TY - JOUR
T1 - Nanomolar Copper Enhances Mercury Methylation by Desulfovibrio desulfuricans ND132
AU - Lu, Xia
AU - Johs, Alexander
AU - Zhao, Linduo
AU - Wang, Lihong
AU - Pierce, Eric M.
AU - Gu, Baohua
N1 - Funding Information:
The authors thank Xiangping Yin for technical assistance in Hg(II) and MeHg analyses. This research was sponsored by the U.S. Department of Energy (DOE) Office of Science, Office of Biological and Environmental Research, as part of the Mercury Science Focus Area at the Oak Ridge National Laboratory (ORNL), which is managed by UT-Battelle, LLC, under Contract DE-AC05-00OR22725 with the DOE.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/6/12
Y1 - 2018/6/12
N2 - 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. 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.
AB - 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. 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.
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U2 - 10.1021/acs.estlett.8b00232
DO - 10.1021/acs.estlett.8b00232
M3 - Article
AN - SCOPUS:85048059502
SN - 2328-8930
VL - 5
SP - 372
EP - 376
JO - Environmental Science and Technology Letters
JF - Environmental Science and Technology Letters
IS - 6
ER -