Department of Biological Sciences and Canadian Rivers Institute (CRI Genomics), University of New Brunswick, Saint John, New Brunswick E2L 4L5, Canada.
Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, Manitoba R3T 2N2, Canada.
Comp Biochem Physiol Part D Genomics Proteomics. 2023 Mar;45:101058. doi: 10.1016/j.cbd.2023.101058. Epub 2023 Jan 16.
In comparison to most modern teleost fishes, sturgeons generally display muted stress responses. While a muted stress response appears to be ubiquitous across sturgeon species, the mechanisms unpinning this muted response have not been fully described. The objective of this study was to determine the patterns of hematological and transcriptomic change in muscle tissue following an acute high temperature stress (critical thermal maxima; CT) in two locally co-occurring but evolutionarily distant sturgeon species (Atlantic and shortnose sturgeon). The most striking pattern found was that Atlantic sturgeon launched a vigorous transcriptomic response at CT, whereas shortnose sturgeon did not. In contrast, shortnose sturgeon have significantly higher cortisol than Atlantics at CT, reconfirming that shortnose have a less muted cortisol stress response. Atlantic sturgeon downregulated a number of processes, included RNA creation/processing, methylation and immune processes. Furthermore, a number of genes related to heat shock proteins were differentially expressed at CT in Atlantic sturgeon but none of these genes were significantly changed in shortnose sturgeon. We also note that the majority of differentially expressed genes of both species are undescribed and have no known orthologues. These results suggest that, while sturgeons as a whole may show muted stress responses, individual sturgeon species likely use different inducible strategies to cope with acute high temperature stress.
与大多数现代硬骨鱼类相比，鲟鱼通常表现出较为温和的应激反应。虽然这种温和的应激反应似乎在鲟鱼物种中普遍存在，但支撑这种温和反应的机制尚未完全描述。本研究的目的是确定两种在当地共同出现但进化上相距甚远的鲟鱼物种（大西洋鲟和短吻鲟）在经历急性高温应激（临界热极值；CT）后肌肉组织中血液学和转录组变化的模式。最显著的模式是，大西洋鲟在 CT 时会启动强烈的转录组反应，而短吻鲟则不会。相比之下，短吻鲟在 CT 时的皮质醇水平明显高于大西洋鲟，这再次证实短吻鲟的皮质醇应激反应较弱。大西洋鲟下调了许多过程，包括 RNA 生成/处理、甲基化和免疫过程。此外，在 CT 时，大西洋鲟中有许多与热休克蛋白相关的基因表达存在差异，但在短吻鲟中没有这些基因发生明显变化。我们还注意到，两个物种中大多数差异表达的基因都是未知的，没有已知的同源物。这些结果表明，虽然鲟鱼整体上可能表现出温和的应激反应，但个别鲟鱼物种可能会使用不同的诱导策略来应对急性高温应激。
