Viant Mark R, Pincetich Christopher A, Tjeerdema Ronald S
School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
Aquat Toxicol. 2006 May 25;77(4):359-71. doi: 10.1016/j.aquatox.2006.01.009. Epub 2006 Feb 20.
Pesticide pulses in the Sacramento River, California, originate from storm-water discharges and non-point source aquatic pollution that can last from a few days to weeks. The Sacramento River and its tributaries have historically supported the majority of California's Chinook salmon (Oncorhynchus tshawytscha) spawning grounds. Three pesticides currently used in the Sacramento Valley-- dinoseb, diazinon, and esfenvalerate-- were chosen to model the exposure of salmon embryos to storm-water discharges. Static-renewal (96 h) exposures to eyed eggs and alevins resulted in both toxicity and significant changes in metabolism assessed in whole-embryo extracts by (1)H nuclear magnetic resonance (NMR) spectroscopy based metabolomics and HPLC with UV detection (HPLC-UV). The 96-h LC(50) values of eyed eggs and alevins exposed to dinoseb were 335 and 70.6 ppb, respectively, and the corresponding values for diazinon were 545 and 29.5 ppm for eyed eggs and alevins, respectively. The 96-h LC(50) of eyed eggs exposed to esfenvalerate could not be determined due to lack of mortality at the highest exposure concentration, but in alevins was 16.7 ppb. All esfenvalerate exposed alevins developed some degree of lordosis or myoskeletal abnormality and did not respond to stimulus or exhibit normal swimming behavior. ATP concentrations measured by HPLC-UV decreased significantly in eyed eggs due to 250 ppb dinoseb and 10 and 100 ppb esfenvalerate (p < 0.05). Phosphocreatine, as measured by HPLC-UV, decreased significantly in eyed eggs due to 250 ppb dinoseb, 10 and 100 ppb esfenvalerate, and 100 ppm diazinon (p < 0.05). Principal components analyses of (1)H NMR metabolite fingerprints of eyed egg and alevin extracts revealed both dose-dependent and mechanism of action-specific metabolic effects induced by the pesticides. Furthermore, NMR based metabolomics proved to be more sensitive than HPLC-UV in identifying significant changes in sublethal metabolism of pesticide exposed alevins. In conclusion, we have demonstrated several benefits of a metabolomics approach for chemical risk assessment, when used in conjunction with a fish embryo assay, and have identified significant metabolic perturbations to the early life stages of Chinook salmon by currently used pesticides.
加利福尼亚州萨克拉门托河的农药脉冲源自雨水排放和非点源水污染，这种污染可持续数天至数周。萨克拉门托河及其支流历来是加利福尼亚州大多数奇努克鲑（Oncorhynchus tshawytscha）产卵地。选择萨克拉门托山谷目前使用的三种农药——地乐酚、二嗪农和乙氰菊酯——来模拟鲑鱼胚胎接触雨水排放的情况。对眼点卵和仔鱼进行静态更新（96小时）暴露，通过基于（1）H核磁共振（NMR）光谱的代谢组学和带紫外检测的高效液相色谱法（HPLC-UV）对全胚胎提取物进行毒性评估和代谢变化评估。暴露于地乐酚的眼点卵和仔鱼的96小时半数致死浓度（LC(50)）值分别为335和70.6 ppb，暴露于二嗪农的眼点卵和仔鱼的相应值分别为545和29.5 ppm。由于在最高暴露浓度下没有出现死亡情况，所以无法确定暴露于乙氰菊酯的眼点卵的96小时LC(50)，但仔鱼的96小时LC(50)为16.7 ppb。所有暴露于乙氰菊酯的仔鱼都出现了一定程度的脊柱前凸或肌肉骨骼异常，对刺激无反应，也不表现出正常的游泳行为。通过HPLC-UV测定，由于250 ppb地乐酚、10和100 ppb乙氰菊酯，眼点卵中的三磷酸腺苷（ATP）浓度显著降低（p < 0.05）。通过HPLC-UV测定，由于250 ppb地乐酚、10和100 ppb乙氰菊酯以及100 ppm二嗪农，眼点卵中的磷酸肌酸显著降低（p < 0.05）。对眼点卵和仔鱼提取物的（1）H NMR代谢物指纹图谱进行主成分分析，揭示了农药诱导的剂量依赖性和作用机制特异性代谢效应。此外，基于NMR 的代谢组学在识别暴露于农药的仔鱼亚致死代谢的显著变化方面比HPLC-UV更敏感。总之，我们证明了代谢组学方法与鱼类胚胎试验结合用于化学风险评估的几个优点，并确定了目前使用的农药对奇努克鲑早期生命阶段的显著代谢扰动。
