On the evolution and physiology of cable bacteria

Cable bacteria are globally occurring multicellular filamentous bacteria that are electrically conductive: they transfer electrons from sulfide oxidation at one end over centimeter distances to oxygen reduction at the other end. Unlike any other organism known, cable bacteria thus split their central energy-conserving redox reaction into 2 half-reactions that occur in different cells as far as several centimeters apart. Before this study, the molecular foundation, evolutionary origin, and genomic basis of this unique metabolism were unknown. Here we reconstructed 5 genomes from single filaments and 1 from a cable bacterium enrichment culture to shed light on the evolution and physiology of cable bacteria; and, together with proteomic and experimental data, we propose a metabolic model of how cable bacteria work.