<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lovley, D R</style></author><author><style face="normal" font="default" size="100%">Fraga, J L</style></author><author><style face="normal" font="default" size="100%">Coates, J D</style></author><author><style face="normal" font="default" size="100%">Blunt-Harris, E L</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Humics as an electron donor for anaerobic respiration.</style></title><secondary-title><style face="normal" font="default" size="100%">Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aerobiosis</style></keyword><keyword><style  face="normal" font="default" size="100%">Anaerobiosis</style></keyword><keyword><style  face="normal" font="default" size="100%">Anthraquinones</style></keyword><keyword><style  face="normal" font="default" size="100%">Arsenates</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Fumarates</style></keyword><keyword><style  face="normal" font="default" size="100%">Humic Substances</style></keyword><keyword><style  face="normal" font="default" size="100%">Selenium Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Tumor Cells, Cultured</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1999 Feb</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">1</style></volume><pages><style face="normal" font="default" size="100%">89-98</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The possibility that microorganisms might use reduced humic substances (humics) as an electron donor for the reduction of electron acceptors with a more positive redox potential was investigated. All of the Fe(III)- and humics-reducing microorganisms evaluated were capable of oxidizing reduced humics and/or the reduced humics analogue anthrahydroquinone-2,6,-disulphonate (AHODS), with nitrate and/or fumarate as the electron acceptor. These included Geobacter metallireducens, Geobacter sulphurreducens, Geothrix fermentans, Shewanella alga, Wolinella succinogenes and 'S. barnesii'. Several of the humics-oxidizing microorganisms grew in medium with AHQDS as the sole electron donor and fumarate as the electron acceptor. Even though it does not reduce Fe(III) or humics, Paracoccus denitrificans could use AHQDS and reduced humics as electron donors for denitrification. However, another denitrifier, Pseudomonas denitrificans, could not. AHODS could also serve as an electron donor for selenate and arsenate reduction by W. succinogenes. Electron spin resonance studies demonstrated that humics oxidation was associated with the oxidation of hydroquinone moieties in the humics. Studies with G. metallireducens and W. succinogenes demonstrated that the anthraquinone-2,6-disulphonate (AQDS)/AHQDS redox couple mediated an interspecies electron transfer between the two organisms. These results suggest that, as microbially reduced humics enter less reduced zones of soils and sediments, the reduced humics may serve as electron donors for microbial reduction of several environmentally significant electron acceptors.</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11207721?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Stolz, J F</style></author><author><style face="normal" font="default" size="100%">Ellis, D J</style></author><author><style face="normal" font="default" size="100%">Blum, J S</style></author><author><style face="normal" font="default" size="100%">Ahmann, D</style></author><author><style face="normal" font="default" size="100%">Lovley, D R</style></author><author><style face="normal" font="default" size="100%">Oremland, R S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Sulfurospirillum barnesii sp. nov. and Sulfurospirillum arsenophilum sp. nov., new members of the Sulfurospirillum clade of the epsilon Proteobacteria.</style></title><secondary-title><style face="normal" font="default" size="100%">Int J Syst Bacteriol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Int. J. Syst. Bacteriol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Arsenates</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacterial Typing Techniques</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Ribosomal</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, rRNA</style></keyword><keyword><style  face="normal" font="default" size="100%">Gram-Negative Bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Ribosomal, 16S</style></keyword><keyword><style  face="normal" font="default" size="100%">Selenium Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Analysis, DNA</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1999 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">49 Pt 3</style></volume><pages><style face="normal" font="default" size="100%">1177-80</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Two strains of dissimilatory arsenate-reducing vibrio-shaped bacteria are assigned to the genus Sulfurospirillum. These two new species, Sulfurospirillum barnesii strain SES-3T and Sulfurospirillum arsenophilum strain MIT-13T, in addition to Sulfurospirillum sp. SM-5, two strains of Sulfurospirillum deleyianum, and Sulfurospirillum arcachonense, form a distinct clade within the epsilon subclass of the Proteobacteria based on 16S rRNA analysis.</style></abstract><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10425777?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Newman, D K</style></author><author><style face="normal" font="default" size="100%">Kennedy, E K</style></author><author><style face="normal" font="default" size="100%">Coates, J D</style></author><author><style face="normal" font="default" size="100%">Ahmann, D</style></author><author><style face="normal" font="default" size="100%">Ellis, D J</style></author><author><style face="normal" font="default" size="100%">Lovley, D R</style></author><author><style face="normal" font="default" size="100%">Morel, F M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Dissimilatory arsenate and sulfate reduction in Desulfotomaculum auripigmentum sp. nov.</style></title><secondary-title><style face="normal" font="default" size="100%">Arch Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Arch. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Arsenates</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacteria, Anaerobic</style></keyword><keyword><style  face="normal" font="default" size="100%">Biotransformation</style></keyword><keyword><style  face="normal" font="default" size="100%">Geologic Sediments</style></keyword><keyword><style  face="normal" font="default" size="100%">Gram-Positive Endospore-Forming Rods</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Ribosomal, 16S</style></keyword><keyword><style  face="normal" font="default" size="100%">Substrate Specificity</style></keyword><keyword><style  face="normal" font="default" size="100%">Sulfates</style></keyword><keyword><style  face="normal" font="default" size="100%">Sulfides</style></keyword><keyword><style  face="normal" font="default" size="100%">Sulfur-Reducing Bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Water Microbiology</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1997</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1997 Nov</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">168</style></volume><pages><style face="normal" font="default" size="100%">380-8</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A newly discovered arsenate-reducing bacterium, strain OREX-4, differed significantly from strains MIT-13 and SES-3, the previously described arsenate-reducing isolates, which grew on nitrate but not on sulfate. In contrast, strain OREX-4 did not respire nitrate but grew on lactate, with either arsenate or sulfate serving as the electron acceptor, and even preferred arsenate. Both arsenate and sulfate reduction were inhibited by molybdate. Strain OREX-4, a gram-positive bacterium with a hexagonal S-layer on its cell wall, metabolized compounds commonly used by sulfate reducers. Scorodite (FeAsO42. H2O) an arsenate-containing mineral, provided micromolar concentrations of arsenate that supported cell growth. Physiologically and phylogenetically, strain OREX-4 was far-removed from strains MIT-13 and SES-3: strain OREX-4 grew on different electron donors and electron acceptors, and fell within the gram-positive group of the Bacteria, whereas MIT-13 and SES-3 fell together in the epsilon-subdivision of the Proteobacteria. Together, these results suggest that organisms spread among diverse bacterial phyla can use arsenate as a terminal electron acceptor, and that dissimilatory arsenate reduction might occur in the sulfidogenic zone at arsenate concentrations of environmental interest. 16S rRNA sequence analysis indicated that strain OREX-4 is a new species of the genus Desulfotomaculum, and accordingly, the name Desulfotomaculum auripigmentum is proposed.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/9325426?dopt=Abstract</style></custom1></record></records></xml>