Levesque Kelly D, Wright Patricia A, Bernier Nicholas J
Physiol Biochem Zool. 2019 Jul/Aug;92(4):349-364. doi: 10.1086/703178.
Environmental stressors, such as warm temperatures and hypoxia, can interact and pose a threat to aquatic species. Cross talk between the hypoxia and heat stress cellular pathways can lead to enhanced cross tolerance between these environmental stressors. In this study, we questioned whether elevated temperatures (from 27° to 32°C) during rearing would enhance the hypoxia-inducible transcription factor-1 (HIF-1)-mediated transcriptional response to hypoxia (5% dissolved O) in early stages of zebrafish development and whether these differences would be associated with enhanced larval tolerance and survival to hypoxia. We found that embryos reared at 32°C had an enhanced cellular HIF-1 response (elevated and insulin-like growth factor binding-protein mRNA level) and that acute hypoxia (4 h) activated the heat-shock response (elevated and mRNA levels). Elevated rearing temperatures and hypoxia exposure also induced precocious hatching, but neither environmental stressor had an effect on the hypoxia tolerance (critical O tension) of 4-d-old larvae and did not protect larvae against the lethal effects of a second acute hypoxia exposure. Overall, during early zebrafish development, cross talk between the hypoxia and heat stress cellular pathways at the gene expression level did not confer cross tolerance at the whole-animal level with respect to hypoxia stress.
环境应激源，如高温和低氧，可能相互作用并对水生物种构成威胁。低氧和热应激细胞通路之间的相互作用可导致这些环境应激源之间的交叉耐受性增强。在本研究中，我们探讨了饲养期间温度升高（从27°C至32°C）是否会增强斑马鱼发育早期低氧诱导转录因子-1（HIF-1）介导的对低氧（溶解氧5%）的转录反应，以及这些差异是否与幼体对低氧的耐受性和存活率提高有关。我们发现，在32°C饲养的胚胎具有增强的细胞HIF-1反应（升高的 和胰岛素样生长因子结合蛋白mRNA水平），并且急性低氧（4小时）激活了热休克反应（升高的 和 mRNA水平）。饲养温度升高和低氧暴露也诱导了早熟孵化，但这两种环境应激源均对4日龄幼体的低氧耐受性（临界氧张力）没有影响，也不能保护幼体免受第二次急性低氧暴露的致死效应。总体而言，在斑马鱼早期发育过程中，低氧和热应激细胞通路在基因表达水平上的相互作用并未在全动物水平上赋予对低氧应激的交叉耐受性。
