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1、第33卷第2期高电压技术Vol.33No.2·90·2007年2月HighVoltageEngineeringFeb.20073强脉冲电场对细胞膜通透性及其DNA的影响张鹰,曾新安,温其标,冯洁(华南理工大学轻工与食品学院,广州510641)摘要:为探讨脉冲电场(PEF)致死微生物的机理,研究了不同场强与处理时间对悬浮在温度为30°C,电导率σ为340μS/cm的NaCl溶液中大肠杆菌的灭菌效果。紫外分光光度计分析PEF处理前后核酸与蛋白质的溢出情况的结果显示,电场强度为30kV/cm,处理时间266m
2、s时,大肠杆菌全部杀灭。经PEF处理后的大肠杆菌液中的核酸与蛋白质相对于未处理的大肠杆菌液有明显提高,说明用PEF处理提高了细胞膜的通透性。采用ERIC-PCR技术比较脉冲电场处理前后大肠杆菌的DNA指纹图谱变化的结果表明:强PEF(场强≥20kV/cm)导致大肠杆菌的DNA链损伤与降解,在指纹图谱上表现为DNA大分子条带的缺失与小分子量条带的增加。关键词:高强脉冲电场;大肠杆菌;细胞膜通透性;ERIC2PCR指纹图谱;DNA降解中图分类号:TS205.9;Q689文献标识码:A文章编号:1003265
3、20(2007)0220090204EffectofHighIntensityPulsedElectricFieldontheMembranePermeabilityandDNAofEcoliZHANGYing,ZENGXin’an,WENQibiao,FENGJie(CollegeofLightIndustryandFoodTechnology,SouthChinaUniversityofTechnology,Guangzhou510641,China)Abstract:Thispaperstudie
4、stheeffectsofdifferentelectricfieldstrengthandtreatmenttimeontheinactivationofEcolisuspendedinsodiumchloride(electricconductivityδ=340μS/cm,30°C)byacontinuoushighintensitypulsede2lectricfield(PEF)treatmentsystem.Theplatecountingmethodisusedtodeterminethe
5、viabilityofthecells.TheresultsshowthatthesurvivalofEcolidecreaseswithincreasingtheelectricfieldstrengthandtreatmenttime,andE.coliisinactivatedby30kV/cm,266mstreatment.ThesubsequentleakageofproteinandnucleicacidofEcoliduetothePEFprocessingisinvestigatedby
6、usingtheultravioletspectrophotometricmethod.Andtherelativea2mountsoftheleakedproteinandnucleicacidfromEcoliincreaseafterthePEFtreatment,andincreasewithincreas2ingtheelectricfieldstrengthandtreatmenttime,showingthatPEFtreatmentincreasesthemembranepermeabi
7、liza2tionofEcoli.ERIC(EnterbacteriaRepetitiveIntergenicConsensus)2PCRmethodisusedtodeterminetheinactiva2tionofPEFonEcoli.ERIC2PCRfingerprintingdemonstratedthatDNAofthetreatedEcoliisinjuredandDNAdegradationappeareswhentheelectricfieldstrengthisupto20kV/cm
8、for539msormoreseverePEFtreatment(30kV/cmfor266ms;35kV/cmfor266ms;50kV/cmfor177ms),andmacromoleculeDNAisdegradedintosmallmoleculefragments.TheresultsindicatetheincreasedmembranepermeabilityandDANdegradationmayresultedinthel
