Biology:Roseiflexus castenholzii
| Roseiflexus castenholzii | |
|---|---|
Scientific classification 
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| Domain: | Bacteria |
| Phylum: | Chloroflexota |
| Class: | Chloroflexia |
| Order: | Chloroflexales |
| Family: | Roseiflexaceae |
| Genus: | Roseiflexus |
| Species: | R. castenholzii
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| Binomial name | |
| Roseiflexus castenholzii Hanada et al., 2002
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Roseiflexus castenholzii is a heterotrophic, thermophilic, filamentous anoxygenetic phototroph (FAP) bacterium.[1] This species is in one of two genera of FAPs that lack chlorosomes.[2][3] R. castenholzii was first isolated from red-colored bacterial mats located Nakabusa hot springs in Japan.[1] Because this organism is a phototroph, it utilizes photosynthesis to fix carbon dioxide and build biomolecules. R. castenholzii has three photosynthetic complexes: light-harvesting only, reaction center only, and light-harvesting with reaction center.[4]
Morphology
This bacterium has a cell diameter is of 0.8–1.0 micrometers but does not have a definite length because of its multicelluar filamentous structure. The bacterium is red to reddish-brown forms distinct red bacterial mats in the natural environment.[2] R. castenholzii lacks internal vesicles, internal membranes, and complex structures. This species has gliding motility.[1]
Phylogeny
The five currently known genera of FAP organisms are Chlorofelxus, Choronema, Oscillochloris, Roseiflexus, and Heliothrix. Of these five, only two do not contain chlorosomes: Roseiflexus and Heliothrix.[3] Roseiflexus and Heliothrix are both red due to only having Bchl a as a photosyntheic pigment. In most other aspects, both phenotypically and genetically, the genera Roseiflexus and Heliothrix are different from each other.[3] Little is known about the taxonomy of the Roseiflexus genus due to it only containing one known species: Roseiflexus casternholzii.
Habitat
When first discovered, Roseiflexus castenholzii was isolated from the lowest layer of a three layered bacterial mat; the top two layers contained cyanobacteria and Chloroflexus spp.[3] These mats were found in multiple Japanese hot springs ranging in temperature from 45.5 °C to 68.5 °C and with a neutral to alkaline pH range.[1][3]
This bacterium is able to grow photoheterotrophically under anaerobic light conditions and chemoheterotrophically under aerobic dark conditions. Optimal growth conditions for this organism are 50 °C and pH 7.5–8.0. The first isolated type strain was HLO8T (= DSM 13941T = JCM 11240T).[1][2]
Photosynthesis
In order to conduct photosynthesis, Roseiflexus castenholzii contains three different complexes: light-harvesting only (LH), reaction center only (RC) and light-harvesting with reaction center (LHRC).[4] In contrast to most other FAPs, R. castenholzii does not have chlorosomes, which contain great amounts of photosynthetic pigments.[4] Because chlorosomes can obstruct observations of photosynthetic complexes, Roseiflexus castenholzii is considered a model organism to study the reaction centers FAPs have.[4]
The LHRC contains both light harvesting and reaction center peptides that allow for absorbing light and exciting electrons in one complex.[5] The light-harvesting complex contains antenna pigments that allow the bacterium to absorb light around 800 nanometers.[5] The majority of these pigments are bacteriochlorophyll (BChl).[4] The reaction center in Roseiflexus castenholzii is closely related to the RC of Chloroflexus aurantiacus. R. castenholzii's RC complex contains three subunits: L, M, and a c-type cytochrome. It lacks the H subunit common in purple bacteria.[5] The RC also contains BChl and bacteriopheophytin (BPhe) pigments.[6][4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 "Roseiflexus castenholzii gen. nov., sp. nov., a thermophilic, filamentous, photosynthetic bacterium that lacks chlorosomes". International Journal of Systematic and Evolutionary Microbiology 52 (Pt 1): 187–193. January 2002. doi:10.1099/00207713-52-1-187. PMID 11837302.
- ↑ 2.0 2.1 2.2 The prokaryotes. Vol. 7. Proteobacteria : delta and epsilon subclasses, deeply rooting bacteria : a handbook on the biology of bacteria (3rd ed.). New York: Springer. 2006. ISBN 978-0-387-30747-3. OCLC 262687432. https://www.worldcat.org/oclc/262687432.
- ↑ 3.0 3.1 3.2 3.3 3.4 "The Family Chloroflexaceae" (in en). The Prokaryotes. New York, NY: Springer New York. 2006. pp. 815–842. doi:10.1007/0-387-30747-8_33. ISBN 978-0-387-25497-5.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 "Light-harvesting antenna system from the phototrophic bacterium Roseiflexus castenholzii". Biochemistry 49 (35): 7524–7531. September 2010. doi:10.1021/bi101036t. PMID 20672862.
- ↑ 5.0 5.1 5.2 "Pigment organization in the photosynthetic apparatus of Roseiflexus castenholzii". Biochimica et Biophysica Acta (BBA) - Bioenergetics 1787 (8): 1050–1056. August 2009. doi:10.1016/j.bbabio.2009.02.027. PMID 19272352.
- ↑ "Structural and spectroscopic properties of a reaction center complex from the chlorosome-lacking filamentous anoxygenic phototrophic bacterium Roseiflexus castenholzii". Journal of Bacteriology 187 (5): 1702–1709. March 2005. doi:10.1128/JB.187.5.1702-1709.2005. PMID 15716441.
Further reading
- "Characterization of a blue-copper protein, auracyanin, of the filamentous anoxygenic phototrophic bacterium Roseiflexus castenholzii". Archives of Biochemistry and Biophysics 490 (1): 57–62. October 2009. doi:10.1016/j.abb.2009.08.003. PMID 19683508.
- "Alkane-1,2-diol-based glycosides and fatty glycosides and wax esters in Roseiflexus castenholzii and hot spring microbial mats". Archives of Microbiology 178 (3): 229–237. September 2002. doi:10.1007/s00203-002-0449-8. PMID 12189424.
- "Excitation energy transfer and trapping dynamics in the core complex of the filamentous photosynthetic bacterium Roseiflexus castenholzii". Photosynthesis Research 111 (1–2): 149–156. March 2012. doi:10.1007/s11120-011-9669-6. PMID 21792612.
External links
- Propagation of LexA regulog to Roseiflexus castenholzii DSM 13941
- Type strain of Roseiflexus castenholzii at BacDive - the Bacterial Diversity Metadatabase
Wikidata ☰ Q16992318 entry
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