The influence of sulfide on solid phase mercury bioavailability for methylation by pure cultures of Desulfobulbus propionicus (1pr3)
The influence of sulfide on solid phase mercury bioavailability for methylation by pure cultures of Desulfobulbus propionicus (1pr3)
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DOI：
10.1021/es001415n
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发表时间：
2001-01-01
影响因子：
11.4
通讯作者：
Mason, RP
中科院分区：
文献类型：
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作者：
Benoit, JM;Gilmour, CC;Mason, RP
为了帮助了解汞甲基化细菌的汞摄取机制和控制，我们调查了硫化物对汞甲基化的影响，通过纯培养的硫酸盐还原菌Desulfobulbus propionicus（1 pr 3）。我们以前在天然沉积物中的研究表明，当硫化物浓度有利于形成中性溶解Hg-S物种时，汞甲基化发生得最快。在这项研究中，汞在培养基中的化学形态的操纵生长D，propionicus在一个范围内的硫化物浓度，无机汞（汞-1）的形式添加到地面矿石。一个固相，而不是溶解的汞源，被用来模拟控制汞之间的固体和水相的天然沉积物中发现的分配。甲基汞（MeHg）生产的文化是不相关的绝对固相浓度的汞在矿石中，它只是弱相关的介质中溶解的Hg-1浓度。然而，MeHg的产生与溶液中主要中性复合物的计算浓度（HgS度）呈线性相关。此外，扩散膜渗透性的硫化氢度，估计从其辛醇-水分配系数，被认为是足以支持甲基汞生产的细胞。本文扩展了我们之前的工作，为我们的假设提供了实验支持，即硫化物通过影响溶解的Hg-1的形态及其通过被动扩散的吸收来影响甲基化。
To help understand the mechanism and control of Hg uptake in Hg-methylating bacteria, we investigated the effect of sulfide on Hg methylation by pure cultures of the sulfate-reducing bacterium Desulfobulbus propionicus (1pr3). Our previous research in natural sediments has Suggested that Hg methylation occurs most rapidly when sulfide concentrations favor formation of neutral dissolved Hg-S species. In this study, the chemical speciation of Hg in culture media was manipulated by growing D, propionicus across a range of sulfide concentrations, with inorganic Hg (Hg-1) added in the form of ground ores. A solid-phase, rather than a dissolved source of Hg, was used to simulate the controls on Hg partitioning between solid and aqueous phases found in natural sediments. Methylmercury (MeHg) production by cultures was not related to the absolute solid-phase concentration of Hg in the ores, and it was only weakly related to the dissolved Hg-1 concentration in the medium. However, MeHg production was linearly related to the calculated concentration of the dominant neutral complex in solution, HgS degrees. Furthermore, the diffusive membrane permeability of HgS degrees, as estimated from its octanol-water partitioning coefficient, was found to be sufficient to support MeHg production by cells. The present paper expands on our previous work by providing experimental support of our hypothesis that sulfide influences methylation by affecting the speciation of dissolved Hg-1 and its uptake via passive diffusion.