Niven Gordon W, Miles Christopher A, Mackey Bernard M
Institute of Food Research, Reading Laboratory, Earley Gate, Whiteknights Road, Reading RG6 6BZ, UK.
University of Bristol School of Clinical Veterinary Science, Churchill Building, Langford, Bristol BS40 5DU, UK.
Microbiology (Reading). 1999 Feb;145 ( Pt 2):419-425. doi: 10.1099/13500872-145-2-419.
Differential scanning calorimetry of whole Escherichia coil cells allowed the detection in vivo of changes in ribosome conformation. This enabled for the first time an analysis of the effects of high hydrostatic pressures on ribosomes in living cells. A correlation was observed between loss of cell viability and decrease in ribosome-associated enthalpy in cells subjected to pressures of 50-250 MPa for 20 min. Cell death and ribosome damage were therefore closely related phenomena. In pressure-treated cells, the thermogram peak temperatures decreased, suggesting that the remaining ribosomes had adopted a less stable conformation. During subsequent incubation of the cultures at 37 degrees C, peak temperatures and enthalpies gradually increased over a period of 5 h. This change in ribosome conformation had no apparent effect on cell survival, as viability continued to decrease. The addition of 5 mM MgCl2 before pressure treatment of cells prevented the reduction in stability of surviving ribosomes but had no effect on the initial loss of enthalpy or on cell viability.
对完整的大肠杆菌细胞进行差示扫描量热法，能够在体内检测核糖体构象的变化。这首次使得对高静水压对活细胞中核糖体的影响进行分析成为可能。在50 - 250 MPa压力下处理20分钟的细胞中，观察到细胞活力丧失与核糖体相关焓的降低之间存在相关性。因此，细胞死亡和核糖体损伤是密切相关的现象。在压力处理的细胞中，热谱峰温度降低，这表明剩余的核糖体采用了不太稳定的构象。在随后将培养物于37℃孵育期间，峰温度和焓在5小时内逐渐升高。核糖体构象的这种变化对细胞存活没有明显影响，因为活力继续下降。在对细胞进行压力处理之前添加5 mM MgCl2可防止存活核糖体稳定性的降低，但对初始焓损失或细胞活力没有影响。
