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Correlation Between Freeze-tolerance of Bakers' Yeasts and Their Cellular Content of Trehalose

面包酵母的耐冻性与其细胞内海藻糖含量的相关性

基本信息

批准号：
07680019
负责人：
KAWAI Hiroyasu
金额：
$ 1.47万
依托单位：
Nara Women's University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

This study was undertaken to clarify the correlation between freeze-tolerance of bakers' yeasts and their intracellular trehalose, a reserve carbohydrate in yeast. 1. The amount of trehalose in a freeze-tolerant cells of Torulaspora delbrueckii was higher than that of a freeze-sensitive mutant. The result suggested that the freeze-tolerance of yeast has a close relationship to its trehalose content. 2. The trehalose content of growing yeast cells was increased by a heat-shock, i.e., a temporal increase in culture temperature, and these yeast cells were found to have higher survival ratio after freeze-thawing. This indicated that intracellular trehalose of yeast has an important role to lower the freeze-injury of yeast. 3. There were found no clear correlation between trehalose content of commercial compressed bakers' yeasts belonging to Saccharomyces cerevisiae and their freeze-tolerance, but their cultured yeast cellsshowed a positive relationship between them. 4. A trehalase-deficient mutant of T.delbrueckii had a high trehalose content, while a mutant having a weak trehalose-phosphate synthetase activity had a low trehalose content. These results reflected a close relationship between freeze-tolerance and cellular content of trehalose. 5. It was found that freeze-tolerant strain had a higher trehalose-phoshpate synthetase activity and a lower neutral trehalase activity than that of freeze-sensitive strain, the results indicating that those enzyme activities were closely related to the amount of cellular trehalose and freeze-tolerance of yeast.

本研究旨在阐明面包酵母的耐冻性与其胞内海藻糖的关系。1.德氏圆孢酵母耐冻突变体细胞中海藻糖含量高于冻敏突变体。结果表明，酵母菌的耐冻性与其海藻糖含量密切相关。2.生长中的酵母细胞的海藻糖含量通过热激增加，即，培养温度的暂时升高，并且发现这些酵母细胞在冻融后具有较高的存活率。这表明酵母胞内海藻糖对降低酵母的冷冻损伤具有重要作用。3.啤酒酵母（Saccharomycescerevisiae）的商业压缩面包酵母的海藻糖含量与其耐冷冻性之间没有明显的相关性，但其培养的酵母细胞的海藻糖含量与其耐冷冻性之间存在正相关。4.德氏锥虫的海藻糖酶缺陷突变体具有高海藻糖含量，而具有弱海藻糖-磷酸合成酶活性的突变体具有低海藻糖含量。这些结果反映了细胞内海藻糖含量与细胞耐冻性之间的密切关系。5.结果表明，耐冻菌株的海藻糖磷酸合成酶活性高于不耐冻菌株，而中性海藻糖酶活性低于不耐冻菌株，说明中性海藻糖酶活性与酵母细胞内海藻糖含量及耐冻性密切相关。