Ecophysiological Correlates of Vertebrate Freeze Tolerance

9507437耐冻性是一种适应，允许某些生物在其体内容忍结冰。以前的耐冻性研究是在实验室进行的，条件与动物在自然界中经历的条件相去甚远。这项研究结合了田间和实验室的研究，阐明了耐寒性在促进两个耐寒性物种越冬存活方面的作用。冬季自然经历的冰冻事件将使用计算机辅助监测系统来记录体温、环境温度以及发生越冬的微环境的水分和水势。并行测量保护反应，包括葡萄糖动员和器官水的重新定位，将有助于理解保护细胞、组织和器官免受冰冻伤害的生理机制，以及这些反应在自然环境中的生态重要性。一些研究将侧重于冬眠的能量成本，特别是关于冻结和解冻的成本。核磁共振成像将被用来确定细胞的能量状态，并显示在冰冻状态下的生存时间是否受到有限能量储备的限制。这些综合的现场和实验室研究将提供对在低于组织冰点的温度下促进存活的生理机制的洞察，以及它们的生态意义。这项研究还可能为开发通过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.