Drinking and Na/K-ATPase Alpha-Subunit Isoform Expression in Antarctic Fish

生活在麦克默多湾近冰点（-2C）水域的南极鱼的血清和细胞钠（Na）浓度是所有海洋硬骨鱼中最高的，而鳃钠/钾- atp酶（Na/ k - atp酶，钠/钾泵）活性是最低的。Na/ k - atp酶调节许多生物体细胞中的Na浓度。在这些鱼的细胞中保持高盐含量可以降低冰点，使它们能够在寒冷的南极水域生存，并减少鱼和海水之间的盐梯度。基于之前的研究温度的影响,假设南极nototheniids饮酒率较低,低盐排泄率和更高比例的低细胞内Na Na的亲和力为特定亚基/ K-ATPase (a3-isoform)新西兰nototheniids相比,居住在温暖的水域。这些独特的渗透调节特性解释了在南极极地锋以南的南极鱼中发现的高血清和细胞钠浓度。该研究将比较和对比的独特的渗透调节的机制与新西兰南极nototheniids nototheniids 1)海水饮酒率和血清和细胞化学成分的鱼,2)mRNA和蛋白和酶的性质和表达模式,3)时间和空间定位的Na / K-ATPase a3-isoform亚基在鱼鳃。为了实现这些目标，将研究代表南极极锋上下生态多样性习性的四种南极鱼。该项目的广泛影响包括增加我们对na - k - atp酶在许多生物细胞功能中的作用的认识，加强我们对南极南极南极鱼的生化和生理适应的理解，这些适应使它们能够在南极极地锋面以南的冰载水域中生存和茁壮成长，为研究生和本科生提供实地和实验室研究经验。对中小学生和教师进行科学教育的重要推广活动。

Nototheniid fishes inhabiting the near freezing (-2C) waters of McMurdo Sound have some of the highest serum and cellular sodium (Na) concentrations and lowest gill sodium/potassium-ATPase (Na/K-ATPase, the sodium/potassium pump) activities of any marine teleost. The enzyme Na/K-ATPase regulates the Na concentration in the cells of many organisms. Maintaining a high salt content in the cells of these fish lowers the freezing point to allow habitation of cold Antarctic waters and reduces the salt gradient between the fish and the seawater. Based on previous studies of temperature effects, it is hypothesized that Antarctic nototheniids have lower drinking rates, lower salt excretion rates and a higher proportion of the low intracellular Na affinity for a specific subunit of the Na/K-ATPase (a3-isoform) compared to New Zealand nototheniids that inhabit warmer waters. These unique osmoregulatory properties explain the high serum and cellular Na concentrations found in nototheniids south of the Antarctic Polar Front. The proposed studies will compare and contrast the unique osmoregulatory mechanisms of Antarctic nototheniids with those of New Zealand nototheniids with respect to 1) seawater drinking rates and serum and cellular chemical composition of the fish, 2) enzymatic properties and expression pattern of mRNA and protein and 3) temporal and spatial localization of the Na/K-ATPase a3-isoform subunit in the fish gills. To accomplish these objectives four species of nototheniids, representing ecologically diverse habits above and below the Antarctic Polar Front will be studied. The broader impacts of this project include increasing our knowledge about the role of Na-K-ATPase in the cellular function in many organisms, strengthening our understanding of the biochemical and physiological adaptations of the Antarctic nototheniids that allow them to survive and thrive in the ice-laden waters south of the Antarctic Polar Front, providing field and laboratory research experience for graduate and undergraduate students, and significant outreach activities in science education to elementary and high school students and teachers.