Molecular mechanisms of chilling injury and freezing injury

冷害和冻害的分子机制

基本信息

批准号：
62304004
负责人：
YOSHIDA Shizuo
金额：
$ 11.2万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62304004/
关键词：
Mechanisms of chilling injury Mechanisms of freezing injury Phase transition of membrane lipids Chilling injury and tonoplasts Low temperature and tonoplast proton pumps Glycerol-3-phosphate acyltransferase Purification of enzymes and cDNA clo

项目摘要

Experimental results obtained through this Research Project are summarized as follows: 1) Molecular mechanisms of chilling injury. Following two factors were determined to be primary important for chilling injury in plant cells. First, a) a dysfunction of chloroplasts due to a low temperature-induced phase separation of disaturated molecular species of phosphatidylglycerol in the lipid bilayers. The correlation between the content of disaturated phosphatidylglycerol and the chilling sensitivity of plants was established both in hevaceous and woody plant species. The phase separation of disaturated phosphatoidylglycerol in intact membrane systems under low temperatures was determined by an analysis of msec delayed fluorescence.The key enzyme which controls the synthesis of the disaturated molecular species of phosphatidylglycerol was purified from chilling sensitive squash cotyledons and the CDNA was successfully cloned. Second, b) a disturbance of an iconic environment of cytoplasms du … More e to a low temperature-induced dysfunction of tonoplast proton transports. In mung bean cells, the tonoplast H^+-ATPase is impaired by a relatively short time of chilling in vivo, giving rise to an acidification of the cytoplasms. Two types of the proton transporting enzymes, i.e., H^+-ATPase and H^+-PPase, were purified from mung bean seedlings and characterized. The low temperature-induced inactivation of the H^+-ATPase is found to be related to a specific release of 57, 68 and 32 kDa subunits. 2) Mechanisms of freezing injury. Based on electronmicroscopic studies, it was confirmed that a freeze-induced ultrastructural changes in plasma membranes is primary important factor for cell injury. Upon a lethal freezing of cells, an aggegation of intramebranous particles and a formation of particle-free area, and a formation of Hexagonal THY phase structure were observed in plasma membranes specifically related to chill injury. However, these ultrastructural changes seemed to be dependent on plant species and the cell types, suggesting a diversity in the mechanisms of freezing injury. In sold acclimation of plants, a molecular rearrangement of plasma membranes, which includes qualitative changes in membrane proteins and enrichment of unsaturated phospholipids, is considered to play an important role in stabilization of plasma membranes against freezing stress.These results may provide a basis for molecularbiological approaches to the mechanisms of chilling injury and freezing injury in plants in future. Less

所获得的剧院项目的实验结果总结如下：1）寒冷损伤的分子机制对植物细胞的寒冷是主要的重要性。脂质双层中的hosphatidyl -Glycerol的磷脂酰甘油和木质植物的寒冷敏感性。从寒冷的suash子叶中纯化了hosphatidyl-Glycerol，并成功克隆了cDNA的标志性环境。，从绿豆幼苗中纯化了两种类型的促进酶，即H^+ - PPase，引起了两种类型的促进酶。基于电子显微镜研究的特定释放，68个和32 kDa亚基。无粒子区域和一种与寒冷损伤有关的膜。在备忘录中蛋白质和不饱和磷脂的质膜在植物中较少