Metabolic Control of Intracellular Organic Solute Accumulation During Salt Stress

高等动物(肠道、肾脏等)组织中的各种植物、海洋或河口动物、微生物和某些细胞。通过使用各种小分子、电中性有机分子作为细胞内渗透缓冲剂来显示对盐胁迫(高浓度盐溶液)的抵抗力。抗旱机制与抗盐机制密切相关。不能调节这些有机溶质浓度的细胞不耐盐胁迫。这项拟议的研究建立在以前工作的基础上，重点放在细胞用来调节这些有机溶质细胞内浓度的机制上。我们认为，这些溶质的产生和代谢周转在细胞内的细胞器中被分割，如线粒体和/或叶绿体，而细胞的其余部分作为积累的隔室。我们计划以一种高度耐盐的双壳软体动物的鳃组织作为模型系统，鉴定线粒体中调节这些溶质产生的元素(酶)，并研究细胞如何控制这些元素的调节，以调节细胞的内渗透压，使其与培养基浴细胞的渗透压大致相同。这项研究涉及使用各种分析化学设备、放射化学示踪剂、一些组织培养研究、酶分析以及使用各种离心法、层析法、电泳法和抗体沉淀法分离代谢元素以进行特定分析。其结果将是更好地理解细胞耐盐胁迫的机制以及调控这些过程的生理调控。

A wide variety of plants, marine or estuarine animals, microorganisms and certain cells in the tissues of higher animals (gut, kidneys, etc.) show resistance to salt stress (highly concentrated salt solutions) by using a variety of small molecular weight, electrically neutral organic molecules as intracellular osmotic buffers. The mechanism of drought resistance is closely tied to the mechanism of salt stress resistance. Cells that cannot regulate these organic solute concentrations are not salt stress resistant. The proposed research builds on previous work and focuses on the mechanisms used by cells to regulate the intracellular concentration of these organic solutes. We propose that production and metabolic turnover of these solutes are compartmentalized within intracellular organelles such as the mitochondria and/or chloroplasts and that the rest of the cell serves as the compartment of accumulation. Using gill tissue from a highly salt stress resistant bivalve mollusc as a model system, we plan to identify the elements (enzymes) regulating production of these solutes in the mitochondria and study how the cell controls the regulation of these elements so as to adjust the internal osmotic pressure of the cell to be more or less equal to that of the media bathing cell. The research involves use of a variety of analytical chemical equipment, radiochemical tracers, some tissue culture studies, enzymatic assays and the separation of metabolic elements using various centrifugation, chromatographic, electrophoretic, and antibody precipitation techniques for specific analysis. The result will be a better understanding of the mechanisms of cellular salt stress resistance and the physiological controls regulating these processes.