Anderson R L, Tao T W, Hahn G M
Department of Radiation Oncology, Stanford University, CA 94305.
Int J Radiat Biol. 1988 Nov;54(5):813-23. doi: 10.1080/09553008814552241.
Membrane lipid composition and fluidity of a series of B16 melanoma cell variants with increased resistance to heat were analysed for changes within the lipid component that may contribute to the acquisition of heat resistance. Within one series of heat-resistant lines the cholesterol content of the cells decreased as their heat resistance increased. The most heat-resistant line, WH75, had 40 per cent less cholesterol than the parent line. No change in the composition of phospholipid fatty acids was found. An increased level of membrane fluidity in WH75 was demonstrated by electron paramagnetic resonance using 5- or 12-doxyl stearic acid. When challenged by heat the increase in membrane fluidity was similar for WH75 and for the parent line. Thus the increased heat resistance of the variants is probably not due to their ability to adapt to heat challenge by increasing membrane thermostability. The inverse relationship between heat resistance and cholesterol content was not demonstrated in two other series of heat-resistant variants. The cholesterol decrease, therefore, is not a universal response of cells as they acquire heat resistance.
分析了一系列对热抗性增强的B16黑色素瘤细胞变体的膜脂组成和流动性，以寻找脂质成分中可能有助于获得耐热性的变化。在一系列耐热细胞系中，细胞的胆固醇含量随着耐热性的增加而降低。耐热性最强的细胞系WH75的胆固醇含量比亲本细胞系少40%。未发现磷脂脂肪酸组成有变化。使用5-或12-硬脂酰基硬脂酸通过电子顺磁共振证明WH75的膜流动性增加。当受到热刺激时，WH75和亲本细胞系的膜流动性增加情况相似。因此，变体耐热性的提高可能不是由于它们通过增加膜热稳定性来适应热刺激的能力。在另外两个耐热变体系列中未发现耐热性与胆固醇含量之间的反比关系。因此，胆固醇降低并非细胞获得耐热性时的普遍反应。
