Diamond R J, Rose A H
J Bacteriol. 1970 May;102(2):311-9. doi: 10.1128/jb.102.2.311-319.1970.
Spheroplasts were prepared from cells of Saccharomyces cerevisiae NCYC 366, grown at 30 or 15 C, by incubating cells with snail-gut juice after pretreatment with 2-mercaptoethanol. Walls of cells grown batchwise or in continuous culture at 15 C were more resistant to digestion with snail juice than walls on cells grown under the same conditions as 30 C. Spheroplasts lysed when suspended in hypotonic solutions of mannitol. The resistance of spheroplasts to osmotic lysis tended to increase when the test temperature was lowered below 30 C. The increased resistance was greater with spheroplasts from cells grown at 15 C. Cations, especially Ca(2+), protected spheroplasts against osmotic lysis. In general, the protective effects, measured at 30 C, were smaller with spheroplasts from cells grown at 15 C compared with 30 C. Citrate and ethylenediaminetetraacetate (EDTA) decreased the resistance of spheroplasts to osmotic lysis. On the whole, the decrease was greater with spheroplasts from cells grown at 30 C rather than 15 C. In the presence of EDTA, spheroplasts from cells grown at 30 C were less resistant to osmotic lysis at 5 C than at 30 C; when spheroplasts from cells grown at 15 C were similarly examined, they were more resistant to lysis at 5 C than at 30 C. Spheroplast membranes from cells grown at 15 C had slightly but significantly greater contents of Mg(2+), Ca(2+), K(+), and Na(+) compared with spheroplast membranes from cells grown at 15 C. Mg(2+) and Ca(2+) were more easily extracted with EDTA from membranes of 30 C-grown cells than from 15 C-grown cells.
通过在2-巯基乙醇预处理后用蜗牛胃液孵育，从在30℃或15℃下生长的酿酒酵母NCYC 366细胞制备原生质球。在15℃下分批培养或连续培养的细胞的细胞壁比在30℃相同条件下生长的细胞的细胞壁更耐蜗牛液消化。原生质球悬浮在甘露醇低渗溶液中时会裂解。当测试温度降至30℃以下时，原生质球对渗透裂解的抗性趋于增加。来自在15℃下生长的细胞的原生质球增加的抗性更大。阳离子，尤其是Ca(2+)，可保护原生质球免受渗透裂解。一般来说，在30℃下测量时，与在30℃下生长的细胞相比，来自在15℃下生长的细胞的原生质球的保护作用较小。柠檬酸盐和乙二胺四乙酸（EDTA）降低了原生质球对渗透裂解的抗性。总体而言，来自在30℃下生长的细胞的原生质球的降低幅度大于在15℃下生长的细胞。在EDTA存在下，来自在30℃下生长的细胞的原生质球在5℃时比在30℃时对渗透裂解的抗性更低；当对来自在15℃下生长的细胞的原生质球进行类似检查时，它们在5℃时比在30℃时更耐裂解。与来自在15℃下生长的细胞的原生质球膜相比，来自在15℃下生长的细胞的原生质球膜中Mg(2+)、Ca(2+)、K(+)和Na(+)的含量略有但显著更高。与来自在15℃下生长的细胞的膜相比，Mg(2+)和Ca(2+)更容易用EDTA从在30℃下生长的细胞的膜中提取。
