Rhodobacter sphaeroides is a kind of purple bacterium; a group of bacteria that can obtain energy through photosynthesis. Its best growth conditions are anaerobic phototrophy (photoheterotrophic and photoautotrophic) and aerobic chemoheterotrophy in the absence of light. R. sphaeroides is also able to fix nitrogen. It is remarkably metabolically diverse, as it is able to grow heterotrophically via fermentation and aerobic and anaerobic respiration.
(van Niel, 1944) Imhoff et al., 1984
Rhodbacter sphaeroides has been isolated from deep lakes and stagnant waters.
Rhodbacter sphaeroides is one of the most pivotal organisms in the study of bacterial photosynthesis. It requires no unusual conditions for growth and is incredibly efficient. The regulation of its photosynthetic machinery is of great interest to researchers, as R. sphaeroides has an intricate system for sensing O2 tensions. Also, when exposed to a reduction in the partial pressure of oxygen, R. sphaeroides develops invaginations in its cellular membrane. The photosynthetic apparatus is housed in these invaginations. These invaginations are also known as chromatophores.
The genome of R. sphaeroides is also somewhat intriguing. It has two chromosomes, one of 3 Mb (CI) and one of 900 Kb (CII), and five naturally occurring plasmids. Many genes are duplicated between the two chromosomes but appear to be differentially regulated. Moreover, many of the open reading frames (ORFs) on CII seem to code for proteins of unknown function. When genes of unknown function on CII are disrupted, many types of auxotrophy result, emphasizing that the CII is not merely a truncated version of CI.
Small non-coding RNAEdit
Bacterial small RNAs have been identified as components of many regulatory networks. Twenty sRNAs were experimentally identified in Rhodbacter spheroids, and the abundant ones were shown to be affected by singlet oxygen (1O2) exposure. 1O2 which generates photooxidative stress, is made by bacteriochlorophyll upon exposure to oxygen and light. One of the 1O2 induced sRNAs SorY (1O2 resistance RNA Y) was shown to be induced under several stress conditions and conferred resistance against 1O2 by affecting a metabolite transporter. SorX is the second 1O2 induced sRNA that counteracts oxidative stress by targeting mRNA for a transporter. It also has an impact on resistance against organic hydroperoxides. A cluster of four homologous sRNAs called CcsR for conserved CCUCCUCCC motif stress-induced RNA has been shown to play a role in photo-oxidative stress resistance as well. PcrZ (photosynthesis control RNA Z) identified in R. sphaeroides, is a trans-acting sRNA which counteracts the redox-dependent induction of photosynthesis genes, mediated by protein regulators.
- Rhodbacter sphaeroides (van Niel 1944) Imhoff et al., 1984
- Rhodcoccus minor Molisch 1907
- Rhodcoccus capsulatus Molisch 1907
- Rhodsphaera capsulata (Molisch) Buchanan 1918
- Rhodsphaera minor (Molisch) Bergey et al. 1923
- Rhodrhagus minor (Molisch) Bergey et al. 1925
- Rhodrhagus capsulatus (Molisch) Bergey et al. 1925
- Rhodrrhagus capsulatus Bergey et al. 1939
- Rhodpseudomonas sphaeroides van Niel 1944
- Rhodpseudomonas spheroides van Niel 1944
- Rhodrrhagus spheroides (van Niel) Brisou 1955
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- Peng, Tao; Berghoff, Bork A.; Oh, Jeong-Il; Weber, Lennart; Schirmer, Jasmin; Schwarz, Johannes; Glaeser, Jens; Klug, Gabriele (2016-10-02). "Regulation of a polyamine transporter by the conserved 3' UTR-derived sRNA SorX confers resistance to singlet oxygen and organic hydroperoxides in Rhodbacter sphaeroides". RNA biology. 13 (10): 988–999. doi:10.1080/15476286.2016.1212152. ISSN 1555-8584. PMC 5056773. PMID 27420112.
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- Bacteriology Insight Orienting System over Rhodbacter sphaeroides[permanent dead link]
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