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Science 15 August 2008:
Vol. 321. no. 5891, pp. 967 - 970
DOI: 10.1126/science.1160799
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Reports

Arsenic(III) Fuels Anoxygenic Photosynthesis in Hot Spring Biofilms from Mono Lake, California

T. R. Kulp,1 S. E. Hoeft,1 M. Asao,2 M. T. Madigan,2 J. T. Hollibaugh,3 J. C. Fisher,3* J. F. Stolz,4 C. W. Culbertson,5 L. G. Miller,1 R. S. Oremland1{dagger}

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.

1 U.S. Geological Survey (USGS), Menlo Park, CA 94025, USA.
2 Department of Microbiology, Southern Illinois University, Carbondale, IL 62901, USA.
3 Department of Marine Sciences, University of Georgia, Athens, GA 30602, USA.
4 Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282, USA.
5 USGS Water Sciences Center, Augusta, ME 04330, USA.

* Present address: Division of Earth and Ecosystem Science, Desert Research Institute, Las Vegas, NV 89119, USA.

{dagger} To whom correspondence should be addressed. E-mail: roremlan{at}usgs.gov

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ecophysiology of "Halarsenatibacter silvermanii" Strain SLAS-1T, gen. nov., sp. nov., a Facultative Chemoautotrophic Arsenate Respirer from Salt-Saturated Searles Lake, California.
J. S. Blum, S. Han, B. Lanoil, C. Saltikov, B. Witte, F. R. Tabita, S. Langley, T. J. Beveridge, L. Jahnke, and R. S. Oremland (2009)
Appl. Envir. Microbiol. 75, 1950-1960
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Biotransformation of arsenic by a Yellowstone thermoacidophilic eukaryotic alga.
J. Qin, C. R. Lehr, C. Yuan, X. C. Le, T. R. McDermott, and B. P. Rosen (2009)
PNAS 106, 5213-5217
   Abstract »    Full Text »    PDF »
Comment on "Arsenic (III) Fuels Anoxygenic Photosynthesis in Hot Spring Biofilms from Mono Lake, California".
B. Schoepp-Cothenet, S. Duval, J. M. Santini, and W. Nitschke (2009)
Science 323, 583c
   Abstract »    Full Text »    PDF »
Response to Comment on "Arsenic(III) Fuels Anoxygenic Photosynthesis in Hot Spring Biofilms from Mono Lake, California".
R. S. Oremland, J. F. Stolz, M. Madigan, J. T. Hollibaugh, T. R. Kulp, S. E. Hoeft, J. Fisher, L. G. Miller, C. W. Culbertson, and M. Asao (2009)
Science 323, 583d
   Abstract »    Full Text »    PDF »


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