Heat tolerance, temperature acclimation, acute oxidative damage and canalization of haemoglobin expression in Daphnia
Heat tolerance, temperature acclimation, acute oxidative damage and canalization of haemoglobin expression in Daphnia
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水蚤的耐热性、温度驯化、急性氧化损伤和血红蛋白表达的管道化
DOI：
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发表时间：
2012
影响因子：
1.9
通讯作者：
L. Yampolsky
中科院分区：
文献类型：
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作者：
Patricia J. Williams;Kenneth B. Dick;L. Yampolsky
水蚤是一种分布广泛的淡水浮游动物，是生态生理学、生态毒理学和适应新环境的进化生物学研究的经典模型和新兴模型。众所周知，水蚤的耐热性既取决于基因型的进化历史，也取决于个体对高温的适应，并与血红蛋白表达水平相关。我们证明了北美红花的耐热性存在南北梯度，这与血红蛋白表达的任何平行变化无关。地理上不同的克隆由于适应亚压力（28°C）温度而导致血红蛋白表达变化的方式有所不同，但这些变化与克隆起源的纬度无关。同样，适应亚应激温度的影响独立于适应过程中的血红蛋白表达变化，并且不能完全由其解释。血红蛋白的氧化损伤程度（以驯化温度下 540:576 nm 处的吸光度比率来测量）是 28°C 驯化的水蚤在急性热暴露期间存活的有力预测因子。适应不同温度的抗性和耐受性克隆中血红蛋白表达的比较表明，耐受性克隆表现出血红蛋白表达的管道化，即使在非应激温度下也具有高水平的血红蛋白。我们讨论了全球气候变化背景下淡水生态系统重要组成部分对高温的适应和适应的进化生物学。
Daphnia is a widespread freshwater zooplankton species, which is both a classic and emerging new model for research in ecological physiology, ecotoxicology and evolutionary biology of adaptation to novel environments. Heat tolerance in Daphnia is known to depend both upon evolutionary history of a genotype and on individuals’ acclimation to elevated temperature and to correlate with the level of haemoglobin expression. We demonstrate the existence of north–south gradient of heat tolerance in North American D. pulex, which is not associated with any parallel changes in haemoglobin expression. Geographically distinct clones differ in the way their haemoglobin expression changes due to acclimation to a sub-stressful (28°C) temperature, but these changes are not correlated with the latitude of clones’ origin. Likewise, the effect of acclimation to sub-stressful temperature is independent from, and cannot be fully explained by, haemoglobin expression changes during acclimation. The degree of oxidative damage to haemoglobin, measured as the ratio of absorbance at 540:576 nm at the acclimation temperature, is a strong predictor of 28°C-acclimated Daphnia survival during an acute heat exposure. The comparison of haemoglobin expression in resistant and tolerant clones acclimated to different temperatures indicates that tolerant clones exhibit canalization of haemoglobin expression, possessing a high level of haemoglobin even at non-stressful temperatures. We discuss the evolutionary biology of adaptation and acclimation to elevated temperatures in an ecologically important component of freshwater ecosystems in the context of global climate change.
影响因子：
4.8
作者：
Beckerman, Andrew P.;Rodgers, Gwendolen M.;Dennis, Stuart R.
通讯作者：
Dennis, Stuart R.