Antifreeze Proteins in Antarctic Fishes: Integrated Studies of Freezing Environments and Organismal Freezing Avoidance, Protein Structure-Function and Mechanism, Genes & Evolut

该项目包括正在进行的和新的关于抗冻糖蛋白(AFGP)和一种新的抗冻增强蛋白(AFPP)在冰冻的南极环境中避免南极鱼类、其卵和幼体受冻的作用的研究。有待研究的具体领域是：(1)无冰标本对内源性冰的吸收速率；(2)AFPP的结构及其增强大AFGP而不是小AFGP的抗冻活性的机制；(3)通过定向进化方法阐明鳗鱼嘴AFP的结构与功能；(4)胚胎和幼鱼避免冷冻的机制，以及AFGP和AFPP在胚胎发生过程中表达的时间方面；(5)在蛋白质和基因水平上对Notothenioidei亚目的抗冻能力的综合分析；(6)AFGP基因家族和基因座的进化；(7)AFPP的进化；(8)与南极特有的诺氏种类相近的最大的非南极诺氏动物分支--巴塔哥托斯血统的起源。麦克默多海湾海洋环境的极端寒冷和结冰条件是由于它与巨大的罗斯冰架和冰架冷水的影响有关。为了阐明麦克默多环境与本地鱼类种群的冰暴露之间的关系，将对Sound的不同微环境中的冰形成深度和程度进行平行的物理测量，并将完成生物实验，通过测量鱼类脾中的冰晶数量以及冰进入鱼类的速度来确定这些位置的鱼的冰负荷。这些研究将确定环境极端程度与鱼类冰负荷之间的关系。该项目有广泛的国际合作，研究结果可能对农业、食品科学和冷冻医学产生广泛影响。公共宣传和对研究生和本科生的培训是计划工作的组成部分。

This project includes on-going and new studies on the role of antifreeze glycoproteins (AFGPs) and a new antifreeze potentiating protein (AFPP) in the freezing avoidance of Antarctic fishes, their eggs and larvae in the freezing Antarctic environment. The specific areas of research to be investigated are: (1) the rate of uptake of endogenous ice by ice-free specimens; (2) structure of AFPP and the mechanism whereby it potentiates the antifreeze activity of the large AFGPs, but not the small ones; (3) structure-function elucidation of eel pout AFP through directed-evolution methodologies; (4) mechanism of freezing avoidance in embryos and young larval fish, and the temporal aspects of AFGP and AFPP expression during embryogenesis; (5) comprehensive analyses of the antifreeze capacity at both the protein and gene levels across the suborder Notothenioidei; (6) evolution of the AFGP gene family and gene locus; (7) evolution of AFPP; and (8) origin of the Patagonotothen lineage, the largest clade of non-Antarctic nototheniids who are close relatives to the endemic Antarctic notothenioid species. Extreme cold and icy conditions of the McMurdo Sound marine environment arise from its association with the massive Ross Ice Shelf and the influence of cold shelf water. To elucidate the relationship between the McMurdo environment and ice exposure in the local fish population, parallel physical measurements of the depth and extent of ice formation in various microenvironments in the Sound will be conducted and biological experiments will be completed to determine ice load in fish at these locations by measuring the number of ice crystals in their spleens, as well as the rate of ice entry into fish. These studies will ascertain the relationship between the degree of environmental extremes and the ice load in fish.This project has extensive international collaborations and findings may have broad implications for agriculture, food science, and cryomedicine. Public outreach and training of graduate and undergraduate students are integral components of the planned work.