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Yasuhiro Oda Bastiaan Star Louis A. Huisman Jan C. Gottschal Larry J. Forney 《Applied microbiology》2003,69(9):5186-5191
The biogeography of the purple nonsulfur bacterium Rhodopseudomonas palustris on a local scale was investigated. Thirty clones of phototrophic bacteria were isolated from each of five unevenly spaced sampling locations in freshwater marsh sediments along a linear 10-m transect, and a total of 150 clones were characterized by BOX-PCR genomic DNA fingerprinting. Cluster analysis of 150 genomic fingerprints yielded 26 distinct genotypes, and 106 clones constituted four major genotypes that were repeatedly isolated. Representatives of these four major genotypes were tentatively identified as R. palustris based on phylogentic analyses of 16S rRNA gene sequences. The differences in the genomic fingerprint patterns among the four major genotypes were accompanied by differences in phenotypic characteristics. These phenotypic differences included differences in the kinetics of carbon source use, suggesting that there may be functional differences with possible ecological significance among these clonal linages. Morisita-Horn similarity coefficients (CMH), which were used to compare the numbers of common genotypes found at pairs of sampling locations, showed that there was substantial similarity between locations that were 1 cm apart (CMH, ≥0.95) but there was almost no similarity between locations that were ≥9 m apart (CMH, ≤0.25). These calculations showed there was a gradual decrease in similarity among the five locations as a function of distance and that clones of R. palustris were lognormally distributed along the linear 10-m transect. These data indicate that natural populations of R. palustris are assemblages of genetically distinct ecotypes and that the distribution of each ecotype is patchy. 相似文献
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Continuous photosynthetic production of hydrogen by Rhodospirillum rubrum in batch cultures was observed up to 80 days with the hydrogen donor, pure lactate or lactic acid-containing wastes, supplied periodically. Hydrogen was produced at an average rate of 6 ml/h per g (dry weight) of cells with whey as a hydrogen donor. In continuous cultures with glutamate as a growth-limiting nitrogen source and lactate as a hydrogen donor, hydrogen was evolved at a rate of 20 ml/h per g (dry weight). The composition of the gas evolved remained practically constant (70 to 75% H2, 25 to 30% CO2). Photosynthetic bacteria processing specific organic wastes could be an advantage in large-scale production of hydrogen together with food protein of high value, compared to other biological systems. 相似文献
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Rhodospirillum tenue sp. n., a New Species of the Purple Nonsulfur Bacteria 总被引:1,自引:2,他引:1
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Norbert Pfennig 《Journal of bacteriology》1969,99(2):619-620
Rhodospirillum tenue sp. n. differs from the rhodospirilla described so far by its small size, ultrastructure, and physiological and biochemical characteristics. 相似文献
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Hitoshi Ohmori Hisashi Ishitani Kazuyoshi Sato Shoichi Shimizu Saburo Fukui 《Bioscience, biotechnology, and biochemistry》2013,77(2):359-365
Purple nonsulfur bacteria, Rhodospirillum rubrum and Rhodopseudomonas spheroides were found to possess coenzyme B12-dependent glutamate mutase activity. Cell-free extracts of these bacteria grown on Co2+-containing media catalyzed the conversion of glutamate to β-methylaspartate and further to mesaconate. The activity of the cell-free extracts of these organisms cultivated on Co2+-deficient media was markedly lower than that of the normal cells. Addition of coenzyme B12 to the former reaction mixture enhanced the mesaconate formation via β-methylaspartate. These results indicate the involvement of coenzyme Independent glutamate mutase of these bacteria in the dissimilation of glutamate to acetyl-CoA and pyruvate through the following pathway.glutamate→β→methylaspartate→mesaconate→citramalate→→acetyl-CoA, pyruvate On the other hand, a greater part of glutamate was converted to α-hydroxyglutarate and succinate with the cell-free extracts of these photosynthetic bacteria. This fact, taking account of the presence of propionyl-CoA carboxylase in these bacteria, implies the participation of coenzyme B12-dependent (R)-methylmalonyl-CoA mutase in the formation of succinate via the following route.glutamate→α-ketoglutarate→α-hydroxyglutarate→propionate→propionyl-CoA→(S)-methylmalonyl-CoA→(R)-methylmalonyl-CoA→succinyl-CoA 相似文献
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Guo-Shu Wang Hartmut Grammel Khaled Abou-Aisha Rudolf S?gesser Robin Ghosh 《Applied and environmental microbiology》2012,78(20):7205-7215
The biosynthesis of the major carotenoid spirilloxanthin by the purple nonsulfur bacterium Rhodospirillum rubrum is thought to occur via a linear pathway proceeding through phytoene and, later, lycopene as intermediates. This assumption is based solely on early chemical evidence (B. H. Davies, Biochem. J. 116:93–99, 1970). In most purple bacteria, the desaturation of phytoene, catalyzed by the enzyme phytoene desaturase (CrtI), leads to neurosporene, involving only three dehydrogenation steps and not four as in the case of lycopene. We show here that the chromosomal insertion of a kanamycin resistance cassette into the crtC-crtD region of the partial carotenoid gene cluster, whose gene products are responsible for the downstream processing of lycopene, leads to the accumulation of the latter as the major carotenoid. We provide spectroscopic and biochemical evidence that in vivo, lycopene is incorporated into the light-harvesting complex 1 as efficiently as the methoxylated carotenoids spirilloxanthin (in the wild type) and 3,4,3′,4′-tetrahydrospirilloxanthin (in a crtD mutant), both under semiaerobic, chemoheterotrophic, and photosynthetic, anaerobic conditions. Quantitative growth experiments conducted in dark, semiaerobic conditions, using a growth medium for high cell density and high intracellular membrane levels, which are suitable for the conventional industrial production in the absence of light, yielded lycopene at up to 2 mg/g (dry weight) of cells or up to 15 mg/liter of culture. These values are comparable to those of many previously described Escherichia coli strains engineered for lycopene production. This study provides the first genetic proof that the R. rubrum CrtI produces lycopene exclusively as an end product. 相似文献
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Reduction of Selenite and Detoxification of Elemental Selenium by the Phototrophic Bacterium Rhodospirillum rubrum 总被引:4,自引:0,他引:4
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The effect of selenite on growth kinetics, the ability of cultures to reduce selenite, and the mechanism of detoxification of selenium were investigated by using Rhodospirillum rubrum. Anoxic photosynthetic cultures were able to completely reduce as much as 1.5 mM selenite, whereas in aerobic cultures a 0.5 mM selenite concentration was only reduced to about 0.375 mM. The presence of selenite in the culture medium strongly affected cell division. In the presence of a selenite concentration of 1.5 mM cultures reached final cell densities that were only about 15% of the control final cell density. The cell density remained nearly constant during the stationary phase for all of the selenite concentrations tested, showing that the cells were not severely damaged by the presence of selenite or elemental selenium. Particles containing elemental selenium were observed in the cytoplasm, which led to an increase in the buoyant density of the cells. Interestingly, the change in the buoyant density was reversed after selenite reduction was complete; the buoyant density of the cells returned to the buoyant density of the control cells. This demonstrated that R. rubrum expels elemental selenium across the plasma membrane and the cell wall. Accordingly, electron-dense particles were more numerous in the cells during the reduction phase than after the reduction phase. 相似文献
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Roderick K. Clayton 《Archives of microbiology》1953,19(2):141-165
Summary The threshold strength-duration relationships were determined for the phototactic excitation of Rhodospirillum rubrum by various pulses and pairs of pulses of change in light intensity. The recovery of excitability after a response was followed, and examples of rhythmic behavior were recorded.Exprimental results were found to be in fair agreement with data for other irritable systems and with the predictions of the theories of Rashevsky and Hill.The hypothesis was considered that all excitable systems might share a common mechanism for irritability, and the phototactic mechanisms of various unicellular organisms were discussed in this connection. 相似文献
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Roderick K. Clayton 《Archives of microbiology》1957,26(1):29-31
Summary As in the case of oxidative metabolism, the photosynthetic metabolism of propionate in Rhodospirillum rubrum begins with a carboxylation yielding succinate. This conclusion is based on experiments in which radioactive propionate (1-C14 and 2-C14) is administered in the presence of carrier lactate, pyruvate, succinate, and acrylate, and on studies of the inhibitory action of malonate. 相似文献
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光和蛋白合成抑制剂对水稻RubisCO大、小亚基和RubisCO亚基结合蛋白基因表达的影响 总被引:3,自引:0,他引:3
水稻RubiCO在体内周转率很低,而其亚基结合蛋白(rbcBP)的周转却很迅速。水稻黄化幼苗随照光时间增加,在24h内Ru—bisCO蛋白量迅速上升,而 rbcBP在照光 6h后,其蛋白含量即维持恒定。 在转录水平上,RubisCO小亚基(rbcS)对光最为敏感;同样,rbcS的转录对蛋白合成抑制剂的反应也最为敏感。用亚胺环己酮和氯霉素处理水稻叶片,得到结果与光处理基本一致。 光与蛋白质合成抑制剂对rbcL、rbcS和rbcBP在基因表达各种水平上均有不同程度的影响,而以翻译水平上的调控较为灵敏。rbcS在基因表达调控上可能起某种支配作用;rbcBP与 rbcL、rbcS表达调控协调性不很紧密。 相似文献
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Roderick K. Clayton Franz H. Dettmer Arthur E. Robertson Jr. 《Archives of microbiology》1957,26(1):20-28
Summary Studies were conducted of the oxidative metabolism of propionate in Rhodospirillum rubrum, using C14-labeled compounds. The results, taken in conjunction with a carbon dioxide requirement described previously (Clayton et al., 1957), reveal that the first step is a carboxylation of propionic acid, yielding succinic acid. This result is confirmed through manometric studies of inhibition by malonate. 相似文献
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The complete nucleotide sequence of tRNAPhe and 5S RNA from the photosynthetic bacterium Rhodospirillum rubrum has been elucidated. A combination of in vitro and in vivo labelling techniques was used. The tRNAPhe sequence is 76 nucleotides long, 7 of which are modified. The primary structure is typically prokaryotic and is most similar to the tRNAPhe of Escherichia coli and Anacystis nidulans (14 differences of 76 positions). The 5S ribosomal RNA sequence is 120 nucleotides long and again typical of other prokaryotic 5S RNAs. The invariable GAAC sequence is found starting at position 45. When aligned with other prokaryotic 5S RNA sequences, a surprising amount of nucleotide substitution is noted in the prokaryotic loop region of the R. rubrum 5S RNA. However, nucleotide complementarity is maintained reinforcing the hypothesis that this loop is an important aspect of prokaryotic 5S RNA secondary structure. The 5S and tRNAPhe are the first complete RNA sequences available from the photosynthetic bacteria. 相似文献