@article {462,
	title = {Anode biofilm transcriptomics reveals outer surface components essential for high density current production in Geobacter sulfurreducens fuel cells.},
	journal = {PLoS One},
	volume = {4},
	year = {2009},
	month = {2009},
	pages = {e5628},
	abstract = {The mechanisms by which Geobacter sulfurreducens transfers electrons through relatively thick (>50 microm) biofilms to electrodes acting as a sole electron acceptor were investigated. Biofilms of Geobacter sulfurreducens were grown either in flow-through systems with graphite anodes as the electron acceptor or on the same graphite surface, but with fumarate as the sole electron acceptor. Fumarate-grown biofilms were not immediately capable of significant current production, suggesting substantial physiological differences from current-producing biofilms. Microarray analysis revealed 13 genes in current-harvesting biofilms that had significantly higher transcript levels. The greatest increases were for pilA, the gene immediately downstream of pilA, and the genes for two outer c-type membrane cytochromes, OmcB and OmcZ. Down-regulated genes included the genes for the outer-membrane c-type cytochromes, OmcS and OmcT. Results of quantitative RT-PCR of gene transcript levels during biofilm growth were consistent with microarray results. OmcZ and the outer-surface c-type cytochrome, OmcE, were more abundant and OmcS was less abundant in current-harvesting cells. Strains in which pilA, the gene immediately downstream from pilA, omcB, omcS, omcE, or omcZ was deleted demonstrated that only deletion of pilA or omcZ severely inhibited current production and biofilm formation in current-harvesting mode. In contrast, these gene deletions had no impact on biofilm formation on graphite surfaces when fumarate served as the electron acceptor. These results suggest that biofilms grown harvesting current are specifically poised for electron transfer to electrodes and that, in addition to pili, OmcZ is a key component in electron transfer through differentiated G. sulfurreducens biofilms to electrodes.},
	keywords = {Amino Acid Sequence, Bacterial Outer Membrane Proteins, Bioelectric Energy Sources, Biofilms, Cytochromes, Electrodes, Electron Transport, Fumarates, Gene Deletion, Gene Expression Profiling, Gene Expression Regulation, Bacterial, Genetic Complementation Test, Geobacter, Microscopy, Confocal, Molecular Sequence Data, Oligonucleotide Array Sequence Analysis, Oxidation-Reduction, RNA, Messenger, Up-Regulation},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0005628},
	author = {Nevin, Kelly P and Kim, Byoung-Chan and Glaven, Richard H and Johnson, Jessica P and Woodard, Trevor L and Meth{\'e}, Barbara A and Didonato, Raymond J and Covalla, Sean F and Franks, Ashley E and Liu, Anna and Lovley, Derek R}
}
@article {522,
	title = {DNA microarray and proteomic analyses of the RpoS regulon in Geobacter sulfurreducens.},
	journal = {J Bacteriol},
	volume = {188},
	year = {2006},
	month = {2006 Apr},
	pages = {2792-800},
	abstract = {The regulon of the sigma factor RpoS was defined in Geobacter sulfurreducens by using a combination of DNA microarray expression profiles and proteomics. An rpoS mutant was examined under steady-state conditions with acetate as an electron donor and fumarate as an electron acceptor and with additional transcriptional profiling using Fe(III) as an electron acceptor. Expression analysis revealed that RpoS acts as both a positive and negative regulator. Many of the RpoS-dependent genes determined play roles in energy metabolism, including the tricarboxylic acid cycle, signal transduction, transport, protein synthesis and degradation, and amino acid metabolism and transport. As expected, RpoS activated genes involved in oxidative stress resistance and adaptation to nutrient limitation. Transcription of the cytochrome c oxidase operon, necessary for G. sulfurreducens growth using oxygen as an electron acceptor, and expression of at least 13 c-type cytochromes, including one previously shown to participate in Fe(III) reduction (MacA), were RpoS dependent. Analysis of a subset of the rpoS mutant proteome indicated that 15 major protein species showed reproducible differences in abundance relative to those of the wild-type strain. Protein identification using mass spectrometry indicated that the expression of seven of these proteins correlated with the microarray data. Collectively, these results indicate that RpoS exerts global effects on G. sulfurreducens physiology and that RpoS is vital to G. sulfurreducens survival under conditions typically encountered in its native subsurface environments.},
	keywords = {Adaptation, Physiological, Amino Acids, Bacterial Proteins, Biological Transport, Citric Acid Cycle, Cytochromes, Electrophoresis, Gel, Two-Dimensional, Gene Deletion, Gene Expression Regulation, Bacterial, Geobacter, Mass Spectrometry, Mutagenesis, Insertional, Oligonucleotide Array Sequence Analysis, Oxidative Stress, Protein Biosynthesis, Proteome, Regulon, Sigma Factor, Signal Transduction},
	issn = {0021-9193},
	doi = {10.1128/JB.188.8.2792-2800.2006},
	author = {N{\'u}{\~n}ez, Cinthia and Esteve-N{\'u}{\~n}ez, Abraham and Giometti, Carol and Tollaksen, Sandra and Khare, Tripti and Lin, Winston and Lovley, Derek R and Meth{\'e}, Barbara A}
}
