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This content will become publicly available on May 29, 2019

Title: Nanomolar Copper Enhances Mercury Methylation by Desulfovibrio desulfuricans ND132

Methylmercury (MeHg) is produced by certain anaerobic microorganisms, such as the sulfate-reducing bacterium Desulfovibrio desulfuricans ND132, but environmental factors affecting inorganic mercury [Hg(II)] uptake and methylation remain unclear. We report that the presence of a small amount of copper ions [Cu(II), <100 nM] enhances Hg(II) uptake and methylation by washed cells of ND132, while Hg(II) methylation is inhibited at higher Cu(II) concentrations because of the toxicity of copper to the microorganism. The enhancement or inhibitory effect of Cu(II) is dependent on both time and concentration. The presence of nanomolar concentrations of Cu(II) facilitates rapid uptake of Hg(II) (within minutes) and doubles MeHg production within a 24 h period, but micromolar concentrations of Cu(II) completely inhibit Hg(II) methylation. Metal ions such as zinc [Zn(II)] and nickel [Ni(II)] also inhibit but do not enhance Hg(II) methylation under the same experimental conditions. Furthermore, these observations suggest a synergistic effect of Cu(II) on Hg(II) uptake and methylation, possibly facilitated by copper transporters or metallochaperones in this organism, and highlight the fact that complex environmental factors affect MeHg production in the environment.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [2] ;  [2] ; ORCiD logo [2] ; ORCiD logo [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lanzhou Univ., Lanzhou (China)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Environmental Science & Technology Letters (Online)
Additional Journal Information:
Journal Name: Environmental Science & Technology Letters (Online); Journal Volume: 5; Journal Issue: 6; Journal ID: ISSN 2328-8930
Publisher:
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES
OSTI Identifier:
1456798