{"id":12445,"date":"2018-03-01T11:23:50","date_gmt":"2018-03-01T19:23:50","guid":{"rendered":"https:\/\/www.darkenergybiosphere.org\/?post_type=publication&#038;p=12445"},"modified":"2018-03-15T10:54:20","modified_gmt":"2018-03-15T17:54:20","slug":"tracking-electron-uptake-from-a-cathode-into-shewanella-cells-implications-for-energy-acquisition-from-solid-substrate-electron-donors","status":"publish","type":"publication","link":"https:\/\/www.darkenergybiosphere.org\/publication\/tracking-electron-uptake-from-a-cathode-into-shewanella-cells-implications-for-energy-acquisition-from-solid-substrate-electron-donors\/","title":{"rendered":"Tracking Electron Uptake from a Cathode into Shewanella Cells: Implications for Energy Acquisition from Solid-Substrate Electron Donors"},"content":{"rendered":"<p>While typically investigated as a microorganism capable of extracellular electron transfer to minerals or anodes,\u00a0<em>Shewanella oneidensis<\/em>\u00a0MR-1 can also facilitate electron flow from a cathode to terminal electron acceptors, such as fumarate or oxygen, thereby providing a model system for a process that has significant environmental and technological implications. This work demonstrates that cathodic electrons enter the electron transport chain of\u00a0<em>S.\u00a0oneidensis<\/em>\u00a0when oxygen is used as the terminal electron acceptor. The effect of electron transport chain inhibitors suggested that a proton gradient is generated during cathode oxidation, consistent with the higher cellular ATP levels measured in cathode-respiring cells than in controls. Cathode oxidation also correlated with an increase in the cellular redox (NADH\/FMNH<sub>2<\/sub>) pool determined with a bioluminescence assay, a proton uncoupler, and a mutant of proton-pumping NADH oxidase complex I. This work suggested that the generation of NADH\/FMNH<sub>2<\/sub>\u00a0under cathodic conditions was linked to reverse electron flow mediated by complex I. A decrease in cathodic electron uptake was observed in various mutant strains, including those lacking the extracellular electron transfer components necessary for anodic-current generation. While no cell growth was observed under these conditions, here we show that cathode oxidation is linked to cellular energy acquisition, resulting in a quantifiable reduction in the cellular decay rate. This work highlights a potential mechanism for cell survival and\/or persistence on cathodes, which might extend to environments where growth and division are severely limited.<\/p>\n","protected":false},"template":"","tags":[],"publication_type":[19],"_links":{"self":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication\/12445"}],"collection":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication"}],"about":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/types\/publication"}],"wp:attachment":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/media?parent=12445"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/tags?post=12445"},{"taxonomy":"publication_type","embeddable":true,"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication_type?post=12445"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}