@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 {538,
	title = {DNA microarray analysis of nitrogen fixation and Fe(III) reduction in Geobacter sulfurreducens.},
	journal = {Appl Environ Microbiol},
	volume = {71},
	year = {2005},
	month = {2005 May},
	pages = {2530-8},
	abstract = {A DNA microarray representing the genome of Geobacter sulfurreducens was constructed for use in global gene expression profiling of cells under steady-state conditions with acetate as the electron donor and Fe(III) or fumarate as the electron acceptor. Reproducible differences in transcript levels were also observed in comparisons between cells grown with ammonia and those fixing atmospheric nitrogen. There was a high correlation between changes in transcript levels determined with microarray analyses and an evaluation of a subset of the genome with quantitative PCR. As expected, cells required to fix nitrogen had higher levels of transcripts of genes associated with nitrogen fixation, further demonstrating that the microarray approach could reliably detect important physiological changes. Cells grown with Fe(III) as the electron acceptor had higher levels of transcripts for omcB, a gene coding for an outer membrane c-type cytochrome that is essential for Fe(III) reduction. Several other c-type cytochrome genes also appeared to be up-regulated. An unexpected result was significantly higher levels of transcripts for genes which have a role in metal efflux, potentially suggesting the importance of maintaining metal homeostasis during release of soluble metals when reducing Fe(III). A substantial proportion (30\%) of significantly expressed genes during Fe(III) reduction were genes of unknown function or hypothetical proteins, suggesting differences in Fe(III) reduction physiology among microorganisms which perform this metabolic process.},
	keywords = {Ferric Compounds, Fumarates, Geobacter, Microarray Analysis, Nitrogen Fixation, Oxidation-Reduction, Polymerase Chain Reaction},
	issn = {0099-2240},
	doi = {10.1128/AEM.71.5.2530-2538.2005},
	author = {Meth{\'e}, Barbara A and Webster, Jennifer and Nevin, Kelly and Butler, Jessica and Lovley, Derek R}
}
