The Genetic Basis for Bacterial Mercury Methylation

Mercury Methylating Microbes Mercury (Hg) most commonly becomes bioavailable and enters the food web as the organic form methylmercury, where it induces acute toxicity effects that can be magnified up the food chain. But most natural and anthropogenic Hg exists as inorganic Hg 2+ and is only transformed into methylmercury by anaerobic microorganisms—typically sulfur-reducing bacteria. Using comparative genomics, Parks et al. (p. 1332 , published online 7 February; see the Perspective by Poulain and Barkay ) identified two genes that encode a corrinoid and iron-sulfur proteins in six known Hg-methylating bacteria but were absent in nonmethylating bacteria. In two distantly related model Hg-methylating bacteria,…

• BA
  Biological and Environmental Research