Arsenic(III) fuels anoxygenic photosynthesis in hot spring biofilms from Mono Lake, California

Science
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Abstract

Phylogenetic analysis indicates that microbial arsenic metabolism is ancient and probably extends back to the primordial Earth. In microbial biofilms growing on the rock surfaces of anoxic brine pools fed by hot springs containing arsenite and sulfide at high concentrations, we discovered light-dependent oxidation of arsenite [As(III)] to arsenate [As(V)] occurring under anoxic conditions. The communities were composed primarily of Ectothiorhodospira-like purple bacteria or Oscillatoria-like cyanobacteria. A pure culture of a photosynthetic bacterium grew as a photoautotroph when As(III) was used as the sole photosynthetic electron donor. The strain contained genes encoding a putative As(V) reductase but no detectable homologs of the As(III) oxidase genes of aerobic chemolithotrophs, suggesting a reverse functionality for the reductase. Production of As(V) by anoxygenic photosynthesis probably opened niches for primordial Earth's first As(V)-respiring prokaryotes.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Arsenic(III) fuels anoxygenic photosynthesis in hot spring biofilms from Mono Lake, California
Series title Science
DOI 10.1126/science.1160799
Volume 321
Issue 5891
Year Published 2008
Language English
Contributing office(s) Toxic Substances Hydrology Program
Description 4 p.
First page 967
Last page 970