Abstract

Biochemical adaptations of energy metabolism and some pathways of glucose oxidation during a change in salinity of the environment in larvae and smolts of the pink salmon Oncorhynchus gorbuscha (Walb.) inhabiting the White Sea were studied. We assayed the activity of energy and carbohydrate metabolism enzymes (cytochrome c oxidase (COХ), lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PDH), 1-glycerophosphate dehydrogenase (1-GPDH), and aldolase) in pink salmon larvae in a short-term aquarium experiment and in pink salmon smolts in a long-term cage experiment simulating the transition of juveniles from freshwater to a marine environment. A decrease in the activity of COX, LDH, 1‑GPDH, and aldolase already in the first hour after the transfer of larvae to seawater was shown. Smolts kept in the estuary and in the sea had low levels of activity of 1-GPDH and aldolase in comparison with individuals from the river. Most likely, in the salmon juveniles studied, there was a redistribution of carbohydrates between the reactions of aerobic and anaerobic metabolism in favor of anaerobic ATP synthesis. No changes in the enzyme activity of the pentose phosphate pathway, G-6-PDH, were found in either larvae or smolts compared with the individuals kept in freshwater. Maintenance of the required levels of anaerobic metabolism and of the pentose phosphate pathway is probably one of the mechanisms of biochemical adaptation of pink salmon to changes in salinity.

中文翻译：

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粉红鲑鱼幼鱼 Oncorhynchus gorbuscha (Walb.) 从淡水环境向海洋环境过渡期间能量和碳水化合物代谢酶的活性

摘要

研究了生活在白海的粉红鲑鱼Oncorhynchus gorbuscha (Walb.)在环境盐度变化期间能量代谢的生化适应和葡萄糖氧化的一些途径。我们测定了能量和碳水化合物代谢酶（细胞色素c在短期水族馆实验和粉红鲑鱼幼鱼中的氧化酶 (COХ)、乳酸脱氢酶 (LDH)、葡萄糖-6-磷酸脱氢酶 (G6PDH)、1-甘油磷酸脱氢酶 (1-GPDH) 和醛缩酶）在模拟幼鱼从淡水过渡到海洋环境的长期网箱实验中。在将幼虫转移到海水后的第一个小时内，COX、LDH、1-GPDH 和醛缩酶的活性已经降低。与河流中的个体相比，在河口和海中饲养的小鲑鱼的 1-GPDH 和醛缩酶活性水平较低。最有可能的是，在所研究的鲑鱼幼鱼中，碳水化合物在有氧和无氧代谢反应之间重新分配，有利于无氧 ATP 合成。与饲养在淡水中的个体相比，在幼虫或幼鱼中未发现戊糖磷酸途径 G-6-PDH 的酶活性发生变化。维持所需的厌氧代谢水平和磷酸戊糖途径可能是粉红鲑鱼生化适应盐度变化的机制之一。