ELECTRON-MICROSCOPY INVESTIGATION OF INTE RMEDIATES AT THE TEMPERATURE-INDUCED MICELLE-VESICLE TRANSFORMATION IN SYSTEM OF DIMYRISTOYLPHOSPHATIDYLCHOLINE WITH SODIUM CHOLATE

The intermediate structutes formed at the reversible temperature-induc ed micelle-vesicle transformation in binary mixtures of dimyristoylpho sphatidylcholine with sodium cholate were characterized by freeze-frac ture and negative staining electron microscopy. Three types of the int ermediates were observed: fragments of membrane bilayers, nets of flex ible cylindrical micelles, and extended multilayer membrane structures . Their relative contents were shown to depend on temperature and lipi d/detergent ratio in the mixture. The scheme of structural transition from micelles into vesicles in such process was suggested.