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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

本研究取得的主要研究成果如下：1）低温冷害的分子机制。以下两个因素被确定为植物细胞冷害的主要重要因素。首先，a）由于脂质双层中磷脂酰甘油的二饱和分子种类的低温诱导的相分离导致的叶绿体功能障碍。在木本和木本植物中，二饱和磷脂酰甘油的含量与植物的冷敏感性之间建立了相关性。用毫秒延迟荧光分析法研究了低温条件下完整膜系统中二饱和磷脂酰甘油的相分离，并从冷敏南瓜子叶中分离纯化了控制二饱和磷脂酰甘油合成的关键酶，成功地克隆了其cDNA。第二，B）干扰细胞内的标志性环境， ...更多信息即低温诱导的液泡膜质子运输功能障碍。在绿豆细胞中，液泡膜H^+-ATP酶在体内相对较短时间的低温下受损，导致细胞膜酸化。两种类型的质子转运酶，即，从绿豆幼苗中分离纯化了H^+-ATP酶和H^+-PPase，并对其进行了表征。低温诱导的H^+-ATP酶失活与57、68和32 kDa亚基的特异性释放有关。2)冻伤的机制。电镜观察证实，冷冻诱导的质膜超微结构变化是细胞损伤的主要因素。在致死性冷冻细胞后，在质膜中观察到与冻伤特异性相关的膜内颗粒的聚集和无颗粒区的形成，以及Hiscononal THY相结构的形成。然而，这些超微结构的变化似乎是依赖于植物种类和细胞类型，表明在冻害的机制的多样性。在植物低温驯化过程中，质膜的分子重排，包括膜蛋白质的质的变化和不饱和磷脂的富集，被认为在植物质膜抵御低温胁迫的稳定性中起着重要作用，这些结果为进一步从分子生物学角度研究植物冷害和冻害的发生机制提供了基础。少