| carotenoids of purple nonsulfur bacteria. composition and biosynthesis of the carotenoids of some strains of rhodopseudomonas acidophila, rhodospirillum tenue, and rhodocyclus purpureus. | | 1971 | 4932469 |
| membrane topography of anaerobic carbon monoxide oxidation in rhodocyclus gelatinosus. | rhodocyclus gelatinosus 1 grows anaerobically in the dark at the expense of carbon monoxide. topographical studies with methyl viologen as the membrane probe indicated that co oxidation and h2 production sites were on the cytoplasmic side of the cell membrane. membrane-associated hydrogen gas production appeared to be a unidirectional reaction. in the dark, strain 1 whole cells oxidized co and incorporated about 306 pmol of 32pi into atp per min per mg of protein. with co as the sole energy-yiel ... | 1987 | 3308854 |
| 1h-nmr investigation of oxidized and reduced high-potential iron-sulfur protein from rhodopseudomonas globiformis. | 1h one-dimensional and two-dimensional nmr spectra have been recorded for the oxidized and reduced forms of the high-potential iron-sulfur protein (hipip) from rhodopseudomonas globiformis which has the highest known reduction potential. the spectrum of the oxidized protein is similar to that of chromatium vinosum and rhodocyclus gelatinosus hipip but different from that of the hipip ii from ectothiorhodospira halophila. surprisingly, site-specific assignment has shown that in the oxidized prote ... | 1993 | 8444166 |
| malate dehydrogenases in phototrophic purple bacteria. thermal stability, amino acid composition and immunological properties. | purified malate dehydrogenases from four species of non-sulphur purple phototrophic bacteria were examined for their heat-stability, amino acid composition and antigenic relationships. malate dehydrogenase from rhodospirillum rubrum, rhodobacter capsulatus and rhodomicrobium vannielii (which are all tetrameric proteins) had an unusually high glycine content, but the enzyme from rhodocyclus purpureus (which is a dimer) did not. r. rubrum malate dehydrogenase was extremely heat-stable relative to ... | 1988 | 3137931 |
| malate dehydrogenase in phototrophic purple bacteria: purification, molecular weight, and quaternary structure. | the citric acid cycle enzyme malate dehydrogenase was purified to homogeneity from the nonsulfur purple bacteria rhodobacter capsulatus, rhodospirillum rubrum, rhodomicrobium vannielii, and rhodocyclus purpureus. malate dehydrogenase was purified from each species by either a single- or a two-step protocol: triazine dye affinity chromatography was the key step in purification of malate dehydrogenase in all cases. purification of malate dehydrogenase resulted in a 130- to 240-fold increase in mal ... | 1987 | 3114237 |
| cloning and sequencing the genes encoding uptake-hydrogenase subunits of rhodocyclus gelatinosus. | rhodocyclus gelatinosus grew photosynthetically in the light and consumed h2 at a rate of about 665 nmol/min per mg protein. the uptake-hydrogenase (h2ase) was found to be membrane bound and insensitive to inhibition by co. the structural genes of r. gelatinosus uptake-h2ase were isolated from a 40 kb cosmid gene library of r. gelatinosus dna by hybridization with the structural genes of uptake-h2ase of bradyrhizobium japonicum and rhodobacter capsulatus. the r. gelatinosus genes were localized ... | 1990 | 2325631 |
| molecular biology studies of the uptake hydrogenase of rhodobacter capsulatus and rhodocyclus gelatinosus. | in the photosynthetic bacteria, as in other n2-fixing bacteria, two main enzymes are involved in h2 metabolism: nitrogenase, which catalyses the photoproduction of h2, and a membrane-bound (nife) hydrogenase, which functions as an h2-uptake enzyme. the structural genes for rhodobacter capsulatus and rhodocyclus gelatinosus uptake hydrogenases were isolated and sequenced. they present the same organization, with the gene encoding the small subunit (hups) (molecular masses 34.2 and 34.6 kda, respe ... | 1990 | 2094292 |
| resolution of rhodocyclus gelatinosus photoreceptor unit components by temperature-induced phase separation in the presence of decyltetraoxyethylene. | a simple method for dissociating photoreceptor units from rhodocyclus gelatinosus is described. incubation of a chromatophore extract (agalidis, i., rivas, e. and reiss-husson, f. (1990) photosynth. res. 23, 249-255) at 4 degrees c with decyltetraoxyethylene and octyl-beta-d-thioglucopyranoside, followed by temperature-induced phase separation at 20 degrees c, led to the formation of three phases: a pellet composed of pure b875 antenna; an oily layer containing cytochrome c and other proteins; a ... | 1991 | 2059201 |
| three-dimensional structure of the high-potential iron-sulfur protein isolated from the purple phototrophic bacterium rhodocyclus tenuis determined and refined at 1.5 a resolution. | the molecular structure of the high-potential iron-sulfur protein (hipip) isolated from the phototrophic bacterium, rhodocyclus tenuis, has been solved and refined to a nominal resolution of 1.5 a with a crystallographic r-factor of 17.3% for all measured x-ray data from 30 a to 1.5 a. it is the smallest of the hipip structures studied thus far with 62 amino acid residues. crystals used in the investigation belonged to the space group p2(1) with unit cell dimensions of a = 36.7 a, b = 52.6 a, c ... | 1992 | 1453470 |
| purification of glutaryl-coa dehydrogenase from pseudomonas sp., an enzyme involved in the anaerobic degradation of benzoate. | cell-free extracts of pseudomonas sp. strains kb 740 and k 172 both contained high levels of glutaryl-coa dehydrogenase when grown anaerobically on benzoate or other aromatic compounds and with nitrate as electron acceptor. these aromatic compounds have in common benzoyl-coa as the central aromatic intermediate of anaerobic metabolism. the enzymatic activity was almost absent in cells grown aerobically on benzoate regardless whether nitrate was present. glutaryl-coa dehydrogenase activity was al ... | 1993 | 8439237 |
| the electronic structure of [fe4s4]3+ clusters in proteins. an investigation of the oxidized high-potential iron-sulfur protein ii from ectothiorhodospira vacuolata. | within the framework of an investigation of the electronic structure of oxidized high-potential iron-sulfur proteins (hipip), we have studied the hipip ii from ectothiorhodospira vacuolata, which was known to have a peculiar temperature dependence of the 1h nmr isotropic hyperfine shifts. the signals of the cysteine ligand protons have been sequence specifically assigned through noe, noesy, and tocsy experiments. nine hyperfine-shifted signals are observed: seven in the downfield and two in the ... | 1993 | 8396428 |
| one- and two-dimensional nmr characterization of oxidized and reduced cytochrome c' from rhodocyclus gelatinosus. | 1d and 2d nmr spectra of both the reduced and oxidized forms of cytochrome c' from rhodocyclus gelatinosus have been recorded. the analysis of the ph dependence of the 1h nmr spectrum of the ferric form has been performed, and two main ionizing groups have been identified. by comparison of the ph dependence of the available spectra of cytochromes c', an ambiguity remaining from previous studies on related cytochromes c' has been solved. by means of 2d spectra, an assignment of all the paramagnet ... | 1993 | 8380709 |
| phylogeny and phenotypic characterization of the stalk-forming and iron-oxidizing bacterium gallionella ferruginea. | the 16s rrna gene of gallionella ferruginea was amplified by polymerase chain reaction and sequenced by direct double-stranded sequencing. the phylogenetic analysis placed g. ferruginea in the beta-group of the proteobacteria, with 90.0% similarity to nitrosolobus multiformis and 88.6% to rhodocyclus purpureus. the published phenotypic characteristics of g. ferruginea were compiled and supplemented with growth experiments using ferrous iron, thiosulphate and sulphide as electron donor, and nitra ... | 1993 | 8371116 |
| 1h one-dimensional and two-dimensional nmr studies of the ferricytochrome c 551 from rhodocyclus gelatinosus. | 1h two-dimensional nmr spectroscopy has been applied to the oxidized form of cytochrome c 551 from rhodocyclus gelatinosus, which is paramagnetic with s = 1/2. the investigation has allowed a complete and unambiguous assignment of the heme protons and some residues around the heme. we have learned that: the conformation of the axial methionine is equal to that of horse heart cytochrome c and different from two isoenzymes of the same cytochrome c 551 from a different strain; pka of 6.6 +/- 0.3 ha ... | 1994 | 8307031 |
| primary structure and transcription of genes encoding b870 and photosynthetic reaction center apoproteins from rubrivivax gelatinosus. | we determined the nucleotide sequence of the puf operon of rubrivivax gelatinosus (formerly called rhodocyclus gelatinosus), a photosynthetic bacterium belonging to the beta subclass of purple bacteria (proteobacteria). the operon contains two unknown open reading frames (orfs) in addition to five photosynthetic genes which have been reported in species belonging to the alpha subclass. these genes include pufb, -a, -l, -m, and -c coding for the beta and alpha subunits of the b870 light-harvestin ... | 1994 | 8300574 |
| expression and characterization of recombinant rhodocyclus tenuis high potential iron-sulfur protein. | the high potential iron-sulfur protein (hipip) from rhodocyclus tenuis strain 2761 has been overproduced in escherichia coli from its structural gene, purified to apparent homogeneity, and then characterized by an array of methods. uv-visible spectra of the reduced and oxidized recombinant protein were similar to those of the native protein. epr of the oxidized protein shows g values of 2. 11, 2.03, and 2.03. esi-ms gave a mass difference of 350 da between the holoprotein and acid-treated protei ... | 2000 | 10873539 |
| influence of the supramolecular structure of free lipid a on its biological activity. | the three-dimensional supramolecular structures and the states of order of the acyl chains of lipid a from different gram-negative species were investigated at 40 degrees c, high water content (80-90%), and different [lipid a]/[mg2+] molar ratios using synchrotron radiation x-ray diffraction and fourier-transform infrared spectroscopy. measurements were made on free lipid a from salmonella minnesota r595, mono- and bi-phosphoryl, as well as those from the non-enterobacterial strains rhodobacter ... | 1993 | 8269946 |
| molecular systematics of the genus zoogloea and emendation of the genus. | phylogenetic relationships among strains of zoogloea and related taxa were determined by 16s rdna sequencing and genomic dna hybridization techniques. the 16s rrna gene was amplified by the polymerase chain reaction with a pair of eubacterial consensus primers and sequenced directly by using an automated fluorescent dna sequencer. sequence comparisons and distance matrix tree analysis revealed that zoogloea ramigera iam 12136 (= n. c. dondero 106, type strain) and zoogloea sp. atcc 19324 formed ... | 1993 | 8240962 |
| amino acid sequence of a high redox potential ferredoxin (hipip) from the purple phototrophic bacterium rhodopila globiformis, which has the highest known redox potential of its class. | rhodopila globiformis hipip has a redox potential (ca. 450 mv) that is 100 mv higher than any other known iron-sulfur protein. the amino acid sequence contains 57 residues and can be aligned with that of thiobacillus ferrooxidans without any insertions or deletions and is 51% identical. rp. globiformis hipip is also similar to that of rhodocyclus tenuis, but six- and two-residue gaps must be postulated and there is only 37% identity. most of the amino acid residues near the iron-sulfur cluster a ... | 1993 | 8215406 |
| structural and spectral characterisation of the antenna complexes of rhodocyclus gelatinosus. indications of a hairpin-like-arranged antenna apoprotein with an unusually high alanine content. | the core antenna/reaction-centre complex rc-b875 and the peripheral antenna complex b800-850 of the two strains dsm 149 and dsm 151 of the purple non-sulphur bacterium rhodocyclus gelatinosus have been isolated from photosynthetic membranes by means of lauryl-n,n-dimethyl-amineoxide as a detergent and subsequent sucrose-gradient centrifugation. the two complexes were characterised spectroscopically by absorption and circular dichroism (cd) spectroscopy at room temperature. cd measurements reveal ... | 1994 | 8020505 |
| phylogenetic origins of the plant mitochondrion based on a comparative analysis of 5s ribosomal rna sequences. | the complete nucleotide sequences of 5s ribosomal rnas from rhodocyclus gelatinosa, rhodobacter sphaeroides, and pseudomonas cepacia were determined. comparisons of these 5s rna sequences show that rather than being phylogenetically related to one another, the two photosynthetic bacterial 5s rna sequences show that rather than being phylogenetically related to one another, the two photosynthetic bacterial 5s rnas share more sequence and signature homology with the rnas of two nonphotosynthetic ... | 1985 | 11542018 |
| identification of grass-associated and toluene-degrading diazotrophs, azoarcus spp., by analyses of partial 16s ribosomal dna sequences. | the genus azoarcus includes nitrogen-fixing, grass-associated strains as well as denitrying toluene degraders. in order to identify and group members of the genus azoarcus, phylogenetic analysis based on partial sequences of 16s rrna genes (16s rdnas) is proposed. 16s rrna-targeted pcr using specific primers to exclude amplification in the majority of other members of the beta subclass of the class proteobacteria was combined with direct sequencing of the pcr products. tree inference from compar ... | 1995 | 7793946 |
| influence of charge and polarity on the redox potentials of high-potential iron-sulfur proteins: evidence for the existence of two groups. | we have investigated the hipips from ectothiorhodospira vacuolata (iso-1 and iso-2), chromatium vinosum, rhodocyclus gelatinosus, rhodocyclus tenuis (strain 2761), rhodopila globiformis, and rhodospirillum salinarum (iso-2) by direct electrochemistry. using a glassy carbon electrode with a negatively charged surface, direct, unpromoted electrochemistry is possible with the positively charged hipips. with the negatively charged hipips, the positively charged and flexible bridging promoter poly(l- ... | 1995 | 7578075 |
| bacterial community structures of phosphate-removing and non-phosphate-removing activated sludges from sequencing batch reactors. | the bacterial community structures of phosphate- and non-phosphate-removing activated sludges were compared. sludge samples were obtained from two sequencing batch reactors (sbrs), and 16s rdna clone libraries of the bacterial sludge populations were established. community structures were determined by phylogenetic analyses of 97 and 92 partial clone sequences from sbr1 (phosphate-removing sludge) and sbr2 (non-phosphate-removing sludge), respectively. for both sludges, the predominant bacterial ... | 1995 | 7544094 |
| 16s rrna-targeted polymerase chain reaction and oligonucleotide hybridization to screen for azoarcus spp., grass-associated diazotrophs. | phylogenetic analyses after reverse transcriptase sequencing of 16s rrna of nitrogen-fixing, grass-associated azoarcus strains confirmed their affiliation to the beta subdivision of the proteobacteria. strains representing three different species formed a phylogenetically coherent unit related to rhodocyclus purpureus, with actual percent similarities among the three sequences ranging from 93.1 to 97.3%. within variable regions v2 and v5, we found stretches of sequences considerably conserved wi ... | 1993 | 7506895 |
| phylogenetic affiliations of rhodoferax fermentans and related species of phototrophic bacteria as determined by automated 16s rdna sequencing. | 16s rdna sequences of strains of rhodoferax fermentans were analyzed and compared with those of species of the genera rubrivivax and rhodocyclus. approximately 1.5-kb fragments of 16s rdna from crude cell lysates were amplified by the polymerase chain reaction (pcr) and sequenced directly by using tth dna polymerase with the linear pcr sequencing protocol, followed by on-line detection with an automated laser fluorescent dna sequencer. pairwise sequence comparisons and distance matrix tree analy ... | 1994 | 7506088 |
| o-acetylserine sulfhydrylase and s-sulfocysteine synthase activities of rhodospirillum tenue. | o-acetylserine sulfhydrylase in cell-free extracts of rhodospirillum tenue was markedly repressed after growth in the presence of sulfide or thiosulfate, whereas s-sulfocysteine synthase activity remained almost unchanged. purification on de52 cellulose resulted in the separation of two proteins: protein i with a molecular weight of 57000 had o-acetylserine sulfhydrylase activity only, while protein ii with a molecular weight of 46000 had s-sulfocysteine synthase activity in addition. the activi ... | 1983 | 6615127 |
| nitrogen fixation and nitrogenase activities in members of the family rhodospirillaceae. | strains of all 18 species of the family rhodospirillaceae (nonsulfur photosynthetic bacteria) were studied for their comparative nitrogen-fixing abilities. all species, with the exception of rhodocyclus purpureus, were capable of growth with n2 as the sole nitrogen source under photosynthetic (anaerobic) conditions. most rapid growth on n2 was observed in strains of rhodopseudomonas capsulata. within the genus rhodopseudomonas, the species r. capsulata, r. sphaeroides, r. viridis, r. gelatinosa, ... | 1984 | 6581158 |
| sutterella wadsworthensis gen. nov., sp. nov., bile-resistant microaerophilic campylobacter gracilis-like clinical isolates. | campylobacter gracilis (formerly bacteroides gracilis) is an asaccharolytic, nitrate-positive, urease-negative organism that requires formate and fumarate or hydrogen as a growth additive and may pit agar media. clinical isolates that were obtained primarily from appendiceal and peritoneal fluid specimens and initially were identified in our laboratory as b. gracilis were later found to include "unusual" strains that could be distinguished by biochemical and genetic criteria. these unusual c. gr ... | 1996 | 8573504 |
| a high-potential soluble cytochrome c-551 from the purple phototrophic bacterium chromatium vinosum is homologous to cytochrome c8 from denitrifying pseudomonads. | a minor cytochrome c-551 component of chromatium vinosum was previously found to efficiently couple electron transfer between the cytochrome bc1 complex and the photosynthetic reaction center. we have now determined the amino acid sequence of this cytochrome c-551 and find that it is homologous to cytochrome c8 (formerly called pseudomonas cytochrome c-551). it is most similar to methylophilus methylotrophus, rhodocyclus tenuis, and azotobacter vinelandii cytochromes c8 (respectively, 57%, 52% a ... | 1996 | 8612646 |
| the antenna complexes of the purple non-sulfur photosynthetic bacterium rhodocyclus tenuis. structural and spectral characterization. | the photoreceptor complex (b885-rc) and the peripheral antenna complex (b800-860) were isolated from photosynthetic membranes of the purple non-sulfur bacterium rhodocyclus tenuis dsm 109 using a detergent combination of deriphate-160 and octyl glucoside and subsequent linear sucrose gradient centrifugation. the two complexes were characterized by room-temperature absorption, circular dichroism and fluorescence spectroscopy. the b800-860 complex has a more red-shifted b860 absorbance band. the a ... | 1996 | 8681949 |
| anaerobic mineralization of cholesterol by a novel type of denitrifying bacterium | a novel denitrifying bacterium, strain 72chol, was enriched and isolated under strictly anoxic conditions on cholesterol as sole electron donor and carbon source. strain 72chol grew on cholesterol with oxygen or nitrate as electron acceptor. strictly anaerobic growth in the absence of oxygen was demonstrated using chemically reduced culture media. during anaerobic growth, nitrate was initially reduced to nitrite. at low nitrate concentrations, nitrite was further reduced to nitrogen gas. ammonia ... | 1997 | 9094222 |
| enrichment, phylogenetic analysis and detection of a bacterium that performs enhanced biological phosphate removal in activated sludge. | activated sludge communities which performed enhanced biological phosphate removal (ebpr) were phylogenetically analyzed by 16s rrna-targeted molecular methods. two anaerobic-aerobic sequencing batch reactors were operated with two different carbon sources (acetate vs. a complex mixture) for three years and showed anaerobic-aerobic cycles of polyhydroxybutyrate- (phb) and phosphate-accumulation characteristic for ebpr-systems. in situ hybridization showed that the reactor fed with the acetate me ... | 1999 | 10553298 |
| identification of polyphosphate-accumulating organisms and design of 16s rrna-directed probes for their detection and quantitation. | laboratory-scale sequencing batch reactors (sbrs) as models for activated sludge processes were used to study enhanced biological phosphorus removal (ebpr) from wastewater. enrichment for polyphosphate-accumulating organisms (paos) was achieved essentially by increasing the phosphorus concentration in the influent to the sbrs. fluorescence in situ hybridization (fish) using domain-, division-, and subdivision-level probes was used to assess the proportions of microorganisms in the sludges. the a ... | 2000 | 10698788 |
| recent developments in the biochemistry and ecology of enhanced biological phosphorus removal. | most of the genes encoding the enzymes involved in polyp synthesis and degradation and in phosphate transport have been studied in various gram-negative bacteria. progress has also been made in studying the biochemical mechanisms underlying the process of enhanced biological phosphorus removal (ebpr), in particular in lab-scale systems fed with acetate or acetate plus glucose as the sole carbon and energy sources. by applying 13c-nmr, previous models concerning anaerobic carbon metabolism have b ... | 2000 | 10739476 |
| microbial selection of polyphosphate-accumulating bacteria in activated sludge wastewater treatment processes for enhanced biological phosphate removal. | activated sludge processes with alternating anaerobic and aerobic conditions (the anaerobic-aerobic process) have been successfully used for enhanced biological phosphate removal (ebpr) from wastewater. it is known that polyphosphate-accumulating bacteria (pab) play an essential role for ebpr in the anaerobic-aerobic process. the present paper reviews limited information available on the metabolism and the microbial community structure of ebpr, highlighting the microbial ecological selection of ... | 2000 | 10739477 |
| sterolibacterium denitrificans gen. nov., sp. nov., a novel cholesterol-oxidizing, denitrifying member of the beta-proteobacteria. | a bacterial strain (chol-1s(t)) that is able to oxidize cholesterol to co2 and reduce nitrate to dinitrogen was enriched and isolated from an upflow sludge bed (usb) anoxic reactor that treats sanitary landfill leachate from the city of montevideo, uruguay. cells of strain chol-1s(t) were gram-negative, rod-shaped to slightly curved, measured 0.5-0.6 x 1.0-1.3 microm and were motile by a single polar flagellum. strain chol-1s(t) grew optimally at 30-32 degrees c and ph 7.0, with a doubling time ... | 2003 | 12892131 |
| reassessment of the taxonomic structure of the diazotrophic genus azoarcus sensu lato and description of three new genera and new species, azovibrio restrictus gen. nov., sp. nov., azospira oryzae gen. nov., sp. nov. and azonexus fungiphilus gen. nov., sp. nov. | the taxonomic structure of members of the genus azoarcus sensu lato was reassessed in a polyphasic approach. two species, azoarcus communis and azoarcus indigens, three unnamed species containing diazotrophs associated with kallar grass roots (groups c, d) and a group of strains (e) isolated from fungi were analysed. they were compared by page analyses of cellular proteins, genomic fingerprints, morphological and nutritional features to new isolates from rice roots. all strains within groups c, ... | 2000 | 10758872 |
| primary structure characterization of a rhodocyclus tenuis diheme cytochrome c reveals the existence of two different classes of low-potential diheme cytochromes c in purple phototropic bacteria. | the complete amino acid sequence of a 26-kda low redox potential cytochrome c-551 from rhodocyclus tenuis was determined by a combination of edman degradation and mass spectrometry. there are 240 residues including two heme binding sites at positions 41, 44, 128, and 132. there is no evidence for gene doubling. the only known homolog of rc. tenuis cytochrome c-551 is the diheme cytochrome c-552 from pseudomonas stutzeri which contains 268 residues and heme binding sites at nearly identical posit ... | 2000 | 11019819 |
| reduction of (per)chlorate by a novel organism isolated from paper mill waste. | as part of a study on the microbiology of chlorate reduction, several new dissimilatory chlorate-reducing bacteria were isolated from a broad diversity of environments. one of these, strain ckb, was selected for a more complete characterization. strain ckb was enriched and isolated from paper mill waste with acetate as the sole electron donor and chlorate as the sole electron acceptor. strain ckb is a completely oxidizing, non-fermentative, gram-negative, facultative anaerobe. cells of strain ck ... | 1999 | 11207750 |
| dechloromonas agitata gen. nov., sp. nov. and dechlorosoma suillum gen. nov., sp. nov., two novel environmentally dominant (per)chlorate-reducing bacteria and their phylogenetic position. | previous studies on the ubiquity and diversity of microbial (per)chlorate reduction resulted in the isolation of 20 new strains of dissimilatory (per)chlorate-reducing bacteria. phylogenetic analysis revealed that all of the isolates were members of the proteobacteria with representatives in the alpha-, beta- and gamma-subclasses. the majority of the new isolates were located in the beta-subclass and were closely related to each other and to the phototrophic rhodocyclus species. here an in-depth ... | 2001 | 11321099 |
| characterisation of the microbial 16s rdna diversity of an aerobic phosphorus-removal ecosystem and monitoring of its transition to nitrate respiration. | the microbial community of a conventional anaerobic-aerobic sequencing batch reactor was investigated by cloning and sequencing bacterial 16s rdna. the 92 16s rdna sequences analysed ranged across 50 different operational taxonomic units (otu). the majority of these sequences were not closely related to known species. they belonged to 12 different groups, but essentially to the cytophagales and the proteobacteria beta, which represented 38% and 17% of the retrieved sequences respectively. no otu ... | 2001 | 11398934 |
| the evolution of glutathione metabolism in phototrophic microorganisms. | of the many roles ascribed to glutathione (gsh) the one most clearly established is its role in the protection of higher eucaryotes against oxygen toxicity through destruction of thiol-reactive oxygen byproducts. if this is the primary function of gsh then gsh metabolism should have evolved during or after the evolution of oxygenic photosynthesis. that many bacteria do not produce gsh is consistent with this view. in the present study we have examined the low-molecular-weight thiol compositio ... | 1987 | 11542078 |
| characterization of denitrifying phosphate-accumulating organisms cultivated under different electron acceptor conditions using polymerase chain reaction-denaturing gradient gel electrophoresis assay. | to investigate the characteristics and the microbial diversity of denitrifying phosphate-accumulating organisms (dnpaos) that are capable of conducting enhanced biological phosphorus removal (ebpr) using nitrate as electron acceptor, three sequencing batch reactors were operated under three different electron acceptor conditions, i.e., only oxygen, oxygen together with nitrate and only nitrate. based on the chemical analysis concerning the biochemical transformation of each reactor, it was found ... | 2002 | 11827346 |
| population changes in a biofilm reactor for phosphorus removal as evidenced by the use of fish. | induction of denitrification was investigated for a lab-scale phosphate removing biofilm reactor where oxygen was replaced with nitrate as the electron acceptor. acetate was used as the carbon source. the original biofilm (acclimatised with oxygen) was taken from a well-established large-scale reactor. during the first run, a decrease in the denitrifying bio-p activity was observed after 1 month following a change in the anaerobic phase length. this was initially interpreted as a shift in the mi ... | 2002 | 11827355 |
| quadricoccus australiensis gen. nov., sp. nov., a beta-proteobacterium from activated sludge biomass. | a gram-negative coccus, designated strain ben 117t, was obtained in axenic culture by micromanipulation from an australian activated sludge biomass sample, which had been subjected to chlorination in order to alleviate problems associated with foaming and bulking. this isolate was a strict aerobe and grew in axenic culture, also appearing in biomass samples as cocci or clusters of cocci in tetrads, thus resembling the morphotype 'g-bacteria' seen commonly in activated sludge samples. strain ben ... | 2002 | 11858148 |
| which are the polyphosphate accumulating organisms in full-scale activated sludge enhanced biological phosphate removal systems in australia? | to see if the compositions of the microbial communities in full scale enhanced biological phosphorus removal activated sludge systems were the same as those from laboratory scale sequencing batch reactors fed a synthetic sewage. | 2006 | 16430499 |
| propionivibrio limicola sp. nov., a fermentative bacterium specialized in the degradation of hydroaromatic compounds, reclassification of propionibacter pelophilus as propionivibrio pelophilus comb. nov. and amended description of the genus propionivibrio. | strain golchi1t, a mesophilic, anaerobic bacterium, was isolated with quinic acid (1,3,4,5-tetrahydroxy-cyclohexane-1-carboxylic acid) as the sole source of carbon and energy. of more than 30 substrates tested, only the hydroaromatic compounds quinic acid and shikimic acid (3,4,5-trihydroxy-1-cyclohexene-1-carboxylic acid) were utilized, yielding acetate and propionate as the only fermentation products. sugars, alcohols, (di-)carboxylic acids, amino acids and aromatic compounds were not fermente ... | 2002 | 11931155 |
| oxidation of c-type cytochromes by the membrane-bound cytochrome oxidase (cytochrome aa(3)) of blue-green algae. | respiratory particles containing an aa(3)-type cytochrome oxidase were prepared from anacystis nidulans, synechocystis 6714, synechococcus lividus, anabaena variabilis, nostoc sp. strain mac, nostoc muscorum, and mastigocladus laminosus. oxidation of c-type cytochromes by membrane preparations of the different blue-green algae was observed using purified cytochromes from horse heart, candida krusei, tuna, saccharomyces oviformis, rhodospirillum rubrum, rhodospirillum molischianum, rhodopseudomon ... | 1982 | 16662253 |
| involvement of rhodocyclus-related organisms in phosphorus removal in full-scale wastewater treatment plants. | the participation of organisms related to rhodocyclus in full-scale enhanced biological phosphorus removal (ebpr) was investigated. by using fluorescent in situ hybridization techniques, the communities of rhodocyclus-related organisms in two full-scale wastewater treatment plants were estimated to represent between 13 and 18% of the total bacterial population. however, the fractions of these communities that participated in polyphosphate accumulation depended on the type of treatment process ev ... | 2002 | 12039731 |
| functional analysis of microbial communities in aerobic-anaerobic sequencing batch reactors fed with different phosphorus/carbon (p/c) ratios. | fluorescence in situ hybridization (fish) was used to analyse the community composition of a sequencing batch reactor (sbr) operating with aerobic-anaerobic cycling and fed acetate as its sole carbon source. phosphorus was removed from the sbr microbiologically. marked shifts in the community structure occurred as the phosphorus/carbon (p/c) ratio in the feed was changed. when the p/c ratio was shifted from 1:10 to 1:50, fish analysis showed that the percentage of beta-proteobacteria fell from c ... | 2002 | 12177324 |
| presence of rhodocyclus in a full-scale wastewater treatment plant and their participation in enhanced biological phosphorus removal. | the objective of this research was to assess the relevance of organisms related to rhodocyclus in enhanced biological phosphorus removal in full-scale wastewater treatment plants. the presence of these organisms in full-scale plants was first confirmed by fluorescent in situ hybridization. to address which organisms were involved in phosphorus removal, a method was developed which selected polyphosphate-accumulating organisms from activated sludge samples by dapi staining and flow cytometry. sor ... | 2002 | 12216613 |
| flow cytometric sorting and rflp analysis of phosphate accumulating bacteria in an enhanced biological phosphorus removal system. | phosphate accumulating organisms (paos) stained with 4',6-diamidino-2-phenylindol dihydrochloride (dapi) at polyphosphate probing concentration were sorted from enhanced biological phosphorus removal (ebpr) sludge by flow cytometric sorting. all the genome dna was extracted from the sorted bacteria and the 16s rdna genes were cloned. cloned 16s rdna was pcr-amplified and analyzed by restriction fragment length polymorphism (rflp) analysis. eighty eight clones were analyzed and the rflp patterns ... | 2002 | 12216615 |
| analysis of microbial community that performs enhanced biological phosphorus removal in activated sludge fed with acetate. | enhanced biological phosphorus removal (ebpr) activated sludge was operated in a laboratory-scale sequencing batch reactor (sbr) fed with acetate as the sole carbon source. the microbial community of the sludge was analyzed using the polymerase chain reaction (pcr)-denaturing gradient gel electrophoresis (dgge) method for about 2 months of start-up period. as a result, the number of major bands decreased during the enrichment, indicating that the microbial community structure was getting simpler ... | 2002 | 12216616 |
| characterization of the reaction center bound tetraheme cytochrome of rhodocyclus tenuis. | properties of the tetrahemic reaction center bound cytochrome have been investigated by different techniques. the mid-point potentials of the four hemes were determined by redox titration. the best fit of the data was obtained with a (n = 1) nernst curve by using the following values of the redox parameters: em = +420 mv for the two high-potential hemes and em = +110 and +60 mv for the two low-potential hemes. the mid-point potentials of the two high-potential hemes are the highest reported so f ... | 1997 | 9315854 |
| photoinduced cyclic electron transfer in rhodocyclus tenuis cells: participation of hipip or cyt c8 depending on the ambient redox potential. | we demonstrate the participation of a cytochrome c8 and a high-potential iron-sulfur protein (hipip) in the photoinduced electron transfer in whole cells of rhodocyclus tenuis depending on the redox state or background continuous illumination. at high redox potentials (above 350 mv) or under a strong background illumination (5 w m-2), the cytochrome c8 acts as the physiological electron donor to the photo-oxidized high-potential hemes of the tetraheme cytochrome bound to the reaction center. for ... | 1997 | 9315855 |
| fermentative bacteria from estuarine mud: phylogenetic position of acidaminobacter hydrogenoformans and description of a new type of gram-negative, propionigenic bacterium as propionibacter pelophilus gen. nov., sp. nov. | the phylogenetic positions of two strains of fermentative bacteria that had been isolated from the highest positive tubes inoculated with serial dilutions of estuarine mud in agar media with either glutamate or aspartate as substrate were determined by comparative sequence analysis of their 16s rrna genes. the strain isolated with glutamate (glu 65) utilized several substrates, including a number of amino acids but no sugars. the degradation of certain substrates was enhanced by or dependent upo ... | 1999 | 10425761 |
| isolation and molecular characterization of pmg160, a mobilizable cryptic plasmid from rhodobacter blasticus. | a 3.4-kb cryptic plasmid was obtained from a new isolate of rhodobacter blasticus. this plasmid, designated pmg160, was mobilizable by the conjugative strain escherichia coli s17.1 into rhodobacter sphaeroides, rhodobacter capsulatus, and rhodopseudomonas palustris. it replicated in the latter strains but not in rhodospirillum rubrum, rhodocyclus gelatinosus, or bradyrhizobium species. plasmid pmg160 was stably maintained in r. sphaeroides for more than 100 generations in the absence of selectio ... | 2003 | 12570988 |
| nitrogen metabolism in the phototrophic bacteria rhodocyclus purpureus and rhodospirillum tenue. | studies of the nitrogen nutrition and pathways of ammonia assimilation in rhodocyclus purpureus and rhodospirillum tenue have shown that these two seemingly related bacteria differ considerably in aspects of their nitrogen metabolism. when grown photoheterotrophically with malate as carbon source, r. purpureus utilized only nh4+ or glutamine as sole nitrogen sources and was unable to fix n2. by contrast, r. tenue was found to utilize a variety of amino acids as nitrogen sources and was a good n2 ... | 1983 | 6863218 |
| phylogenetic analysis of formivibrio citricus, propionivibrio dicarboxylicus, anaerobiospirillum thomasii, succinimonas amylolytica and succinivibrio dextrinosolvens and proposal of succinivibrionaceae fam. nov. | the phylogenetic position of gram-negative, strictly anaerobic, non-spore-forming bacteria, representing four different genera, was determined by analysis of their 16s rdna sequences. formivibrio citricus and propionivibrio dicarboxylicus are members of the beta-subclass of the class proteobacteria. while formivibrio citricus stands phylogenetically isolated, propionivibrio dicarboxylicus is moderately related to members of the genus rhodocyclus. succinimonas amylolytica and succinivibrio dextri ... | 1999 | 10319502 |
| the dynamic progression of evolved character states for aromatic amino acid biosynthesis in gram-negative bacteria. | a systematic analysis of the evolution of aromatic amino acid biosynthesis in the proteobacteria, previously focussed mainly upon the gamma subdivision, has now been extended to the beta subdivision. five lineages were studied, represented by neisseria gonorrhoeae, nitrosomonas europaea, alcaligenes faecalis, rrna group-iii pseudomonads/rubrivivax gelatinosus, and rrna group-ii pseudomonads/rhodocyclus tenuis. within the phenylalanine pathway, the bifunctional p-protein (chorismate mutase/prephe ... | 1994 | 7533594 |
| microbial communities in activated sludge performing enhanced biological phosphorus removal in a sequencing batch reactor. | microbial communities of activated sludge in an anaerobic/aerobic sequencing batch reactor (sbr) supplied with acetate as sole carbon source were analyzed to identify the microorganisms responsible for enhanced biological phosphorus removal. various analytical methods were used such as electron microscopy, quinone, slot hybridization, and 16s rrna gene sequencing analyses. electron photomicrographs showed that coccus-shaped microorganisms of about 1 microm diameter dominated the microbial commun ... | 2003 | 12691905 |
| effect of aspartate and glutamate on the fate of enhanced biological phosphorus removal process and microbial community structure. | this study investigated the fate of enhanced biological phosphorus removal (ebpr) and changes in microbial speciation in a sequencing batch reactor (sbr) fed with aspartate and glutamate. it involved sbr operation for 288 days, batch tests for observation of metabolic functions together with microscopic and phylogenetic analyses. polyphosphate accumulating organisms (paos) were observed in abundance with complete removal of phosphorus. fluorescence in situ hybridization (fish) combined with 4',6 ... | 2010 | 20926291 |
| long-term population dynamics and in situ physiology in activated sludge systems with enhanced biological phosphorus removal operated with and without nitrogen removal. | quantitative fluorescence in situ hybridization (fish) and the combination of fish with microautoradiography (mar) were used in order to study the long-term population dynamics (2.5 years) and the in situ physiology in two parallel activated sludge pilot systems with enhanced biological phosphorus removal (ebpr). the two systems received the same influent wastewater, but were differently operated (with and without nitrogen removal, respectively). both systems showed a significant p removal that ... | 2003 | 12866848 |
| molecular characterization of the microbial community structure in two activated sludge systems for the advanced treatment of domestic effluents. | although activated sludge systems with enhanced biological phosphorus removal (ebpr) represent state-of-the-art technology for phosphate removal from wastewater it is still unknown which species of bacteria are responsible for the ebpr process. the aim of this study was to compare the bacterial composition of activated sludge from two laboratory plants with different modes of operation, anoxic/oxic- (ebpr, no nitrification) and phoredox-system (ebpr, nitrification and denitrification) with parti ... | 2003 | 14509710 |
| the application of two-dimensional polyacrylamide gel electrophoresis and downstream analyses to a mixed community of prokaryotic microorganisms. | summary in the post-genomic era, the focus of numerous researchers has moved to studying the functional products of gene expression. in microbiology, these "omic" approaches have largely been limited to pure cultures of microorganisms. consequently, they do not provide information on gene expression in a complex mixture of microorganisms as found in the environment. our method enabled the successful extraction and purification of the entire proteome from a laboratory-scale activated sludge syste ... | 2004 | 15305916 |
| microautoradiographic study of rhodocyclus-related polyphosphate-accumulating bacteria in full-scale enhanced biological phosphorus removal plants. | the ecophysiology of uncultured rhodocyclus-related polyphosphate-accumulating organisms (pao) present in three full-scale enhanced biological phosphorus removal (ebpr) activated sludge plants was studied by using microautoradiography combined with fluorescence in situ hybridization. the investigations showed that these organisms were present in all plants examined and constituted 5 to 10, 10 to 15, and 17 to 22% of the community biomass. the behavior of these bacteria generally was consistent w ... | 2004 | 15345424 |
| the large pao cells in full-scale ebpr biomass samples are not yeast spores but possibly novel members of the beta-proteobacteria. | large, homogenous clusters of coccobacilli were found to be abundant in the biomasses from a conventional plant at rosebud, victoria, australia. the identity and the in situ physiology of these dominant microorganisms were investigated in this study. these large clustered cells were revealed to be neither gram positive nor gram negative bacteria and contain polyp granules. cells with similar features were also observed in some enhanced biological phosphate removal (ebpr) systems and reported as ... | 2004 | 15536999 |
| small-scale, hydrogen-oxidizing-denitrifying bioreactor for treatment of nitrate-contaminated drinking water. | nitrate removal by hydrogen-coupled denitrification was examined using flow-through, packed-bed bioreactors to develop a small-scale, cost effective system for treating nitrate-contaminated drinking-water supplies. nitrate removal was accomplished using a rhodocyclus sp., strain hod 5, isolated from a sole-source drinking-water aquifer. the autotrophic capacity of the purple non-sulfur photosynthetic bacterium made it particularly adept for this purpose. initial tests used a commercial bioreacto ... | 2005 | 15890383 |
| in situ identification and characterization of the microbial community structure of full-scale enhanced biological phosphorous removal plants in japan. | fluorescent in situ hybridization (fish) and polyphosphate (polyp) staining methods were used to characterize the microbial community structure of 13 activated sludge samples taken from nine different japanese wastewater treatment plants with and without enhanced biological phosphorous removal (ebpr) activities. fish with published rrna-targeted oligonucleotide probes for important bacterial groups involving in the ebpr process revealed that rhodocyclus-related polyphosphate accumulating organis ... | 2005 | 15993461 |
| identity and ecophysiology of uncultured actinobacterial polyphosphate-accumulating organisms in full-scale enhanced biological phosphorus removal plants. | microautoradiography combined with fluorescence in situ hybridization (mar-fish) was used to screen for potential polyphosphate-accumulating organisms (pao) in a full-scale enhanced biological phosphorus removal (ebpr) plant. the results showed that, in addition to uncultured rhodocyclus-related pao, two morphotypes hybridizing with gene probes for the gram-positive actinobacteria were also actively involved in uptake of orthophosphate (pi). clone library analysis and further investigations by m ... | 2005 | 16000823 |
| characterization of denitrifying polyphosphate-accumulating organisms in activated sludge based on nitrite reductase gene. | nitrite reductase gene (nirs) fragments in the activated sludge obtained from a sequencing batch reactor (sbr) under anaerobic-aerobic condition were cloned and classified by restriction fragment length polymorphism (rflp) analysis, and representative fragments were sequenced. one of the nirs clones was approximately 70% of all nirs clones in anaerobic/aerobic (existing oxygen and nitrate) cycle operation in which a large amount of anoxic phosphate uptake was observed. although the activated slu ... | 2005 | 16233809 |
| characterization of naturally occurring atrazine-resistant isolates of the purple non-sulfur bacteria. | six isolates of the purple non-sulfur bacteria, which upon primary isolation were naturally resistant to the herbicide atrazine, were characterized with respect to their taxonomic identity and the mechanism of their resistance. on the basis of electron microscopy, photopigment analysis, and other criteria, they were identified as strains of rhodopseudomonas acidophila, rhodopseudomonas palustris, or rhodocyclus gelatinosus. these isolates exhibited degrees of atrazine resistance which ranged fro ... | 1990 | 16348126 |
| ecophysiology of a group of uncultured gammaproteobacterial glycogen-accumulating organisms in full-scale enhanced biological phosphorus removal wastewater treatment plants. | the presence of glycogen-accumulating organisms (gaos) in enhanced biological phosphorus removal (ebpr) plants can seriously deteriorate the biological p-removal by out-competing the polyphosphate-accumulating organisms (paos). in this study, uncultured putative gaos (the gb group, belonging to the gammaproteobacteria) were investigated in detail in 12 full-scale ebpr plants. fluorescence in situ hybridization (fish) revealed that the biovolume of the gb bacteria constituted 2-6% of total bacter ... | 2006 | 16478454 |
| changes in respiratory quinone profiles of enhanced biological phosphorus removal activated sludge under different influent phosphorus/carbon ratio conditions. | changes in the microbial community of an enhanced biological phosphorus removal (ebpr) activated sludge system under different influent phosphorus/carbon (p/c) ratio conditions were investigated through evaluation of population respiratory quinone profiles. a total of 13 types of respiratory quinone homologs consisting of 3 types of ubiquinones (uq) and 10 types of menaquinones (mk) were identified in this study. the dominant quinones were uq-8 and mk-7 throughout the operational period. a highe ... | 2006 | 16799800 |
| examining substrate uptake patterns of rhodocyclus-related pao in full-scale ebpr plants by using the mar-fish technique. | while recognised as the important population responsible for enhanced biological phosphorus removal (ebpr), detailed knowledge on the physiology of rhodocyclus-related polyphosphate accumulating organisms (pao) has yet to be grasped. the objective of this study was to examine the in situ substrate uptake patterns of rhodocyclus-related pao present in full-scale ebpr plants by the combined technique of microautoradiography-fluorescent in situ hybridization (mar-fish). the presence of these pao in ... | 2006 | 16898138 |
| proliferation of glycogen accumulating organisms induced by fe(iii) dosing in a domestic wastewater treatment plant. | to meet the effluent requirements given for the sensitive receiving body, the southpest wastewater treatment plant of budapest, hungary uses a combined activated sludge-biofilter system with chemical precipitation for p removal. causes of the proliferation of glycogen accumulating organisms (gaos) observed in the unaerated/oxic activated sludge unit of this system were investigated both in full-scale and in lab-scale experiments combined with a detailed analysis of the microbial communities. con ... | 2006 | 16898142 |
| towards exposure of elusive metabolic mixed-culture processes: the application of metaproteomic analyses to activated sludge. | protein expression is a direct reflection of specific microbial activities in any ecosystem. in order to assess protein expression in mixed microbial communities, the feasibility of applying proteomic techniques to activated sludge samples has recently been demonstrated. we report the application of metaproteomics to two activated sludges from a laboratory-scale sequencing batch reactor with dissimilar phosphorus removal performances. fluorescence in situ hybridization (fish) revealed that the s ... | 2006 | 16898155 |
| effects of the internal recycling rate on biological nutrient removal and microbial community structure in a sequential anoxic/anaerobic membrane bioreactor. | this study investigated the effects of the internal recycling rate on nutrients removal in a sequential anoxic/anaerobic membrane bioreactor (sam). microbial community structure in sludge from the sam was studied using quinone profile method. above 98% cod, 68% nitrogen, and 55% phosphorus removal efficiencies were achieved when the internal recycling rate was 2.5 times influent flow. at that rate, the optimum specific nitrate loading rate and cod/no(3)-n ratio were found to be 2.24 mgno(3)-n g( ... | 2007 | 17120059 |
| polyphosphate kinase genes from activated sludge carrying out enhanced biological phosphorus removal. | the community structure and metabolic function of activated sludge carrying out enhanced biological phosphorus removal have been investigated. laboratory-scale sequencing batch reactors were operated at several influent cod/p ratios to obtain sludges with a range of phosphorus contents. molecular microbiological techniques based on small subunit ribosomal rna were used to characterize the structure of these sludges. the dominant polyphosphate accumulating organism was a close relative of rhodocy ... | 2002 | 12216617 |
| population dynamics in wastewater treatment plants with enhanced biological phosphorus removal operated with and without nitrogen removal. | the population dynamics of activated sludge in a pilot plant with two activated sludge systems, both designed for enhanced biological phosphorus removal (ebpr), but one of them with (bnp) and the other without (bp) nitrogen removal, was monitored during a period of 2.5 years. the influent water to the pilot plant was periodically manipulated by external addition of phosphorus (p), acetate and glucose, respectively. the population dynamics and the in situ physiology were monitored by quantitative ... | 2002 | 12216618 |
| polyphosphate kinase from activated sludge performing enhanced biological phosphorus removal. | a novel polyphosphate kinase (ppk) was retrieved from an uncultivated organism in activated sludge carrying out enhanced biological phosphorus removal (ebpr). acetate-fed laboratory-scale sequencing batch reactors were used to maintain sludge with a high phosphorus content (approximately 11% of the biomass). pcr-based clone libraries of small subunit rrna genes and fluorescent in situ hybridization (fish) were used to verify that the sludge was enriched in rhodocyclus-like beta-proteobacteria kn ... | 2002 | 12324346 |
| microbial community associated with glucose-induced enhanced biological phosphorus removal. | the microbial community associated with enhanced biological phosphorus removal with glucose as the main carbon source at 11 degrees c was investigated using microscopy and molecular fingerprinting techniques. the study lasted 77 days and comprised two stages-stage 1 when the mixture of glucose, yeast and dried milk was the organic carbon source and stage 2 when glucose was the single carbon source. rhodocyclus-related polyphosphate accumulating organisms, alpha-proteobacteria and bacteroidetes c ... | 2009 | 19844057 |
| microbial population dynamics during sludge granulation in an anaerobic-aerobic biological phosphorus removal system. | the evolution of a microbial community was investigated during sludge granulation using a wide range of micro-scale and molecular biology techniques. experimental results demonstrate that polyphosphate-accumulating granules were successfully cultured during the anaerobic/aerobic cycle. improvement in sludge sedimentation performance occurred prior to the formation of granular sludge and was not affected by change in granule size. rod-shaped and filamentous bacteria appeared to initiate granule f ... | 2010 | 21123057 |
| molecular analysis of bacterial communities in uranium ores and surrounding soils from banduhurang open cast uranium mine, india: a comparative study. | bacterial community structure of heavy metal rich- uranium ores and surrounding soils was explored using 16s rrna gene based clone library analysis and denaturing gradient gel electrophoresis (dgge) to provide baseline microbial diversity data on autochthonous communities. sequence analysis of major ribotypes and/or dgge bands revealed proteobacteria and acidobacteria as the two most frequently present bacterial phyla across the samples, although relative abundance of each phyla and identity of ... | 2011 | 21308598 |
| floc-forming properties of polyphosphate accumulating organisms in activated sludge. | the physico-chemical characteristics of polyphosphate-accumulating organisms (pao) involved in enhanced biological phosphorus removal (ebpr) was investigated in order to find a novel method for phosphorus recovery. if the physico-chemical characteristics of pao are different from those of other main floc components, it may be possible to enrich pao in bulk water or in the floc material for improved recovery of phosphorus. a combination of shear tests, chemical manipulation, and quantification of ... | 2006 | 16898159 |
| ecophysiology of abundant denitrifying bacteria in activated sludge. | the abundance of potential denitrifiers in full-scale wastewater treatment plants with biological nitrogen and phosphorus removal was investigated by fish and various oligonucleotide probes. the potential denitrifiers were characterized as probe-defined populations that were able to consume radiolabelled substrate with oxygen, nitrate and nitrite as electron acceptor as determined by microautoradiography. the most abundant potential denitrifiers were related to the genera aquaspirillum, azoarcus ... | 2007 | 17391331 |
| production of lipases by four anoxygenic purple non-sulphur phototrophic bacteria. | production of lipases by rhodopseudomonas palustris, rhodobacter sphaeroides, rhodocyclus gelatinosus and rhodocyclus tenuis in different synthetic media was investigated. rc. gelatinosus followed by rb. sphaeroides were good producers of lipases, while rps. palustris and rc. tenuis were poor in lipase secretion. lipase secretion by rc. gelatinosus was adaptive in nature, while other three bacterial behavior was inconsistent. no positive correlation could be observed between growth and lipase pr ... | 2005 | 18697729 |
| autohydrogenotrophic denitrification of drinking water using a polyvinyl chloride hollow fiber membrane biofilm reactor. | a hollow fiber membrane biofilm reactor (mbfr) using polyvinyl chloride (pvc) hollow fiber was evaluated in removing nitrate form contaminated drinking water. during a 279-day operation period, the denitrification rate increased gradually with the increase of influent nitrate loading. the denitrification rate reached a maximum value of 414.72 g n/m(3)d (1.50 g n/m(2)d) at an influent no(3)(-)-n concentration of 10mg/l and a hydraulic residence time of 37.5 min, and the influent nitrate was compl ... | 2009 | 19473764 |