Abstract

The significant seasonal temperature fluctuations in the arid zones of northwestern Dagestan lead to a broad population of heterothermic mammals that have the unique ability to fall into a state of hibernation at low ambient temperatures. Their significant fluctuations in physiological and biochemical processes during and after hibernation indicate that heterotherms have flexible mechanisms to change the functional characteristics of key metabolic enzymes. In this paper, the temperature dependence of the lactate dehydrogenase (LDH) activity in the skeletal muscles of the small ground squirrel Spermophilus pygmaeus Pall. was studied during the period of summer wakefulness, deep hibernation, and at various stages of awakening, accompanied by warming of the animal bodies to temperatures of 10, 20, 30, and 37°C. It was found that the LDH activity substantially decreases in hibernating ground squirrels, regardless of its incubation temperature in vitro. In the dynamics of warming, there is an increase in LDH activity, the progressive nature of which is most pronounced in the range of animal body temperatures of 1.6–20°C. The temperature dependence of LDH activity in Arrhenius coordinates was approximated with nonlinear graphs; their inflection position during hibernation shifted to the low temperature region, returning to the control values after total warming. Hibernation contributed to a significant increase in the energy and enthalpy of LDH activation. In the warming dynamics, the levels of these parameters are disproportionally reduced and reach the control values of summer animals. The results supported the assumption that the mechanisms of LDH catalysis are substantially modified during hibernation and at various stages of awakening in the skeletal muscles of ground squirrels and had an adaptive character.

中文翻译：

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温度对草原生态系统小地松鼠骨骼肌能量代谢关键酶功能特性的影响

摘要

达吉斯坦西北部干旱地区的明显季节性温度波动导致大量的异温热哺乳动物种群，它们具有在低环境温度下进入冬眠状态的独特能力。冬眠期间和之后它们在生理和生化过程中的显着波动表明，异温体具有改变关键代谢酶功能特征的灵活机制。本文研究了小型地松鼠Spermophilus pygmaeus骨骼肌中乳酸脱氢酶（LDH）活性的温度依赖性。颇尔 在夏季的清醒，深度冬眠和觉醒的各个阶段，伴随着动物体升温至10、20、30和37°C的温度下进行了研究。已经发现，不管其在体外的温育温度如何，在冬眠地松鼠中LDH活性都显着降低。在变暖的过程中，LDH活性增加，其渐进性在动物体温1.6–20°C范围内最为明显。Arrhenius坐标系中LDH活性的温度依赖性通过非线性图近似得出。它们在冬眠期间的拐点位置转移到了低温区域，在完全变暖后返回到控制值。休眠导致LDH激活的能量和焓显着增加。在变暖动态中，这些参数的水平成比例地降低，并达到夏季动物的控制值。结果支持这样的假设，即LDH催化的机理在冬眠期间和地松鼠的骨骼肌觉醒的各个阶段都得到了实质性的改变，并且具有适应性。