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

南极鱼的饮水和 Na/K-ATP 酶 α 亚基亚型表达

• 批准号: 0229462
• 负责人: David Petzel
• 金额: $ 40.71万
• 依托单位: Creighton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229462&HistoricalAwards=false
• 关键词: Drinking; Na; ATPase; Alpha; Subunit

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.

生活在麦克默多湾接近冰点（-2 ℃）的沃茨中的Nototheniid鱼类，其血清和细胞钠（Na）浓度最高，鳃钠/钾-ATP酶（Na/K-ATP酶，钠/钾泵）活性最低。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降低了冰点，使其能够在寒冷的南极沃茨中栖息，并减少了鱼和海水之间的盐梯度。根据以前的研究温度的影响，据推测，南极的nototheniids有较低的饮用率，较低的盐排泄率和较高比例的低细胞内Na亲和力的Na/K-ATP酶（α 3亚型）的一个特定的亚基相比，新西兰nototheniids居住在温暖的沃茨。这些独特的钠离子调节特性解释了南极极地锋南部的南极鱼中发现的高血清和细胞钠浓度。拟开展的研究将从以下几个方面对南极和新西兰两种拟南极和新西兰拟南极南极鱼类独特的呼吸调节机制进行比较和对比：1）鱼类的海水饮用率和血清及细胞化学组成; 2）酶的性质和mRNA及蛋白质的表达模式; 3）鳃中Na/K-ATP酶α 3亚型亚基的时空定位。为了实现这些目标，将研究四种代表南极极锋以上和以下生态多样性习性的南极鱼。该项目的更广泛影响包括增加我们对Na-K-ATPase在许多生物体细胞功能中的作用的了解，加强我们对南极鱼的生物化学和生理适应的理解，使它们能够在南极极锋以南的冰载沃茨中生存和繁衍，为研究生和本科生提供实地和实验室研究经验，以及面向中小学学生和教师的重大科学教育推广活动。