Nakayama H, Ohki K, Mitsui T, Nozawa Y
Biochim Biophys Acta. 1984 Jan 25;769(2):311-6. doi: 10.1016/0005-2736(84)90311-0.
Changes in the thermal phase transition temperature of membrane lipids were studied by X-ray wide-angle diffraction during adaptation of Tetrahymena pyriformis to a lower growth temperature. After a shift in growth temperature from 39 to 15 degrees C, the phase transition temperature was lowered gradually in microsomal and pellicular phospholipids, whereas that in mitochondrial phospholipids was unchanged for 10 h after the temperature shift. Only a small decrease in the transition temperature of mitochondrial phospholipids was observed, even after 24 h following the shift. Transition temperatures of microsomal, pellicular and mitochondrial phospholipids reached the growth temperature (15 degrees C) about 6, 10 and 24 h after the temperature shift. The temperature dependence of the solid phase in membrane phospholipids was estimated from the 4.2 A peak of the X-ray diffraction pattern. In the case of the phospholipids extracted from cells grown at 39 degrees C, the solid phase was increased upon lowering temperature in a similar manner in all three membrane fractions: mitochondria, pellicles and microsomes. However, in the case of the phospholipids from cells exposed to a lower growth temperature (15 degrees C) for 10 h, the increase in the solid phase was significantly smaller in mitochondrial phospholipids than in two other membrane fractions. The difference in the thermal behaviour of mitochondrial lipid from pellicular and microsomal lipids is discussed in terms of phase transition and phase separation.
在梨形四膜虫适应较低生长温度的过程中，通过X射线广角衍射研究了膜脂热相变温度的变化。生长温度从39℃转变为15℃后，微粒体和表膜磷脂的相变温度逐渐降低，而线粒体磷脂的相变温度在温度转变后10小时内未发生变化。即使在转变后24小时，也仅观察到线粒体磷脂转变温度有小幅下降。温度转变后约6、10和24小时，微粒体、表膜和线粒体磷脂的转变温度分别达到生长温度（15℃）。根据X射线衍射图谱的4.2 Å峰估计膜磷脂中固相的温度依赖性。对于从39℃生长的细胞中提取的磷脂，在所有三个膜组分（线粒体、表膜和微粒体）中，固相均以类似方式随温度降低而增加。然而，对于在较低生长温度（15℃）下暴露10小时的细胞中的磷脂，线粒体磷脂中固相的增加明显小于其他两个膜组分。从相变和相分离的角度讨论了线粒体脂质与表膜和微粒体脂质热行为的差异。
