Geomicrobiology of selenium: Life and death by selenite

Abstract

Selenite oxyanions are readily assimilated by microorganisms for the synthesis of selenoproteins. However, at elevated concentrations, selenite becomes highly toxic due to the intracellular formation of reactive oxygen species. Remarkably, some microorganisms have evolved the ability to not only survive toxic levels of selenite, but to flourish in its presence. The cultivation and genomic sequencing of dissimilatory selenite-respiring Bacteria and Archaea have begun to help elucidate the molecular mechanisms of selenite respiration.