关键词: 脉冲电场, 鼠伤寒沙门氏菌 Salmonella Typhimurium, 拉曼光谱;磷脂构象, 细胞膜流动性

Abstract:

In the investigation,the effects of the pulsed electric field (PEF) treatment on the survival ratio and cytomembrane permeability of Salmonella Typhimurium are discussed,and the effect of the PEF treatment time on the phospholipid conformation of S. Typhimurium is also analyzed by using the Raman spectra.The results show that (1) as the energy of PEF inputs continuously,the cell viability decreases and the cytomembrane permeability increases; (2) with the increase of the PEF treatment time,the peak value ratio of the Raman spectra of S. Typhimurium phospholipid,namely I₁₁₃₉ /I₁₀₈₂ ,first increases and then decreases,and it is always higher than that without PEF treatment (P ＜0. 05),which indicates that the PEF treatment can increase the number of the all-trans conformation of C—C and decrease the number of the gauche conformation of C—C; and (3) as the PEF treatment time increases,I₂₈₇₄ /I₂₈₆₂ increases (P ＜0. 05),which means that the PEF treatment increases the lateral chain interaction of C—H and thus results in the increase of the intrachain order of phospholipid molecules and the decrease of the cytomembrane fluidity of S. Typhimurium.Therefore,it is concluded that the PEF treat- ment can cause cell damage or cell death by increasing the cytomembrane permeability and decreasing the cytomem- brane fluidity.This investigation provides a theoretical basis for the mechanism research of inactivating micro-or- ganisms with the PEF treatment.

Key words: pulsed electric field, Salmonella Typhimurium, Raman spectra, phospholipid conformation, cytomembrane fluidity