@article {3072,
	title = {Syntrophus conductive pili demonstrate that common hydrogen-donating syntrophs can have a direct electron transfer option.},
	journal = {ISME J},
	volume = {14},
	year = {2020},
	month = {2020 Mar},
	pages = {837-846},
	abstract = {<p>Syntrophic interspecies electron exchange is essential for the stable functioning of diverse anaerobic microbial communities. Hydrogen/formate interspecies electron transfer (HFIT), in which H and/or formate function as diffusible electron carriers, has been considered to be the primary mechanism for electron transfer because most common syntrophs were thought to lack biochemical components, such as electrically conductive pili (e-pili), necessary for direct interspecies electron transfer (DIET). Here we report that Syntrophus aciditrophicus, one of the most intensively studied microbial models for HFIT, produces e-pili and can grow via DIET. Heterologous expression of the putative S. aciditrophicus type IV pilin gene in Geobacter sulfurreducens yielded conductive pili of the same diameter (4 nm) and conductance of the native S. aciditrophicus pili and enabled long-range electron transport in G. sulfurreducens. S. aciditrophicus lacked abundant c-type cytochromes often associated with DIET. Pilin genes likely to yield e-pili were found in other genera of hydrogen/formate-producing syntrophs. The finding that DIET is a likely option for diverse syntrophs that are abundant in many anaerobic environments necessitates a reexamination of the paradigm that HFIT is the predominant mechanism for syntrophic electron exchange within anaerobic microbial communities of biogeochemical and practical significance.</p>},
	keywords = {Deltaproteobacteria, Electric Conductivity, Electron Transport, Electrons, Fimbriae Proteins, Fimbriae, Bacterial, Formates, Geobacter, Hydrogen},
	issn = {1751-7370},
	doi = {10.1038/s41396-019-0575-9},
	author = {Walker, David J F and Nevin, Kelly P and Holmes, Dawn E and Rotaru, Amelia-Elena and Ward, Joy E and Woodard, Trevor L and Zhu, Jiaxin and Ueki, Toshiyuki and Nonnenmann, Stephen S and McInerney, Michael J and Lovley, Derek R}
}
@article {3087,
	title = {Electrically conductive pili from pilin genes of phylogenetically diverse microorganisms.},
	journal = {ISME J},
	volume = {12},
	year = {2018},
	month = {2018 Jan},
	pages = {48-58},
	abstract = {<p>The possibility that bacteria other than Geobacter species might contain genes for electrically conductive pili (e-pili) was investigated by heterologously expressing pilin genes of interest in Geobacter sulfurreducens. Strains of G. sulfurreducens producing high current densities, which are only possible with e-pili, were obtained with pilin genes from Flexistipes sinusarabici, Calditerrivibrio nitroreducens and Desulfurivibrio alkaliphilus. The conductance of pili from these strains was comparable to native G. sulfurreducens e-pili. The e-pili derived from C. nitroreducens, and D. alkaliphilus pilin genes are the first examples of relatively long (>100 amino acids) pilin monomers assembling into e-pili. The pilin gene from Candidatus Desulfofervidus auxilii did not yield e-pili, suggesting that the hypothesis that this sulfate reducer wires itself with e-pili to methane-oxidizing archaea to enable anaerobic methane oxidation should be reevaluated. A high density of aromatic amino acids and a lack of substantial aromatic-free gaps along the length of long pilins may be important characteristics leading to e-pili. This study demonstrates a simple method to screen pilin genes from difficult-to-culture microorganisms for their potential to yield e-pili; reveals new sources for biologically based electronic materials; and suggests that a wide phylogenetic diversity of microorganisms may use e-pili for extracellular electron exchange.</p>},
	keywords = {Deltaproteobacteria, Electric Conductivity, Fimbriae Proteins, Fimbriae, Bacterial, Methane, Oxidation-Reduction, Phylogeny},
	issn = {1751-7370},
	doi = {10.1038/ismej.2017.141},
	author = {Walker, David Jf and Adhikari, Ramesh Y and Holmes, Dawn E and Ward, Joy E and Woodard, Trevor L and Nevin, Kelly P 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}
}
