Cold adaptation mechanisms in the ghost moth Hepialus xiaojinensis: Metabolic regulation and thermal compensation.
Cold adaptation mechanisms in the ghost moth Hepialus xiaojinensis: Metabolic regulation and thermal compensation.
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DOI：
10.1016/j.jinsphys.2015.11.008
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发表时间：
2016-02
影响因子：
2.2
通讯作者：
Wei Zhu;Huan Zhang;Xuan Li;Q. Meng;Ruihao Shu;Menglong Wang;Guiling Zhou;Hong-tuo Wang;L. Miao;Jihong Zhang;Q. Qin
中科院分区：
文献类型：
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作者：
Wei Zhu;Huan Zhang;Xuan Li;Q. Meng;Ruihao Shu;Menglong Wang;Guiling Zhou;Hong-tuo Wang;L. Miao;Jihong Zhang;Q. Qin
鬼蛾（鳞翅目：蝙蝠蛾科）是栖息于青藏高原高寒草甸的适应寒冷的窄温物种。它们的最佳发育温度为 12–16 °C，但可以在 0 °C 下维持摄食和生长。它们的生存策略很少受到关注，但这些昆虫是环境适应的有前途的模型。在这里，研究了小金蛾幼虫对寒冷的生化适应和能量代谢反应。随着温度（15-4℃）的降低，代谢率和呼吸商急剧下降，表明鬼蛾的能量代谢，特别是糖代谢对寒冷敏感。然而，4°C 时的代谢率随着冷暴露时间的延长而增加，这表明在寒冷条件下有热补偿来维持能量预算。通过分析冷驯化（4°C 48 小时）和对照幼虫（15°C）之间的代谢差异来研究潜在的调节策略。在冷驯化的幼虫中，碳水化合物的能量产生途径，而不是碳水化合物的总体消耗，通过改善相关酶的转录在脂肪体内得到补偿。脂质的动员也得到促进，血淋巴中二酰基甘油、单酰基甘油和游离脂肪酸含量较高。这些结果表明，冷驯化诱导了代谢结构的重组，以优先考虑能量代谢。在有氧过程中，脂肪体内促进了整个三羧酸（TCA）循环的流动，并且α-酮戊二酸脱氢酶的活性是可能的补偿目标。在冷驯化幼虫的中肠中观察到线粒体嵴密度增加。鬼蛾的热补偿策略跨越了能量代谢的整个过程，包括代谢底物降解、TCA循环和氧化磷酸化，并从能量预算的角度解释了鬼蛾如何在寒冷环境中维持生理活动。
Ghost moths (Lepidoptera: Hepialidae) are cold-adapted stenothermal species inhabiting alpine meadows on the Tibetan Plateau. They have an optimal developmental temperature of 12–16 °C but can maintain feeding and growth at 0 °C. Their survival strategies have received little attention, but these insects are a promising model for environmental adaptation. Here, biochemical adaptations and energy metabolism in response to cold were investigated in larvae of the ghost mothHepialus xiaojinensis. Metabolic rate and respiratory quotient decreased dramatically with decreasing temperature (15–4 °C), suggesting that the energy metabolism of ghost moths, especially glycometabolism, was sensitive to cold. However, the metabolic rate at 4 °C increased with the duration of cold exposure, indicating thermal compensation to sustain energy budgets under cold conditions. Underlying regulation strategies were studied by analyzing metabolic differences between cold-acclimated (4 °C for 48 h) and control larvae (15 °C). In cold-acclimated larvae, the energy generating pathways of carbohydrates, instead of the overall consumption of carbohydrates, was compensated in the fat body by improving the transcription of related enzymes. The mobilization of lipids was also promoted, with higher diacylglycerol, monoacylglycerol and free fatty acid content in hemolymph. These results indicated that cold acclimation induced a reorganization on metabolic structure to prioritise energy metabolism. Within the aerobic process, flux throughout the tricarboxylic acid (TCA) cycle was encouraged in the fat body, and the activity of α-ketoglutarate dehydrogenase was the likely compensation target. Increased mitochondrial cristae density was observed in the midgut of cold-acclimated larvae. The thermal compensation strategies in this ghost moth span the entire process of energy metabolism, including degration of metabolic substrate, TCA cycle and oxidative phosphorylation, and from an energy budget perspective explains how ghost moths sustain physiological activity in cold environments.