学科分类
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214 个结果
  • 简介:ThegenomeoftheenterohemorrhagicEscherichiacoliO157:H7EDL933contains177“O”-islands(OIs).TostudytheirpotentialcontributiontotheO157-specificpathogenicity,wesurveyedthedistributionof22OIsbyPCRandDNAhybridizationin17isolatesofShigatoxinproducing(Stx-positive)E.coliO157:H7,andcomparedwiththeirdistributionin21isolatesofStx-negativeE.coliO157and21isolatesofnon-O157entericpathogens.Fourteenof22OIswerepresentinnon-O157entericpathogensanalyzed.Eightof22OIswerefoundonlyinthe17Shigatoxin-(Stx)positiveE.coliO157:H7isolates,buttheywereabsentfromthe21Stx-negativeE.coliO157:NMandO157Hundisolatestested.Amongthe8OIs,onlyOI43orOI48wereexclusivelydetectedinStx-positiveE.coliO157:H7,absentfromneitherofStx-negativeE.coliO157andnon-O157entericpathogens,suchasSalmonella,ShigeUa,Citrobacter,Vibriocholera,enteropathogen-icE.coli(EPEC),enteroadherentE.coli(EAEC),enteroinvasiveE.coli(E1EC)andenterotoxingenicE.coli(ETEC).TheOI43andOI48are83kbinsizeandidenticalinDNAsequences,whichencodegenesforurease,telluriteresistanceandadherence.ByanalyzingtheirjunctiongeneswithPCRandDNAhybridization,wefoundthat21ChineseisolateshaveOI48only.However,for7Japanesepatientisolates,4haveOI43and3haveOI48;forAmericanisolates,2havebothofO143andOI48,2haveOI48only.ThesedataconfirmedthehighlyplasticityofthepathogenicE.coligenome.TheuniquepresenceofOI43/OI48inStx-positiveE.coli0157:H7denotesitscriticalroleinthepathogenicityspecifictothispathogen.

  • 标签: O-岛 埃希氏菌属 大肠菌O157 肠病原体 E.大肠菌 O157:H7
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  • 简介:ToconstructandexpressthefusionproteinStx2B-IntiminC300ofEHEC0157:H7,andtofurtherinvestigateitsimmunoprophyiacticpotential,thegeneofStx2B(stx2b)fromEHEC0157:H7chromosomewasclonedintopMD18-Tvector.Thereafter,theamplifiedgenewasclonedintoprokaryoticexpressionplasmidpET-28a(+)-eaeC300,whichwasconstructedpreviously.TherecombinantpasmidpET-28a(+)-stx2b-eaeC300wastransformedintoE.coliBL21(DE3).Afterinducement,theproteinStx2B-IntiminC300wassuccessfullyexpressedandanalyzedwithsodiumdodecylsulfatepolyacrylamidegelelectrophoresis(SDS-PAGE),WesternblottingandN-terminalaminoacidresidualsequencing.Toevaluateitsimmunoprophyiacticpotential,itwasprimarilypurifiedbyion-exchangechromatographyandinjectedinto30BALB/cmicewithAl(OH)3inthesubscapularregion.Tendaysafterthelastboostervaccination,20micewereattackedwithEHEC0157:H7lysateandtheprotectiveefficacywasobserved.Inthepresentstudy,thegeneofStx2B-IntiminC300wassuccessfullyclonedintopET-28a(+)vector.TheresultsofSDS-PAGEandWesternblottingassayshowedthatthefusionproteinwassuccessfullyexpressedintheinclusionbodyform,accountingfor25%oftotalexpressionproducts,anditsmolecularweightwasabout43kDa.TheresultoftheN-terminalaminoacidresidualsequencingshowedthatitwasidenticaltothatofthemoleculardesigned.Thepuritywasabout75%afterprimarypurification.AnimaltestsrevealedthatthefusionproteinStx2B-IntiminC300haselicitedhightiterofprotectiveantibodyrelatively.TheseresultsdemonstratethatthefusionproteinStx2B-IntiminC300issuccessfullyexpressedinprokaryoticexpressionsystemandshowscertainimmunoprophyiacticpotential.

  • 标签: 疫苗 免疫机制 蛋白质 原核表达
  • 简介:Thepurposeofthestudyistoestablishafluorescencequantitativereversetranscriptionpoly-merasechainresponse(FQ-RT-PCR)methodforthequantitativedeterminationofIL-2mRNAandIL-4mRNAinThcells,withwhichtheThcellsstatusofthepatientswithgynaecologicaltumorsandchronicrenalfailure(CRF)canbeanalyzed.IL-2cDNAandIL-4cDNAwereprepared,andtheplasmidpMD18carryingIL-2cDNAorIL-4cDNAfragmentwasconstructedandclonedasthetemplateforquantitativedetermination.Theprimersandprobeslabelledwith6-carboxy-fluorescein(FAM)and6-carboxy-tetrarnethylrhodamine(TAMRA)wereprepared,andtheexperimentalconditionswereoptimizedtosetuptheFQ-RT-PCRmethodforquantitativedeterminationofIL-2mRNAandEL-4mRNA.Thcellsenrichedfromperipheralbloodmononuclearcells(PBMCs)of20healthyvolunteers(HVs),16gynaecologicalbenign(GB)cases,18gynaecologicalmalignant(GM)tumorcasesand16chronicrenalfailure(CRF)patientsweretestedforIL-2mRNAandIL-4mRNAbyFQ-RT-PCR.Thehouse-keepinggeneβ-actinwasusedastheinternalcontrolgeneoftheexperiment.Thestandardcurveforlogconcentrationofseriesofquantitativetemplatesvsthresholdcycle(CT)wasestablishedbylinearregression,andthelinearrangewas102-107copies/μl.TheimprecisiontestshowedtheCVofinter-assayandintra-assayofahighcontentsamplebyFQ-RT-PCRwere7.8%and12.5%,respectively.TheCVofinter-assayandintra-assayofalowcontentsamplewere10.8%and19.5%,respectively.TheIL-2mRNAexpressionsinThofthepatientswithgynaecologicalmalignanttumor(comparedwiththeHVsandthepatientswithgynaecologicalbenigndisease)andinThoftheCRFpatients(comparedwiththeHVs)weredeclinedsignificantlyandatthesametimetheIL-4mRNAexpressionincreasedsignificantly(P<0.001).Asimple,sensitiveandaccurateFQ-RT-PCRmethodforthequantitativedetectionofIL-2mRNAandIL-4mRNAhasbeenestablished.TheIL-2mRNAandIL-4m

  • 标签: IL-2 IL-4 MRNA 定量测定 FQ-RT-PCR法 细胞因子
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  • 简介:Toinvestigatetheroleofnegative-regulatoryfactorsA20,IRF-4andTRAF4ofthetoll-likereceptor(TLR)signalpathwaysinimmunologicalpathogenesisofKawasakidisease(KD),48childrenwithKawasakidisease,16childrenwithinfectiousdisease(ID)and16age-matchedhealthychildrenwerestudied.Reverse-transcriptionPCR(RT-PCR)andreal-timePCRwereusedtoevaluatetheexpres-sionlevelsofnegative-regulatoryandeffectivefactorsintoll-likereceptor4(TLR4)signalpathwaysandproinflammatoryfactorsinperipheralbloodmonocyte/macrophage(MC).Inthisstudy,expressionlevelsofTLR4,MD-2,MyD88,IRAK-4,TRAF6,TAK1,andTAB2mRNAinKDgroupweredetectedtobeelevatedsignificantlyduringacutephaseofKD.Transcriptionlevelsofnegative-regulatoryfactorsA20,IRF-4andTRAF4mRNAinKDorIDpatientsincreasedremarkably.However,expressionsofIRF-4andTRAF4inKDpatientsweredetectedtobelowerthanthatinIDpatients,exceptthattran-scriptionlevelsofA20werefoundtobehigherthanthatinIDpatients.Simultaneously,expressionsofproinflammatorycytokinessuchasL-1β,IL-6andTNF-αinKDpatientsweresignificantlyelevatedcom-paredwiththoseinIDpatients.Furthermore,itwasfoundthatstimulationoflipopolysaccharide(LPS)remarkablyup-regulatedtheexpressionsofnegative-regulatoryfactorsA20,IRF-4andTRAF4inKDpa-tientsorhealthyvolunteers.ThemRNAlevelsofallthethreefactorsinKDpatientswerefoundtobelowerthanthatinthelatter.Inaddition,transcriptionlevelsofIRF-4andTRAF4inKDpatientswithcoronaryarterylesion(KD-CAL~+)weredetectedtobelowerthanthoseinKDpatientswithoutcoronaryarterylesion(KD-CAL~-)duringacutephase,whilethatofA20inKD-CAL~+groupwerelowerthanthatinthelatter.AndthelevelsofexpressionsofproinflammatorycytokinesinKD-CAL~+groupwerefoundtobehigherthanthoseinKD-CAL-group(P<0.01).Thesefindingssuggestthataberrantexpressionofnegative-regulatoryfactorsofTLRssignalpathwaysmaybeinvolved

  • 标签: 川崎病 受体 A20 IRF-4 TRAFd
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