简介:DNAcondensationisanimportantprocessinmanyfieldsincludinglifesciences,polymerphysics,andappliedtechnology.Inthenucleus,DNAiscondensedintochromosomes.Inpolymerphysics,DNAistreatedasasemi-flexiblemoleculeandapolyelectrolyte.Manyagents,includingmulti-valentcations,surfactants,andneutralpoorsolvents,cancauseDNAcondensation,alsoreferredtoascoil–globuletransition.Moreover,DNAcondensationhasbeenusedforextractionandgenedeliveryinappliedtechnology.ManyphysicaltheorieshavebeenpresentedtoelucidatethemechanismunderlyingDNAcondensation,includingthecounterioncorrelationtheory,theelectrostaticzippertheory,andthehydrationforcetheory.Recentlyseveralsingle-moleculestudieshavefocusedonDNAcondensation,sheddingnewlightonoldconcepts.Inthisdocument,themulti-fieldconceptsandtheoriesrelatedtoDNAcondensationareintroducedandclarifiedaswellastheadvancesandconsiderationsofsingle-moleculeDNAcondensationexperimentsareintroduced.
简介:TheeffectofCdionsonsalmonspermDNAwasstudiedbymeansofcirculardichroism(CD),Ramanspectroscopy,X-rayphotoelectronspectroscopy(XPS)andfluorescencespectroscopy.TheCDspectralandfluorescentprobe-acriflavineresultsindicatethattheDNAunderwentaconformationchangeupontheadditionofCdions.XPSandRamanstudiesrevealthatthereexistedinteractionsbetweenCdionsandthephosphategroupsoftheDNA.Inaddition,anewbandappearedat803cm-1intheRamanspectra,whichcanbeattributedtocharacterizing"marker"bandofA-DNA.ItisconcludedthatCdionscanbecoordinatedbythephosphategroupsoftheDNAandinducetheconformationchangesoftheDNAfromB-DNAtoA-DNA.
简介:HydrolysisofDNAisanimportantenzymaticreaction,butitisexceedinglydifficulttomimicinthelaboratorybecauseofthestabilityofhydrolysisofDNA.Inthispaper,thecleavageactivityofcomplexesformedbetweenCu(Ⅱ)andfourdifferentaminoacidoraminoacidmethylesteronDNAisstudiedbygelelec-trophoresis.ItisfoundthatDNAcouldbecleavedbyCu(Ⅱ)-L-HisandCu(Ⅱ)-L-Hismethylestercomplexesandtheefficiencyofcleavageislargelydependentonthemetalion-to-ligandratio.FurtherexperimentsshowthatthecleavageofDNAmediatedbyCu(Ⅱ)-L-HiscomplexesoccursviaahydrolyticmechanismandtheactivechemicalspeciesthataffectsDNAcleavageisproposedtobeMI2H+andML2H22+.
简介:1 如果有一天,有人问你要不要去做亲子鉴定,从而进一步证明你与父母或子女的血缘关系,抑或权当是好玩,去检验一下现代科学技术是否可靠,你一定不会认为这是一个乐于让人接受的愉快的建议。人类发展到今天,还没有任何一项技术像DNA鉴定一样,犹如一面魔镜,能如此不容置疑地反映出我们现存生活状态的某种真相,并使人产生一种畏惧感。人生就像棋局,我们已经从我们的人生经历中接受了许多既成的事实,并基于对这些事实的认识和有关法律、道德、伦理、家庭等方面的文化传统建立起了我们对生活的信念,我们并不想对此产生怀疑,颠覆我们原有的生活理念和秩序。然而,大千世界,众生芸芸,并不是所有的人生都遵循着传统的生活模式和法则
简介:Someantitumoractivitiesofcomponent(E),extractedfromtherootofFagopynumCymosum(Trev)Meisn(FCTM),haverecentlybeendiscoveredinvivoandinvitro.ThecomponentE(CE)’spatternofactionwithtumorcellularDNAatthemolecularpharmacologicallevelwasinvestigatedbymacromolecularsynthesisexperiment(MSE)andhumanDNAinteractionsystemestablishedinourlaboratory.Theexperimentsdemonstratedthat,invitro,theagentcouldmarkedlyinhibittheincorporationof3H-TdRintothecellularDNA,andtheIC50inP388leukemiacellandinSGC-7901cellwas17.86μg/mland110.4μg/ml,respectively.Theagent,atmg/mllevel,couldproduceanintercalationreversionpatternwithDNAwithinashorttime(2hours).Butwhentheintervalwasprolongedforover4hours,theactionchangedtointercalationirreversiblepattern.Accordingtotheseobservations,theauthorsinferthatCEinteractswithDNAintwoways-directlyandindirectly.Theindirectaction,especiallyinlowconcentr
简介:目的探讨骨骼DNA提取与快速检验的方法.方法取1年内的碎骨片37份,采用优化的PrepFilerBTAForensicDNA试剂盒法提取DNA,以GlobalfilerTMExpress复合扩增,经3130xL基因分析仪电泳分离进行STR分型检测.结果37份骨骼样本均获得完整的STR分型,各等位基因峰为200~7500rfu,峰型较均衡.结论采用本文建立的骨骼DNA快速检验法提取骨骼DNA,检验时间短,STR分型结果好,可在实际检案中使用,特别适合于灾害事故遇难者身份识别(disastervictimidenti?cation,DVI)的身源鉴定.
简介:Themitochondrial12SrRNAhasbeenshowntobethehotspotformutationsassociatedwithbothaminoglycoside-inducedandnon-syndromichearingloss.Ofallthemutations,thehomoplasmicA1555GandC1494Tmutationsatahighlyconserveddecodingregioninthe12SrRNAhavebeenassociatedwithaminoglycoside-inducedandnon-syndromichearinglossinmanyfamiliesworldwide.TheA1555GorC1494Tmutationisexpectedtoformnovel1494C-G1555or1494U-A1555base-pairatthehighlyconservedA-siteof12SrRNA.ThesetransitionsmakethesecondarystructureofthisRNAmorecloselyresemblethecorrespondingregionofbacterial16SrRNA.Thus,thenewU-AorG-Cpairin12SrRNAcreatedbytheC1494TorA1555Gtransitionfacilitatesthebindingofaminoglycosides,therebyaccountingforthefactthattheexposuretoaminoglycosidescaninduceorworsenhearinglossinindividualscarryingthesemutations.Furthermore,thegrowthdefectandimpairmentofmitochondrialtranslationwereobservedincelllinescarryingtheA1555GorC1494Tmutationinthepresenceofhighconcentrationofaminoglycosides.Inaddition,nuclearmodifiergenesandmitochondrialhaplotypesmodulatethephenotypicmanifestationoftheA1555GandC1494Tmutations.TheseobservationsprovidethedirectgeneticandbiochemicalevidencesthattheA1555GorC1494TmutationisapathogenicmtDNAmutationassociatedwithaminoglycoside-inducedandnonsyndromichearingloss.Therefore,thesedatahavebeenprovidingvaluableinformationandtechnologytopredictwhichindividualsareatriskforototoxicity,toimprovethesafetyofaminoglycosideantibiotictherapy,andeventuallytodecreasetheincidenceofdeafness.