Plant and Insect Thermal Hysteresis Antifreeze Proteins

产生抗冻蛋白的热滞作用通过一种特殊的机制降低了水的冰点，而不是熔点，这使它们成为非常有效的抗冻物。这些抗冻蛋白（AFPs）已经在许多冷血动物（极地海鱼、昆虫、蜘蛛、蜈蚣）中被报道过，但它们在鱼类中得到了最好的研究，因为鱼类中抗冻蛋白的生物化学已经得到了很好的理解，而且某些AFP基因已经被克隆并转移到其他生物（鲑鱼、植物、细菌）中。来自加拿大石斛甲虫越冬幼虫的afp是迄今为止已知的最活跃的afp。本提案中概述的研究将使我们能够继续研究这些有趣的afp。我们将继续进行甲胎蛋白的生化鉴定，并克隆石斛甲胎蛋白基因。该基因将被测序，提供蛋白质的氨基酸序列，并允许与鱼类的afp进行比较。此外，还将研究位于幼虫角质层下的表皮细胞膜上的AFPs的功能。这些研究将进一步加深我们对AFPs在昆虫抗寒性中的作用的认识。由于该蛋白的高活性，研究结果可应用于低温保存、农业和冷冻食品技术。

Thermal hysteresis producing antifreeze proteins lower the freezing point, but not the melting point, of water by a special mechanism which makes them extremely effective antifreezes. These antifreeze proteins (AFPs) have been reported in many cold blooded animals (polar marine fishes, insects, spiders, centipedes), but they have been best studied in fish where the biochemistry of the AFPs are well understood and certain of the AFP genes have cloned and transferred to other organisms (salmon, plants, bacteria). The AFPs from the overwintering larvae of the beetle Dendroides canadensis are by far the most active AFPs known. The studies outlined in this proposal will allow us to continue our work on these interesting AFPs. Biochemical characterization of the AFP will continue and in addition we will clone the Dendroides AFP gene. The gene will be sequenced, providing the amino acid sequence of the protein and allowing comparisons to the fish AFPs. Also, the function of the AFPs in the membranes of epidermal cells located just under the cuticle of the larvae will be investigated. These studies will further our understanding of the role of AFPs in insect cold tolerance. Because of the high activity of this AFP the results could have applications in cryopreservation, agriculture and frozen food technology.