简介：TostudythegeneticcharacterizationoffourstrainsofBorreliaburgdorferiisolatedinChina.PCRtechniquewasusedtoamplifythe5S-23SrRNAintergenicspacerDNAfromthewholecellularDNAofisolatedGXLD-4,9,18andChang14,andthentheamplifiedproductswereclonedintoplasmidpGEM-TEasyandsequenced.Itwasfoundthatthe5S-23SrRNAintergenicspacerDNAofthefourisolateswas242bp,revealingthenucleotidesequenceidentityofmorethan99%.ThefourisolateshadhighersequenceidentifywithBorreliavalaisianathanwithothergeneticgroups.ThesefourisolatesmostlikelybelongtoBorreliavalaisianagenomicgroup.

简介：Toinvestigatetheprevalenceandgenotypeofextendedspectrumbeta-lactamases(ESBLs)mediatedbyplasmidinGram-negativebacteriafoundinsouthernChina,atotalof1184clinicalisolatesofnon-repetitivestrainsofGram-negativebacteriawerecollectedin2001from5differentcitiesinsouthernChina.TheESBLs-producingisolatesweredistinguishedbymeansofthephenotypeconfimatorytestbasedontheNCCLScriteriaandweresubjectedtoplasmidconjugationandelectroporationexperiments.Thoseclinicalisolatessucceededinplasmidtransfershadundergoneplasmidconjugationandelectro-transformation,plasmidDNAextractionandPstⅠdigestlinger-printinganalysis,aswellasthetmiversalprimerPCRamplificationoftheTEM,SHV,CTX-M,VEB,PERandSFOgenesandtheDNAsequencinginordertodeterminethegenotypesofESBLsandtheirplasmidlocations.ItwasfoundthattheincidenceoftheESBLs-producingstrainsofGram-negativebacteriawas14.6%(173/1184)with67strainsoftransconjugantsand11strainsofelectro-transformants,inwhichCTX-M-14typewas33.3%(26/78);CTX-M-3typewas23.1%(18/78);CTX-M-9typewas14.1%(11/78);CTX-M-5typewas6.4%(5/78);CTX-M-13typewas2.6%(2/78);SHV-5typewas7.7%(6/78);SHV-12typewas5.1%(4/78),SHV-2atypewas2.6%(2/78)andunidentifiedtypewas5.1%(4/78).29.5%ofthewildstrainsalsocarriedbroad-spectrumbeta-lactamasesTEM-1andSHV-1types.TheabovementionedESBLsgeneswerelocatedontransferableplasmidswithvariablesizes(from35to190kb).TheCTX-MtypeESBLswascharacterizedbyhigh-levelofresistancetocefotaxime.ItconcludedthattheCTX-M-typewasthemostprevalentgenotypeinclinicalisolatesofGram-negativebacteriainsouthernChina,andtheSHVtyperanksinthesecondplace.TEM-,VEB-,Toho-andPER-typeswerenotfoundintheseisolates.

简介：During2004,atotalof124batchesofHIVantibodyELISAsfromdomesticandoverseasmanufacturers,comprisingapproximately60milliontests,weretestedforqualityandreleasedforscreeningbloodinChina.Theinter-andintra-batchvariation,specificity,andsensitivitywereevaluatedusingalaboratorypanelandclinicalsamples.Theinter-batchvariationwaslessthan15%andonly2of12assayshadintra-batchvariationoflessthan20%for4dilutionsofacontrolspecimen.257samplesconfirmedpositiveforHIVantibodyand4826negativesamplesfromdifferentregionsinChinawereusedtoevaluatethesensitivityandspecificityoftheassays.Theresultsshowedthatthesensitivityisintherangefrom93.7%to100%forassayssampleddirectlyfromthemanufacturers,and91.4%-99.6%forthoseretrievedfromtheconsumers;thespecificitywasintherangefrom97.88%to99.97%.ThetestingenvironmentmayvaryindifferentregionsofChina.Therefore,manufacturersshouldproviderobustassaystosatisfytherequirementsofthesediverseenvironments,andespeciallyreducetheintra-assayvariationandimprovethestabilityofthekits.

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简介：Toinvestigatetheexistenceofthemajoroutermembranepmtein(MOMP)geneLip132in15dominantChinesestrainsof15semgroupsofLeptospirairaerrogansand2intemationalstrainsof2semgroupsofLeptospirabiflexa,andtocloneandconstructtheexpressionsystemaswellastoidentifytherecombinantpmteins,genomicDNAsfromstrainsofleptospirawerepreparedbymutinephenol-chloroformmethod,andthefragmentsoftheLipL32genewiththewholelengthfromthestrainswereamplifiedwithhighfidelityPCR.Thetargetamplificationproductswere,sequencedafterT-Acloning,andtheexpressionsystemforthegenesweretherebyconstructed,ExpressionoftherecombinantproteinswasidentifiedbyusingSDSPAGEafterinductionwithIPTGatdifferentdosages.WesternblotassayswithrabbitantiserumagainstthewholecellofTR/PatocⅠofLeptospiraandimmunizedserumwithrMOMPswereusedtodeterminetheimmunoreactivityandimmunogenicityoftherecombinantproteins.Microscopicagglutinationtestwasusedtodeterminethecross-agglutinationtitresinrabbitseraimmunizedwithrMOMPs,andthecelladherencemodelofLeptospirawasusedtoexaminetheblockingeffectsofrabbitantiseraagainsttheserMOMPs.ItwasfoundthattheLipL32genecouldbefoundinallthe17strainsofLeptospiramentionedabovewithtwodifferentgenotypes,i.e.LipL32/1andLipL32/2.AmountsofexpressionsofrMOMP1andrMOMP2afterIPTGaccountedfor40%and10%ofthetotalbacterialpmteinsrespectively.BothrMOMP1andrMOMP2couldcombinewiththerab-bitantiserumagainstleptospiralTR/PatocⅠ,andcouldinducetheproductionofagglutinationantibodiestothese17strainsofLeptospirawith1:2to1:64MATtitres.Therabbitanti-rMOMP1andanti-MOMP2antibodiesat1:2to1:16dilutionscouldefficientlyblockadherenceofLeptospira.ItconcludesthatalltheLeptospiratestedinthepresentstudypossessLipL32/1orLipL32/2genes,andtheconstructedexpressionsystemcanexpresstherMOMP1andrMOMP2.

简介：TherelationshipbetweenembBmutationofMycobacteriumtuberculosisandethambutol(EMB)resistanceoftheclinicalisolatesoftuberculouspatientsinChinawasinvestigatedbyreversedotblothybridization(RDBH)inadditiontoevaluatingtheclinicalvaluewithapplicationofPCR-RDBHtechniquetodetectEMBresistance.Inthepresentstudy,thegenotypesofthe258bpfragmentsofembBgenesfrom196clinicalisolatesofM.tuberculosiswereanalysedwithRDBHandDNAsequencing.Itwasdemonstratedthat60outof91phenotypicallyEMB-resistantisolates(65.9%)showed5typesofmissensemutationsatcodon306ofembBgene,resultinginthereplacementoftheMetresidueofthewildtypestrainwithVal,IleorLeuresidues.Inthesemutations,theGTPmutation(38/91,41.8%)andtheATAmutation(16/91,17.6%)werethemostencounteredgenotypes.TheembBmutationatcodon306couldalsobefoundin69isolatesofphenotypicallyEMB-sensitivebutresistanttootheranti-tuberculousdrugs,butnosuchgenemutationcouldbefoundin36strainsofdrug-sensitiveisolates.Meanwhile,theconcordancewiththeresultsofDNAsequencingforonewide-typeprobeand5probesforspecificmutationswas100%.ItwasconcludedthattheEMB-resistanceoccurringinmostM.tuberculosisisduetoappearanceofembBmutationatcodon306,andthePCR-RDBHassaywasprovedtobearapid,simpleandreliablemethodforthedetectionofgenemutations,whichmightbeagoodalternativeforthedrug-resistancescreening.