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首页> 外文期刊>Environmental Science & Technology >Heliobacteria Reveal Fermentation As a Key Pathway for Mercury Reduction in Anoxic Environments
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Heliobacteria Reveal Fermentation As a Key Pathway for Mercury Reduction in Anoxic Environments

机译：Heliobacteria显示出发酵是缺氧环境中汞还原的关键途径

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摘要

The accumulation of mercury (Hg) in rice, a dietary staple for over half of the world’s population, is rapidly becoming a global food safety issue. Rice paddies support the anaerobic production of toxic methylmercury that accumulates in plant tissue, however the microbial controls of Hg cycling in anoxic environments remain poorly understood. In this study, we reveal a novel reductive Hg metabolism in a representative of the family Heliobacteria (Heliobacterium modesticaldum Ice1) that we confirm in model chemotrophic anaerobes. Heliobacteria served as our initial model because they are a family of spore-forming fermentative photoheterotrophs commonly isolated from terrestrial environments. We observed that H. modesticaldum reduced up to 75% of Hg~(II) under phototrophic or fermentative conditions. Fermentative Hg~(II) reduction relied on the ability of cells to oxidize pyruvate whereas phototrophic Hg~(II) reduction could be supported even in the absence of a carbon source. Inhibiting pyruvate fermentation eliminated Hg~(II) reduction in all chemotrophic strains tested, whereas phototrophic cells remained unaffected. Here we propose a non mer -operon dependent mechanism for Hg~(0) production in anoxic environments devoid of light where external electron acceptors are limited. These mechanistic details provide the foundation for novel bioremediation strategies to limit the negative impacts of Hg pollution.
机译：大米中的汞是主要食物，而大米是世界上一半以上人口的饮食主粮，它正迅速成为全球食品安全问题。稻田支持厌氧生产在植物组织中积累的有毒甲基汞，但是对在缺氧环境中汞循环的微生物控制仍然知之甚少。在这项研究中，我们揭示了在模型化营养厌氧菌中证实的家族Heliobacteria（幽门螺杆菌Ice1）的代表中一种新颖的还原汞代谢。 Heliobacteria成为我们的初始模型，因为它们是通常从陆地环境中分离出来的形成孢子的发酵光异养菌家族。我们观察到H。在光养或发酵条件下，modesticaldum最多可减少75％的Hg〜（II）。发酵的Hg〜（II）还原依赖于细胞氧化丙酮酸的能力，而即使在没有碳源的情况下，也可以支持光养性的Hg〜（II）还原。抑制丙酮酸发酵消除了测试的所有化学营养菌株中的Hg〜（II）减少，而光养细胞则不受影响。在此，我们提出了一种在缺氧环境下，在缺乏光的情况下，外部电子受体受到限制的Hg〜（0）产生Hg〜（0）的非依赖于操纵子的机理。这些机制细节为新型生物修复策略提供了基础，以限制汞污染的负面影响。

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  • 来源
    《Environmental Science & Technology》 |2018年第7期|4145-4153|共9页
  • 作者

    D. S. Grégoire; N. C. Lavoie; A. J. Poulain;

  • 作者单位

    Biology Department, University of Ottawa, 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada;

    Biology Department, University of Ottawa, 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada;

    Biology Department, University of Ottawa, 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada;

  • 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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