@article {480,
	title = {Insights into genes involved in electricity generation in Geobacter sulfurreducens via whole genome microarray analysis of the OmcF-deficient mutant.},
	journal = {Bioelectrochemistry},
	volume = {73},
	year = {2008},
	month = {2008 Jun},
	pages = {70-5},
	abstract = {Geobacter sulfurreducens effectively produces electricity in microbial fuel cells by oxidizing acetate with an electrode serving as the sole electron acceptor. Deletion of the gene encoding OmcF, a monoheme outer membrane c-type cytochrome, substantially decreased current production. Previous studies demonstrated that inhibition of Fe(III) reduction in the OmcF-deficient mutant could be attributed to poor transcription of the gene for OmcB, an outer membrane c-type cytochrome that is required for Fe(III) reduction. However, a mutant in which omcB was deleted produced electricity as well as wild type. Microarray analysis of the OmcF-deficient mutant versus the wild type revealed that many of the genes with the greatest decreases in transcript levels were genes whose expression was previously reported to be upregulated in cells grown with an electrode as the sole electron acceptor. These included genes with putative functions related to metal efflux and/or type I secretion and two hypothetical proteins. The outer membrane cytochromes, OmcS and OmcE, which previous studies have demonstrated are required for optimal current generation, were not detected on the outer surface of the OmcF-deficient mutant even though the omcS and omcE genes were still transcribed, suggesting that the putative secretion system could be involved in the export of outer membrane proteins necessary for electron transfer to the fuel cell anode. These results suggest that the requirement for OmcF for optimal current production is not because OmcF is directly involved in extracellular electron transfer but because OmcF is required for the appropriate transcription of other genes either directly or indirectly involved in electricity production.},
	keywords = {Bacterial Outer Membrane Proteins, Cytochromes c, Down-Regulation, Electricity, Gene Expression Regulation, Bacterial, Genome, Bacterial, Geobacter, Mutation, Oligonucleotide Array Sequence Analysis, Transcription, Genetic},
	issn = {1567-5394},
	doi = {10.1016/j.bioelechem.2008.04.023},
	author = {Kim, Byoung-Chan and Postier, Bradley L and Didonato, Raymond J and Chaudhuri, Swades K and Nevin, Kelly P and Lovley, Derek R}
}
@article {515,
	title = {c-Type cytochromes in Pelobacter carbinolicus.},
	journal = {Appl Environ Microbiol},
	volume = {72},
	year = {2006},
	month = {2006 Nov},
	pages = {6980-5},
	abstract = {Previous studies failed to detect c-type cytochromes in Pelobacter species despite the fact that other close relatives in the Geobacteraceae, such as Geobacter and Desulfuromonas species, have abundant c-type cytochromes. Analysis of the recently completed genome sequence of Pelobacter carbinolicus revealed 14 open reading frames that could encode c-type cytochromes. Transcripts for all but one of these open reading frames were detected in acetoin-fermenting and/or Fe(III)-reducing cells. Three putative c-type cytochrome genes were expressed specifically during Fe(III) reduction, suggesting that the encoded proteins may participate in electron transfer to Fe(III). One of these proteins was a periplasmic triheme cytochrome with a high level of similarity to PpcA, which has a role in Fe(III) reduction in Geobacter sulfurreducens. Genes for heme biosynthesis and system II cytochrome c biogenesis were identified in the genome and shown to be expressed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels of protein extracted from acetoin-fermenting P. carbinolicus cells contained three heme-staining bands which were confirmed by mass spectrometry to be among the 14 predicted c-type cytochromes. The number of cytochrome genes, the predicted amount of heme c per protein, and the ratio of heme-stained protein to total protein were much smaller in P. carbinolicus than in G. sulfurreducens. Furthermore, many of the c-type cytochromes that genetic studies have indicated are required for optimal Fe(III) reduction in G. sulfurreducens were not present in the P. carbinolicus genome. These results suggest that further evaluation of the functions of c-type cytochromes in the Geobacteraceae is warranted.},
	keywords = {Bacterial Proteins, Cytochromes c, Deltaproteobacteria, Heme, Polymerase Chain Reaction, Proteomics, Reverse Transcriptase Polymerase Chain Reaction, RNA, Messenger},
	issn = {0099-2240},
	doi = {10.1128/AEM.01128-06},
	author = {Haveman, Shelley A and Holmes, Dawn E and Ding, Yan-Huai R and Ward, Joy E and Didonato, Raymond J and Lovley, Derek R}
}
