The Role of Antifreeze Proteins in Freezing Avoidance of Antarctic Fishes

9317629 DeVries McMurdo海湾的鱼是最耐冻的，在南极的任何鱼类中，它们都能暴露在最极端的冰和温度下。该项目将重点关注冰协会的范围及其在这些极地鱼类中的命运。冰层暴露的最深深度也将被确定。这些结果将与生活在南极半岛附近不受冰架影响的少冰、温暖环境中的鱼类的结果进行比较。实验引入的内源冰的命运将被确定，以确定南极鱼类是否具有处理积冰的机制。通过测定一些抗冻肽（AFPs）的三维结构，并寻找其极性残基与冰吸附面之间的晶格匹配，还将研究抗冻液的结构与功能的关系。二维核磁共振和分子建模技术将被使用。使用抗冻糖肽（AFGPs），大小对吸附到特定平面的重要性将被确定。这些研究将表明在结构多样的分子中产生防冻功能的重要特征是什么。各种防冻液（AFs）对冰生长的抑制作用的研究也将继续在各种冰面上的吸附如何导致冰生长的抑制。到目前为止，这个问题仍然没有答案，他们希望通过检查各种AFs对单个冰晶生长形式的影响来解决这个问题。通过鉴定和测序高分子量afgp的编码基因，并将其与小分子量afgp的组织结构进行比较，研究南极鱼类抗冻基因的组织结构。AFGP多蛋白基因家族的大小将通过荧光原位杂交确定。有关组织和结构的信息将有助于了解导致在这种极端寒冷的南极环境中生存所必需的高水平心房颤动的因素。＊＊＊

9317629 DeVries McMurdo Sound fishes are the most freeze resistant, and are exposed to greatest extremes of ice and temperature of any fishes in Antarctica. The project will focus on the extent of the ice association and its fate within these polar fishes. The deepest depths of ice exposure will also be determined. These results will be compared to those obtained for fishes living in less icy, warmer environments near the Antarctic Peninsula where the influence of ice shelves is absent. The fate of experimentally introduced endogenous ice will be determine to find out whether Antarctic fish possess mechanisms for disposing of accumulated ice. The relationship of structure to function of the antifreezes will also be investigated by determining the three- dimensional structures of some of the antifreeze peptides (AFPs) and searching for lattice matches between their polar residues and their ice adsorption plane. Two-Dimensional Nuclear Magnetic Resonance and molecular modeling techniques will be used. With the antifreeze glycopeptides (AFGPs), the importance of size for adsorption to specific planes will be determined. These studies will indicate what the important features are which give rise to antifreeze function in structurally diverse molecules. The investigation of the inhibition of ice growth by the various antifreezes (AFs) will also be continued on how adsorption to various ice planes leads to inhibition of ice growth. This question remains thus far unanswered, which they hope to address by examining the effects of the various AFs on the growth forms of single ice crystals. The organization and structure of the antifreeze genes of Antarctic fish will also be investigated by identifying and sequencing genes that code for the high molecular weight AFGPs and comparing them to organization of the small AFGPs. The sizes of the AFGP polyprotein gene family will be determined by fluorescent in situ hybridization. Information on the organization and struc ture will lead to an understanding of the factors that lead to the necessarily high levels of AF needed for survival in this extreme freezing Antarctic environment. ***