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首页> 外文期刊>Environmental Science & Technology >Volatile Arsenic Species Released from Escherichia coli Expressing the Aslll S-adenosylmethionine Methyltransferase Gene
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Volatile Arsenic Species Released from Escherichia coli Expressing the Aslll S-adenosylmethionine Methyltransferase Gene

机译：表达Aslll S-腺苷甲硫氨酸甲基转移酶基因的大肠杆菌释放的挥发性砷

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摘要

Biological systems, ranging from bacteria and fungi to humans, can methylate arsenic. Recent studies have suggested that the Aslll S-adenosylmethionine methyltransferase (arsM) gene in bacteria was responsible for the removal of arsenic as the volatile arsines from the bacteria. However, there has been no direct measure of the arsines released from bacteria cultures. We describe here an integrated system incorporating the bacterial incubation and volatile arsenic species analysis, and we demonstrate its application to the identification of the volatile arsines produced in bacterial cultures. The headspace of the bacterial cultures was purged with helium, and the volatile arsenic species were trapped in a chromatographic column immersed in liquid nitrogen. The cryogenically trapped arsines [AsH_3, (CH_3)AsH_2, (CH_3)_2AsH, and (CH_3)_3As] were separated by gas chromatography and were detected by inductively coupled plasma mass spectrometry. A hydride generation system was coupled to the bacterial culture system, allowing for spiking standards and for generating calibration arsines necessary for quantitative analysis. Both bacteria containing the arsM gene or its variant arsMC2 gene were able to produce 400-500 ng of trimethylarsine. No trimethylarsine was detectable in bacteria lacking the arsM gene (containing the vector plasmid as negative control). These results confirm that arsM is responsible for releasing arsenic as volatile species from the arsenic-resistant bacteria. Our results also show traces of AsH_3, CH_3AsH_2, and (CH_3)_2AsH in cultures of bacteria expressing arsM. The method detection limits for AsH_3, CH_3AsH_2, (CH_3)_2AsH, and (CH_3)_3As were 0.5, 0.5, 0.7, and 0.6 pg, respectively. The ability to quantify trace levels of these volatile arsenic species makes it possible to study the biotransformation and biochemical roles of the evolution of these volatile arsenic species by biological systems.
机译：从细菌，真菌到人类，生物系统都可以使砷甲基化。最近的研究表明细菌中的Aslll S-腺苷甲硫氨酸甲基转移酶（arsM）基因负责从细菌中去除砷作为挥发性a。但是，尚没有直接测量从细菌培养物中释放出的砷化氢的方法。我们在这里描述了一个结合了细菌培养和挥发性砷物质分析的综合系统，并且我们展示了其在鉴定细菌培养物中产生的挥发性砷化氢中的应用。用氦气吹扫细菌培养液的顶空，并将挥发性砷物质截留在浸入液氮中的色谱柱中。低温捕获的砷化氢[AsH_3，（CH_3）AsH_2，（CH_3）_2AsH和（CH_3）_3As]通过气相色谱分离，并通过电感耦合等离子体质谱法进行检测。将氢化物生成系统与细菌培养系统耦合，以实现加标标准并生成定量分析所必需的校准a。包含arsM基因或其变体arsMC2基因的两种细菌均能够产生400-500 ng的三甲基ar。在缺少arsM基因的细菌（包含载体质粒作为阴性对照）中没有检测到三甲基ar。这些结果证实arsM负责从抗砷细菌释放作为挥发性物质的砷。我们的结果还显示了在表达arsM的细菌培养物中的AsH_3，CH_3AsH_2和（CH_3）_2AsH的痕迹。 AsH_3，CH_3AsH_2，（CH_3）_2AsH和（CH_3）_3As的方法检测限分别为0.5 pg，0.5 pg，0.7 pg和0.6 pg。量化这些挥发性砷物质的痕量水平的能力使得有可能研究通过生物系统进化这些挥发性砷物质的生物转化和生化作用。

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  • 来源
    《Environmental Science & Technology》 |2008年第9期|p.3201-3206|共6页
  • 作者

    CHUNGANG YUAN; XIUFEN LU; JIE QIN; BARRY P. ROSEN; X. CHRIS LE;

  • 作者单位

    Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, T6G 2G3, 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);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境化学;
  • 关键词

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