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User:Fungus enthusiast/Roseiflexus castenholzii

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Roseiflexus casternholzii is a thermophillic, filamentous anoxygenetic phototroph (FAP) bacterium that lacks chlorosomes.[1][2] This species was first isolated from red-colored bacterial mats located Nakabusa hot springs in Japan.[1] (I will add a summary of the mechanisms here as well).

A taxobox already exists for this article, so I will be sure to review it.

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*may change the order of these to determine the best flow

Morphology

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The first isolated strain of R. casternholzii (HLO8T) appeared red to reddish-brown in color. This bacterium has a narrow cell diameter of 0.8 - 1.0 micrometers and does not have a definite length due to having a multicelluar filamentous structure. R. casternholzii lacks internal vesicles, internal membranes, and complex structures. This species has shown the ability of gliding motility.[1]

(might upload picture - need to see if it is allowed first)

Taxonomy

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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. Roseiflexus and Heliothrix are both red in color 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.[2] Little is known about the taxonomy of Roseiflexus due to it only containing one known species: Roseiflexus casternholzii.

Habitat

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When first discovered, Roseiflexus casternholzii was isolated from the lowest layer of a three layered bacterial mat; the top two contained cyanobacteria and Chloroflexus spp.[2] 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][2]

Mechanisms

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Photosynthesis

In order to conduct photosythesis, Roseiflexus casternholzii contains light-harvesting - reaction center (LHRC), light-harvesting (LH) only, and reaction center (RC) only complexes.[3] In contrast to most other FAPs, R. casternholzii does not have chlorosomes, which contain great amounts of photosynthetic pigments.[3]

The LHRC contains both light harvesting and reaction center peptides that allow for absorbing light and exciting electrons in one complex.[4]

The light-harvesting complex contains antenna pigments that allow the bacterium to absorb light around 800 nanometers.[4] The majority of these pigments are bacteriochlorophyll (BChl).[3]

The reaction center in Roseiflexus casternholzii is closely related to the RC of Chloroflexus aurantiacus. R. casternholzii's RC complex contains three subunits: L, M, and a c-type cytochrome. It lacks the H subunit common in purple bacteria.[4] The RC also contains BChl and bacteriopheophytin (BPhe) pigments.[5][3]

Because chlorosomes can obstruct observations of RCs, Roseiflexus casternholzii is considered a model organism to study the reaction centers FAPs have.[3]


(I will move this section once it is a little more finished).

(I will change this heading in the future so it flows better) R. castenholzii does not have cholorplasts like most photosynthetic organism, yet it still undergoes photosythesis. I will use this section to describe what is known about its light systems and how it ultilzes them for fixation and energy. There are a couple of articles lined up in my biolography sandbox that I will refrence in this section. I will also add any other significant mechanims that this organism has that is different from others (if there are any). If there are multiple different mechanisms, then I will create subsections in this section for each one.

References

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  1. ^ a b c d Hanada, Satoshi; Takaichi, Shinichi; Matsuura, Katsumi; Nakamura, Kazunori (2002-01-01). "Roseiflexus castenholzii gen. nov., sp. nov., a thermophilic, filamentous, photosynthetic bacterium that lacks chlorosomes". International Journal of Systematic and Evolutionary Microbiology. 52 (1): 187–193. doi:10.1099/00207713-52-1-187. ISSN 1466-5026.
  2. ^ a b c d Hanada, Satoshi; Pierson, Beverly K. (2006), Dworkin, Martin; Falkow, Stanley; Rosenberg, Eugene; Schleifer, Karl-Heinz (eds.), "The Family Chloroflexaceae", The Prokaryotes, New York, NY: Springer New York, pp. 815–842, doi:10.1007/0-387-30747-8_33, ISBN 978-0-387-25497-5, retrieved 2022-09-30
  3. ^ a b c d e Collins, Aaron M.; Qian, Pu; Tang, Qun; Bocian, David F.; Hunter, C. Neil; Blankenship, Robert E. (2010-09-07). "Light-Harvesting Antenna System from the Phototrophic Bacterium Roseiflexus castenholzii". Biochemistry. 49 (35): 7524–7531. doi:10.1021/bi101036t. ISSN 0006-2960.
  4. ^ a b c Collins, Aaron M.; Xin, Yueyong; Blankenship, Robert E. (2009-08-01). "Pigment organization in the photosynthetic apparatus of Roseiflexus castenholzii". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1787 (8): 1050–1056. doi:10.1016/j.bbabio.2009.02.027. ISSN 0005-2728.
  5. ^ Yamada, Mitsunori; Zhang, Hui; Hanada, Satoshi; Nagashima, Kenji V. P.; Shimada, Keizo; Matsuura, Katsumi (2005). "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. doi:10.1128/JB.187.5.1702-1709.2005. ISSN 0021-9193. PMC 1063993. PMID 15716441.{{cite journal}}: CS1 maint: PMC format (link)