The University of Sydney, Sydney, New South Wales, Australia.
Environ Toxicol Chem. 2011 Aug;30(8):1810-8. doi: 10.1002/etc.568. Epub 2011 May 23.
Chemical toxicants, particularly metal ions, are a major contaminant in global waterways. Live-organism bioassays used to monitor chemical toxicants commonly involve measurements of activity or survival of a freshwater cladoceran (Ceriodaphnia dubia) or light emitted by the marine bacterium Vibrio fischeri, used in the commercial Microtox® bioassay. Here we describe a novel molecule-based assay system employing DNA as the chemical biosensor. Metals bind to DNA, causing structural changes that expel a bound (intercalated) fluorescent reporter dye. Analyses of test data using 48 wastewater samples potentially contaminated by metal ions show that the DNA-dye assay results correlate with those from C. dubia and Microtox bioassays. All three assays exhibit additive, antagonistic, and synergistic responses that cannot be predicted by knowing individual metal concentrations. Analyses of metals in these samples imply the presence of chemical toxicants other than metal ions. The DNA-dye assay is robust, has a 12-month shelf life, and is only slightly affected by sample pH in the range 4 to 9. The assay is completed in a matter of minutes, and its portability makes it well suited as a screening assay for use in the field. We conclude that the DNA-dye test is a surrogate bioassay suitable for screening chemical toxicity.
化学毒物，特别是金属离子，是全球水道的主要污染物。用于监测化学毒物的活体生物测定通常涉及淡水枝角类动物（Ceriodaphnia dubia）或海洋细菌 Vibrio fischeri 的活性或存活的测量，后者用于商业 Microtox®生物测定。在这里，我们描述了一种使用 DNA 作为化学生物传感器的新型分子测定系统。金属与 DNA 结合，导致结构发生变化，从而逐出结合的（嵌入的）荧光报告染料。使用可能被金属离子污染的 48 个废水样本对测试数据进行分析表明，DNA-染料测定结果与 C. dubia 和 Microtox 生物测定结果相关。所有三种测定方法都表现出加性、拮抗和协同反应，仅凭了解单个金属浓度是无法预测的。对这些样品中的金属进行分析表明，存在除金属离子以外的化学毒物。DNA-染料测定法稳健，保质期为 12 个月，并且在 4 到 9 的 pH 值范围内仅受样品 pH 值的轻微影响。测定在几分钟内完成，其便携性使其非常适合作为现场筛选测定法使用。我们得出结论，DNA-染料测试是一种替代生物测定法，适用于筛选化学毒性。
