| reclassification of species of the spiral-shaped phototrophic purple non-sulfur bacteria of the alpha-proteobacteria: description of the new genera phaeospirillum gen. nov., rhodovibrio gen. nov., rhodothalassium gen. nov. and roseospira gen. nov. as well as transfer of rhodospirillum fulvum to phaeospirillum fulvum comb. nov., of rhodospirillum molischianum to phaeospirillum molischianum comb. nov., of rhodospirillum salinarum to rhodovibrio salexigens. | the 165 rdna sequence of rhodospirillum mediosalinum was determined and compared with corresponding sequences from other spiral-shaped purple non-sulfur bacteria classified as or related to the genus rhodospirillum in the alpha subclass of the proteobacteria. sequence similarities separate the currently recognized rhodospirillum species into five different groups with no more than 91% sequence similarity, clearly indicating the necessity to recognize these groups as different genera. major diagn ... | 1998 | 9734033 |
| inhibition of acetate and propionate assimilation by itaconate via propionyl-coa carboxylase in isocitrate lyase-negative purple bacterium rhodospirillum rubrum. | itaconate is known as a potent inhibitor of isocitrate lyase. unexpectedly, itaconate was a strong inhibitor of acetate and propionate assimilation in isocitrate lyase-negative purple non-sulfur bacterium rhodospirillum rubrum. it was shown that in cell extracts of r. rubrum itaconate inhibited propionyl-coa carboxylase (pcc) activity. the participation of pcc in propionate assimilation in r. rubrum is well-documented, but the inhibition of acetate assimilation suggests that pcc is also involved ... | 2002 | 12423751 |
| interactions stabilizing the structure of the core light-harvesting complex (lh1) of photosynthetic bacteria and its subunit (b820). | reconstitution experiments with a chemically synthesized core light-harvesting (lh1) beta-polypeptide analogue having 3-methylhistidine instead of histidine in the position that normally donates the coordinating ligand to bacteriochlorophyll (bchl) have provided the experimental data needed to assign to b820 one of the two possible alphabeta.2bchl pairs that are observed in the crystal structure of lh2 from phaeospirillum (formerly rhodospirillum) molischianum, the one with rings iii and v of bc ... | 2004 | 15170338 |
| defluvicoccus vanus gen. nov., sp. nov., a novel gram-negative coccus/coccobacillus in the 'alphaproteobacteria' from activated sludge. | a novel gram-negative coccus/coccobacillus, strain ben 114(t), growing in tetrads, clusters or aggregates, was isolated from activated sludge by micromanipulation. 16s rrna gene sequence analysis revealed that it belonged to the 'alphaproteobacteria', with no close relatives among cultured bacterial isolates. on the basis of phylogenetic data, this organism is considered to belong to a new genus, defluvicoccus, represented by the species defluvicoccus vanus sp. nov., a name chosen because of the ... | 2005 | 16166717 |
| architecture of the native photosynthetic apparatus of phaeospirillum molischianum. | the ubiquity and importance of photosynthetic organisms in nature has made the molecular mechanisms of photosynthesis a widely studied subject at both structural and functional levels. a current challenge is to understand the supramolecular assembly of the proteins involved in photosynthesis in native membranes. we have used atomic force microscopy to study the architecture of the photosynthetic apparatus and analyze the structure of single molecules in chromatophores of phaeospirillum molischia ... | 2005 | 16330228 |
| novel facultative anaerobic acidotolerant telmatospirillum siberiense gen. nov. sp. nov. isolated from mesotrophic fen. | three facultative anaerobic acidotolerant gram-negative motile spirilla strains designated 26-4b1, 26-2 and k-1 were isolated from mesotrophic siberian fen as a component of methanogenic consortia. the isolates were found to grow chemoorganotrophically on several organic acids and glucose under anoxic and low oxygen pressure in the dark, tolerant up to 5kpa of oxygen. at low oxygen supply, faint autotrophic growth on the h(2):co(2) mixture was also observed. all three isolates were able to fix n ... | 2007 | 16876366 |
| organisation and function of the phaeospirillum molischianum photosynthetic apparatus. | we have investigated the organisation of the photosynthetic apparatus in phaeospirillum molischianum, using biochemical fractionation and functional kinetic measurements. we show that only a fraction of the atp-synthase is present in the membrane regions which contain most of the photosynthetic apparatus and that, despite its complicated stacked structure, the intracytoplasmic membrane delimits a single connected space. we find that the diffusion time required for a quinol released by the reacti ... | 2008 | 18948077 |
| atomic force microscopy studies of native photosynthetic membranes. | in addition to providing the earliest surface images of a native photosynthetic membrane at submolecular resolution, examination of the intracytoplasmic membrane (icm) of purple bacteria by atomic force microscopy (afm) has revealed a wide diversity of species-dependent arrangements of closely packed light-harvesting (lh) antennae, capable of fulfilling the basic requirements for efficient collection, transmission, and trapping of radiant energy. a highly organized architecture was observed with ... | 2009 | 19265434 |
| static and dynamic protein impact on electronic properties of light-harvesting complex lh2. | a comparative analysis of the temperature dependence of the absorption spectra of the lh2 complexes from different species of photosynthetic bacteria, i.e., rhodobacter sphaeroides, rhodoblastus acidophilus, and phaeospirillum molischianum, was performed in the temperature range from 4 to 300 k. qualitatively, the temperature dependence is similar for all of the species studied. the spectral bandwidths of both b800 and b850 bands increases with temperature while the band positions shift in oppos ... | 2008 | 19367872 |
| phaeospirillum chandramohanii sp. nov., a phototrophic alphaproteobacterium with carotenoid glycosides. | a gram-negative, spiral-shaped, phototrophic, purple non-sulfur bacterial strain, designated ja145t, was isolated from a freshwater habitat. cells of strain ja145t were motile by means of a monopolar flagellum. intracellular photosynthetic membranes were of the stacked type. bacteriochlorophyll a and the carotenoid lycopene and its glucosides were present as photosynthetic pigments. there was no vitamin requirement for strain ja145t. the predominant cellular fatty acids were c16:1omega7c/c16:1om ... | 2009 | 19605708 |
| membrane curvature induced by aggregates of lh2s and monomeric lh1s. | the photosynthetic apparatus of purple bacteria is contained within organelles called chromatophores, which form as extensions of the cytoplasmic membrane. the shape of these chromatophores can be spherical (as in rhodobacter sphaeroides), lamellar (as in rhodopseudomonas acidophila and phaeospirillum molischianum), or tubular (as in certain rb. sphaeroides mutants). chromatophore shape is thought to be influenced by the integral membrane proteins light harvesting complexes i and ii (lh1 and lh2 ... | 2009 | 19948127 |
| antenna mixing in photosynthetic membranes from phaeospirillum molischianum. | we have investigated the adaptation of the light-harvesting system of the photosynthetic bacterium phaeospirillum molischianum (dsm120) to very low light conditions. this strain is able to respond to changing light conditions by differentially modulating the expression of a family of puc operons that encode for peripheral light-harvesting complex (lh2) polypeptides. this modulation can result in a complete shift between the production of lh2 complexes absorbing maximally near 850 nm to those abs ... | 2010 | 20212143 |
| phaeovibrio sulfidiphilus gen. nov., sp. nov., phototrophic alphaproteobacteria isolated from brackish water. | two strains (ja480(t) and ja481) of phototrophic alphaproteobacteria were isolated from sediment samples collected from brackish water near nagapattinam, india. they were gram-negative, vibrioid cells containing bacteriochlorophyll a and rhodopin as major photosynthetic pigments. most cells of both strains were non-flagellated; 1 % of cells showed two monopolar flagella. cells showed positive phototaxis. both strains showed chimeric intracellular photosynthetic membranes, where both lamellar sta ... | 2011 | 20495036 |
| effect of pine bark and compost on the biological denitrification process of non-hazardous landfill leachate: focus on the microbiology. | in an attempt to optimize the cost-efficiency of landfill leachate treatment by biological denitrification process, our study focused on finding low-cost alternatives to traditional expensive chemicals such as composted garden refuse and pine bark, which are both available in large amount in south african landfill sites. the overall objective was to assess the behaviour of the bacterial community in relation to each substrate while treating high strength landfill leachates. denitrification proce ... | 2010 | 20554377 |
| phaeospirillum oryzae sp. nov., a spheroplast forming phototrophic alphaproteobacterium from a paddy soil. | two strains (ja317t, ja559) of spiral shaped, spheroplast forming, anaerobic, gram negative, motile purple non-sulfur bacteria were isolated from rhizosphere soils of paddy and were characterized by a polyphasic taxonomic approach. bacteriochlorophyll a, and carotenoids, rhodopin and rhodopin glucoside, are present as photosynthetic pigments. intracellular photosynthetic membranes are of stacked type. the major fatty acids were c18:1omega7c, c16:0, c16:1omega6c/c16:1omega7c in both strains. the ... | 2010 | 20709914 |
| genus specific unusual carotenoids in purple bacteria, phaeospirillum and roseospira: structures and biosyntheses. | phototrophic bacteria necessarily contain carotenoids for photosynthesis, and a few phototrophic purple bacteria accumulate unusual carotenoids. the carotenoids in the genera phaeospirillum and roseospira were identified using spectroscopic methods. all species of the genus phaeospirillum contained characteristic polar carotenoids in addition to lycopene and hydroxylycopene (rhodopin); hydroxylycopene glucoside, dihydroxylycopene, and its mono- and/or diglucosides. from the structures of these c ... | 2011 | 21547544 |
| the effects of protein crowding in bacterial photosynthetic membranes on the flow of quinone redox species between the photochemical reaction center and the ubiquinol-cytochrome c(2) oxidoreductase. | atomic force microscopy (afm) of the native architecture of the intracytoplasmic membrane (icm) of a variety of species of purple photosynthetic bacteria, obtained at submolecular resolution, shows a tightly packed arrangement of light harvesting (lh) and reaction center (rc) complexes. since there are no unattributed structures or gaps with space sufficient for the cytochrome bc(1) or atpase complexes, they are localized in membrane domains distinct from the flat regions imaged by afm. this has ... | 2011 | 21691621 |
| phaeospirillum tilakii sp. nov., a phototrophic alphaproteobacterium isolated from nelapattu birds sanctuary and from western ghats of india. | two strains (ja492t, ja590) of spiral shaped, anaerobic, gram-stain-negative, motile purple non-sulfur bacteria were isolated from a birds sanctuary and a stream respectively and were characterized by a polyphasic taxonomic approach. bacteriochlorophyll a and carotenoids (rhodopin, lycopene, hydroxylycopene glucoside and dihydroxylycopene diglucoside) are present as photosynthetic pigments. intracellular photosynthetic membranes are of stacked type. the major fatty acids were c18:1¤ë7c, c16:0 an ... | 2011 | 21705442 |
| changes in the bacterial community structure and diversity during bamboo retting. | microbial retting is a critical step in obtaining fiber bundles from bamboo culm using indigenous microorganisms. a cultivation-independent technique for monitoring the changes in bacteria community during bamboo retting was applied in this work. this technique involves genetic profiling of pcr-amplified small-subunit rrna and the single-strand conformation polymorphism (sscp) gel analysis of the pcr-amplified 16s rdna fragments. the study revealed that both the structure and the diversity of in ... | 2011 | 21695788 |