EFFECT OF ELECTRICAL ENERGY ON THE ELECTROPERMEABILIZATION OF YEAST-CELLS

A suspension of yeast cells (Saccharomyces cerevisiae) in NaCl solutio n was exposed to high voltage pulses under defined conditions. The res ults on perforation through the membrane and the cell wall structure ( electropermeabilization) and the resealing process was presented. Capa citor discharges were applied to yeast cells in their logarithmic grow th phase. A dye was added at a predetermined time after the electric p ulse. Dyed and total (dyed plus undyed) yeast cells were counted micro scopically and the rate was calculated. Dyed cells were assumed to hav e pores. For simplicity, the time constant of the electric circuit was adjusted so that it was almost the same for each capacitance by chang ing the conductivity of the yeast suspension. The capacitances used in the experiments were 1, 2, 4 and 8 muF yielding different initial fie ld strengths. It was calculated that, under similar perforation and re sealing conditions, almost the same energy was applied to the yeast su spension. Our conclusion is that the electrical energy is closely conc erned with the electropermeabilization and resealing of the membrane a nd cell wall.