Toxic Selection

摘要

Arsenic is highly toxic to living organisms because it disrupts metabolic pathways, but, chemically, arsenate behaves in a similar way to phosphate, and it is theoretically possible for organisms to substitute one for the other under certain conditions. Wolfe-Simon et al. (p. 1163, published online 2 December) have found a living example of a bacterium that does not find arsenate poisonous (see related Editor's Note, Technical Comments, and Response p. 1149). Isolates of a halomonad bacterium, originating from the toxic and briny Mono Lake, California, were selected by successive laboratory culture in which phosphate was gradually replaced by arsenate until the bacteria were growing in the absence of the usual salt.