中国大陆草蜥的温度适应性及其生理生化基础

The adaptation of animals in response to temperature is a frontier research topic in zoology. Under the background of global climate change, the thermal adaptation of animals has attracted great scientific attention, with focus on the biological processes and underlying mechanisms of thermal adaptation. In mainland China, there are four species of grass lizards (Takydromus sexlineatus, T.septentrionalis, T.wolteri, T.amurensis),with their distributions ranging from tropical to temperate zones. Previous studies have demonstrated that physiological traits may show adaptive varations among these species along the latitudinal cline, but the underlying physiological and biochemical mechanisms are unknown yet. In this project, we first compare thermal sensitivity of metabolic rate, thermal tolerance, and the functions of mitochondria,metabolic enzymes and heat shock proteins (HSP) among species and populations as well. Then, we apply molecular technology to understand the modulation of HSP and metabolic enzymes such as citroyl synthetase, cytochrome c oxidase,and lactate dehydrogenase, because the metabolic enzymes and HSP are closely related to the thermal sensitivity of functional performance and thermal tolerance. At last, temperature manipulation experiments are carried out to explore the phenotypic plasticity of thermal physiology and its response to temperature change in these species. Therefore, our study is designed to identify inter- and intra-specific differences in thermal adaptation at various levels from gene to whole organism, and determines the physiological,biochemical and molecular mechanisms of thermal adaptation in the grass lizards. This study will contribute to theoretical development in thermal biology of reptiles.

动物对环境温度的适应是动物学研究的重要内容和前沿课题。在全球气候变化背景下，动物的温度适应成为国际研究热点，其关注焦点在于动物适应温度变化的过程与机制。中国大陆四种草蜥（南草蜥、北草蜥、白条草蜥和黑龙江草蜥）的分布跨越热带、亚热带和温带，其生理学特征沿着纬度梯度表现出适应性变异，但其生理与生化基础尚不清楚。本研究开展四种草蜥的温度敏感性、温度耐受性、线粒体功能、代谢酶活性和热激蛋白表达的种间和种群间比较。应用分子生物学技术，解析柠檬酸合成酶、细胞色素C 氧化酶、乳酸脱氢酶活性以及热激蛋白表达的调控。开展温度操纵实验，探索草蜥热生理学特征的表型可塑性及其对温度变化的响应。因此，本项目应用整合生理学思想，从基因到个体的多个层次阐明中国大陆草蜥温度适应性的种间和种内差异，揭示温度适应的生理生化基础及其分子调控，取得爬行动物热生物学理论新进展。

了解动物适应温度变化的过程与机制，对于理解动物如何应对全球气候变化具有重要意义。本项目以中国大陆分布的4种主要草蜥物种（栖息于热带的南草蜥、亚热带北草蜥和白条草蜥以及温带的黑龙江草蜥）为研究对象，开展温度敏感性、温度耐受性的种间比较研究；利用南草蜥、北草蜥和白条草蜥为研究对象，开展热生理学的驯化响应研究。进而应用生物化学、分子生物学和组学技术，解析线粒体功能、代谢酶活性调整，以及能量代谢通路的调控，揭示温度适应的生理生化与分子机制。研究结果显示，随着纬度升高，草蜥物种的温度耐受范围逐渐增大，运动能力和代谢率温度敏感性下降，而且此种生理特征的纬度变异与线粒体密度和代谢能力的差异密切相关。温度驯化实验研究揭示，中高纬度分布的白条草蜥和北草蜥能够通过驯化响应的方式应答温度变化。白条草蜥通过线粒体功能与代谢酶活性调控、糖脂氨基酸代谢转换响应温度变化；北草蜥通过组织器官大小调节响应。而低纬度热带物种南草蜥对于温度变异不具有驯化响应。这些结果体现了草蜥物种随纬度分布的温度适应规律和机制，并揭示了未来气候变化可能会对热带物种的影响更为严重。