- ^ "The LTP". Retrieved 10 May 2023.
- ^ "LTP_all tree in newick format". Retrieved 10 May 2023.
- ^ "LTP_06_2022 Release Notes" (PDF). Retrieved 10 May 2023.
- ^ "GTDB release 08-RS214". Genome Taxonomy Database. Retrieved 10 May 2023.
- ^ "ar53_r214.sp_label". Genome Taxonomy Database. Retrieved 10 May 2023.
- ^ "Taxon History". Genome Taxonomy Database. Retrieved 10 May 2023.
- ^ a b Jetten, M (1992). "Methanogenesis from acetate: a comparison of the acetate metabolism in Methanothrix soehngenii and Methanosarcina spp". FEMS Microbiology Letters. 88 (3–4): 181–197. doi:10.1016/0378-1097(92)90802-u. ISSN 0378-1097.
- ^ a b c Welte, Cornelia; Deppenmeier, Uwe (2014-07-01). "Bioenergetics and anaerobic respiratory chains of aceticlastic methanogens". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 18th European Bioenergetics Conference 2014 Lisbon, Portugal. 1837 (7): 1130–1147. doi:10.1016/j.bbabio.2013.12.002. hdl:2066/189998. ISSN 0005-2728. PMID 24333786.
- ^ a b Rotaru, Amelia-Elena; Shrestha, Pravin Malla; Liu, Fanghua; Shrestha, Minita; Shrestha, Devesh; Embree, Mallory; Zengler, Karsten; Wardman, Colin; Nevin, Kelly P.; Lovley, Derek R. (2013-12-13). "A new model for electron flow during anaerobic digestion: direct interspecies electron transfer to Methanosaeta for the reduction of carbon dioxide to methane". Energy & Environmental Science. 7 (1): 408–415. doi:10.1039/C3EE42189A. ISSN 1754-5706.
- ^ a b Lovley, Derek R. (2017-09-08). "Syntrophy Goes Electric: Direct Interspecies Electron Transfer". Annual Review of Microbiology. 71 (1): 643–664. doi:10.1146/annurev-micro-030117-020420. ISSN 0066-4227. PMID 28697668.
- ^ Malvankar, Nikhil S; Lovley, Derek R (2014-06-01). "Microbial nanowires for bioenergy applications". Current Opinion in Biotechnology. Energy biotechnology • Environmental biotechnology. 27: 88–95. doi:10.1016/j.copbio.2013.12.003. ISSN 0958-1669. PMID 24863901.
- ^ Conklin, Anne; Stensel, H. David; Ferguson, John (2006). "Growth Kinetics and Competition Between Methanosarcina and Methanosaeta in Mesophilic Anaerobic Digestion". Water Environment Research. 78 (5): 486–496. doi:10.2175/106143006X95393. ISSN 1061-4303. PMID 16752610.
- ^ Fey, Axel; Conrad, Ralf (2000). "Effect of Temperature on Carbon and Electron Flow and on the Archaeal Community in Methanogenic Rice Field Soil". Applied and Environmental Microbiology. 66 (11): 4790–4797. doi:10.1128/AEM.66.11.4790-4797.2000. ISSN 0099-2240. PMC 92381. PMID 11055925.
- ^ Griffin, M. E.; McMahon, K. D.; Mackie, R. I.; Raskin, L. (1998-02-05). "Methanogenic population dynamics during start-up of anaerobic digesters treating municipal solid waste and biosolids". Biotechnology and Bioengineering. 57 (3): 342–355. doi:10.1002/(sici)1097-0290(19980205)57:3<342::aid-bit11>3.0.co;2-i. ISSN 0006-3592. PMID 10099211.
- ^ Smith, Kerry S.; Ingram-Smith, Cheryl (2007). "Methanosaeta, the forgotten methanogen?". Trends in Microbiology. 15 (4): 150–155. doi:10.1016/j.tim.2007.02.002. ISSN 0966-842X. PMID 17320399.