Ecophysiological Correlates of Vertebrate Freeze Tolerance

9507437抗冻性是一种适应，允许某些生物体在其体内耐受冰的形成。以前的抗冻性研究是在实验室中进行的，条件与自然界中动物所经历的条件相去甚远。本研究结合了野外和实验室研究，阐明了抗冻性在促进两种抗冻物种越冬存活中的作用。将使用计算机辅助监测系统记录越冬发生的体温、环境温度以及微环境的含水量和水势，对冬季自然经历的冻结事件进行表征。平行测量保护性反应，包括葡萄糖动员和器官水的迁移，将提供对细胞，组织和器官的冷冻损伤保护的生理机制的理解，以及这些反应在自然环境中的生态重要性。一些研究将集中在冬眠的能量消耗上，特别是关于冻结和解冻。核磁共振（NMR）成像将用于确定细胞能量状态，并显示冷冻状态下的存活时间是否受到有限能量储备的限制。这些综合性的实地和实验室研究将深入了解在低于组织冰点的温度下促进生存的生理机制及其生态意义。这项研究还可能为开发冷冻保存组织和器官的技术提供有价值的线索。

9507437 Freeze tolerance is an adaptation that permits some organisms to tolerate ice formation within their bodies. Previous studies of freeze tolerance have been conducted in the laboratory, under conditions far removed from those experienced by animals in nature. This research combines both field and laboratory studies to elucidate the role of freeze tolerance in promoting over winter survival in two freeze-tolerant species. Freezing episodes naturally experienced during winter will be characterized using computer-assisted monitoring systems to record body temperature, environmental temperature, and water content and water potential of the microenvironments in which over- wintering occurs. Parallel measurement of protective responses including glucose mobilization and relocation of organ water will provide understanding of the physiological mechanisms that protect against freezing injury to cells, tissues, and organs, and of the ecological importance of these responses in the natural environment. Some studies will focus on the energetic costs of hibernation, particularly with regard to freezing and thawing. Nuclear magnetic resonance (NMR) imaging will be used to determine cell energy status and show whether survival duration in the frozen state is limited by the availability of finite energy reserves. These integrated field and laboratory studies will provide insights into the physiological mechanisms that promote survival at temperatures below the freezing point of tissue, and into their ecological significance. The research may also provide valuable clues for developing technology for the preservation of tissues and organs by freezing.