Green sulfur bacteria

Green sulfur bacteria
Green sulfur bacteria in a Winogradsky column
Scientific classification
Domain: Bacteria
Phylum: Chlorobi
Iino et al. 2010
Genus
  • Class Ignavibacteria
    • Order Ignavibacteriales
      • Family Ignavibacteriaceae
        • Ignavibacterium
        • Melioribacter ♠
  • Class Chlorobea

The green sulfur bacteria (Chlorobiaceae) are a family of obligately anaerobic photoautotrophic bacteria. Together with the non-photosynthetic Ignavibacteriaceae, they form the phylum Chlorobi. 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] Photosynthesis is achieved using a Type 1 reaction centre using bacteriochlorophyll (BChl) a and in chlorosomes which employ BChl c, d, or e; in addition chlorophyll a is also present.[2][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 phylogeny is based on 16S rRNA-based LTP release 123 by The All-Species Living Tree Project.[5]
Ignavibacteriaceae

Ignavibacterium Iino et al. 2010 emend. Podosokorskaya et al. 2013

Melioribacter Podosokorskaya et al. 2013



Chlorobiaceae

Chloroherpeton thalassium Gibson et al. 1985
Prosthecochloris

P. aestuarii Gorlenko 1970 emend. Imhoff 2003 (type sp.)

P. vibrioformis (Pelsh 1936) Imhoff 2003


Chlorobium chlorovibrioides ♦ (Gorlenko et al. 1974) Imhoff 2003


Chlorobaculum

C. tepidum (Wahlund et al. 1996) Imhoff 2003 (type sp.)

C. thiosulfatiphilum Imhoff 2003




Chlorobium

C. luteolum (Schmidle 1901) emend. Imhoff 2003

C. phaeovibrioides Pfennig 1968 emend. Imhoff 2003

C. limicola Nadson 1906 emend. Imhoff 2003 (type sp.)

C. clathratiforme (Szafer 1911) emend. Imhoff 2003

C. phaeobacteroides Pfennig 1968 emend. Imhoff 2003










Taxonomy

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN)[6][7]

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 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. 1 2 3 4 5 Bryant DA; Frigaard DU (November 2006). "Prokaryotic photosynthesis and hototrophy illuminated". Trends Microbiol. 14 (11): 488–96. doi:10.1016/j.tim.2006.09.001. PMID 16997562.
  2. ↑ Green, Beverley R. (2003). Light-Harvesting Antennas in Photosynthesis. p. 8. ISBN 0792363353.
  3. ↑ Beatty JT, Overmann J, Lince MT, Manske AK, Lang AS, Blankenship RE, Van Dover CL, Martinson TA, Plumley FG (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 1166624Freely accessible. PMID 15967984.
  4. ↑ Crowe, S. A.; Jones, C; Katsev, S; Magen, C; O'Neill, A. H.; Sturm, A; Canfield, D. E.; Haffner, G. D.; Mucci, A; Sundby, B; Fowle, D. A. (2008). "Photoferrotrophs thrive in an Archean Ocean analogue". Proceedings of the National Academy of Sciences (published 2008-10-14). 105 (41): 15938–43. doi:10.1073/pnas.0805313105. ISSN 0148-0227. PMC 2572968Freely accessible. PMID 18838679.
  5. ↑ See the All-Species Living Tree Project . Data extracted from the "16S rRNA-based LTP release 123 (full tree)" (PDF). Silva Comprehensive Ribosomal RNA Database. Retrieved 2016-03-20.
  6. ↑ See the List of Prokaryotic names with Standing in Nomenclature. Data extracted from J.P. Euzéby. "Chlorobi". Retrieved 2016-03-20.
  7. ↑ See the NCBI webpage on Chlorobi Data extracted from Sayers; et al. "NCBI Taxonomy Browser". National Center for Biotechnology Information. Retrieved 2016-03-20.

External links

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