Data from: Concurrent effects of cold and hyperkalaemia cause insect chilling injury

Chilling injury and death are the ultimate consequence of low temperature exposure for chill susceptible insects, and low temperature tolerance is considered one of the most important factors determining insect distribution patterns. The physiological mechanisms that cause chilling injury are unknown, but chronic cold exposure that causes injury is consistently associated with elevated extracellular [K+], and cold tolerant insects possess a greater capacity to maintain ion balance at low temperatures. Here, we use the muscle tissue of the migratory locust (Locusta migratoria) to examine whether chill injury occurs during cold exposure or following return to benign temperature and we specifically examine if elevated extracellular [K+], low temperature, or a combination thereof causes cell death. We find that in vivo chill injury occurs during the cold exposure (when extracellular [K+] is high) and that there is limited capacity for repair immediately following the cold stress. Further, we demonstrate that that high extracellular [K+] causes cell death in situ, but only when experienced at low temperatures. These findings strongly suggest that that the ability to maintain ion (particularly K+) balance is critical to insect low temperature survival, and highlight novel routes of study in the mechanisms regulating cell death in insects in the cold.

对于低温敏感昆虫而言，低温暴露最终会引发冷伤害乃至死亡；而低温耐受性被认为是决定昆虫分布格局的关键因素之一。目前学界尚未明确引发冷伤害的生理机制，但可引发损伤的长期低温暴露始终与细胞外钾离子（extracellular [K+]）浓度升高相关，且耐寒昆虫在低温环境下维持离子稳态的能力更强。本研究以飞蝗（Locusta migratoria）的肌肉组织为实验材料，旨在探究冷伤害是发生在低温暴露过程中，还是在恢复至适宜温度后；同时我们专门检验了细胞外钾离子浓度升高、低温，或是二者共同作用是否会引发细胞死亡。研究结果显示，体内冷伤害发生于低温暴露过程中（此时细胞外钾离子浓度较高），且低温胁迫结束后即时的修复能力十分有限。此外，我们证实高浓度细胞外钾离子会引发原位细胞死亡，但该效应仅在低温环境下才会显现。上述研究结果强烈表明，维持离子（尤其是钾离子）稳态的能力对昆虫的低温存活至关重要，同时也为解析昆虫低温环境下的细胞死亡调控机制指明了新的研究方向。