@article {484,
	title = {Geobacter uraniireducens sp. nov., isolated from subsurface sediment undergoing uranium bioremediation.},
	journal = {Int J Syst Evol Microbiol},
	volume = {58},
	year = {2008},
	month = {2008 May},
	pages = {1075-8},
	abstract = {A Gram-negative, rod-shaped, motile bacterium, strain Rf4T, which conserves energy from dissimilatory Fe(III) reduction concomitant with acetate oxidation, was isolated from subsurface sediment undergoing uranium bioremediation. The 16S rRNA gene sequence of strain Rf4T matched sequences recovered in 16S rRNA gene clone libraries constructed from DNA extracted from groundwater sampled at the same time as the source sediment. Cells of strain Rf4T were regular, motile rods, 1.2-2.0 microm long and 0.5-0.6 microm in diameter, with rounded ends. Cells had one lateral flagellum. Growth was optimal at pH 6.5-7.0 and 32 degrees C. With acetate as the electron donor, strain Rf4T used Fe(III), Mn(IV), anthraquinone-2,6-disulfonate, malate and fumarate as electron acceptors and reduced U(VI) in cell suspensions. With poorly crystalline Fe(III) oxide as the electron acceptor, strain Rf4T oxidized the following electron donors: acetate, lactate, pyruvate and ethanol. Phylogenetic analysis of the 16S rRNA gene sequence of strain Rf4T placed it in the genus Geobacter. Strain Rf4T was most closely related to {\textquoteright}Geobacter humireducens{\textquoteright} JW3 (95.9 \% sequence similarity), Geobacter bremensis Dfr1T (95.4 \%) and Geobacter bemidjiensis BemT (95.1 \%). Based on phylogenetic analysis and phenotypic differences between strain Rf4T and closely related Geobacter species, this strain is described as a representative of a novel species, Geobacter uraniireducens sp. nov. The type strain is Rf4T (=ATCC BAA-1134T =JCM 13001T).},
	keywords = {Bacterial Typing Techniques, DNA, Bacterial, Genes, rRNA, Genotype, Geobacter, Geologic Sediments, Molecular Sequence Data, Oxidation-Reduction, Phenotype, Phylogeny, RNA, Ribosomal, 16S, Sequence Analysis, DNA, Species Specificity, Uranium},
	issn = {1466-5026},
	doi = {10.1099/ijs.0.65377-0},
	author = {Shelobolina, Evgenya S and Vrionis, Helen A and Findlay, Robert H and Lovley, Derek R}
}
@article {508,
	title = {Geobacter pickeringii sp. nov., Geobacter argillaceus sp. nov. and Pelosinus fermentans gen. nov., sp. nov., isolated from subsurface kaolin lenses.},
	journal = {Int J Syst Evol Microbiol},
	volume = {57},
	year = {2007},
	month = {2007 Jan},
	pages = {126-35},
	abstract = {The goal of this project was to isolate representative Fe(III)-reducing bacteria from kaolin clays that may influence iron mineralogy in kaolin. Two novel dissimilatory Fe(III)-reducing bacteria, strains G12(T) and G13(T), were isolated from sedimentary kaolin strata in Georgia (USA). Cells of strains G12(T) and G13(T) were motile, non-spore-forming regular rods, 1-2 mum long and 0.6 mum in diameter. Cells had one lateral flagellum. Phylogenetic analyses using the 16S rRNA gene sequence of the novel strains demonstrated their affiliation to the genus Geobacter. Strain G12(T) was most closely related to Geobacter pelophilus (94.7 \%) and Geobacter chapellei (94.1 \%). Strain G13(T) was most closely related to Geobacter grbiciae (95.3 \%) and Geobacter metallireducens (95.1 \%). Based on phylogenetic analyses and phenotypic differences between the novel isolates and other closely related species of the genus Geobacter, the isolates are proposed as representing two novel species, Geobacter argillaceus sp. nov. (type strain G12(T)=ATCC BAA-1139(T)=JCM 12999(T)) and Geobacter pickeringii sp. nov. (type strain G13(T)=ATCC BAA-1140(T)=DSM 17153(T)=JCM 13000(T)). Another isolate, strain R7(T), was derived from a primary kaolin deposit in Russia. The cells of strain R7(T) were motile, spore-forming, slightly curved rods, 0.6 x 2.0-6.0 microm in size and with up to six peritrichous flagella. Strain R7(T) was capable of reducing Fe(III) only in the presence of a fermentable substrate. 16S rRNA gene sequence analysis demonstrated that this isolate is unique, showing less than 92 \% similarity to bacteria of the Sporomusa-Pectinatus-Selenomomas phyletic group, including {\textquoteright}Anaerospora hongkongensis{\textquoteright} (90.2 \%), Acetonema longum (90.6 \%), Dendrosporobacter quercicolus (90.9 \%) and Anaerosinus glycerini (91.5 \%). On the basis of phylogenetic analysis and physiological tests, strain R7(T) is proposed to represent a novel genus and species, Pelosinus fermentans gen. nov., sp. nov. (type strain R7(T)=DSM 17108(T)=ATCC BAA-1133(T)), in the Sporomusa-Pectinatus-Selenomonas group.},
	keywords = {Bacterial Typing Techniques, Base Composition, DNA, Bacterial, DNA, Ribosomal, Ferric Compounds, Genes, rRNA, Geobacter, Geologic Sediments, Georgia, Kaolin, Molecular Sequence Data, Oxidation-Reduction, Phylogeny, RNA, Ribosomal, 16S, Russia, Sequence Analysis, DNA, Species Specificity},
	issn = {1466-5026},
	doi = {10.1099/ijs.0.64221-0},
	author = {Shelobolina, Evgenya S and Nevin, Kelly P and Blakeney-Hayward, Jessie D and Johnsen, Claudia V and Plaia, Todd W and Krader, Paul and Woodard, Trevor and Holmes, Dawn E and Vanpraagh, Catherine Gaw and Lovley, Derek R}
}
@article {505,
	title = {Importance of c-Type cytochromes for U(VI) reduction by Geobacter sulfurreducens.},
	journal = {BMC Microbiol},
	volume = {7},
	year = {2007},
	month = {2007},
	pages = {16},
	abstract = {BACKGROUND: In order to study the mechanism of U(VI) reduction, the effect of deleting c-type cytochrome genes on the capacity of Geobacter sulfurreducens to reduce U(VI) with acetate serving as the electron donor was investigated.

RESULTS: The ability of several c-type cytochrome deficient mutants to reduce U(VI) was lower than that of the wild type strain. Elimination of two confirmed outer membrane cytochromes and two putative outer membrane cytochromes significantly decreased (ca. 50-60\%) the ability of G. sulfurreducens to reduce U(VI). Involvement in U(VI) reduction did not appear to be a general property of outer membrane cytochromes, as elimination of two other confirmed outer membrane cytochromes, OmcB and OmcC, had very little impact on U(VI) reduction. Among the periplasmic cytochromes, only MacA, proposed to transfer electrons from the inner membrane to the periplasm, appeared to play a significant role in U(VI) reduction. A subpopulation of both wild type and U(VI) reduction-impaired cells, 24-30\%, accumulated amorphous uranium in the periplasm. Comparison of uranium-accumulating cells demonstrated a similar amount of periplasmic uranium accumulation in U(VI) reduction-impaired and wild type G. sulfurreducens. Assessment of the ability of the various suspensions to reduce Fe(III) revealed no correlation between the impact of cytochrome deletion on U(VI) reduction and reduction of Fe(III) hydroxide and chelated Fe(III).

CONCLUSION: This study indicates that c-type cytochromes are involved in U(VI) reduction by Geobacter sulfurreducens. The data provide new evidence for extracellular uranium reduction by G. sulfurreducens but do not rule out the possibility of periplasmic uranium reduction. Occurrence of U(VI) reduction at the cell surface is supported by the significant impact of elimination of outer membrane cytochromes on U(VI) reduction and the lack of correlation between periplasmic uranium accumulation and the capacity for uranium reduction. Periplasmic uranium accumulation may reflect the ability of uranium to penetrate the outer membrane rather than the occurrence of enzymatic U(VI) reduction. Elimination of cytochromes rarely had a similar impact on both Fe(III) and U(VI) reduction, suggesting that there are differences in the routes of electron transfer to U(VI) and Fe(III). Further studies are required to clarify the pathways leading to U(VI) reduction in G. sulfurreducens.},
	keywords = {Biodegradation, Environmental, Cytochrome c Group, Ferric Compounds, Geobacter, Microscopy, Electron, Transmission, Mutation, Oxidation-Reduction, Periplasm, Uranium},
	issn = {1471-2180},
	doi = {10.1186/1471-2180-7-16},
	author = {Shelobolina, Evgenya S and Coppi, Maddalena V and Korenevsky, Anton A and DiDonato, Laurie N and Sullivan, Sara A and Konishi, Hiromi and Xu, Huifang and Leang, Ching and Butler, Jessica E and Kim, Byoung-Chan and Lovley, Derek R}
}
@article {525,
	title = {Genetic characterization of a single bifunctional enzyme for fumarate reduction and succinate oxidation in Geobacter sulfurreducens and engineering of fumarate reduction in Geobacter metallireducens.},
	journal = {J Bacteriol},
	volume = {188},
	year = {2006},
	month = {2006 Jan},
	pages = {450-5},
	abstract = {The mechanism of fumarate reduction in Geobacter sulfurreducens was investigated. The genome contained genes encoding a heterotrimeric fumarate reductase, FrdCAB, with homology to the fumarate reductase of Wolinella succinogenes and the succinate dehydrogenase of Bacillus subtilis. Mutation of the putative catalytic subunit of the enzyme resulted in a strain that lacked fumarate reductase activity and was unable to grow with fumarate as the terminal electron acceptor. The mutant strain also lacked succinate dehydrogenase activity and did not grow with acetate as the electron donor and Fe(III) as the electron acceptor. The mutant strain could grow with acetate as the electron donor and Fe(III) as the electron acceptor if fumarate was provided to alleviate the need for succinate dehydrogenase activity in the tricarboxylic acid cycle. The growth rate of the mutant strain under these conditions was faster and the cell yields were higher than for wild type grown under conditions requiring succinate dehydrogenase activity, suggesting that the succinate dehydrogenase reaction consumes energy. An orthologous frdCAB operon was present in Geobacter metallireducens, which cannot grow with fumarate as the terminal electron acceptor. When a putative dicarboxylic acid transporter from G. sulfurreducens was expressed in G. metallireducens, growth with fumarate as the sole electron acceptor was possible. These results demonstrate that, unlike previously described organisms, G. sulfurreducens and possibly G. metallireducens use the same enzyme for both fumarate reduction and succinate oxidation in vivo.},
	keywords = {Culture Media, Dicarboxylic Acids, Fumarates, Geobacter, Molecular Sequence Data, Operon, Oxidation-Reduction, Recombinant Proteins, Substrate Specificity, Succinate Dehydrogenase, Succinic Acid},
	issn = {0021-9193},
	doi = {10.1128/JB.188.2.450-455.2006},
	author = {Butler, Jessica E and Glaven, Richard H and Esteve-N{\'u}{\~n}ez, Abraham and N{\'u}{\~n}ez, Cinthia and Shelobolina, Evgenya S and Bond, Daniel R and Lovley, Derek R}
}
