干酪乳杆菌LC2W对胃癌细胞的黏附作用及对幽门螺杆菌的拮抗作用

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1、上海水产大学硕士学位论文干酪乳杆菌LC2W对胃癌细胞的黏附作用及对幽门螺杆菌的拮抗作用姓名：周方方申请学位级别：硕士专业：食品科学指导教师：郭本恒20070520上海水产大学硕士学位论文作用的结果，但蛋白类物质起主导作用，表明其黏附素的主要成分为蛋白质。最后，利用5M氯化锂对L．caseiLC2W细胞表面蛋白进行了提取。扫描电镜结果显示，抽提后细胞表面被破坏而细胞不破裂，其对MKN-45细胞黏附性降低，表明表面蛋白参与了L．caseiLc2w对细胞的黏附。SDS—PAGE结果表明提取的表面蛋白由分子量为41．6、63．5、66．2kDa的三种蛋白组成。采用葡聚糖凝胶G-75对表

2、面蛋白进行初步分离，并测试其黏附能力。结果表明，分子量为41．6kDa的表面蛋白组分可以明显增强经氯化锂处理过的菌体对MKN-45的黏附能力，表明该蛋白是参与L．caseiLC2W黏附的配体蛋白。关键词：于酪乳杆菌LC2W，黏附，抑制，表面蛋白Ⅱ上海水产大学硕士学位论文TheadhesiveabilityofLactobacilluscaseiLC2WtogastriccellsanditsantagonisticactivityagainstHelicobacterpyloriSSlABSTRACTColonizationinthegastrointestinaltracti

3、stheprerequisiteforprobioticstoexerttheirhealth-promotingactivitiesandtoexcludethecolonizationofpathogenicbacteria．Itishypothesizedthatadhesiontothemucusortheepitheliaisthefirststepforprobioficstocolonizeinthegastrointestinaltract，andthecharacteristicofsurfacesubstancesofprobioficsiscrucialf

4、ortheadhesion．Thus，thesesubstancesarecrucialforelucidatingtheadhesivemechanismsofprobiotics．LcasefLC2WwaschosenastheexperimentalstrainandinvestigatedonitsadhesivefunctionandinhibitoryfunctiontoHpyloriSSlinthedissertation．Meanwhile，thesubstancesinvolvedintheadhesionwerepreliminaryisolatedandi

5、dentified．Firsfly，theadhesiveabilitvofLcaseiLC2Wtogastriceellline～ⅨN．45．Wastestedunderseveralvariables(bacteriaIcellconcentration,resuspendingmedia,thepHoftheresnspendingmedia)viamorphologiealobservationandcellcountingundermicroscope．11heresultsindicatedthatLeaselLC2WCOu／dadheretobetflMKN45a

6、ndHGC一27。especiallytheformer．TheadhesionabilityofL．caseiLC2WtothegastriccellsWasconcentration—dependenttothelactobacilluseellresuspension,withtheaveragenumbersofbacterialcelladheredtopergastriccellincreasinguntilthesurfaceofthegastriccellsweresaturatedbythelactobacillicells．whenthelaetobacil

7、lieellresaspensionreachedl∥CFU，mL．W魁letheresuspendingsolutionaswellas也epHofthesolutiondemonstratedsignificantlyeffectonthebacterialadhesiveability，thespentculturesupematant(scs)ofL．caseiLC2wandpH4．0wereoptimalforthelactobacillicellstoadheretothegas