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首页> 外文期刊>Environmental Science & Technology >Mechanistic Study and the Influence of Oxygen on the Photosensitized Transformations of Microcystins (Cyanotoxins)
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Mechanistic Study and the Influence of Oxygen on the Photosensitized Transformations of Microcystins (Cyanotoxins)

机译：机理和氧气对微囊藻毒素（氰毒素）光敏转化的影响

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摘要

Microcystins (MCs) produced by cyanobacteria are strong hepatotoxins and classified as possible carcinogens. MCs pose a considerable threat to consumers of tainted drinking and surface waters, but the photochemical fate of dissolved MCs in the environment has received limited attention. MCs are released into the environment upon cell lysis along with photoactive pigments including phycocyanin and chlorophyll a. The concentrations of MCs and pigments are expected to be greatest during a bloom event. These blooms occur in sunlit surface water and thus MCs can undergo a variety of solar initiated or photosensitized transformations. We report herein the role of oxygen, sensitizer, and light on the photochemical fate of MCs. The phycocyanin photosensitized transformation of MCs is elucidated, and photosensitized isomerization plays an important role in the process. The UV-A portion of sunlight was simulated using 350 nm light and the phototransformations of three MC variants (-LR, -RR, -LF) were investigated. Singlet oxygen leads to photooxidation of phycocyanin, the predominant pigment of cyanobacteria, hence, reducing the phototransformation rate of MCs. The phototransformation rate of MC-LR increases as pH decreases. The pH effect may be the result of MCs association with phycocyanin. Our results indicate photosensitized processes may play a key role in the photochemical transformation of MCs in the natural water.
机译：蓝细菌产生的微囊藻毒素（MC）是强肝毒素，被归类为可能的致癌物。 MC对饮用受污染的饮用水和地表水的消费者构成相当大的威胁，但是溶解的MC在环境中的光化学命运受到的关注有限。 MC在细胞裂解后与包括藻蓝蛋白和叶绿素a在内的光敏颜料一起释放到环境中。在开花期间，预计MC和色素的浓度最高。这些水华发生在阳光照射的地表水中，因此MC可能会经历各种太阳引发或光敏化的转变。我们在这里报告氧气，敏化剂和光在MC的光化学命运中的作用。阐明了藻蓝蛋白对MCs的光敏转化，并且光敏异构化在该过程中起重要作用。使用350 nm光模拟了太阳光的UV-A部分，并研究了三种MC变体（-LR，-RR，-LF）的光转化。单线态氧导致蓝藻的主要色素藻蓝蛋白发生光氧化，因此降低了MC的光转化率。 pH值降低，MC-LR的光转化率增加。 pH效应可能是MC与藻蓝蛋白缔合的结果。我们的结果表明，光敏过程可能在天然水中MC的光化学转化中起关键作用。

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  • 来源
    《Environmental Science & Technology》 |2007年第15期|5336-5341|共6页
  • 作者

    WEIHUA SONG; SABRINA BARDOWELL; KEVIN E. OSHEA;

  • 作者单位

    Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, Florida 33199;

  • 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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