Extracellular cytochrome nanowires appear to be ubiquitous in microbes

A Geobacter bacteria isolated from a contaminated ditch in Oklahoma has an unusual appendage—a long extracellular nanowire that can conduct electricity. The electron transport chain in this nanowire carries electrons from the bacteria to an insoluble external electron acceptor to help the microbe make energy. Such long-range electron transfers at a micron-scale are thought to have played an important role in microbial metabolism on the early Earth.