Data from: Concurrent effects of cold and hyperkalemia 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，冷害与死亡是暴露于低温环境后的最终结局；而低温耐受性被视为决定昆虫分布格局的核心影响因素之一。目前引发冷害的生理机制尚未阐明，但可引发冷害的长期低温暴露始终与细胞外钾离子浓度（[K+]）升高存在显著关联，且耐寒昆虫在低温条件下维持离子平衡的能力更强。本研究以飞蝗（Locusta migratoria）的肌肉组织为实验材料，旨在探究冷害究竟发生于低温暴露过程中，还是在恢复至适宜温度后才显现；同时专门验证细胞外[K+]升高、低温，或是二者共同作用是否会诱导细胞死亡。研究结果显示，体内冷害发生于低温暴露阶段（此时细胞外[K+]处于高水平），且低温胁迫结束后的即时修复能力极为有限。进一步实验表明，高浓度细胞外[K+]可引发原位细胞死亡，但该效应仅在低温环境下才会显现。本研究结果有力证实，维持离子（尤其是钾离子）平衡的能力对昆虫的低温存活至关重要，同时也为解析低温条件下昆虫细胞死亡的调控机制开辟了全新的研究方向。