Technical Comments

Comment on “A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus”

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Science  27 May 2011:
1201381
DOI: 10.1126/science.1201381

Abstract

Wolfe-Simon et al. (Science Express Research Article, published online 2 December 2010; 10.1126/science.1197258) reported that a naturally occurring bacterium, strain GFAJ-1, can substitute arsenic for phosphorus in its biomolecules. However, straightforward experiments to support this claim, including density gradient centrifugation of DNA assumed to contain arsenic, were either not performed or not presented. As a result, the authors’ conclusions remain uncertain.