Dissimilatory metal reduction is marked by unexpected physiological and genetic complexity: EET taxis in Shewanella and the diverse and rapidly evolving Geobacter cytochrome pool

Abstract

Dissimilatory metal reduction by Shewanella and Geobacter species is more than just respiration with novel electron acceptors. In addition to the physical transfer of electrons out of the cell, EET In these organisms is supported by complex physiological and genetic features that are in the early stages of investigation.In S. oneidensis EET and motility are connected by taxis to extracellular electron acceptors and in particular, electrodes. In Geobacter and, to a lesser extent, Shewanella species, MHC genes are subject to higher mutation rates than the average gene in the cell. Neither taxis to electrodes nor increased mutation rates in MHC genes are understood, underscoring the fact that we have a long way to go in investigating the biology of dissimilatory metal reducers.