Russell A D, Harries D
Appl Microbiol. 1968 Sep;16(9):1394-9. doi: 10.1128/am.16.9.1394-1399.1968.
The effects of temperatures of 50 to 60 C on suspensions of a strain of Escherichia coli are described. At these temperatures, the substances which leaked from the cells were determined as pentoses; the amount leaked over a 30-min period increased with increasing temperature. The leakage materials from suspensions heated in water, sodium chloride, sucrose, and sucrose plus Mg(++) were examined spectrophotometrically, and the ratios of the absorbances at 280 and 260 nm (the 280 to 260 nm ratio) were determined. It was not possible to determine protein by this method, as the ratio was always <0.7. When saline was the suspending medium, the ratio was lower than when water was used, and there was a greater leakage of 260 nm absorbing material. When suspended in sucrose or in sucrose plus Mg(++), penicillin-induced spheroplasts did not undergo lysis, but became less regular in shape, and there was an increase in the extinction at 500 nm. The overall effects of high temperatures on nonsporeforming bacterial cells are discussed; in view of the available evidence, it is concluded that ribonucleic acid degradation is an event which is probably closely related to thermally induced bacterial death.
描述了50至60摄氏度的温度对大肠杆菌菌株悬液的影响。在这些温度下，从细胞中泄漏的物质被确定为戊糖；在30分钟内泄漏的量随温度升高而增加。对在水、氯化钠、蔗糖以及蔗糖加Mg(++)中加热的悬液的泄漏物质进行了分光光度检查，并测定了280和260纳米处的吸光度之比（280至260纳米之比）。由于该比值始终<0.7，因此无法用此方法测定蛋白质。当盐水作为悬浮介质时，该比值低于用水时的情况，并且260纳米吸收物质的泄漏量更大。当悬浮在蔗糖或蔗糖加Mg(++)中时，青霉素诱导的原生质球不会发生裂解，但形状变得不太规则，并且在500纳米处的消光增加。讨论了高温对非芽孢形成细菌细胞的总体影响；鉴于现有证据，得出的结论是核糖核酸降解可能是与热诱导细菌死亡密切相关的一个事件。
