@article {3107,
	title = {Protozoan grazing reduces the current output of microbial fuel cells.},
	journal = {Bioresour Technol},
	volume = {193},
	year = {2015},
	month = {2015 Oct},
	pages = {8-14},
	abstract = {<p>Several experiments were conducted to determine whether protozoan grazing can reduce current output from sediment microbial fuel cells. When marine sediments were amended with eukaryotic inhibitors, the power output from the fuel cells increased 2-5-fold. Quantitative PCR showed that Geobacteraceae sequences were 120 times more abundant on anodes from treated fuel cells compared to untreated fuel cells, and that Spirotrichea sequences in untreated fuel cells were 200 times more abundant on anode surfaces than in the surrounding sediments. Defined studies with current-producing biofilms of Geobacter sulfurreducens and pure cultures of protozoa demonstrated that protozoa that were effective in consuming G. sulfurreducens reduced current production up to 91\% when added to G. sulfurreducens fuel cells. These results suggest that anode biofilms are an attractive food source for protozoa and that protozoan grazing can be an important factor limiting the current output of sediment microbial fuel cells.</p>},
	keywords = {Bioelectric Energy Sources, Biofilms, Electricity, Electrodes, Eukaryota, Geobacter, Geologic Sediments},
	issn = {1873-2976},
	doi = {10.1016/j.biortech.2015.06.056},
	author = {Holmes, Dawn E and Nevin, Kelly P and Snoeyenbos-West, Oona L and Woodard, Trevor L and Strickland, Justin N and Lovley, Derek R}
}
@article {483,
	title = {Genes for two multicopper proteins required for Fe(III) oxide reduction in Geobacter sulfurreducens have different expression patterns both in the subsurface and on energy-harvesting electrodes.},
	journal = {Microbiology},
	volume = {154},
	year = {2008},
	month = {2008 May},
	pages = {1422-35},
	abstract = {Previous studies have shown that Geobacter sulfurreducens requires the outer-membrane, multicopper protein OmpB for Fe(III) oxide reduction. A homologue of OmpB, designated OmpC, which is 36 \% similar to OmpB, has been discovered in the G. sulfurreducens genome. Deletion of ompC inhibited reduction of insoluble, but not soluble Fe(III). Analysis of multiple Geobacter and Pelobacter genomes, as well as in situ Geobacter, indicated that genes encoding multicopper proteins are conserved in Geobacter species but are not found in Pelobacter species. Levels of ompB transcripts were similar in G. sulfurreducens at different growth rates in chemostats and during growth on a microbial fuel cell anode. In contrast, ompC transcript levels increased at higher growth rates in chemostats and with increasing current production in fuel cells. Constant levels of Geobacter ompB transcripts were detected in groundwater during a field experiment in which acetate was added to the subsurface to promote in situ uranium bioremediation. In contrast, ompC transcript levels increased during the rapid phase of growth of Geobacter species following addition of acetate to the groundwater and then rapidly declined. These results demonstrate that more than one multicopper protein is required for optimal Fe(III) oxide reduction in G. sulfurreducens and suggest that, in environmental studies, quantifying OmpB/OmpC-related genes could help alleviate the problem that Pelobacter genes may be inadvertently quantified via quantitative analysis of 16S rRNA genes. Furthermore, comparison of differential expression of ompB and ompC may provide insight into the in situ metabolic state of Geobacter species in environments of interest.},
	keywords = {Acetates, Amino Acid Sequence, Bacterial Outer Membrane Proteins, Electrodes, Ferric Compounds, Gene Deletion, Gene Expression Profiling, Geobacter, Molecular Sequence Data, Oxidation-Reduction, Phylogeny, Sequence Alignment, Sequence Homology, Nucleic Acid, Soil Microbiology, Uranium},
	issn = {1350-0872},
	doi = {10.1099/mic.0.2007/014365-0},
	author = {Holmes, Dawn E and Mester, T{\"u}nde and O{\textquoteright}Neil, Regina A and Perpetua, Lorrie A and Larrahondo, M Juliana and Glaven, Richard and Sharma, Manju L and Ward, Joy E and Nevin, Kelly P and Lovley, Derek R}
}
@article {513,
	title = {Microarray and genetic analysis of electron transfer to electrodes in Geobacter sulfurreducens.},
	journal = {Environ Microbiol},
	volume = {8},
	year = {2006},
	month = {2006 Oct},
	pages = {1805-15},
	abstract = {Whole-genome analysis of gene expression in Geobacter sulfurreducens revealed 474 genes with transcript levels that were significantly different during growth with an electrode as the sole electron acceptor versus growth on Fe(III) citrate. The greatest response was a more than 19-fold increase in transcript levels for omcS, which encodes an outer-membrane cytochrome previously shown to be required for Fe(III) oxide reduction. Quantitative reverse transcription polymerase chain reaction and Northern analyses confirmed the higher levels of omcS transcripts, which increased as power production increased. Deletion of omcS inhibited current production that was restored when omcS was expressed in trans. Transcript expression and genetic analysis suggested that OmcE, another outer-membrane cytochrome, is also involved in electron transfer to electrodes. Surprisingly, genes for other proteins known to be important in Fe(III) reduction such as the outer-membrane c-type cytochrome, OmcB, and the electrically conductive pilin "nanowires" did not have higher transcript levels on electrodes, and deletion of the relevant genes did not inhibit power production. Changes in the transcriptome suggested that cells growing on electrodes were subjected to less oxidative stress than cells growing on Fe(III) citrate and that a number of genes annotated as encoding metal efflux proteins or proteins of unknown function may be important for growth on electrodes. These results demonstrate for the first time that it is possible to evaluate gene expression, and hence the metabolic state, of microorganisms growing on electrodes on a genome-wide basis and suggest that OmcS, and to a lesser extent OmcE, are important in electron transfer to electrodes. This has important implications for the design of electrode materials and the genetic engineering of microorganisms to improve the function of microbial fuel cells.},
	keywords = {Bacterial Outer Membrane Proteins, Blotting, Northern, Cytochromes c, Electrodes, Electrophysiology, Gene Expression Regulation, Bacterial, Geobacter, Oligonucleotide Array Sequence Analysis, Oxidation-Reduction, Reverse Transcriptase Polymerase Chain Reaction, RNA, Bacterial, RNA, Messenger},
	issn = {1462-2912},
	doi = {10.1111/j.1462-2920.2006.01065.x},
	author = {Holmes, Dawn E and Chaudhuri, Swades K and Nevin, Kelly P and Mehta, Teena and Meth{\'e}, Barbara A and Liu, Anna and Ward, Joy E and Woodard, Trevor L and Webster, Jennifer and Lovley, Derek R}
}
@article {529,
	title = {Potential for quantifying expression of the Geobacteraceae citrate synthase gene to assess the activity of Geobacteraceae in the subsurface and on current-harvesting electrodes.},
	journal = {Appl Environ Microbiol},
	volume = {71},
	year = {2005},
	month = {2005 Nov},
	pages = {6870-7},
	abstract = {The Geobacteraceae citrate synthase is phylogenetically distinct from those of other prokaryotes and is a key enzyme in the central metabolism of Geobacteraceae. Therefore, the potential for using levels of citrate synthase mRNA to estimate rates of Geobacter metabolism was evaluated in pure culture studies and in four different Geobacteraceae-dominated environments. Quantitative reverse transcription-PCR studies with mRNA extracted from cultures of Geobacter sulfurreducens grown in chemostats with Fe(III) as the electron acceptor or in batch with electrodes as the electron acceptor indicated that transcript levels of the citrate synthase gene, gltA, increased with increased rates of growth/Fe(III) reduction or current production, whereas the expression of the constitutively expressed housekeeping genes recA, rpoD, and proC remained relatively constant. Analysis of mRNA extracted from groundwater collected from a U(VI)-contaminated site undergoing in situ uranium bioremediation revealed a remarkable correspondence between acetate levels in the groundwater and levels of transcripts of gltA. The expression of gltA was also significantly greater in RNA extracted from groundwater beneath a highway runoff recharge pool that was exposed to calcium magnesium acetate in June, when acetate concentrations were high, than in October, when the levels had significantly decreased. It was also possible to detect gltA transcripts on current-harvesting anodes deployed in freshwater sediments. These results suggest that it is possible to monitor the in situ metabolic rate of Geobacteraceae by tracking the expression of the citrate synthase gene.},
	keywords = {Acetates, Citrate (si)-Synthase, Deltaproteobacteria, DNA, Ribosomal, Electrodes, Ferric Compounds, Fresh Water, Geobacter, Geologic Sediments, Petroleum, Phylogeny, RNA, Ribosomal, 16S, Uranium, Water Pollutants, Chemical, Water Pollutants, Radioactive},
	issn = {0099-2240},
	doi = {10.1128/AEM.71.11.6870-6877.2005},
	author = {Holmes, Dawn E and Nevin, Kelly P and O{\textquoteright}Neil, Regina A and Ward, Joy E and Adams, Lorrie A and Woodard, Trevor L and Vrionis, Helen A and Lovley, Derek R}
}
@article {559,
	title = {Electron transfer by Desulfobulbus propionicus to Fe(III) and graphite electrodes.},
	journal = {Appl Environ Microbiol},
	volume = {70},
	year = {2004},
	month = {2004 Feb},
	pages = {1234-7},
	abstract = {Desulfobulbus propionicus was able to grow with Fe(III), the humic acids analog anthraquinone-2,6-disulfonate (AQDS), or a graphite electrode as an electron acceptor. These results provide an explanation for the enrichment of Desulfobulbaceae species on the surface of electrodes harvesting electricity from anaerobic marine sediments and further expand the diversity of microorganisms known to have the ability to use both sulfate and Fe(III) as an electron acceptor.},
	keywords = {Culture Media, Deltaproteobacteria, Electrodes, Electron Transport, Ferric Compounds, Graphite, Oxidation-Reduction, Pyruvic Acid, Sulfates},
	issn = {0099-2240},
	author = {Holmes, Dawn E and Bond, Daniel R and Lovley, Derek R}
}
@article {588,
	title = {Electrode-reducing microorganisms that harvest energy from marine sediments.},
	journal = {Science},
	volume = {295},
	year = {2002},
	month = {2002 Jan 18},
	pages = {483-5},
	abstract = {Energy in the form of electricity can be harvested from marine sediments by placing a graphite electrode (the anode) in the anoxic zone and connecting it to a graphite cathode in the overlying aerobic water. We report a specific enrichment of microorganisms of the family Geobacteraceae on energy-harvesting anodes, and we show that these microorganisms can conserve energy to support their growth by oxidizing organic compounds with an electrode serving as the sole electron acceptor. This finding not only provides a method for extracting energy from organic matter, but also suggests a strategy for promoting the bioremediation of organic contaminants in subsurface environments.},
	keywords = {Aerobiosis, Anaerobiosis, Anthraquinones, Benzoates, Biodegradation, Environmental, Carbon Dioxide, Colony Count, Microbial, Deltaproteobacteria, DNA, Ribosomal, Electricity, Electrodes, Electrons, Energy Metabolism, Geologic Sediments, Oxidation-Reduction, RNA, Ribosomal, 16S, Seawater, Sodium Acetate},
	issn = {1095-9203},
	doi = {10.1126/science.1066771},
	author = {Bond, Daniel R and Holmes, Dawn E and Tender, Leonard M and Lovley, Derek R}
}
@article {580,
	title = {Harnessing microbially generated power on the seafloor.},
	journal = {Nat Biotechnol},
	volume = {20},
	year = {2002},
	month = {2002 Aug},
	pages = {821-5},
	abstract = {In many marine environments, a voltage gradient exists across the water sediment interface resulting from sedimentary microbial activity. Here we show that a fuel cell consisting of an anode embedded in marine sediment and a cathode in overlying seawater can use this voltage gradient to generate electrical power in situ. Fuel cells of this design generated sustained power in a boat basin carved into a salt marsh near Tuckerton, New Jersey, and in the Yaquina Bay Estuary near Newport, Oregon. Retrieval and analysis of the Tuckerton fuel cell indicates that power generation results from at least two anode reactions: oxidation of sediment sulfide (a by-product of microbial oxidation of sedimentary organic carbon) and oxidation of sedimentary organic carbon catalyzed by microorganisms colonizing the anode. These results demonstrate in real marine environments a new form of power generation that uses an immense, renewable energy reservoir (sedimentary organic carbon) and has near-immediate application.},
	keywords = {Bacteria, Bioelectric Energy Sources, Biotechnology, Carbon, Conservation of Energy Resources, DNA, Ribosomal, Electricity, Electrodes, Environmental Microbiology, Geologic Sediments, Molecular Sequence Data, New Jersey, Oceans and Seas, Oregon, Oxidation-Reduction, RNA, Bacterial, RNA, Ribosomal, 16S, Sulfides},
	issn = {1087-0156},
	doi = {10.1038/nbt716},
	author = {Tender, Leonard M and Reimers, Clare E and Stecher, Hilmar A and Holmes, Dawn E and Bond, Daniel R and Lowy, Daniel A and Pilobello, Kanoelani and Fertig, Stephanie J and Lovley, Derek R}
}
