Species Of Rhodospirillaceae Research Articles

Genome Sequence of the Unusual Purple Photosynthetic Bacterium Phaeovibrio sulfidiphilus, Only Distantly Related to Rhodospirillaceae, Reveals Unique Genes for Respiratory Nitrate Reduction and Glycerol Metabolism.

Phaeovibrio sulfidiphilus was reported to be a divergent member of the purple photosynthetic bacteria with limited ability to metabolize organic compounds. Whole-genome-based analysis shows that it is indeed only distantly related to freshwater species of Rhodospirillaceae Unexpectedly, the genome contains unique gene clusters for potential respiratory nitrate reduction and anaerobic glycerol metabolism.

Arsenic respiration and detoxification by purple non-sulphur bacteria under anaerobic conditions

Two arsenic-resistant purple non-sulphur bacteria (PNSB), Q3B and Q3C, were isolated (from industrial contaminated site and paddy fields) and identified by SSU rRNA gene sequencing as Rhodospirillum and Rhodospirillaceae species, respectively. Maximum arsenic reduction by these PNSB was observed in anaerobic conditions. Rhodospirillum sp. Q3B showed 74.92% (v/v) arsenic reduction while Rhodospirillaceae sp. Q3C reduced arsenic up to 76.67% (v/v) in anaerobic conditions. Rhodospirillaceae sp. Q3C was found to contain highest carotenoid content up to 5.6mg·g−1. Under anaerobic conditions, the isolates were able to respire arsenic in the presence of lactate, citrate, and oxalate. Rhodospirillum sp. Q3B and Rhodospirillaceae sp. Q3C were also found to produce hydrogen gas. Such diverse bacteria can be useful tools for bioremediation purposes. These bacteria can be further exploited and optimized to treat wastewater containing arsenic along with bio-hydrogen production.

Isolation and protein chemical characterization of the B806-866 antenna complex of the green thermophilic bacterium Chloroflexus aurantiacus

The B806-866 antenna complex was isolated from cytoplasmic membranes of the green thermophilic bacterium Chloroflexus aurantiacus. The membranes were treated with 7 M urea at 50 °C, the B806-866 antenna complex was solubilized with a mixture of Noni-fjdet P-40 (octylphenoxypolyethoxyethanol (Sigma)) and sodium dodecylsuphate (2:1) and isolated by sucrose density gradient centrifugation. This antenna complex was characterized by reversed-phase chromatography (fast polypeptide and polynucleotide liquid chromatography), amino acid and sequence analyses. The B806-866 antenna of Chloroflexus aurantiacus consists of two polypeptides: the B806-866-α and B806-866-β polypeptides in an apparent stoichiometric ratio of 1:1, which may be equivalent to the structural elementary unit found in the antenna systems of many species of Rhodospirillaceae.

Long-term preservation of some Rhodospirillaceae by freeze-drying

Lyophilization of phototropically grown cultures is difficult as it is essential to maintain strict anaerobic conditions or to avoid the exposure of the cultures to light. During a systematic investigation it was observed that several species of Rhodospirillaceae are able to grow heterotrophically in darkness on organic media and are not damaged by air oxygen under such conditions. Based on this character several oxygenic species of Rhodospirillaceae were grown under heterotrophic conditions and were lyophilized using raffinose (5% w/v) along with skim milk (20% w/v) as a protective agent. More than 30 strains from nine species of Rhodospirillaceae were successfully freeze-dried with this method. All tested cultures proved viable and showed 10–100% survival after lyophilization. During 2–3 years of storage at 9°C no further loss in viability was observed. In such lyophilized cultures no loss in photoautotrophy, diazotrophy or other desirable characters like hydrogen production, pigmentation, etc. was detected. The method is not suited to such anoxygenic Rhodospirillaceae which are not able to grown aerobically in darkness.

Cellular fatty acid composition with special reference to the existence of hydroxy fatty acids, and the occurrence of squalene and sterols in species of Rhodospirillaceae genera and Erythrobacter longus.

Cellular fatty acids, squalene, and sterols in the bacteriochlorophyll-containing bacteria, which include Rhodospirillaceae genera, and Erythrobacter, were investigated. Hydroxy fatty acid composition, and the existence of squalene, Hop-22(29)-ene and Hopan-22-ol explained the heterogeneity of Rhodospirillaceae genera.Erythrobacter longus is distinguished from Rhodospirillaceae species on the basis of hydroxy fatty acid composition. Protomonas extorquens is similar to Rhodopseudomonas palustris and Rhodopseudomonas rutila on the basis of DNA base composition, the quinone system, cellular fatty acid composition, hydroxy fatty acid composition, and occurrence of Hop-22(29)-ene and Hopan-22-ol.

Purification and characterization of glutamine synthetase fromRhodomicrobium vannielii

Glutamine synthetase (GS) from the purple non-sulfur bacterium Rhodomicrobium vannielii has been purified to electrophoretic homogeneity by affinity chromatography. Molecular weight and catalytic properties of the enzy,e are similar to those described for other species of Rhodospirillaceae. However, the enzyme from this organism appears to be antigenically different from the glutamine synthetases of other species of Rhodospirillaceae studied.

Distribution of rhodoquinone in Rhodospirillaceae and its taxonomic implications.

The rhodoquinone (RQ) composition was studied in representatives of 20 species of Rhodospirillaceae. Thin-layer chromatography, ultraviolet spectrophotometry, mass spectrometry, and high-performance liquid chromatography revealed that six of the 20 test species contained RQ as a major quinone in average amounts of 0.28 to 2.22μmol per g dry weight of cells. The predominant homologue of RQ in the six species was as follows: RQ-8-Rhodospirillum photometricum and an unknown species resembling Rhodocyclus gelatinosus; RQ-9+RQ-10-Rhodopila globiformis; RQ-10-Rhodospirillum rubrum, Rhodopseudomonas acidophila, and Rhodomicrobium vannielii. The taxonomic significance of RQ and other isoprenoid quinones is discussed in comparison with the new classification system for the phototrophic bacteria recently proposed by IMHOFF et al.

Isoprenoid quinone composition in the classification of Rhodospirillaceae.

Fifty five strains of 13 species of Rhodospirillaceae and one strain of Chromatium vinosum were examined for isoprenoid quinone composition. These bacteria were divided into the following five categories on the basis of their predominant quinone patterns: Q-10-Rhodospirillum rubrum, Rhodopseudomonas palustris, Rhodopseudomonas capsulata, Rhodopseudomonas sphaeroides, and Rhodopseudomonas sulfidophila; Q-10+MK-10-Rhodopseudomonas acidophila; Q-9+MK-9-Rhodospirillum fulvum, Rhodospirillum molischianum, Rhodopseudomonas viridis, and Rhodopseudomonas globiformis; Q-8-Rhodospirillum photometricum and atypical strains of Rhodopseudomonas gelatinosa; Q-8+MK-8-Rhodospirillum tenue, R. gelatinosa, and C. vinosum. The significance of the quinone system in Rhodospinillaceae taxonomy is discussed in comparison with available information on other taxonomic properties such as morphology and photosynthetic membrane systems and on some phylogenetic characteristics.

A modified method for the cultivation of phototrophic bacteria

Simplified anaerobic media and a convenient method for the cultivation of Rhodospirillaceae, Chlorobiaceae, Chloroflexaceae and Chromatiaceae are described. The modified conditions assure almost complete anaerobiosis for media, growth and maintenance. Strains representing several species of Rhodospirillaceae, Chlorobiaceae and Chromatiaceae were successfully grown within relatively short times with full pigmentation, indicating that the new media and cultivation conditions were most suited for photoautotrophic growth.

Rhodopseudomonas marina sp. nov., a New Marine Phototrophic Purple Bacterium

Four new isolates from different saline habitats are described as the new species Rhodopseudomonas marina. Cells are short, motile rods with intracytoplasmic membranes lying parallel to the cytoplasmic membrane. Bacteriochlorophyll a, and carotenoids of the normal spirilloxanthin series, are the photosynthetic pigments. The new species grows photo-trophically in the light under anaerobic conditions, but is also capable of growing in the dark under microaerophilic or anaerobic conditions, depending on the carbon source. Under phototrophic conditions a wide variety of organic carbon sources are used. Excellent growth with the sugar alcohols mannitol and sorbitol is the most significant aspect. Only rather low concentrations of sulfide are tolerated, although sulfide tolerance is enhanced in the presence of small amounts of yeast extract. Sulfide is not oxidized to sulfate; thiosulfate and elemental sulfur are the only detectable oxidation products. The different strains require 1-5% NaCl for optimal growth. The DNA base ratio is 61.5-63.8 mol% G + C. Rhodopseudomonas marina can be differentiated from all known Rhodospirillaceae species by its lipid and quinone composition.

Occurrence and evolutionary significance of two sulfate assimilation pathways in the rhodospirillaceae

The ability to use adenosine 5′-phosphosulfate (APS) or 3′-phosphoadenosine 5′-phosphosulfate (PAPS) as the substrate for the initial reductive step in sulfate assimilation has been tested in most of the known Rhodospirillaceae species and in some chemotrophic bacteria. Improved and optimized methods for the synthesis and purification of the sulfonucleotides APS and PAPS are described. The production of acid volatile radioactivity from 35S-APS and 35S-PAPS was measured under various conditions in the presence and absence of non-labeled sulfate. Specific differences in the ability to reduce APS or PAPS were observed among the Rhodospirillaceae species and also the chemotrophic bacteria. APS was found to be the substrate of the thiolsulfotransferase in Rps. acidophila, Rps. globiformis, Rm. vannielii, Rc. purpureus, R. tenue, Rps. gelatinosa, in Alcaligenes eutrophus and Pseudomonas aeruginosa. PAPS was the substrate in Rps. capsulata, Rps. sphaeroides, Rps. sulfidophila, Rps. palustris, Rps. viridis, R. rubrum, R. fulvum, in Paracoccus denitrificans and in several Enterobacteriaceae. The presence of different enzymatic systems for sulfate reduction in the Rhodospirillaceae family is compared with their taxonomical grouping and their possible phylogenetic relatedness.

Radioprotective and haemopoietic effects of some lipopolysaccharides from Rhodospirillaceae species in mice.

Lipopolysaccharides (LPS) from various Rhodopseudomonas and Rhodospirillum species were tested for their radioprotective efficiency against X-irradiation and for their influence on the growth of spleen colony forming units (CFU-s) in mice. The LPS from Rhodopseudomonas gelatinosa Dr2 gave a high survival rate. It also favoured CFU-s formation and erythroid differentiation.

Modifiable chromatophore proteins in photosynthetic bacteria

The chromatophores of Chromatium vinosum, as well as six other photosynthetic bacteria, contained two or more proteins which were insoluble when heated in the presence of sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (beta-ME). When the chromatophores were dissolved at room temperature in SDS-beta-ME, these proteins were present in the SDS-polyacrylamide gel electrophoresis profiles, but when the samples were dissolved at 100 degrees C, they were absent or considerably diminished. When one-dimensional gels of chromatophores solubilized at room temperature were soaked in the SDS-beta-ME solution and heated to 100 degrees C and the gels were run in a second dimension, the proteins became immobilized in the original first-dimension gel, where they could be detected by staining. The two major proteins so affected in C. vinosum had apparent molecular weights of 28,000 and 21,000. The chromatophores of several other photosynthetic bacteria also contained predominant proteins between 30,000 and 19,000 molecular weight, which became insoluble when heated in the presence of SDS and beta-ME. In at least two of the species examined, these appeared to be reaction center proteins. The conditions causing the proteins to become insoluble were complex and involved temperature, SDS concentration, and the presence of sulfhydryl reagents. The chromatophores of four of the Chromatiaceae species and two strains of one of the Rhodospirillaceae species examined had a protein-pigment complex that was visible in SDS-polyacrylamide gel profiles of samples dissolved at room temperature but was absent in samples dissolved at 100 degrees C.