[Fluorescence polarization used to investigate the cell membrane fluidity of Saccharomyces cerevisiae treated by pulsed electric field].
To know the lethal mechanism of microorganisms under pulsed electric field treatment, the relationship between the inactivation of Saccharomyces cerevisiae (CICC1308) cell and the permeability and fluidity changes of its cell membrane treated by pulsed electric field (0-25 kV x cm(-1), 0-266 ms) was investigated. With 1,6-diphenyl-1,3,5-hexatriene (DPH) used as a probe, the cell membrane fluidity of Saccharomyces cerevisiae treated by pulsed electric field was expressed by fluorescence polarization. Results showed that the cell membrane fluidity decreases when the electric flied strength is up to 5 kV x cm(-1), and decreases with the increase in electric field strength and treatment time. The plate counting method and ultraviolet spectrophotometer were used to determine the cell viability and to investigate the cell membrane permeability, respectively, treated by pulsed electric field. Results showed that the lethal ratio and the content of protein and nucleic acid leaked from intracellular plasma increased with the increase in the electric field strength and the extension of treatment time. Even in a quite lower electric field of 5 kV x cm(-1) with a tiny microorganism lethal level, the increase in UV absorption value and the decrease in fluidity were significant. It was demonstrated that the cell membrane fluidity decreases with the increase in lethal ratio and cell membrane permeability. The viscosity of cell membrane increases with the decrease in fluidity. These phenomena indicated that cell membrane is one of the most key sites during the pulsed electric field treatment, and the increased membrane permeability and the decreased cell membrane fluidity contribute to the cell death.
Zhang
Ying
Y
School of Light Industry and Food Technology, South China University of Technology, Guangzhou 510640, China.
Zeng
Xin-An
XA
Wen
Qi-Biao
QB
Li
Lin
L
D002463:Cell Membrane Permeability; D002470:Cell Survival; D004560:Electricity; D005454:Fluorescence Polarization; D008560:Membrane Fluidity; D012441:Saccharomyces cerevisiae / Q000166:cytology*; D013997:Time Factors; D014783:Viscosity