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剧烈变化，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通量，从而将体液浓度维持在一个相对狭窄的范围内。由于鳃在几乎所有硬骨鱼中都负责大部分气体交换，消除含氮废物，酸碱平衡和渗透调节，因此它是动物与环境之间的关键界面。相对较少的关注集中在构成该界面的鳃质膜的化学和物理特性上。克罗克特博士将检验这一假设，即淡水和海水环境下的鱼类，鳃顶端质膜结构域的脂质组成有显著差异。脂质变化的发生可能是为了(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)维持膜的有序和相态等物理特性，以及(4)提供一个允许膜相关蛋白充分活动的微环境。在18个月的计划期间，Crockett博士将描述鱼类在适应不同环境盐度过程中鳃质膜域脂质成分的重组。这项工作将确定哪些脂类（磷脂、糖脂、胆固醇）参与了盐度适应。研究结果将(1)建立一个同时制备鳃顶端和底外侧结构域的方案；(2)首次研究鱼类在盐度适应过程中的鳃质膜重组。

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.