Laboratory of Amphibian Diversity Investigation, College of Ecology, Lishui University, Lishui, 323000, Zhejiang, China; College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, Zhejiang, China.
Administration Center of Zhejiang Jiulongshan National Nature Reserve, Suichang, 323300, Zhejiang, China.
J Therm Biol. 2024 Oct;125:104000. doi: 10.1016/j.jtherbio.2024.104000. Epub 2024 Oct 31.
Variations in thermal environments can provoke diverse physiological responses in amphibians. Despite extensive studies on the thermal sensitivity of amphibian metabolic physiology, including enzyme activity at different temperatures, the rationale for selecting specific metabolic enzymes and their relationship with gene expression remains unclear. Cytochrome c oxidase (CCO), succinate dehydrogenase (SDH), and lactate dehydrogenase (LDH) are key metabolic enzymes within the primary metabolic regulatory tissues of animals. Through a comparative analysis of the effects of two different thermal conditions (12 and 18 °C) on the activities and mRNA expression levels of these enzymes within the kidney and liver tissues of a winter-breeding amphibian (Leptobrachium liui), with the field group during the breeding season as the control, we provide insights into the interplay between temperature and gene expression. The mRNA levels of CCO subunits 1 (cox1), 2 (cox2), and 3 (cox3), and LDH subunit A (ldha) were significantly higher in the kidney than in the liver of all individuals. High-temperature acclimation resulted in significantly decreased expression levels of cox1-3, ldha, and SDH complex flavoprotein subunit A (sdha) in the kidney. In the liver, the expression levels of sdha and ldha significantly reduced under high-temperature treatment, whereas cox3 expression increased. SDH and LDH activities displayed tissue-specific variations, while no significant differences in CCO activity were observed between tissues. CCO, SDH, and LDH activities in both liver and kidney tissues significantly declined after high-temperature acclimation, but simultaneously increased with up-regulated gene expression, indicating that the thermal environment and corresponding gene expression combined affect the activities of these metabolic enzymes. In conclusion, the thermal environment is a key factor affecting the physiological and biochemical responses of L. liui. Prolonged exposure to high temperatures during the breeding season could inhibit the activity of primary metabolic enzymes in the winter-breeding amphibian.
热环境的变化会引起两栖动物产生不同的生理反应。尽管已经对两栖动物代谢生理学的热敏感性进行了广泛研究，包括不同温度下的酶活性，但选择特定代谢酶的原理及其与基因表达的关系仍不清楚。细胞色素 c 氧化酶 (CCO)、琥珀酸脱氢酶 (SDH) 和乳酸脱氢酶 (LDH) 是动物主要代谢调节组织中的关键代谢酶。通过比较两种不同热条件（12 和 18°C）对冬季繁殖两栖动物（刘氏小鲵）肾脏和肝脏组织中这些酶的活性和 mRNA 表达水平的影响，并以繁殖季节的野外组作为对照，我们深入了解了温度与基因表达之间的相互作用。cox1、cox2 和 cox3 的亚基 1（cox1）、2（cox2）和 3（cox3）以及 LDH 亚基 A（ldha）在所有个体的肾脏中的 mRNA 水平均显著高于肝脏。高温驯化导致肾脏中 cox1-3、ldha 和 SDH 复合黄素蛋白亚基 A（sdha）的表达水平显著降低。在肝脏中，高温处理下 sdha 和 ldha 的表达水平显著降低，而 cox3 的表达水平增加。SDH 和 LDH 活性表现出组织特异性变化，而 CCO 活性在组织之间没有差异。高温驯化后，肝脏和肾脏组织中 CCO、SDH 和 LDH 的活性均显著下降，但同时伴随着基因表达的上调，这表明热环境和相应的基因表达共同影响这些代谢酶的活性。总之，热环境是影响刘氏小鲵生理生化反应的关键因素。繁殖季节长时间暴露在高温下可能会抑制冬季繁殖两栖动物主要代谢酶的活性。
