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editRoseiflexus 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.
Article body
edit*may change the order of these to determine the best flow
Morphology
editThe 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
editThe 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
editWhen 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
editIn 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
edit- ^ 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.
- ^ 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
- ^ 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.
- ^ 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.
- ^ 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.
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