Effects of pulsed electric fields on cytomembrane lipids and intracellular nucleic acids of Saccharomyces cerevisiae

In this study, pulsed electric fields (PEF) treatments at 20 kV/cm for 0-500 μs were applied to Saccharomyces cerevisiae to investigate the effects of PEF on the cytomembrane and intracellular nucleic acids. The change in composition of membrane lipids characterized by decrease in the ratio of contents of unsaturated fatty acids versus saturated fatty acids induced by PEF was observed, which was related with the increase in rigidness of cytomembrane (lower cytomembrane fluidity and higher cytomembrane viscosity) after PEF. PEF treatment caused no significant change in DNA but disruption of RNA of S. cerevisiae, which was also confirmed by the increase of PEF resistance and no occurrence of injured microbial cells by supplementation of RNA stabilizer, magnesium. The results showed the damage of cytomembrane and RNA were associated with the sublethally injured S. cerevisiae, suggesting cytomembrane and RNA were primary targets for PEF induced microbial damage.