@article {1563,
	title = {Interference of ferric ions with ferrous iron quantification using the ferrozine assay.},
	journal = {J Microbiol Methods},
	volume = {95},
	year = {2013},
	month = {2013 Dec},
	pages = {366-7},
	abstract = {<p>The ferrozine assay is a widely used colorimetric method for determining soluble iron concentrations. We provide evidence for a heretofore unrecognized interference of ferric ions (Fe(3+)) on ferrous iron (Fe(2+)) measurements performed in the dark. Fe(3+) concentrations affected the absorbance measurements, which linearly increased with incubation time.</p>},
	keywords = {Chemistry Techniques, Analytical, Colorimetry, Darkness, Diagnostic Errors, Ferric Compounds, Ferrous Compounds, Ferrozine, Ions, Iron, Time Factors},
	issn = {1872-8359},
	doi = {10.1016/j.mimet.2013.10.005},
	author = {Im, Jeongdae and Lee, Jaejin and L{\"o}ffler, Frank E}
}
@article {469,
	title = {Polar lipid fatty acids, LPS-hydroxy fatty acids, and respiratory quinones of three Geobacter strains, and variation with electron acceptor.},
	journal = {J Ind Microbiol Biotechnol},
	volume = {36},
	year = {2009},
	month = {2009 Feb},
	pages = {205-9},
	abstract = {The polar lipid fatty acids, lipopolysaccharide hydroxy-fatty acids, and respiratory quinones of Geobacter metallireducens str. GS-15, Geobacter sulfurreducens str. PCA, and Geobacter bemidjiensis str. Bem are reported. Also, the lipids of G. metallireducens were compared when grown with Fe(3+) or nitrate as electron acceptors and G. sulfurreducens with Fe(3+) or fumarate. In all experiments, the most abundant polar lipid fatty acids were 14:0, i15:0, 16:1 omega 7c, 16:1 omega 5c, and 16:0; lipopolysaccharide hydroxy-fatty acids were dominated by 3oh16:0, 3oh14:0, 9oh16:0, and 10oh16:0; and menaquinone-8 was the most abundant respiratory quinone. Some variation in lipid profiles with strain were observed, but not with electron acceptor.},
	keywords = {Culture Media, Electrons, Environmental Microbiology, Fatty Acids, Ferrous Compounds, Geobacter, Lipids, Lipopolysaccharides, Nitrates, Quinones, Vitamin K 2},
	issn = {1476-5535},
	doi = {10.1007/s10295-008-0486-7},
	author = {Hedrick, D B and Peacock, A D and Lovley, D R and Woodard, T L and Nevin, K P and Long, P E and White, D C}
}
@article {488,
	title = {Gene transcript analysis of assimilatory iron limitation in Geobacteraceae during groundwater bioremediation.},
	journal = {Environ Microbiol},
	volume = {10},
	year = {2008},
	month = {2008 May},
	pages = {1218-30},
	abstract = {Limitations on the availability of Fe(III) as an electron acceptor are thought to play an important role in restricting the growth and activity of Geobacter species during bioremediation of contaminated subsurface environments, but the possibility that these organisms might also be limited in the subsurface by the availability of iron for assimilatory purposes was not previously considered because copious quantities of Fe(II) are produced as the result of Fe(III) reduction. Analysis of multiple Geobacteraceae genomes revealed the presence of a three-gene cluster consisting of homologues of two iron-dependent regulators, fur and dtxR (ideR), separated by a homologue of feoB, which encodes an Fe(II) uptake protein. This cluster appears to be conserved among members of the Geobacteraceae and was detected in several environments. Expression of the fur-feoB-ideR cluster decreased as Fe(II) concentrations increased in chemostat cultures. The number of Geobacteraceae feoB transcripts in groundwater samples from a site undergoing in situ uranium bioremediation was relatively high until the concentration of dissolved Fe(II) increased near the end of the field experiment. These results suggest that, because much of the Fe(II) is sequestered in solid phases, Geobacter species, which have a high requirement for iron for iron-sulfur proteins, may be limited by the amount of iron available for assimilatory purposes. These results demonstrate the ability of transcript analysis to reveal previously unsuspected aspects of the in situ physiology of microorganisms in subsurface environments.},
	keywords = {Bacterial Proteins, Biodegradation, Environmental, Culture Media, Ferric Compounds, Ferrous Compounds, Fresh Water, Gene Expression Regulation, Bacterial, Geobacter, Iron, Multigene Family, Phylogeny, Polymerase Chain Reaction, Repressor Proteins, Reverse Transcriptase Polymerase Chain Reaction, Transcription, Genetic, Uranium, Water Pollution, Radioactive},
	issn = {1462-2920},
	doi = {10.1111/j.1462-2920.2007.01537.x},
	author = {O{\textquoteright}Neil, Regina A and Holmes, Dawn E and Coppi, Maddalena V and Adams, Lorrie A and Larrahondo, M Juliana and Ward, Joy E and Nevin, Kelly P and Woodard, Trevor L and Vrionis, Helen A and N{\textquoteright}guessan, Lucie A and Lovley, Derek R}
}
@article {501,
	title = {Lack of electricity production by Pelobacter carbinolicus indicates that the capacity for Fe(III) oxide reduction does not necessarily confer electron transfer ability to fuel cell anodes.},
	journal = {Appl Environ Microbiol},
	volume = {73},
	year = {2007},
	month = {2007 Aug},
	pages = {5347-53},
	abstract = {The ability of Pelobacter carbinolicus to oxidize electron donors with electron transfer to the anodes of microbial fuel cells was evaluated because microorganisms closely related to Pelobacter species are generally abundant on the anodes of microbial fuel cells harvesting electricity from aquatic sediments. P. carbinolicus could not produce current in a microbial fuel cell with electron donors which support Fe(III) oxide reduction by this organism. Current was produced using a coculture of P. carbinolicus and Geobacter sulfurreducens with ethanol as the fuel. Ethanol consumption was associated with the transitory accumulation of acetate and hydrogen. G. sulfurreducens alone could not metabolize ethanol, suggesting that P. carbinolicus grew in the fuel cell by converting ethanol to hydrogen and acetate, which G. sulfurreducens oxidized with electron transfer to the anode. Up to 83\% of the electrons available in ethanol were recovered as electricity and in the metabolic intermediate acetate. Hydrogen consumption by G. sulfurreducens was important for ethanol metabolism by P. carbinolicus. Confocal microscopy and analysis of 16S rRNA genes revealed that half of the cells growing on the anode surface were P. carbinolicus, but there was a nearly equal number of planktonic cells of P. carbinolicus. In contrast, G. sulfurreducens was primarily attached to the anode. P. carbinolicus represents the first Fe(III) oxide-reducing microorganism found to be unable to produce current in a microbial fuel cell, providing the first suggestion that the mechanisms for extracellular electron transfer to Fe(III) oxides and fuel cell anodes may be different.},
	keywords = {Bacteriological Techniques, Deltaproteobacteria, Electricity, Electron Transport, Ferrous Compounds, In Situ Hybridization, Fluorescence, Microscopy, Confocal, Oxidation-Reduction, RNA, Ribosomal, 16S},
	issn = {0099-2240},
	doi = {10.1128/AEM.00804-07},
	author = {Richter, Hanno and Lanthier, Martin and Nevin, Kelly P and Lovley, Derek R}
}
@article {586,
	title = {Geobacter metallireducens accesses insoluble Fe(III) oxide by chemotaxis.},
	journal = {Nature},
	volume = {416},
	year = {2002},
	month = {2002 Apr 18},
	pages = {767-9},
	abstract = {Microorganisms that use insoluble Fe(III) oxide as an electron acceptor can have an important function in the carbon and nutrient cycles of aquatic sediments and in the bioremediation of organic and metal contaminants in groundwater. Although Fe(III) oxides are often abundant, Fe(III)-reducing microbes are faced with the problem of how to access effectively an electron acceptor that can not diffuse to the cell. Fe(III)-reducing microorganisms in the genus Shewanella have resolved this problem by releasing soluble quinones that can carry electrons from the cell surface to Fe(III) oxide that is at a distance from the cell. Here we report that another Fe(III)-reducer, Geobacter metallireducens, has an alternative strategy for accessing Fe(III) oxides. Geobacter metallireducens specifically expresses flagella and pili only when grown on insoluble Fe(III) or Mn(IV) oxide, and is chemotactic towards Fe(II) and Mn(II) under these conditions. These results suggest that G. metallireducens senses when soluble electron acceptors are depleted and then synthesizes the appropriate appendages to permit it to search for, and establish contact with, insoluble Fe(III) or Mn(IV) oxide. This approach to the use of an insoluble electron acceptor may explain why Geobacter species predominate over other Fe(III) oxide-reducing microorganisms in a wide variety of sedimentary environments.},
	keywords = {Bacterial Proteins, Chemotaxis, Deltaproteobacteria, DNA-Binding Proteins, Ferric Compounds, Ferrous Compounds, Fimbriae Proteins, Fimbriae, Bacterial, Flagella, Manganese Compounds, Movement, Oxidation-Reduction, Oxides, Solubility},
	issn = {0028-0836},
	doi = {10.1038/416767a},
	author = {Childers, Susan E and Ciufo, Stacy and Lovley, Derek R}
}
@article {577,
	title = {Multiple influences of nitrate on uranium solubility during bioremediation of uranium-contaminated subsurface sediments.},
	journal = {Environ Microbiol},
	volume = {4},
	year = {2002},
	month = {2002 Sep},
	pages = {510-6},
	abstract = {Microbiological reduction of soluble U(VI) to insoluble U(IV) has been proposed as a remediation strategy for uranium-contaminated groundwater. Nitrate is a common co-contaminant with uranium. Nitrate inhibited U(VI) reduction in acetate-amended aquifer sediments collected from a uranium-contaminated site in New Mexico. Once nitrate was depleted, both U(VI) and Fe(III) were reduced concurrently. When nitrate was added to sediments in which U(VI) had been reduced, U(VI) reappeared in solution. Parallel studies with the dissimilatory Fe(III)-, U(VI)- and nitrate-reducing microorganism, Geobacter metallireducens, demonstrated that nitrate inhibited reduction of Fe(III) and U(VI) in cell suspensions of cells that had been grown with nitrate as the electron acceptor, but not in Fe(III)-grown cells. Suspensions of nitrate-grown G. metallireducens oxidized Fe(II) and U(IV) with nitrate as the electron acceptor. U(IV) oxidation was accelerated when Fe(II) was also added, presumably due to the Fe(III) being formed abiotically oxidizing U(IV). These studies demonstrate that although the presence of nitrate is not likely to be an impediment to the bioremediation of uranium contamination with microbial U(VI) reduction, it is necessary to reduce nitrate before U(VI) can be reduced. These results also suggest that anaerobic oxidation of U(IV) to U(VI) with nitrate serving as the electron acceptor may provide a novel strategy for solubilizing and extracting microbial U(IV) precipitates from the subsurface.},
	keywords = {Ferric Compounds, Ferrous Compounds, Geologic Sediments, Nitrates, Oxidation-Reduction, Proteobacteria, Soil Pollutants, Solubility, Uranium, Water Pollutants, Chemical},
	issn = {1462-2912},
	author = {Finneran, Kevin T and Housewright, Meghan E and Lovley, Derek R}
}
@article {607,
	title = {Direct and Fe(II)-mediated reduction of technetium by Fe(III)-reducing bacteria.},
	journal = {Appl Environ Microbiol},
	volume = {66},
	year = {2000},
	month = {2000 Sep},
	pages = {3743-9},
	abstract = {The dissimilatory Fe(III)-reducing bacterium Geobacter sulfurreducens reduced and precipitated Tc(VII) by two mechanisms. Washed cell suspensions coupled the oxidation of hydrogen to enzymatic reduction of Tc(VII) to Tc(IV), leading to the precipitation of TcO(2) at the periphery of the cell. An indirect, Fe(II)-mediated mechanism was also identified. Acetate, although not utilized efficiently as an electron donor for direct cell-mediated reduction of technetium, supported the reduction of Fe(III), and the Fe(II) formed was able to transfer electrons abiotically to Tc(VII). Tc(VII) reduction was comparatively inefficient via this indirect mechanism when soluble Fe(III) citrate was supplied to the cultures but was enhanced in the presence of solid Fe(III) oxide. The rate of Tc(VII) reduction was optimal, however, when Fe(III) oxide reduction was stimulated by the addition of the humic analog and electron shuttle anthaquinone-2,6-disulfonate, leading to the rapid formation of the Fe(II)-bearing mineral magnetite. Under these conditions, Tc(VII) was reduced and precipitated abiotically on the nanocrystals of biogenic magnetite as TcO(2) and was removed from solution to concentrations below the limit of detection by scintillation counting. Cultures of Fe(III)-reducing bacteria enriched from radionuclide-contaminated sediment using Fe(III) oxide as an electron acceptor in the presence of 25 microM Tc(VII) contained a single Geobacter sp. detected by 16S ribosomal DNA analysis and were also able to reduce and precipitate the radionuclide via biogenic magnetite. Fe(III) reduction was stimulated in aquifer material, resulting in the formation of Fe(II)-containing minerals that were able to reduce and precipitate Tc(VII). These results suggest that Fe(III)-reducing bacteria may play an important role in immobilizing technetium in sediments via direct and indirect mechanisms.},
	keywords = {Culture Media, Deltaproteobacteria, Ferric Compounds, Ferrous Compounds, Fresh Water, Oxidation-Reduction, Technetium},
	issn = {0099-2240},
	author = {Lloyd, J R and Sole, V A and Van Praagh, C V and Lovley, D R}
}
@article {639,
	title = {Fe(III) and S0 reduction by Pelobacter carbinolicus.},
	journal = {Appl Environ Microbiol},
	volume = {61},
	year = {1995},
	month = {1995 Jun},
	pages = {2132-8},
	abstract = {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 been previously evaluated. When a culture of Pelobacter carbinolicus that had grown by fermentation of 2,3-butanediol was inoculated into the same medium supplemented with Fe(III), the Fe(III) was reduced. There was less accumulation of ethanol and more production of acetate in the presence of Fe(III). P. carbinolicus grew with ethanol as the sole electron donor and Fe(III) as the sole electron acceptor. Ethanol was metabolized to acetate. Growth was also possible on Fe(III) with the oxidation of propanol to propionate or butanol to butyrate if acetate was provided as a carbon source. P. carbinolicus appears capable of conserving energy to support growth from Fe(III) respiration as it also grew with H2 or formate as the electron donor and Fe(III) as the electron acceptor. Once adapted to Fe(III) reduction, P. carbinolicus could also grow on ethanol or H2 with S0 as the electron acceptor. P. carbinolicus did not contain detectable concentrations of the c-type cytochromes that previous studies have suggested are involved in electron transport to Fe(III) in other organisms that conserve energy to support growth from Fe(III) reduction.(ABSTRACT TRUNCATED AT 250 WORDS)},
	keywords = {Bacteria, Anaerobic, Base Sequence, Butylene Glycols, Culture Media, Ethanol, Ferrous Compounds, Hydrogen, Molecular Sequence Data, Oxidation-Reduction, Phylogeny, RNA, Ribosomal, 16S, Sulfur},
	issn = {0099-2240},
	author = {Lovley, D R and Phillips, E J and Lonergan, D J and Widman, P K}
}
