State Key Laboratory of Pollution Control and Resource Reuse & School of the Environment, Nanjing University, Nanjing, China.
Environ Sci Technol. 2011 Mar 1;45(5):1984-91. doi: 10.1021/es1032579. Epub 2011 Feb 10.
Mixtures of naphthenic acids (NAs), which include cyclopentyl and cyclohexyl carboxylic acids, have been suggested to be toxic components in oils spills, effluents from the petrochemical industry and in oil sands process waters (OSPW). The present study demonstrated, for the first time, an application of a high throughput live bacterial cell array in a genome-scale investigation of the toxic mechanisms of environmental chemicals, a commercial NAs technical mixture extracted from crude oil. Real time gene profiling of time- and concentration- dependent responses of live cells exposed to NAs for three hours was conducted using a library of 1800 fluorescent transcriptional reporters for Escherichia coli (E. coli) growing in 384-well plates. The response patterns obtained after exposure to NAs suggested that the primary cellular responses were up-regulation of genes in the pentose phosphate pathway, involved in the molecular function of NADP or NADPH binding, and down-regulation of the ATP-binding cassette (ABC) transporter complex. Transcriptional networks that were significantly modulated by NAs included those that were regulated by transcriptional factors such as CRP-, RecA-, and GadE. Down-regulation of the SOS response pathway suggested that DNA damage might not be the direct result of NAs within the first three hours of exposure. However, CRP-dependent genes modulated by exposure to NAs indicated that the cellular level of cyclic AMP was altered immediately upon exposure of cells to NAs. Furthermore, the linear range of the concentration-response curve of the selected gene reporters encompassed a range of concentrations between 10 and 1000 mg NAs/L, which covers concentrations typically observed in the environment and makes this assay system ideal for the detection of environmental NAs.
环烷酸（NA）混合物，包括环戊基和环己基羧酸，被认为是溢油、石化工业废水和油砂加工水中的有毒成分。本研究首次应用高通量活细菌细胞阵列，在基因组范围内研究环境化学物质的毒性机制，该技术混合物是从原油中提取的商业 NA。使用含有 1800 个荧光转录报告基因的文库，对在 384 孔板中生长的大肠杆菌（E. coli）进行实时基因谱分析，研究了活细胞在 3 小时内暴露于 NA 后的时间和浓度依赖性反应。暴露于 NA 后的反应模式表明，主要的细胞反应是上调戊糖磷酸途径中的基因，这些基因与 NADP 或 NADPH 结合的分子功能有关，下调 ABC 转运体复合物。NA 显著调节的转录网络包括那些受 CRP、RecA 和 GadE 等转录因子调节的网络。SOS 反应途径的下调表明，在暴露于 NA 的前三个小时内，DNA 损伤可能不是直接结果。然而，暴露于 NA 后调节的 CRP 依赖性基因表明，细胞内 cAMP 水平在细胞暴露于 NA 后立即发生改变。此外，所选基因报告基因的浓度-反应曲线的线性范围涵盖了 10 至 1000mg NA/L 之间的浓度范围，该范围涵盖了环境中通常观察到的浓度，使该测定系统成为检测环境 NA 的理想选择。
