Genetic Controls of Cell Volume Regulation

渗透胁迫后细胞体积的恢复是每种细胞类型的特性。这种体积调节的机制取决于细胞通过调节细胞内离子和低分子有机溶质(细胞渗透压物质)的水平来控制细胞内水分的获得和损失的能力。具有最大体积调节能力的细胞对有机溶质分子的积累和损失的控制能力最强。Popper博士有很好的证据表明，季铵化合物甘氨酸甜菜碱是海洋马蹄动物心脏细胞中的主要细胞渗透剂。甘氨酸甜菜碱也被许多耐盐植物和细菌菌株使用。波普尔认为，调节甘氨酸甜菜碱水平的机制是所有这些耐盐生物的共同之处，这种螃蟹的心脏将成为阐明这些机制的极好的模式系统。计划中的实验包括表征一些生物合成和分解代谢酶系统，研究前体分子的吸收和利用，以及评估在不同渗透胁迫条件下基因表达调节(酶合成)的变化。这一结果对于我们理解细胞体积调节和抗盐胁迫的机制具有基础科学意义和实用价值。

Cell volume restoration following an osmotic stress is the property of every cell type. The mechanism of this volume regulation depends upon the ability of the cell to control intracellular water gain and loss by regulating the intracellular levels of ions and low molecular weight organic solutes (cellular osmolytes). Cells with the greatest volume regulatory ability have the greatest ability to control the accumulation and loss of the organic solute molecules. Dr. Popper has excellent evidence that the quaternary ammonium compound, glycine betaine, is the primary cellular osmolyte in the heart cells of the marine horseshoe. Glycine betaine is also used by a number of salt resistant strains of plants and bacteria. Popper feels that the mechanisms regulating glycine betaine levels are common to all these salt stress resistant organisms and that the heart of this crab will serve as an excellent model system for elucidating these mechanisms. Planned experiments involve characterization of some of the biosynthetic and catabolic enzyme systems, studies on uptake and utilization of precursor molecules and an evaluation of the changes in the regulation of gene expression (enzyme synthesis) under various conditions of osmotic stress. The results will have both basic science and practical value in terms of our understanding of the mechanisms of cell volume regulation and salt stress resistance.