Department of Zoology, Miami University, Oxford, OH 45056, USA.
J Insect Physiol. 2010 Jul;56(7):679-85. doi: 10.1016/j.jinsphys.2009.12.003. Epub 2009 Dec 16.
The accumulation of cryoprotectants and the redistribution of water between body compartments play central roles in the capacity of insects to survive freezing. Aquaporins (AQPs) allow for rapid redistribution of water and small solutes (e.g. glycerol) across the cell membrane and were recently implicated in promoting freeze tolerance. Here, we examined whether aquaporin-like protein abundance correlated with the seasonal acquisition of freezing tolerance in the goldenrod gall fly, Eurosta solidaginis (Diptera: Tephritidae). Through the autumn, larvae became tolerant of freezing at progressively lower temperatures and accumulated the cryoprotectant glycerol. Furthermore, larvae significantly increased the abundance of membrane-bound aquaporin and aquaglyceroporin-like proteins from July through January. Acute exposure of larvae to cold and desiccation resulted in upregulation of the AQP3-like proteins in October, suggesting that their abundance is regulated by environmental cues. The seasonal increase in abundance of both putative aquaporins and aquaglyceroporins supports the hypothesis that these proteins are closely tied to the seasonal acquisition of freeze tolerance, functioning to permit cells to quickly lose water and take-up glycerol during extracellular ice formation, as well as reestablish water and glycerol concentrations upon thawing.
抗冻剂的积累和水在身体隔室之间的重新分布在昆虫生存冷冻的能力中起着核心作用。水通道蛋白（AQP）允许水和小溶质（例如甘油）快速跨细胞膜重新分布，最近被牵连到促进抗冻性。在这里，我们研究了在欧亚鹅膏菌（双翅目：瘿蚊科）中，水通道样蛋白丰度是否与季节性获得抗冻性相关。通过秋季，幼虫逐渐耐受越来越低的温度并积累了防冻剂甘油。此外，幼虫从 7 月到 1 月显著增加了膜结合水通道蛋白和水通道甘油蛋白样蛋白的丰度。10 月，幼虫对寒冷和干燥的急性暴露导致 AQP3 样蛋白的上调，表明它们的丰度受环境线索的调节。假定水通道蛋白和水通道甘油蛋白样蛋白的季节性增加支持了这样一种假设，即这些蛋白与季节性获得抗冻性密切相关，在细胞外冰形成过程中允许细胞快速失水和摄取甘油，以及在解冻时重新建立水和甘油浓度。
