Microviscosity of the Plasma Membrane of the Nitella Alga Cell in the States of Rest and Excitation

摘要

The states of the polar and nonpolar phases of the lipid bilayer in the plasma membrane of the Nitella alga cell were studied by EPR spectroscopy, Raman spectroscopy, and differential scanning calorimetry during changing the temperature from 0 to 35 ℃ and under the action of NH_4Cl, isopropanol, and p-chloromercuribenzoate. For some parameters of the Raman spectrum of carotenoids and the spin labels used, the temperature dependence was found to have an inflection at 14 ℃. It was shown that, with raising temperature to 30 ℃, the potential difference between the vacuole and the extracellular medium rises; and with elevating the temperature above 32 ℃, it decreases. In excitation of rhythmical changes in the cell potential difference during NH_4Cl perfusion, characteristic changes in the band intensities of the Raman spectra of cell carotenoids were detected. It was assumed that the changes in the microviscosity of the polar and nonpolar phases of the cell plasma membrane lipids correlate with the rhythmical changes in the potential difference.