Wolfe-Simon et al. reported isolation of a strain of Halomonas bacteria, GFAJ-1, which could use arsenic as a nutrient when phosphate is limiting, and which could specifically incorporate arsenic into its DNA in place of phosphorus. We have found that arsenate is not needed for growth of GFAJ-1 when phosphate is limiting . Additionally, we used mass spectrometry to show that DNA purified from cells grown with limiting phosphate and abundant arsenate does not contain detectable arsenate.
A strain of Halomonas bacteria, GFAJ-1, has been reported to be able to use arsenate as a nutrient when phosphate is limiting, and to specifically incorporate arsenic into its DNA in place of phosphorus. However, we have found that arsenate does not contribute to growth of GFAJ-1 when phosphate is limiting and that DNA purified from cells grown with limiting phosphate and abundant arsenate does not exhibit the spontaneous hydrolysis expected of arsenate ester bonds. Furthermore, mass spectrometry showed that this DNA contains only trace amounts of free arsenate and no detectable covalently bound arsenate.
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