Division of Coastal Sciences, School of Ocean Science and Engineering, The University of Southern Mississippi, United States; Department of Biology, Francis Marion University, United States.
Division of Coastal Sciences, School of Ocean Science and Engineering, The University of Southern Mississippi, United States.
Environ Pollut. 2020 Aug;263(Pt B):114325. doi: 10.1016/j.envpol.2020.114325. Epub 2020 Mar 18.
Because oil spills frequently occur in coastal regions that serve as spawning habitat, characterizing the effects of oil in estuarine fish carries both economic and environmental importance. There is a breadth of research investigating the effects of crude oil on fish, however few studies have addressed how transcriptional responses to oil change throughout development or how these responses might be conserved across taxa. To investigate these effects, we performed RNA-seq and pathway analysis following oil exposure 1) in a single estuarine species (Cyprinodon variegatus) at three developmental time points (embryos, yolk-sack larvae, free-feeding larvae), and 2) in two ecologically similar species (C. variegatus and Fundulus grandis), immediately post-hatch (yolk-sack stage). Our results indicate that C. variegatus embryos mount a diminished transcriptional response to oil compared to later stages, and that few transcriptional responses are conserved throughout development. Pathway analysis of larval C. variegatus revealed dysregulation of similar biological processes at later larval stages, including alteration of cholesterol biosynthesis pathways, cardiac development processes, and immune functions. Our cross-species comparison showed that F. grandis exhibited a reduced transcriptional response compared to C. variegatus. Pathway analysis revealed that the two species shared similar immune and cardiac responses, however pathways related to cholesterol biosynthesis exhibited a divergent response as they were activated in C. variegatus but inhibited in F. grandis. Our results suggest that examination of larval stages may provide a more sensitive estimate of oil-impacts than examination of embryos, and challenge assumptions that ecologically comparable species respond to oil similarly.
由于石油经常在作为产卵栖息地的沿海地区泄漏，因此评估石油对河口鱼类的影响具有经济和环境的双重重要性。有大量研究调查了原油对鱼类的影响，但很少有研究探讨过随着鱼类发育，转录反应对石油的变化，以及这些反应如何在不同的分类群中保守。为了研究这些影响，我们在一个河口物种（Cyprinodon variegatus）的三个发育时间点（胚胎、卵黄囊幼虫、自由觅食幼虫）进行了 RNA-seq 和途径分析，并且在两个生态相似的物种（C. variegatus 和 Fundulus grandis），即孵化后立即（卵黄囊阶段）进行了 RNA-seq 和途径分析。我们的结果表明，C. variegatus 胚胎对石油的转录反应与后期阶段相比减弱，并且很少有转录反应在整个发育过程中保守。幼鱼 C. variegatus 的途径分析显示，在后期幼鱼阶段，相似的生物学过程出现失调，包括胆固醇生物合成途径、心脏发育过程和免疫功能的改变。我们的跨物种比较表明，F. grandis 的转录反应与 C. variegatus 相比有所降低。途径分析显示，两个物种具有相似的免疫和心脏反应，但胆固醇生物合成途径表现出不同的反应，因为它们在 C. variegatus 中被激活，而在 F. grandis 中被抑制。我们的结果表明，与胚胎相比，检查幼虫阶段可能会提供对石油影响更敏感的估计，并挑战生态相似的物种对石油的反应相似的假设。
