The Effect of Pulsed Electric Field on Saccharomyces Cerevisiae's Cellular Content Leakage and Cell Death
The application of an external pulsed electric field can induce a critical electrical potential across the cell membrane, which leads to rapid electrical breakdown of the cell membrane.Yet this traditional theory is lack of sufficient date and authentic research results to be supported. The relationships among the leakage of cellular content such as nucleic acid and protein, etc, membrane fluidity, and the lethal ratio of the Saccharomyces cerevisiae cell under various electric field treatment conditions were explored in this paper. UV spectrophotometry was used to measure the relative leakage content of nucleic acid and protein from cell plasma and fluorescence spectra was applied to analysis the membrane fluidity. It was found that both contents of protein and nucleic acid in treated samples were increased with the increase of electric field (0-25 kV cm-1), especially in lower electric field strength area (0-5 kV cm-1).Accordingly, the cell membrane fluidity increased rapidly when the electric field strength increased from 0 to 5 kV cm-1, while afterwards the curve became level off when the electric field strength changed from 5 to 25 kV cm-1. Applied PEF at 5 kV cm-1 had little effect on S.cerevisiae cell’s viability, but significantly caused the leakage of cellular content and meanwhile decreased the membrane fluidity. These results may supply some evidences for the existence of reversible phase of cell membrane breakage induced by pulsed electric field and explain the mechanisms of the prophase of cell lethal.
Key words: Pulsed electric field, Saccharomyces cerevisiae, nucleic acid, cell membrane