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structural and spectroscopic properties of a reaction center complex from the chlorosome-lacking filamentous anoxygenic phototrophic bacterium roseiflexus castenholzii.the photochemical reaction center (rc) complex of roseiflexus castenholzii, which belongs to the filamentous anoxygenic phototrophic bacteria (green filamentous bacteria) but lacks chlorosomes, was isolated and characterized. the genes coding for the subunits of the rc and the light-harvesting proteins were also cloned and sequenced. the rc complex was composed of l, m, and cytochrome subunits. the cytochrome subunit showed a molecular mass of approximately 35 kda, contained hemes c, and functio ...200515716441
albidovulum inexpectatum gen. nov., sp. nov., a nonphotosynthetic and slightly thermophilic bacterium from a marine hot spring that is very closely related to members of the photosynthetic genus rhodovulum.several bacterial isolates, with an optimum growth temperature of about 50 degrees c, were recovered from the marine hot spring at ferraria on the island of são miguel in the azores. the geothermal water emerged from a porous lava flow and rapidly cooled in contact with seawater except at low tide. the bacterial species represented by strains frr-10(t) and frr-11 was nonpigmented, strictly aerobic, and organotrophic. several genes, bchz, pufb, pufa, pufl, or pufm, encoding the photosynthetic rea ...200212200275
photosynthetic apparatus in roseateles depolymerans 61a is transcriptionally induced by carbon limitation.production of a photosynthetic apparatus in roseateles depolymerans 61a, a recently discovered freshwater beta-proteobacterium showing characteristics of aerobic phototrophic bacteria, was observed when the cells were subjected to a sudden decrease in carbon sources (e.g., when cells grown with 0.1 to 0.4% casamino acids were diluted or transferred into medium containing <or=0.04% casamino acids). accumulation of bacteriochlorophyll (bchl) a was observed in the presence of oxygen and was enhance ...200211916683
evaluation of a fluorescent lectin-based staining technique for some acidophilic mining bacteria.a fluorescence-labeled wheat germ agglutinin staining technique (r. k. sizemore et al., appl. environ. microbiol. 56:2245-2247, 1990) was modified and found to be effective for staining gram-positive, acidophilic mining bacteria. bacteria identified by others as being gram positive through 16s rrna sequence analyses, yet clustering near the divergence of that group, stained weakly. gram-negative bacteria did not stain. background staining of environmental samples was negligible, and pyrite and s ...200010788401
aerobic anoxygenic phototrophic bacteria.the aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthet ...19989729607
isolation and characterization of a homodimeric type-i reaction center complex from candidatus chloracidobacterium thermophilum, an aerobic chlorophototroph.the recently discovered thermophilic acidobacterium candidatus chloracidobacterium thermophilum is the first aerobic chlorophototroph that has a type-i, homodimeric rc. this organism and its type-i rcs were initially detected by the occurrence of psca gene sequences, which encode the core subunit of the rc complex, in metagenomic sequence data derived from hot spring microbial mats. here, we report the isolation and initial biochemical characterization of the type-i rc from ca. c. thermophilum. ...201122184116
isolation and characterization of a homodimeric type-i reaction center complex from candidatus chloracidobacterium thermophilum, an aerobic chlorophototroph.the recently discovered thermophilic acidobacterium candidatus chloracidobacterium thermophilum is the first aerobic chlorophototroph that has a type-i, homodimeric rc. this organism and its type-i rcs were initially detected by the occurrence of psca gene sequences, which encode the core subunit of the rc complex, in metagenomic sequence data derived from hot spring microbial mats. here, we report the isolation and initial biochemical characterization of the type-i rc from ca. c. thermophilum. ...201122184116
a bchd (magnesium chelatase) mutant of rhodobacter sphaeroides synthesizes zinc bacteriochlorophyll through novel zinc-containing intermediates.heme and bacteriochlorophyll a (bchl) biosyntheses share the same pathway to protoporphyrin ix, which then branches as follows. fe(2+) chelation into the macrocycle by ferrochelatase results in heme formation, and mg(2+) addition by mg-chelatase commits the porphyrin to bchl synthesis. it was recently discovered that a bchd (mg-chelatase) mutant of rhodobacter sphaeroides produces an alternative bchl in which mg(2+) is substituted by zn(2+). zn-bchl has been found in only one other organism befo ...201121502322
high ratio of bacteriochlorophyll biosynthesis genes to chlorophyll biosynthesis genes in bacteria of humic lakes.recent studies highlight the diversity and significance of marine phototrophic microorganisms such as picocyanobacteria, phototrophic picoeukaryotes, and bacteriochlorophyll- and rhodopsin-holding phototrophic bacteria. to assess if freshwater ecosystems also harbor similar phototroph diversity, genes involved in the biosynthesis of bacteriochlorophyll and chlorophyll were targeted to explore oxygenic and aerobic anoxygenic phototroph composition in a wide range of lakes. partial dark-operative ...200919801478
carbohydrate metabolism and carbon fixation in roseobacter denitrificans och114.the roseobacter clade of aerobic marine proteobacteria, which compose 10-25% of the total marine bacterial community, has been reported to fix co(2), although it has not been determined what pathway is involved. in this study, we report the first metabolic studies on carbohydrate utilization, co(2) assimilation, and amino acid biosynthesis in the phototrophic roseobacter clade bacterium roseobacter denitrificans och114. we develop a new minimal medium containing defined carbon source(s), in whic ...200919794911
absence of the cbb3 terminal oxidase reveals an active oxygen-dependent cyclase involved in bacteriochlorophyll biosynthesis in rhodobacter sphaeroides.the characteristic green color associated with chlorophyll pigments results from the formation of an isocyclic fifth ring on the tetrapyrrole macrocycle during the biosynthesis of these important molecules. this reaction is catalyzed by two unrelated cyclase enzymes employing different chemistries. oxygenic phototrophs such as plants and cyanobacteria utilize an oxygen-dependent enzyme, the major component of which is a diiron protein named acsf, while bche, an oxygen-sensitive [4fe-4s] cluster ...201627215788
photoinduced biohydrogen production from biomass.photoinduced biohydrogen production systems, coupling saccharaides biomass such as sucrose, maltose, cellobiose, cellulose, or saccharides mixture hydrolysis by enzymes and glucose dehydrogenase (gdh), and hydrogen production with platinum colloid as a catalyst using the visible light-induced photosensitization of mg chlorophyll-a (mg chl-a) from higher green plant or artificial chlorophyll analog, zinc porphyrin, are introduced.200819325796
permanent draft genome sequence of acidiphilium sp. ja12-a1.the tenacious association between strains of the heterotrophic alphaproteobacterial genus acidiphilium and chemolithotrophic iron oxidizing bacteria has long been known. in this context the genome of the heterotroph acidiphilium sp. ja12-a1, an isolate from an iron oxidizing mixed culture derived from a pilot plant for bioremediation of acid mine drainage, was determined with the aim to reveal metabolic properties that are fundamental for the syntrophic interaction between acidiphilium sp. ja12- ...201526380040
evolution of microbial "streamer" growths in an acidic, metal-contaminated stream draining an abandoned underground copper mine.a nine year study was carried out on the evolution of macroscopic "acid streamer" growths in acidic, metal-rich mine water from the point of construction of a new channel to drain an abandoned underground copper mine. the new channel became rapidly colonized by acidophilic bacteria: two species of autotrophic iron-oxidizers (acidithiobacillus ferrivorans and "ferrovum myxofaciens") and a heterotrophic iron-oxidizer (a novel genus/species with the proposed name "acidithrix ferrooxidans"). the sam ...201325371339
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