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首页> 外文期刊>Environmental Science & Technology >Effect of Divalent Metals on Hg(Ⅱ) Uptake and Methylation by Bacteria
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Effect of Divalent Metals on Hg(Ⅱ) Uptake and Methylation by Bacteria

机译：二价金属对细菌吸收Hg（Ⅱ）和甲基化的影响

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摘要

The production of methylmercury by some bacteria is a key first step in the accumulation and biomagnification of this toxic substance in aquatic food webs, a major human health concern. By direct measurement of cellular Hg(Ⅱ) uptake in model iron and sulfate reducing bacteria, we have observed that specific trace metals, such as Zn(Ⅱ) and Cd(Ⅱ), inhibit uptake and methylation in these organisms, whereas other metals, such as Ni(Ⅱ), Co(Ⅱ), or Fe(Ⅱ), do not. The inhibition of Hg(Ⅱ) methylation by Zn(Ⅱ) was competitive in nature and related to the concentration of inorganically complexed Zn(Ⅱ) (Zn'). The inhibition of Hg(Ⅱ) methylation was alleviated by decreasing the free Zn' concentration through complexation with nitrilotriacetic acid without altering the speciation of Hg(Ⅱ). The inhibitory effect by Zn(Ⅱ) was observed when either Hg-cysteine complexes or neutral HgCl_2 dominated the speciation of Hg(Ⅱ), demonstrating that both charged and neutral species are transported into the cytosol by an active rather than passive process. We propose that Hg(Ⅱ) uptake is the result of its accidental uptake by metal transporter(s), possibly one effecting the transport of Zn(Ⅱ).
机译：一些细菌生产甲基汞是水生食物网中这种有毒物质的积累和生物放大的关键的第一步，这是人类主要的健康问题。通过直接测量模型铁和硫酸盐还原细菌中细胞对Hg（Ⅱ）的吸收，我们观察到特定的痕量金属（例如Zn（Ⅱ）和Cd（Ⅱ））抑制了这些生物体的吸收和甲基化，而其他金属则诸如Ni（Ⅱ），Co（Ⅱ）或Fe（Ⅱ）等。 Zn（Ⅱ）对Hg（Ⅱ）甲基化的抑制作用具有竞争性，并且与无机络合的Zn（Ⅱ）（Zn′）的浓度有关。通过与次氮基三乙酸络合降低游离Zn'浓度而不改变Hg（Ⅱ）的形态，可以减轻Hg（Ⅱ）甲基化的抑制作用。当Hg-半胱氨酸复合物或中性HgCl_2占据Hg（Ⅱ）的形态时，可观察到Zn（Ⅱ）的抑制作用，这表明带电和中性物质均通过主动而不是被动过程转运到胞质溶胶中。我们认为，Hg（Ⅱ）的吸收是由于金属转运体意外吸收Hg的结果，可能是一种影响Zn（Ⅱ）的转运。

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  • 来源
    《Environmental Science & Technology》 |2014年第5期|3007-3013|共7页
  • 作者

    Jeffra K. Schaefer; Aleksandra Szczuka; Francois M. M. Morel;

  • 作者单位

    Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States,Department of Environmental Science, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901;

    Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States;

    Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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