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The green sulfur bacteria (Chlorobiaceae) are a family of obligately anaerobic photoautotrophic bacteria. Together with the non-photosynthetic Ignavibacteriaceae, they form the phylum Chlorobi.[1] Green sulfur bacteria
Green sulfur bacteria
are nonmotile (except Chloroherpeton thalassium, which may glide) and capable of anoxygenic photosynthesis.[1][2] In contrast to plants, green sulfur bacteria mainly use sulfide ions as electron donors.[3] They are autotrophs that utilize the reverse tricarboxylic acid cycle to fix carbon dioxide.[4] Green sulfur bacteria are often found in the deep sea, which has low light availability.[5]

Contents

1 Metabolism

1.1 Catabolism 1.2 Anabolism

2 Habitat 3 Phylogeny 4 Taxonomy

4.1 Notes

5 Photosynthesis
Photosynthesis
in the Green Sulfur Bacteria 6 Carbon Fixation of Green Sulfur Bacteria 7 See also 8 References 9 External links

Metabolism[edit] Catabolism[edit] Photosynthesis
Photosynthesis
is achieved using a Type 1 reaction centre, which contains bacteriochlorophyll a, and is taken place in chlorosomes.[1][2] Type 1 reaction centre is equivalent to photosystem I found in plants and cyanobacteria. Green sulfur bacteria
Green sulfur bacteria
use sulfide ions, hydrogen or ferrous iron as electron donors and the process is mediated by the Type I reaction centre and Fenna-Matthews-Olson complex. Reaction centre
Reaction centre
contains bacteriochlorophylls, P840, which donates electrons to cytochrome c-551 when it is excited by light. Cytochrome
Cytochrome
c-551 then passes the electrons down the electron chain. P840 is returned to its reduced state by the oxidation of sulfide. Sulfide
Sulfide
donates two electrons to yield elemental sulfur. Elemental sulfur is deposited in globules on the extracellular side of the outer membrane. When sulfide is depleted, the sulfur globules are consumed and oxidized to sulfate. However, the pathway of sulfur oxidation is not well-understood.[3] Anabolism[edit] These autotrophs fix carbon dioxide using the reverse tricarboxylic acid (RTCA) cycle. Energy is consumed to incorporate carbon dioxide in order to assimilate pyruvate and acetate and generate macromolecules. Chlorobium tepidum, a member of green sulfur bacteria was found to be mixotroph due to its ability to use inorganic and organic carbon sources. They can assimilate acetate through the oxidative (forward) TCA (OTCA) cycle in addition to RTCA. In contrast to the RTCA cycle, energy is generated in the OTCA cycle, which may contribute to better growth. However, the capacity of the OTCA cycle is limited because gene that code for enzymes of the OTCA cycle are down-regulated when the bacteria is growing phototrophically.[4] Habitat[edit] The Black Sea, an extremely anoxic environment, was found to house a large population of green sulfur bacteria at about 100 m depth. Due to the lack of light available in this region of the sea, most bacteria were photosynthetically inactive. The photosynthetic activity detected in the sulfide chemocline suggests that the bacteria need very little energy for cellular maintenance.[5] A species of green sulfur bacteria has been found living near a black smoker off the coast of Mexico
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.[6] Phylogeny[edit] The currently accepted phylogeny is based on 16S rRNA-based LTP release 123 by The All-Species Living Tree Project.[7]

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[notes 2](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[edit] The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN)[8][9] See also: Bacterial taxonomy

Phylum Chlorobi Iino et al. 2010 Class Ignavibacteria Iino et al. 2010

Order Ignavibacteriales Iino et al. 2010

Family Ignavibacteriaceae Iino et al. 2010

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

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

Genus Melioribacter roseus Podosokorskaya et al. 2013 ["Melioribacter" Podosokorskaya et al. 2011]

Species Melioribacter roseus Podosokorskaya et al. 2011 ["Melioribacter roseus" Podosokorskaya et al. 2011]

Class Chlorobea
Chlorobea
Cavalier-Smith 2002

Order Chlorobiales
Chlorobiales
Gibbons and Murray 1978

Family Chlorobiaceae
Chlorobiaceae
Copeland 1956

Genus Ancalochloris Gorlenko and Lebedeva 1971

Species Ancalochloris perfilievii[notes 3]Gorlenko and Lebedeva 1971

Genus Chlorobaculum Imhoff 2003

Species "C. macestae"[notes 1]Keppen et al. 2008 Species C. limnaeum Imhoff 2003 Species C. parvum Imhoff 2003 Species C. tepidum (Wahlund et al. 1996) Imhoff 2003 (type sp.) [" Chlorobium tepidum" Wahlund et al. 1991; Chlorobium tepidum Wahlund et al. 1996] Species C. thiosulfatiphilum Imhoff 2003 [" Chlorobium limicola f. sp. thiosulfatophilum" (Larsen 1952) Pfennig & Truper 1971]

Genus Chlorobium Nadson 1906 emend. Imhoff 2003

Species Chlorobium chlorovibrioides[notes 2](Gorlenko et al. 1974) Imhoff 2003 Species C. bathyomarinum[notes 1][6] Species C. chlorochromatii[notes 1]Vogl et al. 2006 (epibiont of the phototrophic consortium Chlorochromatium aggregatum) ["Chlorobium chlorochromatii" Meschner 1957] Species C. gokarna[notes 1]Anil Kumar 2005 Species C. clathratiforme (Szafer 1911) emend. Imhoff 2003 ["Aphanothece clathratiformis" Szafer 1911; "Pelodictyon lauterbornii" Geitler 1925; Pelodictyon clathratiforme (Szafer 1911) Lauterborn 1913] Species C. ferrooxidans Heising et al. 1998 emend. Imhoff 2003 Species C. luteolum (Schmidle 1901) emend. Imhoff 2003 ["Aphanothece luteola" Schmidle 1901; "Pelodictyon aggregatum" Perfil'ev 1914; "Schmidlea luteola" (Schmidle 1901) Lauterborn 1913; Pelodictyon luteolum (Schmidle 1901) Pfennig and Truper 1971] Species C. limicola Nadson 1906 emend. Imhoff 2003 (type sp.) Species C. phaeobacteroides Pfennig 1968 emend. Imhoff 2003 Species C. phaeovibrioides Pfennig 1968 emend. Imhoff 2003

Genus Chloroherpeton Gibson et al. 1985

Species Chloroherpeton thalassium Gibson et al. 1985

Genus Clathrochloris Witt et al. 1989

Species "Clathrochloris sulfurica"[notes 1]Witt et al. 1989

Genus Pelodictyon Lauterborn 1913

Species Pelodictyon phaeum Gorlenko 1972

Genus Prosthecochloris Gorlenko 1970 emend. Imhoff 2003

Species "P. phaeoasteroides"[notes 1]Puchkova & Gorlenko 1976 Species "P. indica"[notes 1]Anil Kumar 2005 Species P. aestuarii Gorlenko 1970 emend. Imhoff 2003 (type sp.) Species P. vibrioformis (Pelsh 1936) Imhoff 2003 [Chlorobium vibrioforme Pelsh 1936]

Notes[edit]

^ a b c d e f g h i Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LSPN) ^ a b c Tang KH, Blankenship RE (November 2010). "Both forward and reverse TCA cycles operate in green sulfur bacteria". The Journal of Biological Chemistry. 285 (46): 35848–54. doi:10.1074/jbc.M110.157834. PMC 2975208 . PMID 20650900.  ^ a b 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

Photosynthesis
Photosynthesis
in the Green Sulfur Bacteria[edit] The green sulfur bacteria use PS I for photosynthesis. Thousands of bacteriochlorophyll(BCHl) c, d and e of the cells absorb light at 720-750 nm, and the light energy is transferred to BChl a-795 and a-808 before being transferred to Fenna-Matthews-Olson (FMO)-proteins which are connected to reaction centers (RC). The FMO complex then transfers the excitemnet to the RC with its special pair which absorbs at 840 nm in the plasma membrane.[10] After the reaction centers receive the energy, electrons are ejected and transferred through electron transport chains (ETCs). Some electrons form Fe-S proteins in electron transport chains are accepted by ferredoxins (Fd) which can be involved in NAD(P) reduction and other metabolic reactions.[11] Carbon Fixation of Green Sulfur Bacteria[edit] The reactions of reversal of the oxidative tricarboxylic acid cycle are catalyzed by four enzymes:[4]

pyruvate:ferredoxin (Fd) oxidoreductase:

acetyl-CoA + CO2 + 2Fdred + 2H+ ⇌ pyruvate + CoA + 2Fdox

ATP citrate lyase:

ACL, acetyl-CoA + oxaloacetate + ADP + Pi ⇌ citrate + CoA + ATP

α-keto-glutarate:ferredoxin oxidoreductase:

succinyl-CoA + CO2 + 2Fdred + 2H+ ⇌ α-ketoglutarate + CoA + 2Fdox

fumarare reductase

succinate + acceptor ⇌ fumarate + reduced acceptor

See also[edit]

Anoxic event Purple sulfur bacteria Green non-sulfur bacteria

References[edit]

^ a b c Bryant DA, Frigaard NU (November 2006). "Prokaryotic photosynthesis and phototrophy illuminated". Trends in Microbiology. 14 (11): 488–96. doi:10.1016/j.tim.2006.09.001. PMID 16997562.  ^ a b Green BR (2003). Light-Harvesting Antennas in Photosynthesis. p. 8. ISBN 0792363353.  ^ a b Sakurai H, Ogawa T, Shiga M, Inoue K (June 2010). "Inorganic sulfur oxidizing system in green sulfur bacteria". Photosynthesis Research. 104 (2–3): 163–76. doi:10.1007/s11120-010-9531-2. PMID 20143161.  ^ a b c Tang KH, Blankenship RE (November 2010). "Both forward and reverse TCA cycles operate in green sulfur bacteria". The Journal of Biological Chemistry. 285 (46): 35848–54. doi:10.1074/jbc.M110.157834. PMC 2975208 . PMID 20650900.  ^ a b Marschall E, Jogler M, Hessge U, Overmann J (May 2010). "Large-scale distribution and activity patterns of an extremely low-light-adapted population of green sulfur bacteria in the Black Sea". Environmental Microbiology. 12 (5): 1348–62. doi:10.1111/j.1462-2920.2010.02178.x. PMID 20236170.  ^ a b Beatty JT, Overmann J, Lince MT, Manske AK, Lang AS, Blankenship RE, Van Dover CL, Martinson TA, Plumley FG (June 2005). "An obligately photosynthetic bacterial anaerobe from a deep-sea hydrothermal vent". Proceedings of the National Academy of Sciences of the United States of America. 102 (26): 9306–10. Bibcode:2005PNAS..102.9306B. doi:10.1073/pnas.0503674102. PMC 1166624 . PMID 15967984.  ^ See the All-Species Living Tree Project
All-Species Living Tree Project
[1]. Data extracted from the "16S rRNA-based LTP release 123 (full tree)" (PDF). Silva Comprehensive Ribosomal RNA Database. Retrieved 2016-03-20.  ^ See the List of Prokaryotic names with Standing in Nomenclature. Data extracted from J.P. Euzéby. "Chlorobi". Archived from the original on 2013-01-27. Retrieved 2016-03-20.  ^ See the NCBI webpage on Chlorobi Data extracted from Sayers; et al. "NCBI Taxonomy Browser". National Center for Biotechnology Information. Retrieved 2016-03-20.  ^ Hauska G, Schoedl T, Remigy H, Tsiotis G (October 2001). "The reaction center of green sulfur bacteria(1)". Biochimica et Biophysica Acta. 1507 (1–3): 260–77. doi:10.1016/S0005-2728(01)00200-6. PMID 11687219.  ^ Ke B (2003). "The Green Bacteria. II. The Reaction Center Photochemistry and Electron Transport". Photosynthesis. Advances in Photosynthesis
Photosynthesis
and Respiration. 10. pp. 159–78. doi:10.1007/0-306-48136-7_9. ISBN 0-7923-6334-5. 

External links[edit]

"The Family Chlorobiaceae". The Prokaryotes. Archived from the original on November 17, 2003. Retrieved July 5, 2005. 

v t e

Prokaryotes: Bacteria
Bacteria
classification (phyla and orders)

Domain Archaea Bacteria Eukaryota (Supergroup Plant Hacrobia Heterokont Alveolata Rhizaria Excavata Amoebozoa Opisthokonta

Animal Fungi)

G-/ OM

Terra-/ Glidobacteria (BV1)

Eobacteria

Deinococcus–Thermus

Deinococcales Thermales

Chloroflexi

Anaerolineales Caldilineales Chloroflexales Herpetosiphonales Dehalococcoidales Ktedonobacterales Thermogemmatisporales Thermomicrobiales Sphaerobacterales

other glidobacteria

Thermodesulfobacteria thermophiles

Aquificae Thermotogae

Cyanobacteria

Proteobacteria (BV2)

Alpha

Caulobacterales Kiloniellales Kordiimonadales Magnetococcales Parvularculales Rhizobiales Rhodobacterales Rhodospirillales Rickettsiales Sneathiellales Sphingomonadales

Beta

Burkholderiales Hydrogenophilales Methylophilales Neisseriales Nitrosomonadales Procabacteriales Rhodocyclales

Gamma

Acidithiobacillales Aeromonadales Alteromonadales Cardiobacteriales Chromatiales Enterobacteriales Legionellales Methylococcales Oceanospirillales Orbales Pasteurellales Pseudomonadales Salinisphaerales Thiotrichales Vibrionales Xanthomonadales

Delta

Bdellovibrionales Desulfarculales Desulfobacterales Desulfovibrionales Desulfurellales Desulfuromonadales Myxococcales Syntrophobacterales Syntrophorhabdales

Epsilon

Campylobacterales Nautiliales

Zeta

Mariprofundales

BV4

Spirochaetes

Spirochaetes

Sphingobacteria (FCB group)

Fibrobacteres Chlorobi

Chlorobiales Ignavibacteriales

Bacteroidetes

Bacteroidales Cytophagales Flavobacteriales Sphingobacteriales

Planctobacteria/ (PVC group)

Chlamydiae Lentisphaerae

Lentisphaerales Oligosphaerales Victivallales

Planctomycetes

Phycisphaerales Planctomycetales

Verrucomicrobia

Puniceicoccales Opitutales Chthoniobacterales Verrucomicrobiales

"Poribacteria"

Other GN

Acidobacteria

Acidobacteriales Acanthopleuribacterales Holophagales Solibacterales

Armatimonadetes

Armatimonadales Chthonomonadales Fimbriimonadales

Caldiserica Chrysiogenetes Deferribacteres Dictyoglomi Elusimicrobia Fusobacteria Gemmatimonadetes Nitrospirae Synergistetes

G+/ no OM

Firmicutes (BV3)

Bacilli

Bacillales Lactobacillales

Clostridia

Clostridiales Halanaerobiales Thermoanaerobacteriales Natranaerobiales

Erysipelotrichia

Erysipelotrichiales

Thermolithobacteria

Thermolithobacterales

Tenericutes/ Mollicutes

Mycoplasmatales Entomoplasmatales Anaeroplasmatales Acholeplasmatales Haloplasmatales

Negativicutes

Selenomonadales

Actinobacteria (BV5)

Actinobacteria

Actinomycetales Bifidobacteriales

Acidimicrobiia

Acidimicrobiales

Coriobacteriidae

Coriobacteriales

Nitriliruptoria

Euzebyales Nitriliruptorales

Rubrobacteria

Gaiellales Rubrobacterales Thermoleophilales Solirubrobacterales

Incertae sedis

†Archaeosphaeroides †Eobacterium †Leptotrichites

Source: Bergey's Manual (2001–2012). Alternative views: Wikispecies.

Taxon identifiers

Wd: Q866342 EoL: 7825 GBIF: 8106 ITIS: 956355 LPSN: chlorobiaceae.html NCBI: 19

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