文稿成果課件-interactions with humans

Intimatestrangers:MicroorganismsinandonLectureLecture17-Human-MicrobeChapter21BROCKBIOLOGYOFShanghaiJiaoTongUniversityII.HarmfulmicrobialinteractionswithhumansHowcanapathogencauseShanghaiJiaoTongInfectionandInfection:ThegrowthofmicroorganismsinthehostDisease:ThedamageorinjurytothehostthatimpairshostfunctionInfectionisnotsynonymouswithdisease ShanghaiJiaoTongPathogensTheabilityoftheparasitetoinflictdamageonthe(susceptibility)抗性/Theabilityofthehosttoberesistanttothe tativemeasureofpathogenicity:CellorviralnumberthatwillelicitapathogenicresponseinahostinagivenperiodMicroorganismsandpathogenesis.Microorganismsandpathogenesis.Thepresenceandevengrowthofmicroorganismsonthehostdoesnotalwaysleadtodisease微生物存在或生ShanghaiJiaoTongAdherenceand Specificity特異性/選擇Bacteriaor esabletoinitiateinfectionoftenadherespecificallytocells(tissuespecificityandhostspecificity)通過特異性吸附完成 Mechanism:protein-proteininteractiononthesurfacesofthepathogenandthehostcell.機(jī)理表ShanghaiJiaoTongAdherenceandInvasionReceptorsonthesurfaceofhosttissueMacromoleculesonthesurfaceofbacteriaCapsuleGlycocalyx胞外糖蛋Slimelayer粘液FimbriaePilicolonization 因子抗ShanghaiJiaoTongColonizationandGrowth定植與生長(zhǎng)Colonization:MultiplicationinhosttissuesOrganicTraceelements-irontransferrinandSiderophores,bactinencodedbyColVEnvironmentalReductionShanghaiJiaoTongLocalizationinthe LocalizedTheboil,carbuncle,orpimplethatcommonlyarisesfromStaphylococcusinfectionsoftheskin.癤,癰,丘疹由葡萄球GeneralizedBacteremia:ifextensivebacterialgrowthintissuesoccurs,someoftheorganismsareusuallyshedintothebloodstreaminlargenumbers.菌血癥ShanghaiJiaoTongVirulenceVirulence:therelativeabilityofaparasitetocausedisease(figure)Lethaldose50(LD50):thedoseofanagentthatkills50%oftheanimalsinatestgroup.半致死劑量Lostvirulence:attenuated減毒Toxicitytheabilityofanorganismtocausediseasebymeansofapreformedtoxinthatinhibitshostcellfunctionorkillshostcells.毒Invasiveness:theabilityofanorganismtogrowinhosttissueinsuchlargenumbersthatthepathogeninhibitshostfunction.侵染III.VirulenceFactorsandShanghaiJiaoTongVirulencefactorsExtracellularproteinsproducedbythepathogentoaidintheestablishmentandmaintenanceofdisease胞外酶的作用Hyaluronidase透明質(zhì)酸酶)breakdownhyaluronicacid-thetissuecementinanimalsProteases,nucleases,lipasestoproduceCollagenase膠原酶todissolvetissueStreptokinase溶栓酶todissolvefibrinCoagulase凝固酶toprotectpathogenwithfibrinShanghaiJiaoTongExotoxins外毒Exotoxins-Extracellularproteins,maytravelfromafocusofinfectiontodistantpartsofthebodyandcausedamageinregionsfarremovedfromthesiteofmicrobialgrowth. ShanghaiJiaoTongThreeCategoriesofActoncellmembraneandcausecellA-BBcomponentbindstoreceptorsonthecellAcomponentgetintothecelltodoInducemassiveorevensystemicinflammatoryreactionsstimulatinglargenumbersofimmuneresponsecells可通過刺激ShanghaiJiaoTongEnterotoxins-Exotoxinsth tonthesmallintestinetocausevomitinganddiarrhea作用于小腸而致 complexglycolipid)intheepithelialcellA-BBforAforactivationofthecellularenzyme,adenylcyclasetocauseconversionofATP-cAMPCholeraActionActionofcholeraThenormalprocessofionmovementintheintestine.ColonizationVibriocholeraebindingofenterotoxinwiththeGM1gangliosideonhostcellsTheA-BtoxinactsinternalizingthetoxicAcomponentandactivatingadenylcyclase.ofnormalsodium(Na+)LossofH2Ointothelumen,andShanghaiJiaoTonglipopolysaccharidesintheouterlayerofcellwallofGram-negativebacteriatheyaregenerallycell-boundandreleasedinlargeamountsonlywhencellsarelysed.內(nèi)毒素：G-細(xì)菌的胞壁外膜的脂多糖，ShanghaiJiaoTongEndotoxins:ModeofFeverinduction:Stimulatehostcelltoreleaseendogenouspyrogens