
Description:

Rapid,sensitiveandpreciseprobe-basedqPCRdetectionandquantitationoftargetDNAandCDNAsequences.
Probe-basedquantitativePCR(qPCR)usesreal-timefluorescencereleasedupon5´→3´exonucleasecleavageofaquenched,target-specificprobetomeasureDNAamplificationateachcycleofaPCR.Atapointwherethefluorescencesignalissignificantlydetectableoverthebackgroundfluorescence,aquantificationcycleorCqvaluecanbedetermined.Cqvaluescanbeusedtoevaluaterelativetargetabundancebetweentwoormoresamplesortocalculateabsolutetargetquantitiesinreferencetoanappropriatestandardcurve,derivedfromaseriesofknowndilutions.
TheNEBLunaUniversalProbeqPCRMasterMixisa2Xreactionmixoptimizedforreal-timeqPCRdetectionandquantitationoftargetDNAsequencesusinghydrolysisprobes.ItcontainsHotStartTaqDNAPolymeraseandhasbeenformulatedwithauniquepassivereferencedyethatiscompatIBLeacrossavarietyofinstrumentplatforms(includingthosethatrequireahighorlowROXreferencesignal).ItalsofeaturesdUTPforcarryoverpreventionandanon-fluorescent,visibledyetomonitorreactionsetup.ThisdyedoesnotspectrallyoverlapfluorophorescommonlyusedforqPCRandwillnotinterferewithreal-timedetection.
Themastermixformulationissuppliedat2XconcentrationandcontainsallPCRcomponentsrequiredforamplificationandquantitationofDNAexceptprimers/probesandDNAtemplate.GenomicDNAorcDNAofinterestcanbequantitatedwithLunaqPCRandexistingaswellascommercialqPCRassayprimer/probesequencescanbeused.



LearnmoreaboutourcomprehensiveqPCR/RT-qPCRtestingand“dotsinboxes”datavisualization
Notes:
AssayDesignTheuseofqPCRprimerdesignsoftware(e.g.,Primer3)maximizesthelikelihoodofamplificationsuccesswhileminimizingnonspecificamplificationandprimerdimers.TargetswithbalancedGC/ATcontent(40–60%)tendtoamplifyefficiently.Wherepossible,entersufficientsequencearoundtheareaofinteresttopermitrobustprimerdesignandusesearchcriteriathatpermitcross-referenceagainstrelevantsequencedatabases(toavoidpotentialoff-targetamplification).ForcDNAtargets,itisadvisabletodesignprimersacrossknownsplicingsitesinordertopreventamplificationfromgenomicDNA.Conversely,primersdesignedtotargetintronicregionscanensureamplificationexclusivelyfromgenomicDNA.PrimerandProbeConcentrationFormosttargets,afinalconcentrationof400nMforeachprimerwillprovideoptimumperformance.Ifneeded,primerconcentrationscanbeoptimizedbetween200–900nM.Probeshouldbeincludedat200nMforbestresults.Probeconcentrationcanbeoptimizedintherangeof100–500nMifoptimizationofperformanceortargetfluorescencelevelisdesired.MultiplexingTodetectorquantitatemultipletargetsinthesameLunareaction,selectdifferentfluorophorescorrespondingtoseparatedetectionchannelsofthereal-timeinstrument.Include400nMofforwardandreverseprimerand200nMprobeforeachtargettobedetectedinthereaction,andadjustconcentrationsifnecessarybasedonperformance(primer200–900nM,probe100–500nM).WhenloADIngqPCRprotocolontothereal-timeinstrument,besuretoselecttheappropriateopticalchannels,assomeinstrumentshaveasinglechannelrecordingmodethatwouldpreventmultiplexdatacollectionandanalysis.ForROX-dependentinstruments,avoidROX-labeledprobes.Thefunctionalityoftheprimerandprobesetsshouldbetestedindividuallybeforeattemptingamultiplexreaction.Whendeterminingwhichfluorophorestoincludeinamultiplexreaction,besuretochoosecompatiblereporterdyesandquenchersthathavewellseparatedfluorescencespectraorexhibitminimaloverlap.AmpliconLengthToensuresuccessfulandconsistentqPCRresults,itisimportanttomaximizePCRefficiency.AnimportantaspectofthisisthedesignofshortPCRamplicons(typically70–200bp).Someoptimizationmayberequired(includingtheuseoflongerextensiontimes),fortargetsthatexceedthatrange.TemplatePreparationandConcentrationLunaqPCRiscompatiblewithDNAsamplespreparedthroughtypicalnucleicacidpurificationmethods.PreparedDNAshouldbestoredinanEDTA-containingbuffer(e.g.,1XTE)forlong-termstability,anddilutionsshouldbefreshlypreparedforaqPCRexperimentbydilutionintoeitherTEorwater.Generally,ausefulconcentrationofstandardandunknownmaterialwillbeintherangeof106copiesto1copy.ForgDNAsamplesfromlargegenomes(e.g.,human,mouse)arangeof50ng–1pgofgDNAistypical.Forsmallgenomes,adjustasnecessaryusing106 –1copyinputasanapproximaterange.Notethatforsinglecopydilutions,somesampleswillcontainmultiplecopiesandsomewillhavenone,asdefinedbythePoissondistribution.ForcDNA,usetheproductofareactioncontaining1μg–0.1pgstartingRNA.cDNAdoesnotneedtobepurifiedbeforeadditiontotheLunareactionbutshouldbedilutedatleast1:10intotheqPCR.ROXReferenceDyeSomereal-timeinstrumentsrecommendtheuseofapassivereferencedye(typicallyROX)toovercomewell-to-wellvariationsthatcouldbecausedbybubbles,smalldifferencesinvolume,andautofluorescencefromdustorparticulatesinthereaction.TheLunaUniversalProbeqPCRMasterMixisformulatedwithauniversalreferencedyethatiscompatiblewithavarietyofqPCRinstrumenttypes,includingthosethatusenopassivereferencenormalizationandthosethatusealoworhighconcentrationofpassivereferencedye(ROX).Therefore,noadditionalcomponentsarerequiredtoensurecompatibilitywiththeseinstruments.CarryoverContaminationPreventionqPCRisanextremelysensitivemethod,andcontaminationinnewqPCRassayswithproductsfrompreviousamplificationreactionscancauseavarietyofissuessuchasfalsepositiveresultsandadecreaseinsensitivity.Thebestwaytopreventthis“carryover”contaminationistopracticegoodlaboratoryproceduresandavoidopeningthereactionvesselpostamplification.However,toaccommodatesituationswhereadditionalanti-contaminationmeasuresaredesired,theLunaUniversalProbeqPCRMasterMixcontainsamixtureofdUTP/dTTPthatresultsintheincorporationofdUintotheDNAproductduringamplification.PretreatmentofqPCRexperimentswithuracilDNAglycosylase(UDG)willeliminatepreviously-amplifieduracil-containingproductsbyexcisingtheuracilbasetoproduceanon-amplifiableDNAproduct.TheuseofaThermolabileUDGisimportant,ascompleteinactivationoftheUDGisrequiredtopreventdestructionofnewlysynthesizedqPCRproducts.Toenablecarryoverprevention,0.025units/μlAntarcticThermolabileUDG(NEB#M0372)shouldbeaddedtothereactionmix.Tomaximizeeliminationofcontaminatingproducts,setuptheqPCRexperimentsatroomtemperatureorincludea10minuteincubationstepat25°Cbeforetheinitialdenaturationstep.ReactionSetupandCyclingConditionsDuetothehotstartnatureofthepolymerase,itisnotnecessarytopreheatthethermocyclerpriortouseorsetupreactionsonice.For96-wellplates,werecommendafinalreactionvolumeof20μl.For384-wellplates,afinalreactionvolumeof10μlisrecommended.Whenprogramminginstrumentcyclingconditions,ensureaplatereadisincludedattheendoftheextensionstep,andadenaturation(melt)curveaftercyclingiscompletetoanalyzeproductspecificity.Amplificationfor40cyclesissufficientformostapplications,butforverylowinputsamples45cyclesmaybeused.ebiomall.com






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一般来说多克隆的阳性率高一些,但出现假阳性的比例也高一些。
制备抗体都需要进行纯化处理
抗体的特异性鉴定 抗体的特异性是指与相应抗原或近似抗原物质的识别能力。抗体的特异性高,它的识别能力就强。衡量特异性通常以交叉反应率来表示。交叉反应率可用竞争抑制试验测定。以不同浓度抗原和近似抗原分别做竞争抑制曲线,计算各自的结合率,求出各自在 IC50时的浓度,并按下列公式计算交叉反应率。 如果所用抗原浓度IC50浓度为pg/管,而一些近似抗原物质的IC50浓度几乎是无穷大时,表示 这一抗血清与其他抗原物质的交叉反应率近似为 0,即该血清的特异性较好。
抗体的亲和力 是指抗体和抗原结合的牢固程度。亲和力的高低是由抗原分子的大小、抗体分子的结合位点与抗原决定簇之间立体构型的合适度决定的。有助于维持抗原抗体复合物稳定的分子间力有氢键、疏水键、侧链相反电荷基因的库仑力、范德华力和空间斥力。亲和力常以亲和常数K表示,K的单位是L/mol,通常K的范围在 108 ~1010 /mol,也有多达 1014 /mol。抗体亲和力的测定对抗体的筛选,确定抗体的用途,验证抗体的均一性等均有重要意义。向左转|向右转
又由于自然存在的抗原大都存在多个抗原表位,会刺激机体产生多种针对同一抗原的不同抗原表位相应的不同抗体.

