<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Szmuc, Eric</style></author><author><style face="normal" font="default" size="100%">Walker, David J F</style></author><author><style face="normal" font="default" size="100%">Kireev, Dmitry</style></author><author><style face="normal" font="default" size="100%">Akinwande, Deji</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author><author><style face="normal" font="default" size="100%">Keitz, Benjamin</style></author><author><style face="normal" font="default" size="100%">Ellington, Andrew</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Engineering Geobacter pili to produce metal:organic filaments.</style></title><secondary-title><style face="normal" font="default" size="100%">Biosens Bioelectron</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biosens Bioelectron</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biosensing Techniques</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Gold</style></keyword><keyword><style  face="normal" font="default" size="100%">Metal Nanoparticles</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2023</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2023 Feb 15</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">222</style></volume><pages><style face="normal" font="default" size="100%">114993</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The organized self-assembly of conductive biological structures holds promise for creating new bioelectronic devices. In particular, Geobacter sulfurreducens type IVa pili have proven to be a versatile material for fabricating protein nanowire-based devices. To scale the production of conductive pili, we designed a strain of Shewanella oneidensis that heterologously expressed abundant, conductive Geobacter pili when grown aerobically in liquid culture. S. oneidensis expressing a cysteine-modified pilin, designed to enhance the capability to bind to gold, generated conductive pili that self-assembled into biohybrid filaments in the presence of gold nanoparticles. Elemental composition analysis confirmed the filament-metal interactions within the structures, which were several orders of magnitude larger than previously described metal:organic filaments. The results demonstrate that the S. oneidensis chassis significantly advances the possibilities for facile conductive protein nanowire design and fabrication.&lt;/p&gt;</style></abstract><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/36525710?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbial nanowires.</style></title><secondary-title><style face="normal" font="default" size="100%">Curr Biol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Curr Biol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2022</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2022 Feb 07</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">32</style></volume><pages><style face="normal" font="default" size="100%">R110-R112</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;In this Quick guide, Derek Lovley introduces microbial nanowires-conductive extracellular appendages made by some bacteria and archaea.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/35134353?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Untangling Geobacter sulfurreducens Nanowires.</style></title><secondary-title><style face="normal" font="default" size="100%">mBio</style></secondary-title><alt-title><style face="normal" font="default" size="100%">mBio</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2022</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2022 Jun 28</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">13</style></volume><pages><style face="normal" font="default" size="100%">e0085022</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/35642973?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Liu, Xinying</style></author><author><style face="normal" font="default" size="100%">Walker, David J F</style></author><author><style face="normal" font="default" size="100%">Nonnenmann, Stephen S</style></author><author><style face="normal" font="default" size="100%">Sun, Dezhi</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Direct Observation of Electrically Conductive Pili Emanating from .</style></title><secondary-title><style face="normal" font="default" size="100%">mBio</style></secondary-title><alt-title><style face="normal" font="default" size="100%">mBio</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrons</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Atomic Force</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2021</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2021 Aug 31</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">e0220921</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Geobacter sulfurreducens is a model microbe for elucidating the mechanisms for extracellular electron transfer in several biogeochemical cycles, bioelectrochemical applications, and microbial metal corrosion. Multiple lines of evidence previously suggested that electrically conductive pili (e-pili) are an essential conduit for long-range extracellular electron transport in G. sulfurreducens. However, it has recently been reported that G. sulfurreducens does not express e-pili and that filaments comprised of multi-heme -type cytochromes are responsible for long-range electron transport. This possibility was directly investigated by examining cells, rather than filament preparations, with atomic force microscopy. Approximately 90% of the filaments emanating from wild-type cells had a diameter (3 nm) and conductance consistent with previous reports of e-pili harvested from G. sulfurreducens or heterologously expressed in Escherichia coli from the G. sulfurreducens pilin gene. The remaining 10% of filaments had a morphology consistent with filaments comprised of the -type cytochrome OmcS. A strain expressing a modified pilin gene designed to yield poorly conductive pili expressed 90% filaments with a 3-nm diameter, but greatly reduced conductance, further indicating that the 3-nm diameter conductive filaments in the wild-type strain were e-pili. A strain in which genes for five of the most abundant outer-surface -type cytochromes, including OmcS, were deleted yielded only 3-nm-diameter filaments with the same conductance as in the wild type. These results demonstrate that e-pili are the most abundant conductive filaments expressed by G. sulfurreducens, consistent with previous functional studies demonstrating the need for e-pili for long-range extracellular electron transfer.  Electroactive microbes have significant environmental impacts, as well as applications in bioenergy and bioremediation. The composition, function, and even existence of electrically conductive pili (e-pili) has been one of the most contentious areas of investigation in electromicrobiology, in part because e-pili offer a mechanism for long-range electron transport that does not involve the metal cofactors common in much of biological electron transport. This study demonstrates that e-pili are abundant filaments emanating from Geobacter sulfurreducens, which serves as a model for long-range extracellular electron transfer in direct interspecies electron transfer, dissimilatory metal reduction, microbe-electrode exchange, and corrosion caused by direct electron uptake from Fe(0). The methods described in this study provide a simple strategy for evaluating the distribution of conductive filaments throughout the microbial world with an approach that avoids artifactual production and/or enrichment of filaments that may not be physiologically relevant.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/34465020?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ueki, Toshiyuki</style></author><author><style face="normal" font="default" size="100%">Walker, David J F</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Ward, Joy E</style></author><author><style face="normal" font="default" size="100%">Woodard, Trevor L</style></author><author><style face="normal" font="default" size="100%">Nonnenmann, Stephen S</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Generation of High Current Densities in Geobacter sulfurreducens Lacking the Putative Gene for the PilB Pilus Assembly Motor.</style></title><secondary-title><style face="normal" font="default" size="100%">Microbiol Spectr</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Microbiol Spectr</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Deletion</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Geologic Sediments</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Atomic Force</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidoreductases</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2021</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2021 Oct 31</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">9</style></volume><pages><style face="normal" font="default" size="100%">e0087721</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Geobacter sulfurreducens is commonly employed as a model for the study of extracellular electron transport mechanisms in the  species. Deletion of , which is known to encode the pilus assembly motor protein for type IV pili in other bacteria, has been proposed as an effective strategy for evaluating the role of electrically conductive pili (e-pili) in G. sulfurreducens extracellular electron transfer. In those studies, the inhibition of e-pili expression associated with  deletion was not demonstrated directly but was inferred from the observation that  deletion mutants produced lower current densities than wild-type cells. Here, we report that deleting  did not diminish current production. Conducting probe atomic force microscopy revealed filaments with the same diameter and similar current-voltage response as e-pili harvested from wild-type G. sulfurreducens or when e-pili are expressed heterologously from the G. sulfurreducens pilin gene in Escherichia coli. Immunogold labeling demonstrated that a G. sulfurreducens strain expressing a pilin monomer with a His tag continued to express His tag-labeled filaments when  was deleted. These results suggest that a reinterpretation of the results of previous studies on G. sulfurreducens  deletion strains may be necessary.  Geobacter sulfurreducens is a model microbe for the study of biogeochemically and technologically significant processes, such as the reduction of Fe(III) oxides in soils and sediments, bioelectrochemical applications that produce electric current from waste organic matter or drive useful processes with the consumption of renewable electricity, direct interspecies electron transfer in anaerobic digestors and methanogenic soils and sediments, and metal corrosion. Elucidating the phenotypes associated with gene deletions is an important strategy for determining the mechanisms for extracellular electron transfer in G. sulfurreducens. The results reported here demonstrate that we cannot replicate the key phenotype reported for a gene deletion that has been central to the development of models for long-range electron transport in G. sulfurreducens.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/34585977?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ueki, Toshiyuki</style></author><author><style face="normal" font="default" size="100%">Walker, David J F</style></author><author><style face="normal" font="default" size="100%">Woodard, Trevor L</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Nonnenmann, Stephen S</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">An  Chassis for Production of Electrically Conductive Protein Nanowires.</style></title><secondary-title><style face="normal" font="default" size="100%">ACS Synth Biol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">ACS Synth Biol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Graphite</style></keyword><keyword><style  face="normal" font="default" size="100%">Microorganisms, Genetically-Modified</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Atomic Force</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword><keyword><style  face="normal" font="default" size="100%">Operon</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Engineering</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2020 Mar 20</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">9</style></volume><pages><style face="normal" font="default" size="100%">647-654</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt; pilin-based electrically conductive protein nanowires (e-PNs) are a revolutionary electronic material. They offer novel options for electronic sensing applications and have the remarkable ability to harvest electrical energy from atmospheric humidity. However, technical constraints limit mass cultivation and genetic manipulation of . Therefore, we designed a strain of  to express e-PNs by introducing a plasmid that contained an inducible operon with  genes for type IV pili biogenesis machinery and a synthetic gene designed to yield a peptide monomer that could be assembled into e-PNs. The e-PNs expressed in  and harvested with a simple filtration method had the same diameter (3 nm) and conductance as e-PNs expressed in . These results, coupled with the robustness of  for mass cultivation and the extensive  toolbox for genetic manipulation, greatly expand the opportunities for large-scale fabrication of novel e-PNs.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/32125829?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author><author><style face="normal" font="default" size="100%">Holmes, Dawn E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Protein Nanowires: the Electrification of the Microbial World and Maybe Our Own.</style></title><secondary-title><style face="normal" font="default" size="100%">J Bacteriol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J Bacteriol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Electron</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Engineering</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2020 Sep 23</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">202</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Electrically conductive protein nanowires appear to be widespread in the microbial world and are a revolutionary &quot;green&quot; material for the fabrication of electronic devices. Electrically conductive pili (e-pili) assembled from type IV pilin monomers have independently evolved multiple times in microbial history as have electrically conductive archaella (e-archaella) assembled from homologous archaellin monomers. A role for e-pili in long-range (micrometer) extracellular electron transport has been demonstrated in some microbes. The surprising finding of e-pili in syntrophic bacteria and the role of e-pili as conduits for direct interspecies electron transfer have necessitated a reassessment of routes for electron flux in important methanogenic environments, such as anaerobic digesters and terrestrial wetlands. Pilin monomers similar to those found in e-pili may also be a major building block of the conductive &quot;cables&quot; that transport electrons over centimeter distances through continuous filaments of cable bacteria consisting of a thousand cells or more. Protein nanowires harvested from microbes have many functional and sustainability advantages over traditional nanowire materials and have already yielded novel electronic devices for sustainable electricity production, neuromorphic memory, and sensing. e-pili can be mass produced with an  chassis, providing a ready source of material for electronics as well as for studies on the basic mechanisms for long-range electron transport along protein nanowires. Continued exploration is required to better understand the electrification of microbial communities with microbial nanowires and to expand the &quot;green toolbox&quot; of sustainable materials for wiring and powering the emerging &quot;Internet of things.&quot;&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">20</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/32747429?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Walker, David J F</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Holmes, Dawn E</style></author><author><style face="normal" font="default" size="100%">Rotaru, Amelia-Elena</style></author><author><style face="normal" font="default" size="100%">Ward, Joy E</style></author><author><style face="normal" font="default" size="100%">Woodard, Trevor L</style></author><author><style face="normal" font="default" size="100%">Zhu, Jiaxin</style></author><author><style face="normal" font="default" size="100%">Ueki, Toshiyuki</style></author><author><style face="normal" font="default" size="100%">Nonnenmann, Stephen S</style></author><author><style face="normal" font="default" size="100%">McInerney, Michael J</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Syntrophus conductive pili demonstrate that common hydrogen-donating syntrophs can have a direct electron transfer option.</style></title><secondary-title><style face="normal" font="default" size="100%">ISME J</style></secondary-title><alt-title><style face="normal" font="default" size="100%">ISME J</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Deltaproteobacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrons</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Formates</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2020 Mar</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">14</style></volume><pages><style face="normal" font="default" size="100%">837-846</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;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.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/31896792?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Filman, David J</style></author><author><style face="normal" font="default" size="100%">Marino, Stephen F</style></author><author><style face="normal" font="default" size="100%">Ward, Joy E</style></author><author><style face="normal" font="default" size="100%">Yang, Lu</style></author><author><style face="normal" font="default" size="100%">Mester, Zoltán</style></author><author><style face="normal" font="default" size="100%">Bullitt, Esther</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author><author><style face="normal" font="default" size="100%">Strauss, Mike</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Cryo-EM reveals the structural basis of long-range electron transport in a cytochrome-based bacterial nanowire.</style></title><secondary-title><style face="normal" font="default" size="100%">Commun Biol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Commun Biol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cryoelectron Microscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">Cytochromes c</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2019</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2019</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">2</style></volume><pages><style face="normal" font="default" size="100%">219</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Electrically conductive pili from  species, termed bacterial nanowires, are intensely studied for their biological significance and potential in the development of new materials. Using cryo-electron microscopy, we have characterized nanowires from conductive  pili preparations that are composed solely of head-to-tail stacked monomers of the six-heme C-type cytochrome OmcS. The unique fold of OmcS - closely wrapped around a continuous stack of hemes that can serve as an uninterrupted path for electron transport - generates a scaffold that supports the unbranched chain of hemes along the central axis of the filament. We present here, at 3.4 Å resolution, the structure of this cytochrome-based filament and discuss its possible role in long-range biological electron transport.&lt;/p&gt;</style></abstract><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/31240257?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Liu, Xing</style></author><author><style face="normal" font="default" size="100%">Zhan, Ji</style></author><author><style face="normal" font="default" size="100%">Jing, Xianyue</style></author><author><style face="normal" font="default" size="100%">Zhou, Shungui</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A pilin chaperone required for the expression of electrically conductive Geobacter sulfurreducens pili.</style></title><secondary-title><style face="normal" font="default" size="100%">Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Environ Microbiol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Chaperones</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2019</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2019 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">21</style></volume><pages><style face="normal" font="default" size="100%">2511-2522</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Mechanisms controlling the expression of the electrically conductive pili (e-pili) of Geobacter species are of interest because of the important role of e-pili in diverse biogeochemical processes, anaerobic digestion and electromicrobiological applications. We investigated the function of the protein, designated Spc (short pilin chaperone), encoded by the gene immediately downstream from the gene for PilA, the monomer that assembles into e-pili. Multiple lines of evidence suggest that Spc forms an oligomer that is associated with the inner membrane. Mutating the start codon of spc to prevent translation increased the transcript abundance of pilA but greatly diminished the abundance of PilA, and e-pili could no longer be detected. Cross-linking, protein capture and two-hybrid studies demonstrated that Spc and PilA interacted. Two sites in PilA for electrostatic interaction with Spc were identified. The results demonstrate that Spc is required for PilA stability prior to incorporation into e-pili, suggesting that Spc has a chaperone function that may be specific to the relatively short PilA monomers that assemble into e-pili. These results are important for identifying microorganisms likely to express e-pili from (meta)genomic data and for the construction of microbial strains expressing e-pili.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/31012224?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Walker, David Jf</style></author><author><style face="normal" font="default" size="100%">Adhikari, Ramesh Y</style></author><author><style face="normal" font="default" size="100%">Holmes, Dawn E</style></author><author><style face="normal" font="default" size="100%">Ward, Joy E</style></author><author><style face="normal" font="default" size="100%">Woodard, Trevor L</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Electrically conductive pili from pilin genes of phylogenetically diverse microorganisms.</style></title><secondary-title><style face="normal" font="default" size="100%">ISME J</style></secondary-title><alt-title><style face="normal" font="default" size="100%">ISME J</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Deltaproteobacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Methane</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2018</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2018 Jan</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">48-58</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;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 (&gt;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.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/28872631?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ueki, Toshiyuki</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Rotaru, Amelia-Elena</style></author><author><style face="normal" font="default" size="100%">Wang, Li-Ying</style></author><author><style face="normal" font="default" size="100%">Ward, Joy E</style></author><author><style face="normal" font="default" size="100%">Woodard, Trevor L</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%"> Strains Expressing Poorly Conductive Pili Reveal Constraints on Direct Interspecies Electron Transfer Mechanisms.</style></title><secondary-title><style face="normal" font="default" size="100%">mBio</style></secondary-title><alt-title><style face="normal" font="default" size="100%">mBio</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cytochromes</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Microbial Interactions</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2018</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2018 Jul 10</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">9</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Cytochrome-to-cytochrome electron transfer and electron transfer along conduits of multiple extracellular magnetite grains are often proposed as strategies for direct interspecies electron transfer (DIET) that do not require electrically conductive pili (e-pili). However, physical evidence for these proposed DIET mechanisms has been lacking. To investigate these possibilities further, we constructed  strain Aro-5, in which the wild-type pilin gene was replaced with the  pilin gene that was previously shown to yield poorly conductive pili in  strain Aro-5.  strain Aro-5 did not reduce Fe(III) oxide and produced only low current densities, phenotypes consistent with expression of poorly conductive pili. Like  strain Aro-5,  strain Aro-5 displayed abundant outer surface cytochromes. Cocultures initiated with wild-type  as the electron-donating strain and  strain Aro-5 as the electron-accepting strain grew via DIET. However,  Aro-5/ wild-type cocultures did not. Cocultures initiated with the Aro-5 strains of both species grew only when amended with granular activated carbon (GAC), a conductive material known to be a conduit for DIET. Magnetite could not substitute for GAC. The inability of the two Aro-5 strains to adapt for DIET in the absence of GAC suggests that there are physical constraints on establishing DIET solely through cytochrome-to-cytochrome electron transfer or along chains of magnetite. The finding that DIET is possible with electron-accepting partners that lack highly conductive pili greatly expands the range of potential electron-accepting partners that might participate in DIET. DIET is thought to be an important mechanism for interspecies electron exchange in natural anaerobic soils and sediments in which methane is either produced or consumed, as well as in some photosynthetic mats and anaerobic digesters converting organic wastes to methane. Understanding the potential mechanisms for DIET will not only aid in modeling carbon and electron flow in these geochemically significant environments but will also be helpful for interpreting meta-omic data from as-yet-uncultured microbes in DIET-based communities and for designing strategies to promote DIET in anaerobic digesters. The results demonstrate the need to develop a better understanding of the diversity of types of e-pili in the microbial world to identify potential electron-donating partners for DIET. Novel methods for recovering as-yet-uncultivated microorganisms capable of DIET in culture will be needed to further evaluate whether DIET is possible without e-pili in the absence of conductive materials such as GAC.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/29991583?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Philips, Jo</style></author><author><style face="normal" font="default" size="100%">Rabaey, Korneel</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author><author><style face="normal" font="default" size="100%">Vargas, Madeline</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Biofilm Formation by Clostridium ljungdahlii Is Induced by Sodium Chloride Stress: Experimental Evaluation and Transcriptome Analysis.</style></title><secondary-title><style face="normal" font="default" size="100%">PLoS One</style></secondary-title><alt-title><style face="normal" font="default" size="100%">PLoS One</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">Biomass</style></keyword><keyword><style  face="normal" font="default" size="100%">Carbon</style></keyword><keyword><style  face="normal" font="default" size="100%">Clostridium</style></keyword><keyword><style  face="normal" font="default" size="100%">Culture Media</style></keyword><keyword><style  face="normal" font="default" size="100%">Culture Techniques</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Flagella</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Profiling</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Glass</style></keyword><keyword><style  face="normal" font="default" size="100%">Graphite</style></keyword><keyword><style  face="normal" font="default" size="100%">Osmotic Pressure</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Ribosomal</style></keyword><keyword><style  face="normal" font="default" size="100%">Sodium Chloride</style></keyword><keyword><style  face="normal" font="default" size="100%">Spores, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Stress, Physiological</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2017</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2017</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">e0170406</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The acetogen Clostridium ljungdahlii is capable of syngas fermentation and microbial electrosynthesis. Biofilm formation could benefit both these applications, but was not yet reported for C. ljungdahlii. Biofilm formation does not occur under standard growth conditions, but attachment or aggregation could be induced by different stresses. The strongest biofilm formation was observed with the addition of sodium chloride. After 3 days of incubation, the biomass volume attached to a plastic surface was 20 times higher with than without the addition of 200 mM NaCl to the medium. The addition of NaCl also resulted in biofilm formation on glass, graphite and glassy carbon, the latter two being often used electrode materials for microbial electrosynthesis. Biofilms were composed of extracellular proteins, polysaccharides, as well as DNA, while pilus-like appendages were observed with, but not without, the addition of NaCl. A transcriptome analysis comparing planktonic (no NaCl) and biofilm (NaCl addition) cells showed that C. ljungdahlii coped with the salt stress by the upregulation of the general stress response, Na+ export and osmoprotectant accumulation. A potential role for poly-N-acetylglucosamines and D-alanine in biofilm formation was found. Flagellar motility was downregulated, while putative type IV pili biosynthesis genes were not expressed. Moreover, the gene expression analysis suggested the involvement of the transcriptional regulators LexA, Spo0A and CcpA in stress response and biofilm formation. This study showed that NaCl addition might be a valuable strategy to induce biofilm formation by C. ljungdahlii, which can improve the efficacy of syngas fermentation and microbial electrosynthesis applications.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/28118386?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Holmes, Dawn E</style></author><author><style face="normal" font="default" size="100%">Dang, Yan</style></author><author><style face="normal" font="default" size="100%">Walker, David J F</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The electrically conductive pili of pecies are a recently evolved feature for extracellular electron transfer.</style></title><secondary-title><style face="normal" font="default" size="100%">Microb Genom</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Microb Genom</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Electromagnetic Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2016</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2016 Aug</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">2</style></volume><pages><style face="normal" font="default" size="100%">e000072</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The electrically conductive pili (e-pili) of  have environmental and practical significance because they can facilitate electron transfer to insoluble Fe(III) oxides; to other microbial species; and through electrically conductive biofilms. E-pili conductivity has been attributed to the truncated PilA monomer, which permits tight packing of aromatic amino acids to form a conductive path along the length of e-pili. In order to better understand the evolution and distribution of e-pili in the microbial world, type IVa PilA proteins from various Gram-negative and Gram-positive bacteria were examined with a particular emphasis on Fe(III)-respiring bacteria. E-pilin genes are primarily restricted to a tight phylogenetic group in the order Desulfuromonadales. The downstream gene in all but one of the Desulfuromonadales that possess an e-pilin gene is a gene previously annotated as '' that has characteristics suggesting that it may encode an outer-membrane protein. Other genes associated with pilin function are clustered with e-pilin and '' genes in the Desulfuromonadales. In contrast, in the few bacteria outside the Desulfuromonadales that contain e-pilin genes, the other genes required for pilin function may have been acquired through horizontal gene transfer. Of the 95 known Fe(III)-reducing micro-organisms for which genomes are available, 80 % lack e-pilin genes, suggesting that e-pili are just one of several mechanisms involved in extracellular electron transport. These studies provide insight into where and when e-pili are likely to contribute to extracellular electron transport processes that are biogeochemically important and involved in bioenergy conversions.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">8</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/28348867?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Xiao, Ke</style></author><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Shu, Chuanjun</style></author><author><style face="normal" font="default" size="100%">Martz, Eric</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author><author><style face="normal" font="default" size="100%">Sun, Xiao</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Low Energy Atomic Models Suggesting a Pilus Structure that could Account for Electrical Conductivity of Geobacter sulfurreducens Pili.</style></title><secondary-title><style face="normal" font="default" size="100%">Sci Rep</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Sci Rep</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Theoretical</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2016</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2016 Mar 22</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">6</style></volume><pages><style face="normal" font="default" size="100%">23385</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The metallic-like electrical conductivity of Geobacter sulfurreducens pili has been documented with multiple lines of experimental evidence, but there is only a rudimentary understanding of the structural features which contribute to this novel mode of biological electron transport. In order to determine if it was feasible for the pilin monomers of G. sulfurreducens to assemble into a conductive filament, theoretical energy-minimized models of Geobacter pili were constructed with a previously described approach, in which pilin monomers are assembled using randomized structural parameters and distance constraints. The lowest energy models from a specific group of predicted structures lacked a central channel, in contrast to previously existing pili models. In half of the no-channel models the three N-terminal aromatic residues of the pilin monomer are arranged in a potentially electrically conductive geometry, sufficiently close to account for the experimentally observed metallic like conductivity of the pili that has been attributed to overlapping pi-pi orbitals of aromatic amino acids. These atomic resolution models capable of explaining the observed conductive properties of Geobacter pili are a valuable tool to guide further investigation of the metallic-like conductivity of the pili, their role in biogeochemical cycling, and applications in bioenergy and bioelectronics.&lt;/p&gt;</style></abstract><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/27001169?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Tan, Yang</style></author><author><style face="normal" font="default" size="100%">Adhikari, Ramesh Y</style></author><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Pi, Shuang</style></author><author><style face="normal" font="default" size="100%">Ward, Joy E</style></author><author><style face="normal" font="default" size="100%">Woodard, Trevor L</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Xia, Qiangfei</style></author><author><style face="normal" font="default" size="100%">Tuominen, Mark T</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Synthetic Biological Protein Nanowires with High Conductivity.</style></title><secondary-title><style face="normal" font="default" size="100%">Small</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Small</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword><keyword><style  face="normal" font="default" size="100%">Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Tryptophan</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2016</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2016 Sep</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">4481-5</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Genetic modification to add tryptophan to PilA, the monomer for the electrically conductive pili of Geobacter sulfurreducens, yields conductive protein filaments 2000-fold more conductive than the wild-type pili while cutting the diameter in half to 1.5 nm.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">33</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/27409066?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Liu, Fanghua</style></author><author><style face="normal" font="default" size="100%">Rotaru, Amelia-Elena</style></author><author><style face="normal" font="default" size="100%">Shrestha, Pravin M</style></author><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Magnetite compensates for the lack of a pilin-associated c-type cytochrome in extracellular electron exchange.</style></title><secondary-title><style face="normal" font="default" size="100%">Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Environ Microbiol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cytochrome c Group</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrons</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferrosoferric Oxide</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Heme</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxides</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2015</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2015 Mar</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">17</style></volume><pages><style face="normal" font="default" size="100%">648-55</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Nanoscale magnetite can facilitate microbial extracellular electron transfer that plays an important role in biogeochemical cycles, bioremediation and several bioenergy strategies, but the mechanisms for the stimulation of extracellular electron transfer are poorly understood. Further investigation revealed that magnetite attached to the electrically conductive pili of Geobacter species in a manner reminiscent of the association of the multi-heme c-type cytochrome OmcS with the pili of Geobacter sulfurreducens. Magnetite conferred extracellular electron capabilities on an OmcS-deficient strain unable to participate in interspecies electron transfer or Fe(III) oxide reduction. In the presence of magnetite wild-type cells repressed expression of the OmcS gene, suggesting that cells might need to produce less OmcS when magnetite was available. The finding that magnetite can compensate for the lack of the electron transfer functions of a multi-heme c-type cytochrome has implications not only for the function of modern microbes, but also for the early evolution of microbial electron transport mechanisms.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/24725505?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Seeing is believing: novel imaging techniques help clarify microbial nanowire structure and function.</style></title><secondary-title><style face="normal" font="default" size="100%">Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Environ Microbiol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cytochromes</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrons</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Atomic Force</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxides</style></keyword><keyword><style  face="normal" font="default" size="100%">Periplasm</style></keyword><keyword><style  face="normal" font="default" size="100%">Shewanella</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2015</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2015 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">17</style></volume><pages><style face="normal" font="default" size="100%">2209-15</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Novel imaging approaches have recently helped to clarify the properties of 'microbial nanowires'. Geobacter sulfurreducens pili are actual wires. They possess metallic-like conductivity, which can be attributed to overlapping pi-pi orbitals of key aromatic amino acids. Electrostatic force microscopy recently confirmed charge propagation along the pili, in a manner similar to carbon nanotubes. The pili are essential for long-range electron transport to insoluble electron acceptors and interspecies electron transfer. Previous claims that Shewanella oneidensis also produce conductive pili have recently been recanted, based on novel live-imaging studies. The putative pili are, in fact, long extensions of the cytochrome-rich outer membrane and periplasm that, when dried, collapse to form filaments with dimensions similar to pili. It has yet to be demonstrated whether the cytochrome-to-cytochrome electron hopping documented in the dried membrane extensions takes place in intact hydrated membrane extensions or whether the membrane extensions enhance electron transport to insoluble electron acceptors such as Fe(III) oxides or electrodes. These findings demonstrate that G. sulfurreducens conductive pili and the outer membrane extensions of S. oneidensis are fundamentally different in composition, mechanism of electron transport and physiological role. New methods for evaluating filament conductivity will facilitate screening the microbial world for nanowires and elucidating their function.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/25384844?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Vargas, Madeline</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly</style></author><author><style face="normal" font="default" size="100%">Tremblay, Pier-Luc</style></author><author><style face="normal" font="default" size="100%">Evans-Lutterodt, Kenneth</style></author><author><style face="normal" font="default" size="100%">Nykypanchuk, Dmytro</style></author><author><style face="normal" font="default" size="100%">Martz, Eric</style></author><author><style face="normal" font="default" size="100%">Tuominen, Mark T</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Structural basis for metallic-like conductivity in microbial nanowires.</style></title><secondary-title><style face="normal" font="default" size="100%">mBio</style></secondary-title><alt-title><style face="normal" font="default" size="100%">mBio</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acids, Aromatic</style></keyword><keyword><style  face="normal" font="default" size="100%">Chemical Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrophysiological Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Molecular</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword><keyword><style  face="normal" font="default" size="100%">X-Ray Diffraction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2015</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2015 Mar 03</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">6</style></volume><pages><style face="normal" font="default" size="100%">e00084</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;b&gt;UNLABELLED: &lt;/b&gt;Direct measurement of multiple physical properties of Geobacter sulfurreducens pili have demonstrated that they possess metallic-like conductivity, but several studies have suggested that metallic-like conductivity is unlikely based on the structures of the G. sulfurreducens pilus predicted from homology models. In order to further evaluate this discrepancy, pili were examined with synchrotron X-ray microdiffraction and rocking-curve X-ray diffraction. Both techniques revealed a periodic 3.2-Å spacing in conductive, wild-type G. sulfurreducens pili that was missing in the nonconductive pili of strain Aro5, which lack key aromatic acids required for conductivity. The intensity of the 3.2-Å peak increased 100-fold when the pH was shifted from 10.5 to 2, corresponding with a previously reported 100-fold increase in pilus conductivity with this pH change. These results suggest a clear structure-function correlation for metallic-like conductivity that can be attributed to overlapping π-orbitals of aromatic amino acids. A homology model of the G. sulfurreducens pilus was constructed with a Pseudomonas aeruginosa pilus model as a template as an alternative to previous models, which were based on a Neisseria gonorrhoeae pilus structure. This alternative model predicted that aromatic amino acids in G. sulfurreducens pili are packed within 3 to 4 Å, consistent with the experimental results. Thus, the predictions of homology modeling are highly sensitive to assumptions inherent in the model construction. The experimental results reported here further support the concept that the pili of G. sulfurreducens represent a novel class of electronically functional proteins in which aromatic amino acids promote long-distance electron transport.&lt;/p&gt;&lt;p&gt;&lt;b&gt;IMPORTANCE: &lt;/b&gt;The mechanism for long-range electron transport along the conductive pili of Geobacter sulfurreducens is of interest because these &quot;microbial nanowires&quot; are important in biogeochemical cycling as well as applications in bioenergy and bioelectronics. Although proteins are typically insulators, G. sulfurreducens pilus proteins possess metallic-like conductivity. The studies reported here provide important structural insights into the mechanism of the metallic-like conductivity of G. sulfurreducens pili. This information is expected to be useful in the design of novel bioelectronic materials.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/25736881?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Rotaru, Amelia-Elena</style></author><author><style face="normal" font="default" size="100%">Shrestha, Pravin Malla</style></author><author><style face="normal" font="default" size="100%">Liu, Fanghua</style></author><author><style face="normal" font="default" size="100%">Markovaite, Beatrice</style></author><author><style face="normal" font="default" size="100%">Chen, Shanshan</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Direct interspecies electron transfer between Geobacter metallireducens and Methanosarcina barkeri.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biological Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ethanol</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">Methane</style></keyword><keyword><style  face="normal" font="default" size="100%">Methanosarcina barkeri</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2014 Aug</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">80</style></volume><pages><style face="normal" font="default" size="100%">4599-605</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Direct interspecies electron transfer (DIET) is potentially an effective form of syntrophy in methanogenic communities, but little is known about the diversity of methanogens capable of DIET. The ability of Methanosarcina barkeri to participate in DIET was evaluated in coculture with Geobacter metallireducens. Cocultures formed aggregates that shared electrons via DIET during the stoichiometric conversion of ethanol to methane. Cocultures could not be initiated with a pilin-deficient G. metallireducens strain, suggesting that long-range electron transfer along pili was important for DIET. Amendments of granular activated carbon permitted the pilin-deficient G. metallireducens isolates to share electrons with M. barkeri, demonstrating that this conductive material could substitute for pili in promoting DIET. When M. barkeri was grown in coculture with the H2-producing Pelobacter carbinolicus, incapable of DIET, M. barkeri utilized H2 as an electron donor but metabolized little of the acetate that P.carbinolicus produced. This suggested that H2, but not electrons derived from DIET, inhibited acetate metabolism. P. carbinolicus-M. barkeri cocultures did not aggregate, demonstrating that, unlike DIET, close physical contact was not necessary for interspecies H2 transfer. M. barkeri is the second methanogen found to accept electrons via DIET and the first methanogen known to be capable of using either H2 or electrons derived from DIET for CO2 reduction. Furthermore, M. barkeri is genetically tractable,making it a model organism for elucidating mechanisms by which methanogens make biological electrical connections with other cells.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">15</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/24837373?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Liu, Xing</style></author><author><style face="normal" font="default" size="100%">Tremblay, Pier-Luc</style></author><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author><author><style face="normal" font="default" size="100%">Vargas, Madeline</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A Geobacter sulfurreducens strain expressing pseudomonas aeruginosa type IV pili localizes OmcS on pili but is deficient in Fe(III) oxide reduction and current production.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Cytochromes c</style></keyword><keyword><style  face="normal" font="default" size="100%">Electricity</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Methanosarcinaceae</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Pseudomonas aeruginosa</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Alignment</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2014 Feb</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">80</style></volume><pages><style face="normal" font="default" size="100%">1219-24</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The conductive pili of Geobacter species play an important role in electron transfer to Fe(III) oxides, in long-range electron transport through current-producing biofilms, and in direct interspecies electron transfer. Although multiple lines of evidence have indicated that the pili of Geobacter sulfurreducens have a metal-like conductivity, independent of the presence of c-type cytochromes, this claim is still controversial. In order to further investigate this phenomenon, a strain of G. sulfurreducens, designated strain PA, was constructed in which the gene for the native PilA, the structural pilin protein, was replaced with the PilA gene of Pseudomonas aeruginosa PAO1. Strain PA expressed and properly assembled P. aeruginosa PilA subunits into pili and exhibited a profile of outer surface c-type cytochromes similar to that of a control strain expressing the G. sulfurreducens PilA. Surprisingly, the strain PA pili were decorated with the c-type cytochrome OmcS in a manner similar to the control strain. However, the strain PA pili were 14-fold less conductive than the pili of the control strain, and strain PA was severely impaired in Fe(III) oxide reduction and current production. These results demonstrate that the presence of OmcS on pili is not sufficient to confer conductivity to pili and suggest that there are unique structural features of the G. sulfurreducens PilA that are necessary for conductivity.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/24296506?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Smith, Jessica A</style></author><author><style face="normal" font="default" size="100%">Tremblay, Pier-Luc</style></author><author><style face="normal" font="default" size="100%">Shrestha, Pravin Malla</style></author><author><style face="normal" font="default" size="100%">Snoeyenbos-West, Oona L</style></author><author><style face="normal" font="default" size="100%">Franks, Ashley E</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Going wireless: Fe(III) oxide reduction without pili by Geobacter sulfurreducens strain JS-1.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Adaptation, Physiological</style></keyword><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Deletion</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Oligonucleotide Array Sequence Analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Proteomics</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Analysis, DNA</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2014 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">80</style></volume><pages><style face="normal" font="default" size="100%">4331-40</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Previous studies have suggested that the conductive pili of Geobacter sulfurreducens are essential for extracellular electron transfer to Fe(III) oxides and for optimal long-range electron transport through current-producing biofilms. The KN400 strain of G. sulfurreducens reduces poorly crystalline Fe(III) oxide more rapidly than the more extensively studied DL-1 strain. Deletion of the gene encoding PilA, the structural pilin protein, in strain KN400 inhibited Fe(III) oxide reduction. However, low rates of Fe(III) reduction were detected after extended incubation (&gt;30 days) in the presence of Fe(III) oxide. After seven consecutive transfers, the PilA-deficient strain adapted to reduce Fe(III) oxide as fast as the wild type. Microarray, whole-genome resequencing, proteomic, and gene deletion studies indicated that this adaptation was associated with the production of larger amounts of the c-type cytochrome PgcA, which was released into the culture medium. It is proposed that the extracellular cytochrome acts as an electron shuttle, promoting electron transfer from the outer cell surface to Fe(III) oxides. The adapted PilA-deficient strain competed well with the wild-type strain when both were grown together on Fe(III) oxide. However, when 50% of the culture medium was replaced with fresh medium every 3 days, the wild-type strain outcompeted the adapted strain. A possible explanation for this is that the necessity to produce additional PgcA, to replace the PgcA being continually removed, put the adapted strain at a competitive disadvantage, similar to the apparent selection against electron shuttle-producing Fe(III) reducers in many anaerobic soils and sediments. Despite increased extracellular cytochrome production, the adapted PilA-deficient strain produced low levels of current, consistent with the concept that long-range electron transport through G. sulfurreducens biofilms is more effective via pili.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">14</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/24814783?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbial nanowires for bioenergy applications.</style></title><secondary-title><style face="normal" font="default" size="100%">Curr Opin Biotechnol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Curr Opin Biotechnol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Anaerobiosis</style></keyword><keyword><style  face="normal" font="default" size="100%">Bioelectric Energy Sources</style></keyword><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electricity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrons</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Methane</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword><keyword><style  face="normal" font="default" size="100%">Shewanella</style></keyword><keyword><style  face="normal" font="default" size="100%">Synthetic Biology</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2014 Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">27</style></volume><pages><style face="normal" font="default" size="100%">88-95</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Microbial nanowires are electrically conductive filaments that facilitate long-range extracellular electron transfer. The model for electron transport along Shewanella oneidensis nanowires is electron hopping/tunneling between cytochromes adorning the filaments. Geobacter sulfurreducens nanowires are comprised of pili that have metal-like conductivity attributed to overlapping pi-pi orbitals of aromatic amino acids. The nanowires of Geobacter species have been implicated in direct interspecies electron transfer (DIET), which may be an important mode of syntrophy in the conversion of organic wastes to methane. Nanowire networks confer conductivity to Geobacter biofilms converting organic compounds to electricity in microbial fuel cells (MFCs) and increasing nanowire production is the only genetic manipulation shown to yield strains with improved current-producing capabilities. Introducing nanowires, or nanowire mimetics, might improve other bioenergy strategies that rely on extracellular electron exchange, such as microbial electrosynthesis. Similarities between microbial nanowires and synthetic conducting polymers suggest additional energy-related applications.&lt;/p&gt;</style></abstract><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/24863901?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Yalcin, Sibel Ebru</style></author><author><style face="normal" font="default" size="100%">Tuominen, Mark T</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Visualization of charge propagation along individual pili proteins using ambient electrostatic force microscopy.</style></title><secondary-title><style face="normal" font="default" size="100%">Nat Nanotechnol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Nat Nanotechnol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Electrochemical, Scanning</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2014 Dec</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">9</style></volume><pages><style face="normal" font="default" size="100%">1012-7</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The nanoscale imaging of charge flow in proteins is crucial to understanding several life processes, including respiration, metabolism and photosynthesis. However, existing imaging methods are only effective under non-physiological conditions or are limited to photosynthetic proteins. Here, we show that electrostatic force microscopy can be used to directly visualize charge propagation along pili of Geobacter sulfurreducens with nanometre resolution and under ambient conditions. Charges injected at a single point into individual, untreated pili, which are still attached to cells, propagated over the entire filament. The mobile charge density in the pili, as well as the temperature and pH dependence of the charge density, were similar to those of carbon nanotubes and other organic conductors. These findings, coupled with a lack of charge propagation in mutated pili that were missing key aromatic amino acids, suggest that the pili of G. sulfurreducens function as molecular wires with transport via delocalized charges, rather than the hopping mechanism that is typical of biological electron transport.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/25326694?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Vargas, Madeline</style></author><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Tremblay, Pier-Luc</style></author><author><style face="normal" font="default" size="100%">Leang, Ching</style></author><author><style face="normal" font="default" size="100%">Smith, Jessica A</style></author><author><style face="normal" font="default" size="100%">Patel, Pranav</style></author><author><style face="normal" font="default" size="100%">Snoeyenbos-West, Oona</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Aromatic amino acids required for pili conductivity and long-range extracellular electron transport in Geobacter sulfurreducens.</style></title><secondary-title><style face="normal" font="default" size="100%">mBio</style></secondary-title><alt-title><style face="normal" font="default" size="100%">mBio</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acids, Aromatic</style></keyword><keyword><style  face="normal" font="default" size="100%">Bioelectric Energy Sources</style></keyword><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">Electricity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrodes</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Graphite</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013 Mar 12</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">4</style></volume><pages><style face="normal" font="default" size="100%">e00105-13</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;b&gt;UNLABELLED: &lt;/b&gt;It has been proposed that Geobacter sulfurreducens requires conductive pili for long-range electron transport to Fe(III) oxides and for high-density current production in microbial fuel cells. In order to investigate this further, we constructed a strain of G. sulfurreducens, designated Aro-5, which produced pili with diminished conductivity. This was accomplished by modifying the amino acid sequence of PilA, the structural pilin protein. An alanine was substituted for each of the five aromatic amino acids in the carboxyl terminus of PilA, the region in which G. sulfurreducens PilA differs most significantly from the PilAs of microorganisms incapable of long-range extracellular electron transport. Strain Aro-5 produced pili that were properly decorated with the multiheme c-type cytochrome OmcS, which is essential for Fe(III) oxide reduction. However, pili preparations of the Aro-5 strain had greatly diminished conductivity and Aro-5 cultures were severely limited in their capacity to reduce Fe(III) compared to the control strain. Current production of the Aro-5 strain, with a graphite anode serving as the electron acceptor, was less than 10% of that of the control strain. The conductivity of the Aro-5 biofilms was 10-fold lower than the control strain's. These results demonstrate that the pili of G. sulfurreducens must be conductive in order for the cells to be effective in extracellular long-range electron transport.&lt;/p&gt;&lt;p&gt;&lt;b&gt;IMPORTANCE: &lt;/b&gt;Extracellular electron transfer by Geobacter species plays an important role in the biogeochemistry of soils and sediments and has a number of bioenergy applications. For example, microbial reduction of Fe(III) oxide is one of the most geochemically significant processes in anaerobic soils, aquatic sediments, and aquifers, and Geobacter organisms are often abundant in such environments. Geobacter sulfurreducens produces the highest current densities of any known pure culture, and close relatives are often the most abundant organisms colonizing anodes in microbial fuel cells that harvest electricity from wastewater or aquatic sediments. The finding that a strain of G. sulfurreducens that produces pili with low conductivity is limited in these extracellular electron transport functions provides further insight into these environmentally significant processes.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/23481602?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Shrestha, Pravin Malla</style></author><author><style face="normal" font="default" size="100%">Rotaru, Amelia-Elena</style></author><author><style face="normal" font="default" size="100%">Aklujkar, Muktak</style></author><author><style face="normal" font="default" size="100%">Liu, Fanghua</style></author><author><style face="normal" font="default" size="100%">Shrestha, Minita</style></author><author><style face="normal" font="default" size="100%">Summers, Zarath M</style></author><author><style face="normal" font="default" size="100%">Malvankar, Nikhil</style></author><author><style face="normal" font="default" size="100%">Flores, Dan Carlo</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Syntrophic growth with direct interspecies electron transfer as the primary mechanism for energy exchange.</style></title><secondary-title><style face="normal" font="default" size="100%">Environ Microbiol Rep</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Environ Microbiol Rep</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acetates</style></keyword><keyword><style  face="normal" font="default" size="100%">Anaerobiosis</style></keyword><keyword><style  face="normal" font="default" size="100%">Citrate (si)-Synthase</style></keyword><keyword><style  face="normal" font="default" size="100%">Cytochrome c Group</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrons</style></keyword><keyword><style  face="normal" font="default" size="100%">Energy Metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Ethanol</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Formate Dehydrogenases</style></keyword><keyword><style  face="normal" font="default" size="100%">Fumarates</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013 Dec</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">5</style></volume><pages><style face="normal" font="default" size="100%">904-10</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Direct interspecies electron transfer (DIET) through biological electrical connections is an alternative to interspecies H2 transfer as a mechanism for electron exchange in syntrophic cultures. However, it has not previously been determined whether electrons received via DIET yield energy to support cell growth. In order to investigate this, co-cultures of Geobacter metallireducens, which can transfer electrons to wild-type G. sulfurreducens via DIET, were established with a citrate synthase-deficient G. sulfurreducens strain that can receive electrons for respiration through DIET only. In a medium with ethanol as the electron donor and fumarate as the electron acceptor, co-cultures with the citrate synthase-deficient G. sulfurreducens strain metabolized ethanol as fast as co-cultures with wild-type, but the acetate that G. metallireducens generated from ethanol oxidation accumulated. The lack of acetate metabolism resulted in less fumarate reduction and lower cell abundance of G. sulfurreducens. RNAseq analysis of transcript abundance was consistent with a lack of acetate metabolism in G. sulfurreducens and revealed gene expression levels for the uptake hydrogenase, formate dehydrogenase, the pilus-associated c-type cytochrome OmcS and pili consistent with electron transfer via DIET. These results suggest that electrons transferred via DIET can serve as the sole energy source to support anaerobic respiration.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/24249299?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Orellana, Roberto</style></author><author><style face="normal" font="default" size="100%">Leavitt, Janet J</style></author><author><style face="normal" font="default" size="100%">Comolli, Luis R</style></author><author><style face="normal" font="default" size="100%">Csencsits, Roseann</style></author><author><style face="normal" font="default" size="100%">Janot, Noemie</style></author><author><style face="normal" font="default" size="100%">Flanagan, Kelly A</style></author><author><style face="normal" font="default" size="100%">Gray, Arianna S</style></author><author><style face="normal" font="default" size="100%">Leang, Ching</style></author><author><style face="normal" font="default" size="100%">Izallalen, Mounir</style></author><author><style face="normal" font="default" size="100%">Mester, Tünde</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">U(VI) reduction by diverse outer surface c-type cytochromes of Geobacter sulfurreducens.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cytochromes</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Deletion</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Electron, Transmission</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Uranium</style></keyword><keyword><style  face="normal" font="default" size="100%">X-Ray Absorption Spectroscopy</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013 Oct</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">79</style></volume><pages><style face="normal" font="default" size="100%">6369-74</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Early studies with Geobacter sulfurreducens suggested that outer-surface c-type cytochromes might play a role in U(VI) reduction, but it has recently been suggested that there is substantial U(VI) reduction at the surface of the electrically conductive pili known as microbial nanowires. This phenomenon was further investigated. A strain of G. sulfurreducens, known as Aro-5, which produces pili with substantially reduced conductivity reduced U(VI) nearly as well as the wild type, as did a strain in which the gene for PilA, the structural pilin protein, was deleted. In order to reduce rates of U(VI) reduction to levels less than 20% of the wild-type rates, it was necessary to delete the genes for the five most abundant outer surface c-type cytochromes of G. sulfurreducens. X-ray absorption near-edge structure spectroscopy demonstrated that whereas 83% ± 10% of the uranium associated with wild-type cells correspond to U(IV) after 4 h of incubation, with the quintuple mutant, 89% ± 10% of uranium was U(VI). Transmission electron microscopy and X-ray energy dispersion spectroscopy revealed that wild-type cells did not precipitate uranium along pili as previously reported, but U(IV) was precipitated at the outer cell surface. These findings are consistent with those of previous studies, which have suggested that G. sulfurreducens requires outer-surface c-type cytochromes but not pili for the reduction of soluble extracellular electron acceptors.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">20</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/23934497?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Long-range electron transport to Fe(III) oxide via pili with metallic-like conductivity.</style></title><secondary-title><style face="normal" font="default" size="100%">Biochem Soc Trans</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biochem Soc Trans</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Outer Membrane Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">Cytochromes</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012 Dec 01</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">40</style></volume><pages><style face="normal" font="default" size="100%">1186-90</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The mechanisms for Fe(III) oxide reduction by Geobacter species are of interest because Geobacter species have been shown to play an important role in Fe(III) oxide reduction in a diversity of environments in which Fe(III) reduction is a geochemically significant process. Geobacter species specifically express pili during growth on Fe(III) oxide compared with growth on soluble chelated Fe(III), and mutants that cannot produce pili are unable to effectively reduce Fe(III) oxide. The pili of Geobacter sulfurreducens are electrically conductive along their length under physiologically relevant conditions and exhibit a metallic-like conductivity similar to that observed previously in synthetic organic metals. Metallic-like conductivity in a biological protein filament is a previously unrecognized mechanism for electron transport that differs significantly from the more well-known biological strategy of electron hopping/tunnelling between closely spaced redox-active proteins. The multihaem c-type cytochrome OmcS is specifically associated with pili and is necessary for Fe(III) oxide reduction. However, multiple lines of evidence, including the metallic-like conductivity of the pili and the fact that OmcS molecules are spaced too far apart for electron hopping/tunnelling, indicate that OmcS is not responsible for long-range electron conduction along the pili. The role of OmcS may be to facilitate electron transfer from the pili to Fe(III) oxide. Long-range electron transport via pili with metallic-like conductivity is a paradigm shift that has important implications not only for Fe(III) oxide reduction, but also for interspecies electron exchange in syntrophic microbial communities as well as microbe-electrode interactions and the emerging field of bioelectronics.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/23176452?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Malvankar, Nikhil S</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbial nanowires: a new paradigm for biological electron transfer and bioelectronics.</style></title><secondary-title><style face="normal" font="default" size="100%">ChemSusChem</style></secondary-title><alt-title><style face="normal" font="default" size="100%">ChemSusChem</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Physiological Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">Biotechnology</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanostructures</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012 Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">5</style></volume><pages><style face="normal" font="default" size="100%">1039-46</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The discovery that Geobacter sulfurreducens can produce protein filaments with metallic-like conductivity, known as microbial nanowires, that facilitate long-range electron transport is a paradigm shift in biological electron transfer and has important implications for biogeochemistry, microbial ecology, and the emerging field of bioelectronics. Although filaments in a wide diversity of microorganisms have been called microbial nanowires, the type IV pili of G. sulfurreducens and G. metallireducens are the only filaments that have been shown to be required for extracellular electron transport to extracellular electron acceptors or for conduction of electrons through biofilms. Studies of G. sulfurreducens pili preparations and intact biofilms under physiologically relevant conditions have provided multiple lines of evidence for metallic-like conduction along the length of pili and for the possibility of pili networks to confer high conductivity within biofilms. This mechanism of electron conduction contrasts with the previously known mechanism for biological electron transfer via electron tunneling or hopping between closely associated molecules, a strategy unlikely to be well adapted for long-range electron transport outside the cell. In addition to promoting electron exchange with abiotic electron acceptors, microbial nanowires have recently been shown to be involved in direct interspecies electron transfer between syntrophic partners. An improved understanding of the mechanisms for metallic-like conductivity in microbial nanowires, as well as engineering microorganisms with desirable catalytic abilities with nanowires, could lead to new applications in microbial electrosynthesis and bioelectronics.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/22614997?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Franks, Ashley E</style></author><author><style face="normal" font="default" size="100%">Glaven, Richard H</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Real-time spatial gene expression analysis within current-producing biofilms.</style></title><secondary-title><style face="normal" font="default" size="100%">ChemSusChem</style></secondary-title><alt-title><style face="normal" font="default" size="100%">ChemSusChem</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Bioelectric Energy Sources</style></keyword><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">Citrate (si)-Synthase</style></keyword><keyword><style  face="normal" font="default" size="100%">Cytochrome c Group</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Quaternary Ammonium Compounds</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012 Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">5</style></volume><pages><style face="normal" font="default" size="100%">1092-8</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The expression of genes involved in central metabolism and extracellular electron transfer was examined in real-time in current-producing anode biofilms of Geobacter sulfurreducens. Strains of G. sulfurreducens were generated, in which the expression of the gene for a short half-life fluorescent protein was placed under control of the promoter of the genes of interest. Anode biofilms were grown in a chamber that permitted direct examination of the cell fluorescence with confocal scanning laser microscopy. Studies on nifD and citrate synthase expression in response to environmental changes demonstrated that the reporter system revealed initiation and termination of gene transcription. Uniform expression throughout the biofilms was noted for the genes for citrate synthase; PilA, the structural protein of the conductive pili; and OmcZ, a c-type cytochrome essential for optimal current production, which was localized at the anode-biofilm interface. These results demonstrate that even cells at great distance from the anode, or within expected low-pH zones, are metabolically active and likely to contribute to current production and that there are factors other than gene expression differences influencing the distribution of OmcZ. This real-time reporter approach is likely to be a useful tool in optimizing the design of technologies relying on microbe-electrode interactions.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><custom1><style face="normal" font="default" size="100%">https://www.ncbi.nlm.nih.gov/pubmed/22577044?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Leang, Ching</style></author><author><style face="normal" font="default" size="100%">Qian, Xinlei</style></author><author><style face="normal" font="default" size="100%">Mester, Tünde</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Alignment of the c-type cytochrome OmcS along pili of Geobacter sulfurreducens.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl. Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cytochromes c</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Immunohistochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Immunoelectron</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010 Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">76</style></volume><pages><style face="normal" font="default" size="100%">4080-4</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Immunogold localization revealed that OmcS, a cytochrome that is required for Fe(III) oxide reduction by Geobacter sulfurreducens, was localized along the pili. The apparent spacing between OmcS molecules suggests that OmcS facilitates electron transfer from pili to Fe(III) oxides rather than promoting electron conduction along the length of the pili.</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/20400557?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Klimes, Anna</style></author><author><style face="normal" font="default" size="100%">Franks, Ashley E</style></author><author><style face="normal" font="default" size="100%">Glaven, Richard H</style></author><author><style face="normal" font="default" size="100%">Tran, Hoa</style></author><author><style face="normal" font="default" size="100%">Barrett, Christian L</style></author><author><style face="normal" font="default" size="100%">Qiu, Yu</style></author><author><style face="normal" font="default" size="100%">Zengler, Karsten</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Production of pilus-like filaments in Geobacter sulfurreducens in the absence of the type IV pilin protein PilA.</style></title><secondary-title><style face="normal" font="default" size="100%">FEMS Microbiol Lett</style></secondary-title><alt-title><style face="normal" font="default" size="100%">FEMS Microbiol. Lett.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Adhesion</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Deletion</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Glass</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Electron, Transmission</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010 Sep 1</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">310</style></volume><pages><style face="normal" font="default" size="100%">62-8</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The pili of Geobacter sulfurreducens are of interest because of the apparent importance of the type IV pili in extracellular electron transfer. A strain of G. sulfurreducens, designated strain MA, produced many more pili than the previously studied DL-1 strain even though genome resequencing indicated that the MA and DL-1 genome sequences were identical. Filaments that looked similar to type IV pili in transmission electron micrographs were abundant even after the gene encoding PilA, the structural pilin protein, was deleted. The results of proteinase K treatment indicated that the filaments were proteinaceous. The simultaneous deletion of several genes encoding homologues of type II pseudopilins was required before the filaments were significantly depleted. The pilA-deficient MA strain attached to glass as well as the wild-type MA did, but strains in which three or four pseudopilin genes were deleted in addition to pilA had impaired attachment capabilities. These results demonstrate that there are several proteins that can yield pilin-like filaments in G. sulfurreducens and that some means other than microscopic observation is required before the composition of filaments can be unambiguously specified.</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/20629752?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Reguera, Gemma</style></author><author><style face="normal" font="default" size="100%">Pollina, Rachael B</style></author><author><style face="normal" font="default" size="100%">Nicoll, Julie S</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Possible nonconductive role of Geobacter sulfurreducens pilus nanowires in biofilm formation.</style></title><secondary-title><style face="normal" font="default" size="100%">J Bacteriol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Bacteriol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Agglutination</style></keyword><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2007 Mar</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">189</style></volume><pages><style face="normal" font="default" size="100%">2125-7</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Geobacter sulfurreducens required expression of electrically conductive pili to form biofilms on Fe(III) oxide surfaces, but pili were also essential for biofilm development on plain glass when fumarate was the sole electron acceptor. Furthermore, pili were needed for cell aggregation in agglutination studies. These results suggest that the pili of G. sulfurreducens also have a structural role in biofilm formation.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/17158673?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Reguera, Gemma</style></author><author><style face="normal" font="default" size="100%">Nevin, Kelly P</style></author><author><style face="normal" font="default" size="100%">Nicoll, Julie S</style></author><author><style face="normal" font="default" size="100%">Covalla, Sean F</style></author><author><style face="normal" font="default" size="100%">Woodard, Trevor L</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Biofilm and nanowire production leads to increased current in Geobacter sulfurreducens fuel cells.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl. Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acetates</style></keyword><keyword><style  face="normal" font="default" size="100%">Bioelectric Energy Sources</style></keyword><keyword><style  face="normal" font="default" size="100%">Biofilms</style></keyword><keyword><style  face="normal" font="default" size="100%">Electricity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrodes</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Confocal</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanowires</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2006 Nov</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">72</style></volume><pages><style face="normal" font="default" size="100%">7345-8</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Geobacter sulfurreducens developed highly structured, multilayer biofilms on the anode surface of a microbial fuel cell converting acetate to electricity. Cells at a distance from the anode remained viable, and there was no decrease in the efficiency of current production as the thickness of the biofilm increased. Genetic studies demonstrated that efficient electron transfer through the biofilm required the presence of electrically conductive pili. These pili may represent an electronic network permeating the biofilm that can promote long-range electrical transfer in an energy-efficient manner, increasing electricity production more than 10-fold.</style></abstract><issue><style face="normal" font="default" size="100%">11</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16936064?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Reguera, Gemma</style></author><author><style face="normal" font="default" size="100%">McCarthy, Kevin D</style></author><author><style face="normal" font="default" size="100%">Mehta, Teena</style></author><author><style face="normal" font="default" size="100%">Nicoll, Julie S</style></author><author><style face="normal" font="default" size="100%">Tuominen, Mark T</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Extracellular electron transfer via microbial nanowires.</style></title><secondary-title><style face="normal" font="default" size="100%">Nature</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Nature</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biotechnology</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Atomic Force</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Electron, Transmission</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanostructures</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2005 Jun 23</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">435</style></volume><pages><style face="normal" font="default" size="100%">1098-101</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">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.</style></abstract><issue><style face="normal" font="default" size="100%">7045</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/15973408?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Childers, Susan E</style></author><author><style face="normal" font="default" size="100%">Ciufo, Stacy</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Geobacter metallireducens accesses insoluble Fe(III) oxide by chemotaxis.</style></title><secondary-title><style face="normal" font="default" size="100%">Nature</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Nature</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Chemotaxis</style></keyword><keyword><style  face="normal" font="default" size="100%">Deltaproteobacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferrous Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fimbriae, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Flagella</style></keyword><keyword><style  face="normal" font="default" size="100%">Manganese Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Movement</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxides</style></keyword><keyword><style  face="normal" font="default" size="100%">Solubility</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002 Apr 18</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">416</style></volume><pages><style face="normal" font="default" size="100%">767-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Microorganisms that use insoluble Fe(III) oxide as an electron acceptor can have an important function in the carbon and nutrient cycles of aquatic sediments and in the bioremediation of organic and metal contaminants in groundwater. Although Fe(III) oxides are often abundant, Fe(III)-reducing microbes are faced with the problem of how to access effectively an electron acceptor that can not diffuse to the cell. Fe(III)-reducing microorganisms in the genus Shewanella have resolved this problem by releasing soluble quinones that can carry electrons from the cell surface to Fe(III) oxide that is at a distance from the cell. Here we report that another Fe(III)-reducer, Geobacter metallireducens, has an alternative strategy for accessing Fe(III) oxides. Geobacter metallireducens specifically expresses flagella and pili only when grown on insoluble Fe(III) or Mn(IV) oxide, and is chemotactic towards Fe(II) and Mn(II) under these conditions. These results suggest that G. metallireducens senses when soluble electron acceptors are depleted and then synthesizes the appropriate appendages to permit it to search for, and establish contact with, insoluble Fe(III) or Mn(IV) oxide. This approach to the use of an insoluble electron acceptor may explain why Geobacter species predominate over other Fe(III) oxide-reducing microorganisms in a wide variety of sedimentary environments.</style></abstract><issue><style face="normal" font="default" size="100%">6882</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11961561?dopt=Abstract</style></custom1></record></records></xml>