Green sulfur bacteria
| Green sulfur bacteria | |
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| Green sulfur bacteria in a Winogradsky column | |
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Chlorobi |
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The green sulfur bacteria are a family of obligately anaerobic photoautotrophic bacteria. Most closely related to the distant Bacteroidetes, they are accordingly assigned their own phylum.[1]
Green sulfur bacteria are nonmotile (except Chloroherpeton thalassium, which may glide)[1] and occur in spheres, rods, and spirals. Photosynthesis is achieved using a Type 1[2] Reaction Centre using bacteriochlorophyll (BChl) a and in chlorosomes which employ BChl c, d, or e; in addition chlorophyll a is also present,.[1] They use sulfide ions, hydrogen or ferrous iron as an electron donor and the process is mediated by the type I reaction centre and Fenna-Matthews-Olson complex. Elemental sulfur deposited outside the cell may be further oxidized. By contrast, the photosynthesis in plants uses water as the electron donor and produces oxygen.[1]
Chlorobium tepidum has emerged as a model organism for the group; although only 10 genomes have been sequenced, these are quite comprehensive of the family's biodiversity. Their 2-3 Mb genomes encode 1750-2800 genes, 1400-1500 of which are common to all strains. The apparent absence of two-component histidine-kinases and response regulators suggest limited phenotypic plasticity. Their small dependence on organic molecule transporters and transcription factors also indicate these organisms are adapted to a narrow range of energy-limited conditions, an ecology shared with the simpler cyanobacteria, Prochlorococcus and Synechococcus[1]
A species of green sulfur bacteria has been found living near a black smoker off the coast of Mexico at a depth of 2,500 m in the Pacific Ocean. At this depth, the bacterium, designated GSB1, lives off the dim glow of the thermal vent since no sunlight can penetrate to that depth.[3]
Green sulfur bacteria appear in Lake Matano, Indonesia, at a depth of about 110–120 m. The population may include the species Chlorobium ferrooxidans.[4]
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN)[5] [6] and the phylogeny is based on 16S rRNA-based LTP release 111 by The All-Species Living Tree Project.[7]
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Notes:
♪ Prokaryotes where no pure (axenic) cultures are isolated or available, i. e. not cultivated or can not be sustained in culture for more than a few serial passages
♦ Type strain lost or not available
♥ Strains not lodged at National Center for Biotechnology Information (NCBI) or listed in the List of Prokaryotic names with Standing in Nomenclature (LPSN)
♠ Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LSPN)
See also
References
- 1 2 3 4 5 D.A. Bryant & N.-U. Frigaard; Frigaard (November 2006). "Prokaryotic photosynthesis and hototrophy illuminated". Trends Microbiol. 14 (11): 488–96. doi:10.1016/j.tim.2006.09.001. PMID 16997562.
- ↑ Green, Beverley R. (2003). Light-Harvesting Antennas in Photosynthesis. p. 8. ISBN 0792363353.
- ↑ Beatty JT, Overmann J, Lince MT, Manske AK, Lang AS, Blankenship RE, Van Dover CL, Martinson TA, Plumley FG.; Overmann; Lince; Manske; Lang; Blankenship; Van Dover; Martinson; Plumley (2005). "An obligately photosynthetic bacterial anaerobe from a deep-sea hydrothermal vent". Proc. Natl Acad. Sci. USA 102 (26): 9306–10. doi:10.1073/pnas.0503674102. PMC 1166624. PMID 15967984.
- ↑ Crowe, Sean; Jones, CarriAyne; Katsev, Sergei; O'Neill, AH; Sturm, A; Canfield, DE; Haffner, GD; et al. (2008). "Photoferrotrophs thrive in an Archean Ocean analogue". Proceedings of the National Academy of Sciences 105 (41) (2008-10-14). pp. 15938–43. doi:10.1073/pnas.0805313105. ISSN 0148-0227. PMC 2572968. PMID 18838679. Retrieved 2009-06-30.
- ↑ See the List of Prokaryotic names with Standing in Nomenclature. Data extracted from J.P. Euzéby. "Chlorobi". Retrieved 2013-03-20.
- ↑ See the NCBI webpage on Chlorobi Data extracted from Sayers; et al. "NCBI Taxonomy Browser". National Center for Biotechnology Information. Retrieved 2013-03-20.
- ↑ See the All-Species Living Tree Project . Data extracted from the "16S rRNA-based LTP release 111 (full tree)" (PDF). Silva Comprehensive Ribosomal RNA Database. Retrieved 2013-03-20.
External links
- "The Family Chlorobiaceae". The Prokaryotes. Retrieved July 5, 2005.