@article {490,
	title = {PilR, a transcriptional regulator for pilin and other genes required for Fe(III) reduction in Geobacter sulfurreducens.},
	journal = {J Mol Microbiol Biotechnol},
	volume = {16},
	year = {2009},
	month = {2009},
	pages = {146-58},
	abstract = {Growth using Fe(III) as a terminal electron acceptor is a critical physiological process in Geobacter sulfurreducens. However, the mechanisms of electron transfer during Fe(III) reduction are only now being understood. It has been demonstrated that the pili in G. sulfurreducens function as microbial nanowires conducting electrons onto Fe(III) oxides. A number of c-type cytochromes have also been shown to play important roles in Fe(III) reduction. However, the regulatory networks controlling the expression of the genes involved in such processes are not well known. Here we report that the expression of pilA, which encodes the pilistructural protein, is directly regulated by a two-component regulatory system in which PilR functions as an RpoN-dependent enhancer binding protein. Surprisingly, a deletion of the pilR gene affected not only insoluble Fe(III) reduction, which requires pili, but also soluble Fe(III) reduction, which, in contrast, does not require pili. Gene expression profiling using whole-genome DNA microarray and quantitative RT-PCR analyses obtained with a PilR-deficient mutant revealed that the expression of pilA and other pilin-related genes are downregulated, while many c-type cytochromes involved in Fe(III) reduction were differentially regulated. This is the first instance of an enhancer binding protein implicated in regulating genes involved in Fe(III) respiratory functions.},
	keywords = {Bacterial Proteins, Ferric Compounds, Fimbriae Proteins, Gene Expression Regulation, Bacterial, Genes, Regulator, Geobacter, Oxidation-Reduction, Transcription, Genetic},
	issn = {1660-2412},
	doi = {10.1159/000115849},
	author = {Ju{\'a}rez, Katy and Kim, Byoung-Chan and Nevin, Kelly and Olvera, Leticia and Reguera, Gemma and Lovley, Derek R and Meth{\'e}, Barbara A}
}
@article {535,
	title = {Extracellular electron transfer via microbial nanowires.},
	journal = {Nature},
	volume = {435},
	year = {2005},
	month = {2005 Jun 23},
	pages = {1098-101},
	abstract = {Microbes that can transfer electrons to extracellular electron acceptors, such as Fe(iii) oxides, are important in organic matter degradation and nutrient cycling in soils and sediments. Previous investigations on electron transfer to Fe(iii) have focused on the role of outer-membrane c-type cytochromes. However, some Fe(iii) reducers lack c-cytochromes. Geobacter species, which are the predominant Fe(iii) reducers in many environments, must directly contact Fe(iii) oxides to reduce them, and produce monolateral pili that were proposed, on the basis of the role of pili in other organisms, to aid in establishing contact with the Fe(iii) oxides. Here we report that a pilus-deficient mutant of Geobacter sulfurreducens could not reduce Fe(iii) oxides but could attach to them. Conducting-probe atomic force microscopy revealed that the pili were highly conductive. These results indicate that the pili of G. sulfurreducens might serve as biological nanowires, transferring electrons from the cell surface to the surface of Fe(iii) oxides. Electron transfer through pili indicates possibilities for other unique cell-surface and cell-cell interactions, and for bioengineering of novel conductive materials.},
	keywords = {Biotechnology, Electric Conductivity, Electron Transport, Ferric Compounds, Fimbriae Proteins, Fimbriae, Bacterial, Genes, Bacterial, Geobacter, Microscopy, Atomic Force, Microscopy, Electron, Transmission, Mutation, Nanostructures, Phylogeny},
	issn = {1476-4687},
	doi = {10.1038/nature03661},
	author = {Reguera, Gemma and McCarthy, Kevin D and Mehta, Teena and Nicoll, Julie S and Tuominen, Mark T and Lovley, Derek R}
}
