Research Planning Grant: Lipid Restructuring in Gill Plasma Membranes: An Investigation of Domain-Specific Responses in Euryhaline Teleosts During Salinity Adaptation

许多河口或潮间带鱼类暴露在波动的盐度中，而其他鱼类则在淡水和海洋地点之间迁徙。这些动物的溶质平衡可能会发生巨大变化，但它们通过一系列行为、系统水平、细胞和生化适应来抵消水和离子的被动流动，将体液的浓度维持在相对较窄的范围内。由于鳃负责几乎所有硬骨鱼的大部分气体交换、氮废物的清除、酸碱平衡和渗透调节，因此它是动物和环境之间的关键界面。相对较少的注意力集中在构成这一界面的鳃质膜的化学和物理性质上。克罗基特博士将检验这一假说，即淡水和海水驯化的鱼类的鳃顶端质膜结构域的脂组成存在显著差异。脂质的改变可能是为了(1)确保膜的完整性和通透性，(2)减少表面电荷密度的变化，(3)保持膜的物理性质，如有序和相态，以及(4)提供允许膜相关蛋白足够活性的微环境。在为期18个月的计划期间，克罗基特博士将描述鱼类在适应不同环境盐度的过程中，鳃质膜结构域中脂类成分的重组。这项工作将确定哪一类脂质(磷脂、糖脂、胆固醇)与盐度适应有关。结果将(1)建立一种同时制备鳃顶端和基侧结构域的方案，(2)为鱼类在盐度适应过程中的鳃质膜重构提供第一个观察。

Many estuarine or intertidal fishes are exposed to fluctuating salinities, while other fishes migrate between freshwater and marine sites. These animals' solute balance might change drastically, but they maintain concentrations of their body fluids in a relatively narrow range with a suite of behavioral, systems-level, cellular, and biochemical adaptations to offset the passive fluxes of water and ions. Because the gill is responsible for the majority of gas exchange, elimination of nitrogenous waste, acid-base balance, and osmoregulation in virtually all teleost fishes, it represents a key interface between animal and environment. Relatively little attention has focused on chemical and physical properties of the plasma membranes of the gill that make up this interface. Dr. Crockett will test the hypothesis that lipid compositions of apical plasma-membrane domains from the gill are significantly different in freshwater- and seawater-acclimated fishes. Lipid changes are likely to occur in order to (1) ensure membrane integrity and permeability properties, (2) reduce changes in surface-charge density, (3) maintain such membrane physical properties as order and phase state, and (4) provide a micro-environment that permits sufficient activity of membrane-associated proteins. During the 18-month planning period, Dr. Crockett will characterize restructuring of the lipid components in gill plasma-membrane domains from fishes during adaptation to varying environmental salinities. This work will establish which lipid class(es) (phospholipids, glycolipids, cholesterol) is (are) involved in salinity adaptation. Results will (1) establish a protocol to prepare simultaneously gill apical and basolateral domains and (2) provide the first look at gill plasma-membrane restructuring during salinity adaptation in fishes.