Arsenic and selenium in microbial metabolism.

TLDR: This review highlights recent advances in ecology, biochemistry, and molecular biology and provides a prelude to the impact of genomics studies.

Abstract: Arsenic and selenium are readily metabolized by prokaryotes, par- ticipating in a full range of metabolic functions including as- similation, methylation, detoxification, and anaerobic respiration. Arsenic speciation and mobility is affected by microbes through oxidation/reduction reactions as part of resistance and respiratory processes. A robust arsenic cycle has been demonstrated in diverse environments. Respiratory arsenate reductases, arsenic methyltrans- ferases, and new components in arsenic resistance have been recently described. The requirement for selenium stems primarily from its in- corporation into selenocysteine and its function in selenoenzymes. Selenium oxyanions can serve as an electron acceptor in anaero- bic respiration, forming distinct nanoparticles of elemental selenium that may be enriched in 76 Se. The biogenesis of selenoproteins has been elucidated, and selenium methyltransferases and a respiratory selenate reductase have also been described. This review highlights recent advances in ecology, biochemistry, and molecular biology and provides a prelude to the impact of genomics studies.