Bugg William S, Yoon Gwangseok R, Schoen Alexandra N, Laluk Andrew, Brandt Catherine, Anderson W Gary, Jeffries Ken M
Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, Manitoba, R3T 2N2, Canada.
Conserv Physiol. 2020 Sep 30;8(1):coaa087. doi: 10.1093/conphys/coaa087. eCollection 2020.
Temperature is one of the most important abiotic factors regulating development and biological processes in ectotherms. By 2050, climate change may result in temperature increases of 2.1-3.4°C in Manitoba, Canada. Lake sturgeon, , from both northern and southern populations in Manitoba were acclimated to 16, 20 and 24°C for 30 days, after which critical thermal maximum (CT) trials were conducted to investigate their thermal plasticity. We also examined the effects of temperature on morphological and physiological indices. Acclimation temperature significantly influenced the CT, body mass, hepatosomatic index, metabolic rate and the mRNA expression of transcripts involved in the cellular response to heat shock and hypoxia (, , , ) in the gill of lake sturgeon. Population significantly affected the above phenotypes, as well as the mRNA expression of -α1 and the hepatic glutathione peroxidase enzyme activity. The southern population had an average CT that was 0.71 and 0.45°C higher than the northern population at 20 and 24°C, respectively. Immediately following CT trials, mRNA expression of and was positively correlated with individual CT of lake sturgeon across acclimation treatments and populations ( = 0.7, = 0.62, respectively; < 0.0001). Lake sturgeon acclimated to 20 and 24°C had decreased hepatosomatic indices (93 and 244% reduction, respectively; < 0.0001) and metabolic suppression (27.7 and 42.1% reduction, respectively; < 0.05) when compared to sturgeon acclimated to 16°C, regardless of population. Glutathione peroxidase activity and mRNA expression -α1 were elevated in the northern relative to the southern population. Acclimation to 24°C also induced mortality in both populations when compared to sturgeon acclimated to 16 and 20°C. Thus, increased temperatures have wide-ranging population-specific physiological consequences for lake sturgeon across biological levels of organization.
温度是调节变温动物发育和生物过程的最重要的非生物因素之一。到2050年，气候变化可能导致加拿大曼尼托巴省的温度升高2.1 - 3.4°C。来自曼尼托巴省北部和南部种群的湖鲟在16、20和24°C下驯化30天，之后进行临界热最大值（CT）试验以研究它们的热可塑性。我们还研究了温度对形态和生理指标的影响。驯化温度显著影响湖鲟鳃中CT、体重、肝体指数、代谢率以及参与细胞对热休克和缺氧反应的转录本的mRNA表达（、、、）。种群显著影响上述表型，以及-α1的mRNA表达和肝脏谷胱甘肽过氧化物酶活性。在20和24°C时，南部种群的平均CT分别比北部种群高0.71和0.45°C。CT试验后，在所有驯化处理和种群中，和的mRNA表达与湖鲟个体的CT呈正相关（分别为 = 0.7， = 0.62； < 0.0001）。与在16°C驯化的湖鲟相比，无论种群如何，在20和24°C驯化的湖鲟肝体指数降低（分别降低93%和244%； < 0.0001）且代谢受抑制（分别降低27.7%和42.1%； < 0.05）。与南部种群相比，北部种群的谷胱甘肽过氧化物酶活性和-α1的mRNA表达升高。与在16和20°C驯化的湖鲟相比，在24°C驯化也导致两个种群出现死亡。因此，温度升高对湖鲟在生物组织的各个水平上都有广泛的种群特异性生理影响。
