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.

中文翻译：

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纳摩尔摩尔铜可增强脱硫脱硫弧菌ND132的汞甲基化

甲基汞（MeHg）由某些厌氧微生物产生，例如硫酸盐还原菌Desulfovibrio desulfuricansND132，但尚不清楚影响无机汞[Hg（II）]吸收和甲基化的环境因素。我们报告说，少量铜离子[Cu（II），<100 nM]的存在增强了ND132的洗涤细胞对Hg（II）的吸收和甲基化，而Hg（II）甲基化在较高的Cu（II）受到抑制由于铜对微生物的毒性，浓度较高。Cu（II）的增强或抑制作用取决于时间和浓度。纳摩尔浓度的Cu（II）的存在有助于在24小时内快速吸收Hg（II）（在几分钟之内）并使MeHg产量增加一倍，但是微摩尔浓度的Cu（II）完全抑制Hg（II）甲基化。在相同的实验条件下，诸如锌[Zn（II）]和镍[Ni（II）]的金属离子也抑制但不增强Hg（II）甲基化。