Membrane properties of an extreme thermophile. I. Detection of the phase transition and its dependence on growth temperature.

Phase transition was detected by a fluorescence polarization technique in the membrane of Thermus thermophilus HB8: it was found to be a function of cell growth temperature when the cell growth temperature was varied between 50-80 degrees C. A systematic relation between the phase transition temperature and the growth temperature was observed. Differential scanning calorimetry was also applied. The phase transition was found to take place between 34 and 55 degrees C for cells grown at 50 degrees C and between 52 and 80 degrees C for cells grown at 80 degrees C.