Effect of temperature on the hypoxia response of embryonic zebrafish, Danio rerio




Levesque, Kelly

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University of Guelph


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, I asked whether elevated temperatures (from 27°C to 32°C) during rearing would enhance the hypoxia-inducible transcription factor-1 (HIF-1) mediated transcriptional response to hypoxia in early stages of zebrafish development and whether these differences would be associated with enhanced larval tolerance and survival to hypoxia. I found that embryos reared at 32°C had an enhanced cellular HIF-1 response and that acute hypoxia activated the heat-shock response. Rearing at 32°C and/or embryonic hypoxia exposure had no effect on the hypoxia tolerance (Pcrit) of four day-old larvae and did not protect larvae against the lethal effects of a second acute hypoxia exposure. Overall, cross-talk at the gene expression level did not predict whole-animal responses when larvae were re-exposed to hypoxic conditions.



temperature, hypoxia-inducible factor-1, zebrafish, developmental plasticity