Protoplast dehydration correlated with heat resistance of bacterial spores
Protoplast dehydration correlated with heat resistance of bacterial spores
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DOI：
10.1128/jb.162.2.571-578.1985
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发表时间：
1985-05
影响因子：
3.2
通讯作者：
S. Nakashio;P. Gerhardt
中科院分区：
文献类型：
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作者：
S. Nakashio;P. Gerhardt
通过使用其中复合物的外套和外（pericortex）膜是遗传缺陷的或化学去除的孢子，证明了皮层对溶菌酶的敏感性和周原生质体珠被对葡萄糖的渗透性，在原位内的完全水合休眠的细菌孢子的原生质体的水含量进行定量。通过平衡渗透性测量，用3 H-标记的水（通过重量测量确认）测定整个孢子的含水量，用14 C-标记的葡萄糖测定内（周细胞质）膜外的珠被的含水量，并通过原生质体的差异测定含水量。将该方法应用于嗜热脂肪芽孢杆菌（Bacillus stearothermophilus，B.）枯草芽孢杆菌（B. subtilis）、B.蜡状芽孢杆菌（B. cereus）、B.苏云金杆菌B. B.巨大菌（四种类型）。采用具有可比性的抗溶菌酶孢子作为对照，其中外膜充当葡萄糖的主要渗透屏障。耐热性表示为D100值。溶菌酶敏感的孢子类型的原生质体含水量与耐热性呈指数相关，在两个不同的集群，与四个B。megaterium类型在一个对齐，并与其他四个物种类型在另一个对齐。B的原生质体含水量。巨大芽孢杆菌孢子类型足够低（26 - 29%，基于湿原生质体重量），几乎完全是它们耐热性较低的原因。其他物种类型的相应值相似或更高（30至55%），表明这些孢子取决于额外的因素，以原生质体脱水，其更大的耐热性。
Water content of the protoplast in situ within the fully hydrated dormant bacterial spore was quantified by use of a spore in which the complex of coat and outer (pericortex) membrane was genetically defective or chemically removed, as evidenced by susceptibility of the cortex to lysozyme and by permeability of the periprotoplast integument to glucose. Water content was determined by equilibrium permeability measurement with 3H-labeled water (confirmed by gravimetric measurement) for the entire spore, with 14C-labeled glucose for the integument outside the inner (pericytoplasm) membrane, and by the difference for the protoplast. The method was applied to lysozyme-sensitive spores of Bacillus stearothermophilus, B. subtilis, B. cereus, B. thuringiensis, and B. megaterium (four types). Comparable lysozyme-resistant spores, in which the outer membrane functioned as the primary permeability barrier to glucose, were employed as controls. Heat resistances were expressed as D100 values. Protoplast water content of the lysozyme-sensitive spore types correlated with heat resistance exponentially in two distinct clusters, with the four B. megaterium types in one alignment, and with the four other species types in another. Protoplast water contents of the B. megaterium spore types were sufficiently low (26 to 29%, based on wet protoplast weight) to account almost entirely for their lesser heat resistance. Corresponding values of the other species types were similar or higher (30 to 55%), indicating that these spores depended on factors additional to protoplast dehydration for their much greater heat resistance.