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Saccharomyces cerevisiae was used as a model organism for investigation of pulsed electric field effects on plasma membrane permeability and structure. Cells were exposed to single, square shaped electric field pulses with different field strengths (E= 2 kV/cm, 4 kV/cm, 6 kV/cm, 8 kV/cm, 10 kV/cm) with 150 µs duration. It was shown that viability of colony forming units decreased with raise in pulsed electric field strength. The membrane permeability showed similar pattern – stronger electric field induced greater permeability of membrane. Exposure of yeast cells to the strongest electric field (E= 10 kV/cm) caused irreversible electroporation. Within one hour after exposure permeability of electroporated cells was 2 times greater when compared with untreated cells. To evaluate lipid peroxidation and antioxidant efficacy we used fluorescent probe (Bodipy C11 581/591). Increasing rate of lipid peroxidation caused by PEF treatment was detected within one hour after treatment and it was greater when compared with untreated cells. Cells which were pretreated with vitamin E showed decreased rate of lipid peroxidation both prior and after PEF treatment. To sum up, exposure of Saccharomyces cerevisiae cells to electric field pulse resulted in increase in plasma membrane permeability, rate of lipid peroxidation and decrease in the viability

Yeast Saccharomyces cerevisiae is eukaryotic unicellular microorganism that have been used in the food industry and in laboratory research as a model organism. In this study, the effect of pulsed electric field on the isogenic strains differing on composition of the cell wall of yeast Saccharomyces cerevisiae (WT, MNN4, MNN9) was evaluated. Strains were affected by single square-shaped electric field pulses (E = 0,5 kV/cm; 2 kV/cm; 5 kV/cm; 8 kV/cm) with 300 µs duration. It was established that the amount of colony forming units (CFU) decreases, while the generation time increases by increasing the intensity of the pulsed electric field. Comparison of viability and generation time of strains after pulsed electric field tratment shows a greater decrease in viability and an increase in generation time of MNN4 strain compared to the wild type strain and therefore it can be assumed that mannosylphosphate is associated with a cellular response to stress conditions caused by pulsed electric field. The resistance of the MNN9 strain to the PEF is the greatest. The difference between the strain viability and the generation time after PEF treatment is observed due to different structure of the yeast cell wall and cell to cell interactions. To investigate mannosylphosphate expression after PEF treatment, cells were dyed with cationic dye alcian blue. It has been shown that stress caused by electric field leads to an increased expression of mannosylphosphate in the yeast cell wall. It has been concluded that PEF causes osmotic stress, and the cellular response depends on the composition of the cell wall components.