| desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. | anaerobic sea or fresh water media with acetate and elemental sulfur yielded enrichments of a new type of strictly anaerobic, rod-shaped, laterally flagellated, gram-negative bacterium. three pure culture-strains from different sulfide-containing sea water sources were characterized in detail and are described as a new genus and species desulfuromonas acetoxidans. the new bacterium is unable to ferment organic substances; it obtains energy for growth by anaerobic sulfur respiration. acetate, eth ... | 1976 | 1015937 |
| iron and manganese in anaerobic respiration: environmental significance, physiology, and regulation. | dissimilatory iron and/or manganese reduction is known to occur in several organisms, including anaerobic sulfur-reducing organisms such as geobacter metallireducens or desulfuromonas acetoxidans, and facultative aerobes such as shewanella putrefaciens. these bacteria couple both carbon oxidation and growth to the reduction of these metals, and inhibitor and competition experiments suggest that mn(iv) and fe(iii) are efficient electron acceptors similar to nitrate in redox abilities and capable ... | 1994 | 7826009 |
| geobacter metallireducens gen. nov. sp. nov., a microorganism capable of coupling the complete oxidation of organic compounds to the reduction of iron and other metals. | the gram-negative metal-reducing microorganism, previously known as strain gs-15, was further characterized. this strict anaerobe oxidizes several short-chain fatty acids, alcohols, and monoaromatic compounds with fe(iii) as the sole electron acceptor. furthermore, acetate is also oxidized with the reduction of mn(iv), u(vi), and nitrate. in whole cell suspensions, the c-type cytochrome(s) of this organism was oxidized by physiological electron acceptors and also by gold, silver, mercury, and ch ... | 1993 | 8387263 |
| the desulfuromonas acetoxidans triheme cytochrome c7 produced in desulfovibrio desulfuricans retains its metal reductase activity. | multiheme cytochrome c proteins that belong to class iii have been recently shown to exhibit a metal reductase activity, which could be of great environmental interest, especially in metal bioremediation. to get a better understanding of these activities, the gene encoding cytochrome c7 from the sulfur-reducing bacterium desulfuromonas acetoxidans was cloned from genomic dna by pcr and expressed in desulfovibrio desulfuricans g201. the expression system was based on the cyc transcription unit fr ... | 1998 | 9546165 |
| purification and characterization of triheme cytochrome c7 from the metal-reducing bacterium, geobacter metallireducens. | a soluble c-type cytochrome was first purified from geobacter metallireducens to an electrophoretically homogeneous state. the purified cytochrome c showed absorption peaks at 530 and 409 nm in the oxidized form and 552, 522, and 418 nm in the reduced form. polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate allowed us to calculate the molecular mass at 9.5 kda. it contained 3 mol of heme c per molecule of the protein on the basis of heme c and protein concentration. the ... | 1999 | 10386369 |
| first evidence for the presence of a hydrogenase in the sulfur-reducing bacterium desulfuromonas acetoxidans. | hydrogenases, which are ubiquitous in sulfate-reducing bacteria, were previously thought to be absent from desulfuromonas acetoxidans. for the first time, a hydrogenase from the strict anaerobic sulfur-respiring bacterium d. acetoxidans, grown on ethanol-malate, was detected and enriched. to assay the role of the hydrogenase in the energetic metabolism of d. acetoxidans, we examined the reactivity of the enzyme with polyheme cytochromes from the same bacterium. | 1999 | 10464227 |
| a proton-nmr investigation of the fully reduced cytochrome c7 from desulfuromonas acetoxidans. comparison between the reduced and the oxidized forms. | the solution structure via 1h nmr of the fully reduced form of cytochrome c7 has been obtained. the protein sample was kept reduced by addition of catalytic amounts of desulfovibrio gigas iron hydrogenase in h2 atmosphere after it had been checked that the presence of the hydrogenase did not affect the nmr spectrum. a final family of 35 conformers with rmsd values with respect to the mean structure of 8.7 +/- 1.5 nm and 12.4 +/- 1.3 nm for the backbone and heavy atoms, respectively, was obtained ... | 1999 | 10561607 |
| tetrachloroethene-dehalogenating bacteria. | tetrachloroethene is a frequent groundwater contaminant often persisting in the subsurface environments. it is recalcitrant under aerobic conditions because it is in a highly oxidized state and is not readily susceptible to oxidation. nevertheless, at least 15 organisms from different metabolic groups, viz. halorespirators (9), acetogens (2), methanogens (3) and facultative anaerobes (2), that are able to metabolize tetrachloroethene have been isolated as axenic cultures to-date. some of these o ... | 1999 | 10664879 |
| resonance raman study of multihemic c-type cytochromes from desulfuromonas acetoxidans. | two multihemic cytochromes c from the sulfur reducing bacteria desulfuromonas acetoxidans have been studied by optical and resonance raman spectroscopy: cytochrome c551.5, a trihemic cytochrome and cytochrome c mr 50 000, a recently isolated high molecular mass cytochrome. the redox and raman characteristics of cytochrome c551.5 are compared to those of the tetrahemic cytochromes c3 from desulfovibrio. while the redox behavior, followed by spectroelectrochemistry, is similar to that of cytochrom ... | 2000 | 10672013 |
| 16s rrna gene-based detection of tetrachloroethene-dechlorinating desulfuromonas and dehalococcoides species. | members of the genera desulfuromonas and dehalococcoides reductively dechlorinate tetrachloroethene (pce) and trichloroethene. two primer pairs specific to hypervariable regions of the 16s rrna genes of the dehalococcoides group (comprising dehalococcoides ethenogenes and dehalococcoides sp. strain fl2) and the acetate-oxidizing, pce-dechlorinating desulfuromonas group (comprising desulfuromonas sp. strain bb1 and desulfuromonas chloroethenica) were designed. the detection threshold of a nested ... | 2000 | 10742213 |
| enzymatic reduction of chromate: comparative studies using sulfate-reducing bacteria. key role of polyheme cytochromes c and hydrogenases. | various sulfate-reducing bacteria of the genera desulfovibrio and desulfomicrobium were tested and compared for enzymatic reduction of chromate. our study demonstrated that the ability to reduce chromate is widespread among sulfate-reducing bacteria. among them, desulfomicrobium norvegicum reduced cr(vi) with the highest reaction rate. this strain grew in the presence of up to 500 microm chromate, but cr(vi) reduction in the absence of sulfate was not associated with growth. the presence of chro ... | 2001 | 11234966 |
| high bacterial diversity in permanently cold marine sediments. | a 16s ribosomal dna (rdna) clone library from permanently cold marine sediments was established. screening 353 clones by dot blot hybridization with group-specific oligonucleotide probes suggested a predominance of sequences related to bacteria of the sulfur cycle (43.4% potential sulfate reducers). within this fraction, the major cluster (19.0%) was affiliated with desulfotalea sp. and other closely related psychrophilic sulfate reducers isolated from the same habitat. the cloned sequences show ... | 1999 | 10473405 |
| continuous steady-state method using tenax for delivering tetrachloroethene to chloro-respiring bacteria. | tenax-ta, a solid-phase sorbent, was used as an alternative to hexadecane for continuous delivery of tetrachloroethene (pce) to desulfuromonas strain bb1, a chloro-respiring microorganism. in both batch and bioreactor configurations, tenax not only maintained low, steady-state concentrations of pce in an active culture for several months but also adsorbed the product of dechlorination, cis-1,2-dichloroethene, before it approached toxic levels. | 2002 | 11872503 |
| 800 mhz 1h nmr solution structure refinement of oxidized cytochrome c7 from desulfuromonas acetoxidans. | the solution structure of desulfuromonas acetoxidans cytochrome c7 has been refined by using 1h-nmr spectra recorded at 800 mhz and by using pseudocontact shifts in the final energy minimization procedure. the protein, composed of 68 amino acids, contains three paramagnetic heme moieties, each with one unpaired electron. the largely distributed paramagnetism broadens the lines in several protein parts. the structure is now relatively well resolved all over the backbone by the use of 1315 meaning ... | 1998 | 9760163 |
| a periplasmic and extracellular c-type cytochrome of geobacter sulfurreducens acts as a ferric iron reductase and as an electron carrier to other acceptors or to partner bacteria. | an extracellular electron carrier excreted into the growth medium by cells of geobacter sulfurreducens was identified as a c-type cytochrome. the cytochrome was found to be distributed in about equal amounts in the membrane fraction, the periplasmic space, and the surrounding medium during all phases of growth with acetate plus fumarate. it was isolated from periplasmic preparations and purified to homogeneity by cation-exchange chromatography, gel filtration, and hydrophobic interaction chromat ... | 1998 | 9658015 |
| purification and characterization of a monomeric isocitrate dehydrogenase from the sulfate-reducing bacterium desulfobacter vibrioformis and demonstration of the presence of a monomeric enzyme in other bacteria. | nadp(+)-specific isocitrate dehydrogenase (ec 1.1.1.42) was purified to homogeneity from the sulfate-reducing bacterium desulfobacter vibrioformis, and shown to be a monomeric protein with a molecular mass of 80 kda. the ph and temperature optima were 8.5 and 45 degrees c, respectively. the n-terminal amino acid sequence (thr, glu, thr, ile, arg, trp, thr, x, thr, asp, glu, ala, pro, leu, leu, ala, thr) showed similarity with that of other known monomeric isocitrate dehydrogenases. catalytically ... | 1998 | 9495015 |
| multiheme cytochromes from the sulfur-reducing bacterium desulfuromonas acetoxidans. | two new multiheme cytochromes were isolated from the anaerobic sulfur reducing bacterium desulfuromonas acetoxidans. they have monomeric molecular masses of 50 and 65 kda and contain six and eight hemes, respectively. visible and epr spectroscopies, in the as-isolated (oxidised) cytochromes, show the presence of only low-spin hemes in the 50-kda cytochrome, and of high-spin and low-spin hemes in the 65-kda cytochrome. the epr spectra of the native 65-kda cytochrome indicate multiple heme-heme in ... | 1997 | 9346284 |
| biochemical and spectroscopic characterization of two new cytochromes isolated from desulfuromonas acetoxidans. | the multimeric cytochromes described to date in sulfate- and sulfur-reducing bacteria are associated with diverse respiratory modes involving the use of elemental sulfur or oxidized sulfur compounds as terminal acceptors. they exhibit no structural similarity with the other cytochrome c classes and are characterized by a bis-histidinyl axial iron coordination and low redox potentials. we have purified two new cytochromes c with markedly different molecular masses (10 000 and 50 000) from the bac ... | 1997 | 9271490 |
| characterization of two tetrachloroethene-reducing, acetate-oxidizing anaerobic bacteria and their description as desulfuromonas michiganensis sp. nov. | two tetrachlorethene (pce)-dechlorinating populations, designated strains bb1 and brs1, were isolated from pristine river sediment and chloroethene-contaminated aquifer material, respectively. pce-to-cis-1,2-dichloroethene-dechlorinating activity could be transferred in defined basal salts medium with acetate as the electron donor and pce as the electron acceptor. taxonomic analysis based on 16s rrna gene sequencing placed both isolates within the desulfuromonas cluster in the delta subdivision ... | 2003 | 12732573 |
| desulfuromonas thiophila sp. nov., a new obligately sulfur-reducing bacterium from anoxic freshwater sediment. | a mesophilic, acetate-oxidizing, sulfur-reducing bacterium, strain nz27t, was isolated from anoxic mud from a freshwater sulfur spring. the cells were ovoid, motile, and gram negative. in addition to acetate, the strain oxidized pyruvate, succinate, and fumarate. sulfur flower could be replaced by polysulfide as an electron acceptor. ferric nitrilotriacetic acid was reduced in the presence of pyruvate; however, this reduction did not sustain growth. these phenotypic characteristics suggested tha ... | 1997 | 9226908 |
| assignment of the ligand geometry and redox potentials of the trihaem ferricytochrome c3 from desulfuromonas acetoxidans. | cytochrome c551.5 is a trihaem cytochrome of the cytochrome c3 family isolated from desulfuromonas acetoxidans. although several x-ray structures are available for tetrahaem cytochromes of this family, there is no x-ray structure for trihaem cytochromes. cytochrome c551.5 was studied in the oxidized form by means of two-dimensional nmr. the pattern of observed interhaem noesy connectivities is in agreement with the haem core structure previously determined by nmr for the reduced protein [coutinh ... | 1997 | 9030775 |
| nmr characterization and solution structure determination of the oxidized cytochrome c7 from desulfuromonas acetoxidans. | the solution structure of the three-heme electron transfer protein cytochrome c7 from desulfuromonas acetoxidans is reported. the determination of the structure is obtained through nmr spectroscopy on the fully oxidized, paramagnetic form. the richness of structural motifs and the presence of three prosthetic groups in a protein of 68 residues is discussed in comparison with the four-heme cytochromes c3 already characterized through x-ray crystallography. in particular, the orientation of the th ... | 1996 | 8962062 |
| phylogenetic analysis of dissimilatory fe(iii)-reducing bacteria. | evolutionary relationships among strictly anaerobic dissimilatory fe(iii)-reducing bacteria obtained from a diversity of sedimentary environments were examined by phylogenetic analysis of 16s rrna gene sequences. members of the genera geobacter, desulfuromonas, pelobacter, and desulfuromusa formed a monophyletic group within the delta subdivision of the class proteobacteria. on the basis of their common ancestry and the shared ability to reduce fe(iii) and/or s0, we propose that this group be co ... | 1996 | 8636045 |
| desulfuromonas palmitatis sp. nov., a marine dissimilatory fe(iii) reducer that can oxidize long-chain fatty acids. | studies on the microorganisms living in hydrocarbon-contaminated sediments in san diego bay, california led to the isolation of a novel fe(iii)-reducing microorganism. this organism, designated strain sdby1, was an obligately anaerobic, non-motile, non-flagellated, gram-negative rod. strain sdby1 conserves energy to support growth from the oxidation of acetate, lactate, succinate, fumarate, laurate, palmitate, or stearate. h2 was also oxidized with the reduction of fe(iii), but growth with h2 as ... | 1995 | 8588742 |
| fe(iii) and s0 reduction by pelobacter carbinolicus. | there is a close phylogenetic relationship between pelobacter species and members of the genera desulfuromonas and geobacter, and yet there has been a perplexing lack of physiological similarities. pelobacter species have been considered to have a fermentative metabolism. in contrast, desulfuromonas and geobacter species have a respiratory metabolism with fe(iii) serving as the common terminal electron acceptor in all species. however, the ability of pelobacter species to reduce fe(iii) had not ... | 1995 | 7793935 |
| sulfate-reducing bacteria in tubes constructed by the marine infaunal polychaete diopatra cuprea. | marine infaunal burrows and tubes greatly enhance solute transport between sediments and the overlying water column and are sites of elevated microbial activity. biotic and abiotic controls of the compositions and activities of burrow and tube microbial communities are poorly understood. the microbial communities in tubes of the marine infaunal polychaete diopatria cuprea collected from two different sediment habitats were examined. the bacterial communities in the tubes from a sandy sediment di ... | 2004 | 15574900 |
| chemolithoautotrophic metabolism of anaerobic extremely thermophilic archaebacteria. | several types of extremely thermophilic archaebacteria have recently been isolated from solfataric water holes, hot springs and hot sea floors. it has been shown that some of them can live using sulphur respiration of reduced carbon substrates as a source of energy, a type of metabolism previously described for the eubacterium desulfuromonas. we report here that several extremely thermophilic archaebacteria can live with carbon dioxide as their sole carbon source, obtaining energy from the oxida ... | 1983 | 6401847 |
| the bacteria of the sulphur cycle. | this paper concentrates on the bacteria involved in the reductions and oxidations of inorganic sulphur compounds under anaerobic conditions. the genera of the dissimilatory sulphate-reducing bacteria known today are discussed with respect to their different capacities to decompose and oxidize various products of fermentative degradations of organic matter. the utilization of molecular hydrogen and formate by sulphate reducers shifts fermentations towards the energetically more favourable formati ... | 1982 | 6127734 |
| nuclear-magnetic-resonance studies of desulfuromonas acetoxidans cytochrome c551.5 (c7). | 1h nuclear magnetic resonance (nmr) spectroscopy has been used to examine cytochrome c551.5 (c7) from the sulfur reducer, desulfuromonas acetoxidans. this protein contains three hemes. two stable oxidation states (the fully oxidized and the fully reduced) as well as intermediate oxidation states were studied. the axial ligands of the iron were found to be neutral histidines. the redox properties of cytochrome c7 were examined and good quantitative agreement found between the nmr results and prev ... | 1984 | 6092073 |
| low-spin sulfite reductases: a new homologous group of non-heme iron-siroheme proteins in anaerobic bacteria. | two new low molecular weight proteins with sulfite reductase activity, isolated from methanosarcina barkeri (dsm 800) and desulfuromonas acetoxidans (strain 5071), were studied by epr and optical spectroscopic techniques. both proteins have visible spectra similar to that of the low-spin sulfite reductase of desulfovibrio vulgaris strain hildenborough and no band at 715 nm, characteristic of high-spin fe3+ complexes in isobacteriochlorins is observed. epr shows that as isolated the siroheme is i ... | 1986 | 3028382 |
| phorphorylative electron transport chains lacking a cytochrome bc1 complex. | electron transport-coupled phosphorylation with fumarate as terminal acceptor in wolinella succinogenes yields less than 1 atp/2 electrons. the delta mu h generated by the electron transport is 0.18 v and the h+/electron ratio is 1. the electron transport chain is made up of two dehydrogenases (hydrogenase and formate dehydrogenase) that catalyze the reduction of menaquinone, and fumarate reductase which catalyzes the oxidation of menaquinol. c-type cytochromes are not involved. the phosphorylat ... | 1986 | 3015897 |
| fermentative degradation of dipicolinic acid (pyridine-2,6-dicarboxylic acid) by a defined coculture of strictly anaerobic bacteria. | degradation of dipicolinic acid (pyridine-2,6-dicarboxylic acid) under strictly anaerobic conditions was studied in enrichment cultures from marine and freshwater sediments. in all cases, dipicolinic acid was completely degraded. from an enrichment culture from a marine sediment, a defined coculture of two bacteria was isolated. the dipicolinic acid-fermenting bacterium was a gram-negative, non-sporeforming strictly anaerobic short rod which utilized dipicolinic acid as sole source of carbon, en ... | 1990 | 1368138 |
| c-type cytochromes in pelobacter carbinolicus. | previous studies failed to detect c-type cytochromes in pelobacter species despite the fact that other close relatives in the geobacteraceae, such as geobacter and desulfuromonas species, have abundant c-type cytochromes. analysis of the recently completed genome sequence of pelobacter carbinolicus revealed 14 open reading frames that could encode c-type cytochromes. transcripts for all but one of these open reading frames were detected in acetoin-fermenting and/or fe(iii)-reducing cells. three ... | 2006 | 16936056 |
| mercury methylation by dissimilatory iron-reducing bacteria. | the hg-methylating ability of dissimilatory iron-reducing bacteria in the genera geobacter, desulfuromonas, and shewanella was examined. all of the geobacter and desulfuromonas strains tested methylated mercury while reducing fe(iii), nitrate, or fumarate. in contrast, none of the shewanella strains produced methylmercury at higher levels than abiotic controls under similar culture conditions. geobacter and desulfuromonas are closely related to known hg-methylating sulfate-reducing bacteria with ... | 2006 | 17056699 |
| reduction of sulfur by spirillum 5175 and syntrophism with chlorobium. | a small spirillum, designated 5175, was isolated from an anaerobic enrichment culture for desulfuromonas in which the major medium constituents were acetate and elemental sulfur. the organisms grew only under anaerobic or microaerophilic conditions. elemental sulfur was formed anaerobically in a malate-sulfide medium, and cell densities of 10(8) cells/ml were obtained. hydrogen and formate were actively oxidized as substrates for growth under anaerobic conditions; s0, s032-, or s2o32-, but not s ... | 1977 | 848960 |
| isolation and characterization of a rubredoxin and an (8fe-8s) ferredoxin from desulfuromonas acetoxidans. | a two cluster (4fe-4s) ferredoxin and a rubredoxin have been isolated from the sulfur-reducing bacterium desulfuromonas acetoxidans. their amino acid compositions are reported and compared to those of other iron-sulfur proteins. the ferredoxin contains 8 cysteine residues, 8 atoms of iron and 8 atoms of labile sulfur per molecule; its minimum molecular weight is 6163. the protein exhibits an abosrbance ratio of a385/a283 = 0.74. storage results in a bleaching of the chromophore; the denatured fe ... | 1978 | 638141 |
| the redox properties and heme environment of cytochrome c-551.5 from desulfuromonas acetoxidans. | the environment of the three heme groups in cytochrome c-551.5 from desulfuromonas acetoxidans was investigated by the technique of solvent perturbation difference spectroscopy. the hemeoctapeptide from cytochrome c plus added imidazole was used as a model compound for the fully exposed chromophore. the average heme exposure in both the ferric and ferrous cytochromes c-551.5 was found to be considerably greater than that previously observed for the monoheme mitochondrial cytochrome c and prosthe ... | 1979 | 231458 |
| crystallization and preliminary crystallographic data for cytochrome c551.5 (c7) from desulfuromonas acetoxidans. | | 1979 | 224192 |
| the dehalococcoides population in sediment-free mixed cultures metabolically dechlorinates the commercial polychlorinated biphenyl mixture aroclor 1260. | microbial reductive dechlorination of commercial polychlorinated biphenyl (pcb) mixtures (e.g., aroclors) in aquatic sediments is crucial to achieve detoxification. despite extensive efforts over nearly two decades, the microorganisms responsible for aroclor dechlorination remained elusive. here we demonstrate that anaerobic bacteria of the dehalococcoides group derived from sediment of the housatonic river (lenox, ma) simultaneously dechlorinate 64 pcb congeners carrying four to nine chlorines ... | 2007 | 17308182 |
| isolation of desulfuromonas acetoxidans cytochrome c-551.5 from the mixed culture 'chloropseudomonas ethylica'. | the mixed culture 'chloropseudomonas ethylica' strain 2k has been grown on a medium which enhanced the yield of cytochrome c-551.5 from desulfuromonas acetoxidans. the cytochrome was purified to homogeneity and an isoelectric point of 8.40 was determined. a determination of the amide content indicated that the cytochrome contains two more amides than previously reported. | 1979 | 218626 |
| cytochrome c-551.5 (c7) from desulfuromonas acetoxidans. | cytochrome c-551.5 of the anaerobic sulfur-reducing bacterium desulfuromonas acetoxidans has been purified to homogeneity and characterized. it elicits absorption bands at 551.5, 522.5 and 418 nm in the reduced form; the absorptivity ratio aalpha(red)/a280nm(ox) equals 3.8 for the pure preparation. the molecular weight was estimated to be 9800 by gel filtration. determination of the amion acid composition and analysis of the n-terminal amino acid sequence showed the cytochrome to be identical wi ... | 1977 | 192288 |
| removal of heavy metals and arsenic from contaminated soils using bioremediation and chelant extraction techniques. | a combined chemical and biological treatment scheme was evaluated in this study aiming at obtaining the simultaneous removal of metalloid arsenic and cationic heavy metals from contaminated soils. the treatment involved the use of the iron reducing microorganism desulfuromonas palmitatis, whose activity was combined with the chelating strength of edta. taking into consideration that soil iron oxides are the main scavengers of as, treatment with iron reducing microorganisms aimed at inducing the ... | 2008 | 18037468 |
| structure of cytochrome c7 from desulfuromonas acetoxidans at 1.9 a resolution. | multihaem cytochromes play a key role in electron-transport reactions in the periplasm of sulfate- and sulfur-reducing bacteria. the redox proteins grouped in the c3 superfamily also display metal-reducing activities, which make them interesting biotechnological tools. the crystal structure of the fully oxidized cytochrome c7 from desulfuromonas acetoxidans has been solved by combined molecular-replacement and mad methods. the structure has been refined at 1.9 a resolution to an r value of 19.1% ... | 2001 | 11320307 |
| a quick solution structure determination of the fully oxidized double mutant k9-10a cytochrome c7 from desulfuromonas acetoxidans and mechanistic implications. | lysines 9 and 10 in desulfuromonas acetoxidans cytochrome c7, which could be involved in the interaction mechanism with the redox partners, have been replaced by alanine residues using site-directed mutagenesis. the solution structure of the fully oxidized form of k9-10a cytochrome c7, which is paramagnetic with three paramagnetic centers, has been determined via 1h nmr. the assignment of the spectra has been performed through an automatic program whose algorithm and strategy are here described. ... | 2002 | 11883773 |
| enrichment of members of the family geobacteraceae associated with stimulation of dissimilatory metal reduction in uranium-contaminated aquifer sediments. | stimulating microbial reduction of soluble u(vi) to insoluble u(iv) shows promise as a strategy for immobilizing uranium in uranium-contaminated subsurface environments. in order to learn more about which microorganisms might be involved in u(vi) reduction in situ, the changes in the microbial community when u(vi) reduction was stimulated with the addition of acetate were monitored in sediments from three different uranium-contaminated sites in the floodplain of the san juan river in shiprock, n ... | 2002 | 11976101 |
| competitive oxidation of volatile fatty acids by sulfate- and nitrate-reducing bacteria from an oil field in argentina. | acetate, propionate, and butyrate, collectively referred to as volatile fatty acids (vfa), are considered among the most important electron donors for sulfate-reducing bacteria (srb) and heterotrophic nitrate-reducing bacteria (hnrb) in oil fields. samples obtained from a field in the neuquén basin, western argentina, had significant activity of mesophilic srb, hnrb, and nitrate-reducing, sulfide-oxidizing bacteria (nr-sob). in microcosms, containing vfa (3 mm each) and excess sulfate, srb first ... | 2008 | 18502934 |
| the metal reductase activity of some multiheme cytochromes c: nmr structural characterization of the reduction of chromium(vi) to chromium(iii) by cytochrome c(7). | the redox reaction between cro(4)(2-) and the fully reduced three-heme cytochrome c(7) from desulfuromonas acetoxidans to give chromium(iii) and the fully oxidized protein has been followed by nmr spectroscopy. the hyperfine coupling between the oxidized protein protons and chromium(iii), which remains bound to the protein, gives rise to line-broadening effects on the nmr resonances that can be transformed into proton-metal distance restraints. structure calculations based on these unconventiona ... | 2002 | 12119407 |
| diversity of beta-propeller phytase genes in the intestinal contents of grass carp provides insight into the release of major phosphorus from phytate in nature. | phytate is the most abundant organic phosphorus compound in nature, and microbial mineralization of phytate by phytase is a key process for phosphorus recycling in the biosphere. in the present study, beta-propeller phytase (bpp) gene fragments were readily amplified from the intestinal contents of grass carp (ctenopharyngodon idellus) directly or from phytate-degrading isolates from the same source, confirming the widespread occurrence of bpp in aquatic communities. the amounts of sequences col ... | 2009 | 19151187 |
| biochemical and genetic characterization of ppca, a periplasmic c-type cytochrome in geobacter sulfurreducens. | a 9.6 kda periplasmic c -type cytochrome, designated ppca, was purified from the fe(iii)-reducing bacterium geobacter sulfurreducens and characterized. the purified protein is basic (pi 9.5), contains three haems and has an n-terminal amino acid sequence closely related to those of the previously described trihaem c (7) cytochromes of geobacter metallireducens and desulfuromonas acetoxidans. the gene encoding ppca was identified from the g. sulfurreducens genome using the n-terminal sequence, an ... | 2003 | 12356333 |
| evolution from a respiratory ancestor to fill syntrophic and fermentative niches: comparative fenomics of six geobacteraceae species. | the anaerobic degradation of organic matter in natural environments, and the biotechnical use of anaerobes in energy production and remediation of subsurface environments, both require the cooperative activity of a diversity of microorganisms in different metabolic niches. the geobacteraceae family contains members with three important anaerobic metabolisms: fermentation, syntrophic degradation of fermentation intermediates, and anaerobic respiration. | 2009 | 19284579 |
| thermodynamic and kinetic characterization of trihaem cytochrome c3 from desulfuromonas acetoxidans. | trihaem cytochrome c3 (also known as cytochrome c551.5 and cytochrome c7) is isolated from the periplasmic space of desulfuromonas acetoxidans, a sulfur-reducing bacterium. thermodynamic and kinetic data for the trihaem cytochrome c3 are presented and discussed in the context of the possible physiological implications of its functional properties with respect to the natural habitat of d. acetoxidans, namely as a symbiont with green sulfur bacteria working as a mini-sulfuretum. the thermodynamic ... | 2002 | 12423372 |
| analysis of the sulfate-reducing bacterial and methanogenic archaeal populations in contrasting antarctic sediments. | the distribution and activity of communities of sulfate-reducing bacteria (srb) and methanogenic archaea in two contrasting antarctic sediments were investigated. methanogenesis dominated in freshwater lake heywood, while sulfate reduction dominated in marine shallow bay. slurry experiments indicated that 90% of the methanogenesis in lake heywood was acetoclastic. this finding was supported by the limited diversity of clones detected in a lake heywood archaeal clone library, in which most clones ... | 2003 | 12788715 |
| family of cytochrome c7-type proteins from geobacter sulfurreducens: structure of one cytochrome c7 at 1.45 a resolution. | the structure of a cytochrome c(7) (ppca) from geobacter sulfurreducens was determined by x-ray diffraction at 1.45 a resolution; the r factor is 18.2%. the protein contains a three-heme core that is surrounded by 71 amino acid residues. an unusual feature of this cytochrome is that it has 17 lysine residues, but only nine hydrophobic residues that are larger than alanine. the details of the structure are described and compared with those of cytochrome c(7) from desulfuromonas acetoxidans and wi ... | 2004 | 14744127 |
| degradation of 1,1,2,2-tetrachloroethane and accumulation of vinyl chloride in wetland sediment microcosms and in situ porewater: biogeochemical controls and associations with microbial communities. | the biodegradation pathways of 1,1,2,2-tetrachloroethane (teca) and 1,1,2-trichloroethane (112tca) and the associated microbial communities in anaerobic wetland sediments were evaluated using concurrent geochemical and genetic analyses over time in laboratory microcosm experiments. experimental results were compared to in situ porewater data in the wetland to better understand the factors controlling daughter product distributions in a chlorinated solvent plume discharging to a freshwater tidal ... | 2004 | 15068871 |
| structure of a novel c7-type three-heme cytochrome domain from a multidomain cytochrome c polymer. | the structure of a novel c(7)-type cytochrome domain that has two bishistidine coordinated hemes and one heme with histidine, methionine coordination (where the sixth ligand is a methionine residue) was determined at 1.7 a resolution. this domain is a representative of domains that form three polymers encoded by the geobacter sulfurreducens genome. two of these polymers consist of four and one protein of nine c(7)-type domains with a total of 12 and 27 hemes, respectively. four individual domain ... | 2004 | 15133162 |
| redox characterization of geobacter sulfurreducens cytochrome c7: physiological relevance of the conserved residue f15 probed by site-specific mutagenesis. | the complete genome sequence of the delta-proteobacterium geobacter sulfurreducens reveals a large abundance of multiheme cytochromes. cytochrome c(7), isolated from this metal ion-reducing bacterium, is a triheme periplasmic electron-transfer protein with m(r) 9.6 kda. this protein is involved in metal ion-reducing pathways and shares 56% sequence identity with a triheme cytochrome isolated from the closely related delta-proteobacterium desulfuromonas acetoxidans (dac(7)). in this work, two-dim ... | 2004 | 15274645 |
| spatial heterogeneity of dechlorinating bacteria and limiting factors for in situ trichloroethene dechlorination revealed by analyses of sediment cores from a polluted field site. | microbiological analyses of sediment samples were conducted to explore potentials and limitations for bioremediation of field sites polluted with chlorinated ethenes. intact sediment cores, collected by direct push probing from a 35-ha contaminated area, were analyzed in horizontal layers. cultivation-independent pcr revealed dehalococcoides to be the most abundant 16s rrna gene phylotype with a suspected potential for reductive dechlorination of the major contaminant trichloroethene (tce). in d ... | 2010 | 20041951 |
| comparison of 16s rrna, nifd, reca, gyrb, rpob and fusa genes within the family geobacteraceae fam. nov. | the sequences of five conserved genes, in addition to the 16s rrna gene, were investigated in 30 members of the geobacteraceae fam. nov. all members of the geobacteraceae examined contained nifd, suggesting that they are capable of nitrogen fixation, which may explain their ability to compete effectively in nitrogen-poor subsurface environments undergoing remediation for petroleum or metal contamination. the phylogenies predicted from rpob, gyrb, fusa, reca and nifd were generally in agreement w ... | 2004 | 15388715 |
| characterization of microbial community structure and population dynamics of tetrachloroethene-dechlorinating tidal mudflat communities. | tetrachloroethene (pce) and trichloroethene (tce) are common groundwater contaminants that also impact tidal flats, especially near urban and industrial areas. however, very little is known about dechlorinating microbial communities in tidal flats. titanium pyrosequencing, 16s rrna gene clone libraries, and dechlorinator-targeted quantitative real-time pcr (qpcr) characterized reductive dechlorinating activities and populations in tidal flat sediments collected from south korea's central west co ... | 2010 | 21053056 |
| analysis of trace hydrogen metabolism. | h2 maintains an important role in bacterial metabolism in anaerobic environments. the ability to measure and analyze h2 concentrations in biological systems is often useful for determining the physiological state of the microbiota. methods for precisely analyzing h2 in bacterial cultures and environmental samples are now available. this chapter discusses h2 measurements from both the theoretical and practical methodology perspective of the analysis and the interpretation of data. | 2005 | 16260294 |
| changes in bacterial community structure correlate with initial operating conditions of a field-scale denitrifying fluidized bed reactor. | high levels of nitrate are present in groundwater migrating from the former waste disposal ponds at the y-12 national security complex in oak ridge, tn. a field-scale denitrifying fluidized bed reactor (fbr) was designed, constructed, and operated with ethanol as an electron donor for the removal of nitrate. after inoculation, biofilms developed on the granular activated carbon particles. changes in the bacterial community of the fbr were evaluated with clone libraries (n = 500 partial sequences ... | 2006 | 16292532 |
| betaine fermentation and oxidation by marine desulfuromonas strains. | two bacterial strains were dominant in anaerobic enrichment cultures with betaine (n,n,n-trimethylglycine) as a substrate and intertidal mud as an inoculum. one was a coccoid bacterium which was a trimethylamine (tma)-fermenting methanogen similar to methanococcoides methylutens. the other strain, a rod-shaped, gram-negative, motile bacterium, fermented betaine. on the basis of its ability to oxidize acetate and ethanol to co(2) with sulfur as an electron acceptor, its inability to reduce sulfat ... | 1989 | 16347897 |
| dissimilatory fe(iii) reduction by the marine microorganism desulfuromonas acetoxidans. | the ability of the marine microorganism desulfuromonas acetoxidans to reduce fe(iii) was investigated because of its close phylogenetic relationship with the freshwater dissimilatory fe(iii) reducer geobacter metallireducens. washed cell suspensions of the type strain of d. acetoxidans reduced soluble fe(iii)-citrate and fe(iii) complexed with nitriloacetic acid. the c-type cytochrome(s) of d. acetoxidans was oxidized by fe(iii)-citrate and mn(iv)-oxalate, as well as by two electron acceptors kn ... | 1993 | 16348888 |
| novel processes for anaerobic sulfate production from elemental sulfur by sulfate-reducing bacteria. | sulfate reducers and related organisms which had previously been found to reduce fe(iii) with h(2) or organic electron donors oxidized s to sulfate when mn(iv) was provided as an electron acceptor. organisms catalyzing this reaction in washed cell suspensions included desulfovibrio desulfuricans, desulfomicrobium baculatum, desulfobacterium autotrophicum, desulfuromonas acetoxidans, and geobacter metallireducens. these organisms produced little or no sulfate from s with fe(iii) as a potential el ... | 1994 | 16349323 |
| desulfuromonas svalbardensis sp. nov. and desulfuromusa ferrireducens sp. nov., psychrophilic, fe(iii)-reducing bacteria isolated from arctic sediments, svalbard. | two psychrophilic, gram-negative, rod-shaped, motile bacteria (strains 112t and 102t) that conserved energy from dissimilatory fe(iii) reduction concomitant with acetate oxidation were isolated from permanently cold arctic marine sediments. both strains grew at temperatures down to -2 degrees c, with respective temperature optima of 14 degrees c and 14-17 degrees c for strains 112t and 102t. the isolated strains reduced fe(iii) using common fermentation products such as acetate, lactate, propion ... | 2006 | 16627667 |
| electricity generation and microbial community analysis of alcohol powered microbial fuel cells. | two different microbial fuel cell (mfc) configurations were investigated for electricity production from ethanol and methanol: a two-chambered, aqueous-cathode mfc; and a single-chamber direct-air cathode mfc. electricity was generated in the two-chamber system at a maximum power density typical of this system (40+/-2 mw/m2) and a coulombic efficiency (ce) ranging from 42% to 61% using ethanol. when bacteria were transferred into a single-chamber mfc known to produce higher power densities with ... | 2007 | 17097875 |
| thermodynamic characterization of triheme cytochrome ppca from geobacter sulfurreducens: evidence for a role played in e-/h+ energy transduction. | the facultative aerobic bacterium geobacter sulfurreducens produces a small periplasmic c-type triheme cytochrome with 71 residues (ppca) under anaerobic growth conditions, which is involved in the iron respiration. the thermodynamic properties of the ppca redox centers and of a protonatable center were determined using nmr and visible spectroscopy techniques. the redox centers have negative and different reduction potentials (-162, -143, and -133 mv for heme i, iii, and iv, respectively, for th ... | 2006 | 17105209 |
| assessment of the natural attenuation of chlorinated ethenes in an anaerobic contaminated aquifer in the bitterfeld/wolfen area using stable isotope techniques, microcosm studies and molecular biomarkers. | the in situ degradation of chlorinated ethenes was assessed in an anaerobic aquifer using stable isotope fractionation approaches, microcosm studies and taxon specific detection of specific dehalogenating groups of bacteria. the aquifer in the bitterfeld/wolfen region in germany contained all chlorinated ethenes, benzene and toluene as contaminants. the concentrations and isotope composition of the chlorinated ethenes indicated biodegradation of the contaminants. microcosm studies confirmed the ... | 2007 | 17123579 |
| [geoalkalibacter ferrihydriticus gen. nov., sp. nov., the first alkaliphilic representative of the family geobacteraceae, isolated from a soda lake]. | investigation of iron reduction in bottom sediments of alkaline soda lakes resulted in the isolation of a new obligately anaerobic iron-reducing bacterium, strain z-0531, from lake khadyn (tuva republic, russia) sediment samples. the cells of strain z-0531 are short (1.0-1.5 by 0.3-0.5 microm), motile, non-spore-forming, gram-negative rods. the isolate is an obligate alkaliphile, developing in the ph range of 7.8-10.0, with an optimum at ph 8.6. it does not require nacl but grows at nacl concent ... | 2006 | 17205802 |
| experimental evaluation and mathematical modeling of microbially enhanced tetrachloroethene (pce) dissolution. | experiments to assess metabolic reductive dechlorination (chlororespiration) at high concentration levels consistent with the presence of free-phase tetrachloroethene (pce) were performed using three pce-to-cis-1,2-dichloroethene (cis-dce) dechlorinating pure cultures (sulfurospirillum multivorans, desulfuromonas michiganensis strain bb1, and geobacter lovleyi strain sz) and desulfitobacterium sp. strain viet1, a pce-to-trichloroethene (tce) dechlorinating isolate. despite recent evidence sugges ... | 2007 | 17328210 |
| distinguishing abiotic and biotic transformation of tetrachloroethylene and trichloroethylene by stable carbon isotope fractionation. | significant carbon isotope fractionation was observed during fes-mediated reductive dechlorination of tetrachloroethylene (pce) and trichloroethylene (tce). bulk enrichment factors (e(bulk)) for pce were -30.2 +/- 4.3 per thousand (ph 7), -29.54 +/- 0.83 per thousand (ph 8), and -24.6 +/- 1.1 per thousand (ph 9). for tce, e(bulk) values were -33.4 +/- 1.5 per thousand (ph 8) and -27.9 +/- 1.3 per thousand (ph 9). a smaller magnitude of carbon isotope fractionation resulted from microbial reducti ... | 2007 | 17993153 |
| phylogenetic diversity of nitrogen-fixing bacteria in mangrove sediments assessed by pcr-denaturing gradient gel electrophoresis. | culture-independent pcr-denaturing gradient gel electrophoresis (dgge) was employed to assess the composition of diazotroph species from the sediments of three mangrove ecosystem sites in sanya, hainan island, china. a strategy of removing humic acids prior to dna extraction was conducted, then total community dna was extracted using the soil dna kit successfully for nifh pcr amplification, which simplified the current procedure and resulted in good dgge profiles. the results revealed a novel ni ... | 2008 | 18347779 |
| catalytic cycles for the reduction of [uo2]2+ by cytochrome c7 proteins proposed from dft calculations. | the mechanism of the reduction of the hydrated uranyl cation, [uo2](2+), by the cytochromes g. sulfurreducens and d. acetoxidans has been studied using density functional theory calculations. we propose that the initial electron transfer step from the heme is to a cation-cation complex in the case of d. acetoxidans, but for g. sulfurreducens, it is to a single uranyl cation, which then forms a u(v)-u(vi) complex with a second uranyl cation. for both enzymes, the subsequent catalytic pathways are ... | 2008 | 18386882 |
| assessment of chromium biostabilization in contaminated soils using standard leaching and sequential extraction techniques. | the iron reducing microorganism desulfuromonas palmitatis was evaluated as potential biostabilization agent for the remediation of chromate contaminated soils. d. palmitatis were used for the treatment of soil samples artificially contaminated with cr(vi) at two levels, i.e. 200 and 500 mg kg(-1). the efficiency of the treatment was evaluated by applying several standard extraction techniques on the soil samples before and after treatment, such as the en12457 standard leaching test, the us epa 3 ... | 2009 | 18945478 |
| modeling the effects of microbial competition and hydrodynamics on the dissolution and detoxification of dense nonaqueous phase liquid contaminants. | the real significance and engineering potential for bioenhanced dissolution of chlorinated ethene dense nonaqueous phase liquid (dnapl) contaminants are currently not well understood, in part because they can be influenced by a complex set of factors, including microbial competition for growth substrates. mathematical simulations were performed to evaluate the effects of competition between dehalococcoides ethenogenes and desulfuromonas michiganensis for the electron acceptor tetrachloroethene ( ... | 2009 | 19245029 |
| geoalkalibacter subterraneus sp. nov., an anaerobic fe(iii)- and mn(iv)-reducing bacterium from a petroleum reservoir, and emended descriptions of the family desulfuromonadaceae and the genus geoalkalibacter. | a strictly anaerobic fe(iii)-reducing bacterium, designated strain red1(t), was isolated from the production water of the redwash oilfield, usa. the cells were motile rods (1-5x0.5-0.6 microm) that stained gram-negative and possessed polar flagella. strain red1(t) obtained energy from the reduction of fe(iii), mn(iv), nitrate, elemental sulfur and trimethylamine n-oxide in the presence of a wide range of electron donors, including a variety of organic acids, alcohols, biological extracts and hyd ... | 2009 | 19329606 |
| determination of intrinsic monod kinetic parameters for two heterotrophic tetrachloroethene (pce)-respiring strains and insight into their application. | a complete set of mathematically identifiable and meaningful kinetic parameters estimates is needed to accurately describe the activity of individual populations that dehalorespire tetrachloroethene (pce) and other chlorinated ethenes. these data may be difficult to extract from the literature because kinetic parameter estimates obtained using mixed cultures may reflect the activity of multiple dehalorespiring populations, while those obtained at low initial substrate-to-biomass ratios (s(0)/x(0 ... | 2009 | 19593756 |
| assessment of in situ reductive dechlorination using compound-specific stable isotopes, functional gene pcr, and geochemical data. | isotopic analysis and molecular-based bioassay methods were used in conjunction with geochemical data to assess intrinsic reductive dechlorination processes for a chlorinated solvent-contaminated site in tucson, arizona. groundwater samples were obtained from monitoring wells within a contaminant plume comprising tetrachloroethene and its metabolites, trichloroethene, cis-1,2-dichloroethene, vinyl chloride, and ethene, as well as compounds associated with free phase diesel present at the site. c ... | 2009 | 19603638 |
| a dehalococcoides-containing co-culture that dechlorinates tetrachloroethene to trans-1,2-dichloroethene. | in the microbial reductive dechlorination of tetrachloroethene (pce) and trichloroethene (tce), dechlorinators usually produce cis-1,2-dichloroethene (cis-dce) as the predominant product or an intermediate. this study shows that dechlorination of pce and tce can also lead to the generation of trans-1,2-dichloroethene (trans-dce) by a co-culture mb. during its enrichment process, the ratio of trans- to cis-dce increased from 1.4 (+/-0.1):1-3.7 (+/-0.4):1, whereas the tce reductive dechlorination ... | 2010 | 19657371 |
| properties of a trichlorodibenzo-p-dioxin-dechlorinating mixed culture with a dehalococcoides as putative dechlorinating species. | an anaerobic mixed culture enriched over 16 transfers (1/10) from saale river sediment reductively dehalogenated 1,2,4- and 1,2,3-trichlorodibenzo-p-dioxin (trcdd) to di- and monochlorinated congeners in the presence of pyruvate (or lactate) and fumarate as cosubstrates. besides trcdd, tetrachloroethene and 1,2,3-trichlorobenzene were dechlorinated. dioxin dehalogenation was sensitive to pasteurization, but was not remarkably influenced by inhibitors of methanogens, sulfate-reducing bacteria or ... | 2004 | 19712337 |
| stable carbon isotope fractionation by acetotrophic sulfur-reducing bacteria. | acetate is the most important intermediate in anaerobic degradation of organic matter. the carbon isotope effects associated with the oxidation of acetate (epsilon(ac)) were examined for four acetotrophic sulfur reducers, desulfuromonas acetoxidans, desulfuromonas thiophila, desulfurella acetivorans, and hippea maritima. during the consumption of acetate and sulfur, acetate was enriched in (13)c by 11.5 and 11.2 per thousand in desulfuromonas acetoxidans and desulfuromonas thiophila, respectivel ... | 2010 | 20002180 |
| thermodynamic characterization of a triheme cytochrome family from geobacter sulfurreducens reveals mechanistic and functional diversity. | a family of five periplasmic triheme cytochromes (ppca-e) was identified in geobacter sulfurreducens, where they play a crucial role by driving electron transfer from the cytoplasm to the cell exterior and assisting the reduction of extracellular acceptors. the thermodynamic characterization of ppca using nmr and visible spectroscopies was previously achieved under experimental conditions identical to those used for the triheme cytochrome c(7) from desulfuromonas acetoxidans. under such conditio ... | 2010 | 20655858 |
| dehalorespiration model that incorporates the self-inhibition and biomass inactivation effects of high tetrachloroethene concentrations. | in the vicinity of dense nonaqueous phase liquid (dnapl) contaminant source zones, aqueous concentrations of tetrachloroethene (pce) in groundwater may approach saturation levels. in this study, the ability of two pce-respiring strains (desulfuromonas michiganensis and desulfitobacterium strain pce1) to dechlorinate high concentrations of pce was experimentally evaluated and depended on the initial biomass concentration. this suggests high pce concentrations permanently inactivated a fraction of ... | 2010 | 21182287 |
| constraint-based modeling analysis of the metabolism of two pelobacter species. | pelobacter species are commonly found in a number of subsurface environments, and are unique members of the geobacteraceae family. they are phylogenetically intertwined with both geobacter and desulfuromonas species. pelobacter species likely play important roles in the fermentative degradation of unusual organic matters and syntrophic metabolism in the natural environments, and are of interest for applications in bioremediation and microbial fuel cells. | 2010 | 21182788 |
| exploration of the 'cytochromome' of desulfuromonas acetoxidans, a marine bacterium capable of powering microbial fuel cells. | recent progress in bacterial genomic analysis has revealed a vast number of genes that encode c-type cytochromes that contain multiple heme cofactors. this high number of multiheme cytochromes in several bacteria has been correlated with their great respiratory flexibility, and in what concerns biotechnological applications, has been correlated with electricity production in microbial fuel cells. desulfuromonas acetoxidans, a member of the geobactereaceae family, is one of these organisms for wh ... | 2011 | 21298162 |
| how do enzymes reduce metals? the mechanism of the reduction of cr(vi) in chromate by cytochrome c7 proteins proposed from dft calculations. | various bacteria are effective in metal reduction, and there is an increasing use of such micro-organisms for decontaminating polluted environments. iron-containing electron transfer proteins, particularly those of the cytochrome c7 family, can bind a number of toxic metals in their high oxidation states, and can reduce them via electron transfer mechanisms. we report a computational investigation of the binding of cro4(2-) to the cytochrome c7 of desulfuromonas acetoxidans and explore possible ... | 2011 | 21322485 |
| na(+)-translocating membrane pyrophosphatases are widespread in the microbial world and evolutionarily precede h(+)-translocating pyrophosphatases. | membrane pyrophosphatases (ppases), divided into k(+)-dependent and k(+)-independent subfamilies, were believed to pump h(+) across cell membranes until a recent demonstration that some k(+)-dependent ppases function as na(+) pumps. here, we have expressed seven evolutionarily important putative ppases in escherichia coli and estimated their hydrolytic, na(+) transport and h(+) transport activities as well as their k(+) and na(+) requirements in inner membrane vesicles. four of these enzymes (fr ... | 2011 | 21527638 |
| pivotal role of the strictly conserved aromatic residue f15 in the cytochrome c (7) family. | cytochromes c (7) are periplasmic triheme proteins that have been reported exclusively in d-proteobacteria. the structures of five triheme cytochromes identified in geobacter sulfurreducens and one in desulfuromonas acetoxidans have been determined. in addition to the hemes and axial histidines, a single aromatic residue is conserved in all these proteins-phenylalanine 15 (f15). ppca is a member of the g. sulfurreducens cytochrome c (7) family that performs electron/proton energy transduction in ... | 2011 | 21805398 |
| Integrated evaluation of the performance of a more than seven year old permeable reactive barrier at a site contaminated with chlorinated aliphatic hydrocarbons (CAHs). | An important issue of concern for permeable reactive iron barriers is the long-term efficiency of the barriers due to the long operational periods required. Mineral precipitation resulting from the anaerobic corrosion of the iron filings and bacteria present in the barrier may play an important role in the long-term performance. An integrated study was performed on the Vapokon permeable reactive barrier (PRB) in Denmark by groundwater and iron core sample characterization. The detailed field gro ... | 2011 | 22115091 |
| Microbial methane cycling in a terrestrial mud volcano in eastern Taiwan. | Microbial communities responsible for methane cycling in mud volcanoes onshore are poorly characterized. This study analysed bubbling fluids and cored sediments retrieved from a mud volcano in eastern Taiwan. The pore water profiles revealed that methane concentrations generally increased with depth and changed dramatically at different depth intervals at different sites. The methane concentrations were inversely correlated with Fe(2+) /Mn(2+) concentrations and d(13) C values of methane, marki ... | 2011 | 22141749 |
| Culture-independent analysis of the soil bacterial assemblage at the Great Salt Plains of Oklahoma. | The Great Salt Plains (GSP) of Oklahoma is a natural inland terrestrial hypersaline environment that forms evaporite crusts of mainly NaCl. Previous work described GSP bacterial assemblages through the phylogenetic and phenetic characterization of 105 isolates from 46 phylotypes. The current report describes the same bacterial assemblages through culture-independent 16S rRNA gene clone libraries. Although from similar hypersaline mud flats, the bacterial libraries from two sites, WP3 and WP6, we ... | 2011 | 21953014 |
| variability in microbial carbon isotope fractionation of tetra- and trichloroethene upon reductive dechlorination. | the variability of stable carbon isotope fractionation upon reductive dechlorination of tetra- and trichloroethene by several microbial strains was investigated to examine the uncertainties related to the in situ application of compound specific isotope analysis (csia) of chlorinated ethenes. carbon isotope fractionation was investigated with a set of microorganisms representative for the currently known diversity of dehalorespirers: dehalococcoides ethenogenes strain 195, desulfitobacterium sp. ... | 2008 | 18155126 |