Standard ecological risk assessment practices often rely on larval and juvenile fish toxicity data as representative of the amphibian aquatic phase. Empirical evidence suggests that endpoints measured in fish early life stage tests are often sufficient to protect larval amphibians. However, the process of amphibian metamorphosis relies on endocrine cues that affect development and morphological restructuring and are not represented by these test endpoints. The present study compares developmental endpoints for zebrafish (Danio rerio) and the African clawed frog (Xenopus laevis), 2 standard test species, exposed to the herbicide trifluralin throughout the larval period. Danio rerio were more sensitive and demonstrated a reduction in growth measurements with increasing trifluralin exposure. Size of X. laevis at metamorphosis was not correlated with exposure concentration; however, time to metamorphosis was delayed relative to trifluralin concentration. Gene expression patterns indicate discrepancies in response by D. rerio and X. laevis, and dose‐dependent metabolic activity suggests that trifluralin exposure perturbed biological pathways differently within the 2 species. Although many metabolites were correlated with exposure concentration in D. rerio, nontargeted hepatic metabolomics identified a subset of metabolites that exhibited a nonmonotonic response to trifluralin exposure in X. laevis. Linking taxonomic distinctions in cellular‐level response with ecologically relevant endpoints will refine assumptions used in interspecies extrapolation of standard test effects and improve assessment of sublethal impacts on amphibian populations. Environ Toxicol Chem 2020;39:1797–1812. Published 2020. This article is a US government work and is in the public domain in the USA.

中文翻译：

---

接触氟乐灵的水生物种发育影响机制的跨类群差异。


标准生态风险评估实践通常依赖幼鱼和幼鱼毒性数据作为两栖动物水生阶段的代表。经验证据表明，鱼类早期生命阶段测试中测量的终点通常足以保护两栖动物幼体。然而，两栖动物变态过程依赖于影响发育和形态重建的内分泌线索，并且不能由这些测试终点代表。本研究比较了斑马鱼 ( Danio rerio ) 和非洲爪蛙 ( Xenopus laevis ) 这两种标准测试物种在整个幼虫期暴露于除草剂氟乐灵的发育终点。斑马鱼更加敏感，并且随着氟乐灵暴露量的增加，生长测量值减少。变态时的非洲小蜥蜴的大小与暴露浓度不相关；然而，变态时间相对于氟乐灵浓度而言被延迟。基因表达模式表明斑马鱼和非洲虎的反应存在差异，剂量依赖性代谢活动表明，氟乐灵暴露对这两个物种内的生物途径的干扰不同。尽管许多代谢物与斑马鱼中的暴露浓度相关，但非靶向肝脏代谢组学鉴定了一个代谢物子集，这些代谢物对斑马鱼中的氟乐灵暴露表现出非单调反应。将细胞水平反应的分类差异与生态相关终点联系起来，将完善标准测试效果的种间外推中使用的假设，并改进对两栖动物种群亚致死影响的评估。 环境毒理学化学2020；39：1797–1812。 2020 年出版。本文是美国政府作品，在美国属于公共领域。