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 O2) 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 hif-1ab and insulin-like growth factor binding-protein mRNA level) and that acute hypoxia (4 h) activated the heat-shock response (elevated hsp70a and hsp90aa mRNA levels). Elevated rearing temperatures and hypoxia exposure also induced precocious hatching, but neither environmental stressor had an effect on the hypoxia tolerance (critical O2 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.

中文翻译：

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没有交叉容忍的相声：饲养温度对胚胎斑马鱼低氧反应的影响。

诸如高温和缺氧之类的环境压力因素可能相互作用，并对水生物种构成威胁。低氧和热应激细胞途径之间的串扰可以导致这些环境应激因子之间的交叉耐受性增强。在这项研究中，我们质疑饲养期间升高的温度（从27°C到32°C）是否会增强缺氧诱导的转录因子1（HIF-1）介导的对缺氧的早期转录反应（5％溶解的O2）斑马鱼的发育以及这些差异是否与幼虫耐受性增强和低氧生存有关。我们发现在32°C饲养的胚胎具有增强的细胞HIF-1反应（hif-1ab和胰岛素样生长因子结合蛋白mRNA水平升高），急性缺氧（4 h）激活了热休克反应（升高hsp70a和hsp90aa mRNA水平）。升高的饲养温度和低氧暴露也会引起早熟孵化，但是环境应激因素均不能影响4 d龄幼虫的低氧耐受性（临界O2张力），也不能保护幼虫免受第二次急性低氧暴露的致死作用。总体而言，在斑马鱼早期发育过程中，低氧和热应激细胞途径之间在基因表达水平上的串扰并未赋予全动物水平关于低氧胁迫的交叉耐受性。升高的饲养温度和低氧暴露也会引起早熟孵化，但是环境应激因素均不能影响4 d龄幼虫的低氧耐受性（临界O2张力），也不能保护幼虫免受第二次急性低氧暴露的致死作用。总体而言，在斑马鱼早期发育过程中，低氧和热应激细胞途径之间在基因表达水平上的串扰并未赋予全动物水平关于低氧胁迫的交叉耐受性。升高的饲养温度和低氧暴露也会引起早熟孵化，但是环境应激因素均不能影响4 d龄幼虫的低氧耐受性（临界O2张力），也不能保护幼虫免受第二次急性低氧暴露的致死作用。总体而言，在斑马鱼早期发育过程中，低氧和热应激细胞途径之间在基因表达水平上的串扰并未赋予全动物水平关于低氧胁迫的交叉耐受性。