Proteins of Oxygen-Binding and Energy Metabolism in Muscles of Antarctic Fishes: Evolutionary Adjustments to Life at Cold Temperature

Notothenoidei亚目是南极周围南大洋的主要鱼类群体，无论是在物种数量还是生物量方面。在大约1400万年的时间里，这些非常成功的鱼类在稳定的温度条件下进化，导致它们整个生命史的体温约为零摄氏度。这种寒冷的进化环境导致了异常的生理和生化特征。在某些情况下，这些特性有助于克服低温对生物过程的限制。在其他情况下，在比南大洋更温暖、氧气更少的环境中可能致命的突变被保留在南极鱼类中。该研究项目的重点是三个主要目标，利用这些不寻常的条件来确定在低温下与正常细胞功能相容的机制，并获得对关键细胞内蛋白质生理作用的独特见解。提出的三条研究路线是肌红蛋白编码基因在某些南极notothenioid鱼类中表达失败的分子基础，脂肪酰辅酶A合成酶的底物特异性的基础，该酶参与脂肪酸的催化，以及肌酸磷酸激酶的不同亚型在南极鱼类运动肌肉中发挥的功能作用。这项研究的结果不仅将提供深入了解南极notothenioid鱼类的进化生物学，但将阐明重要的一般原则，适用于广泛不同的类群超越南极。

The suborder Notothenoidei is the dominant fish group of the Southern Ocean surrounding Antarctica, both in terms of number of species and biomass. For about fourteen million years, these highly successful fish evolved under stable thermal conditions that result in body temperatures of about zero degrees centigrade throughout their life histories. Evolution this cold environment has led to unusual physiological and biochemical characteristics. In some cases, the characteristics contribute to overcoming constraints of cold temperature on biological processes. In other instances, mutations that probably would have been lethal in warmer, less oxygen-rich environments than the Southern Ocean have been retained in Antarctic fishes. This research project focuses on three major objectives that exploit these unusual conditions to identify mechanisms compatible with normal cellular function at cold temperature and to gain unique insights into the physiological roles of key intracellular proteins. The three lines of study proposed are the molecular basis for the failure of the myoglobin encoding gene to be expressed in certain Antarctic notothenioid fishes, the basis of the substrate specificity of the enzyme fatty acyl-CoA synthetase that is involved in the catabolism of fatty acids, and the functional roles played by different isoforms of creatine phosphokinase in locomotory muscle of Antarctic fish. Results from this study will not only provide insight into the evolutionary biology of the Antarctic notothenioid fishes, but will elucidate important general principles that are applicable to widely different taxa beyond the Antarctic.