简介：用复合酶法对大蒜多糖的提取工艺进行研究，并考察了不同浓度沉淀多糖的抗氧化活性；以多糖提取得率为指标，苯酚一硫酸法测定多糖的总糖含量，采用正交实验确定纤维素酶、木瓜蛋白酶和果胶酶的最佳配比，然后在单因素试验的基础上，采用正交实验优化复合酶提取大蒜多糖的最佳工艺；分别用羟基自由基（·OH）和1-二苯基-2-苦基肼基（DPPH·）有机自由基测定了大蒜多糖的抗氧化活性．复合酶法提取大蒜多糖的最佳酶配比：纤维素酶、木瓜蛋白酶、果胶酶的配比为1：60：5；最佳提取工艺条件：提取温度为55℃，提取时间为90min，pH值为4，料液比为1：30g／mL，该工艺条件下多糖提取得率达74．28％；80％的乙醇沉淀多糖对DPPH·和·OH的清除作用最显著，40％次之，粗多糖最弱．复合酶法提取大蒜多糖具有提取得率高的优点，并且大蒜具有一定的抗氧化作用．

简介：ThebindingofCo(bpy)2dppz3+tocalfthymusDNAwasinvestigatedbyusingabsorptionandemissionspectroscopy,DNAmeltingtechniques,cyclicvoltammetry,viscosityandelectro-phoresismeasurements,wherebpyis2,2’-bipyridyl,dppzisdipyrido[3,2-o:2’,3’-c]phenazine.Thebindingcompoundshowsabsorptionhypochromicity,fluorescenceenhancement,andincreasingofDNAmeltingtemperatureandthespecificviscosity.CVmeasurementshowstheshiftsinoxidation-reductionpotentialandchangeinpeakcurrentwithadditionofDNA.ThecompoundisalsoshowntobemoreefficientphotosensitisersforstrandbreaksinplasmidDNA.

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：近年来，以聚多巴胺球支撑的纳米复合材料越来越受到人们的关注。聚多巴胺球有表面功能化基团如-OH、-NH4等，决定了聚多巴胺球可以充当多种纳米复合材料的活性载体。利用聚多巴胺良好的还原性制备并负载银纳米粒子于聚多巴胺球表面，制备出的新型复合材料银纳米粒子一聚多巴胺球（以下简写为Ag@pdop）。Au修饰电极和银纳米粒子对过氧化氢的还原反应均具有很好的催化性能，利用两者特点将其复合制备修饰电极实现对H2O2的无酶传感，检测灵敏度达到了14．7μA／（mm01·L。），检出限可达11．8〉mol／L，线性范围0．2～6．0mmol／L，检测结果及抗干扰能力均令人满意。

简介：Adetectionofanthracyclineantitumordrugdaunomycin(DNR)reactingwithDNAinsimulatemetabolisminvitrohasbeenmade.ItwasfoundthatDNRcouldreactwithDNAtoformDNR-DNAadducts.TheadductcompositionsofDNRwithfishspermDNAandthermallydenaturatedDNAweredetermined.TheequilibriumassociationconstantKofDNRwithfishspermDNAis1.98×10^5L/molandthatofDNRwithdenaturatedDNAis2.29×10^4L/mol.Semiquinonefreeradicals,metabolicproductsofDNR,candestroybothfishspermDNAanditsthermallydenaturatedDNA.ItisverifiedbyhyperchromiceffectincreaseobservedinUVspectrumandAFMexperiments.ThemechanismofDNAdegradationhasalsobeeninvestigated.Resultsobtainedallowonetoexplainthereasonofsideeffectofanthracyclinedrugandgivethewaytodepress,whichwereofclinicalsignificance.

简介：AvohammetricstudyoftheinteractionofneutralRed(NR)withDNAatagoldelectrodeinaphosphatebuffersolutionisdescribed.AfteraddingDNAinanNRsolution,thereductionpeakcurrentofNRdecreases.ThebindingmeehahismsofNRtoDNAindifferentpHrangesaredifferent.ThereductionpeakpotentialofNRinapH7.0phosphatebuffersolutioninthepresenceofDNAshiftspositively,indicatingthatthebindingofNRtoDNAisintercalationaction,butatpH=6.0thereductionpeakpotentialofNRshiftsnegatively,indicatingthatthebindingofNRtoDNAiselectrostaticaction.TheformedcomplexesareDNA-NRwhen[NR]/[DNA]<0.18andDNA-3NRwhen[NR]/[DNA]>0.35,respectively.

简介：MtDNAwassuccessfullyextractedfromtenindividualbones(femurs)inthetombsofancientJushiinTurfanbasin,datedbacktotheyearabout3000-2500yearsago.Bymeansoffouroverlappingprimers,wegotnucleotidesequenceofthe218bplength.AncientmtDNAwasanalyzedbythesequencingofhypervariableregionⅠofthemtDNAcontrolregion.Theresultshowsthat9haplotypeswith24polymorphicsiteswereobtained.ThephylogeneticanalysisindicatedthatMongoliansandAltaiarethepopulationgeneticallyclosesttotheJushigroupsandJushimtDNApoolbeinganadmixtureofeasternAsianandEuropeanlineages.SoourpreliminarydataimplythatanancientminglingofEuro-AsianpopulationhadexistedinTurfanbasinpriortotheearlyIronAge.

简介：Rheumatoidfactors(RFs)arethecharacteristicautoantibodiesofrheumatoidarthritis.Recentresearchesinourlaboratoryshowedthattheimmobilizedsingle-strandedDNA(ss-DNA)immunoadsorbentcanselectivelyremoveRFsfromtheserumofpatients.Inthepresentpaperarestudiedthemodificationofargininine,tryptophan,lysineresiduesandcarboxylterminusofIgGRF,whichwasseparatedfrompatients′serum,with1,2-cyclohexanedione(CHD),N-bromosuccinimide(NBS),pyridoxal5′-phosphate(PP)and1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide(EDC)respectively,andtheireffectsontheadsorptioncapacityoftheimmobilizedss-DNAimmunoadsorbentforIgGRF.Afterthespecificmodification,thecorrespondingadsorptioncapacitiesoftheadsorbentswerechangedfrom48%,46%,44%and54%to84%,14%,21%and81%,respectively.Theseresultsindicatethattheelectrostaticorionic-bondingisessentialfortheinteractionbetweenss-DNAandIgGRF.

简介：TheroleplayedbyDNAinmolecularbiologyisclearlyrecognizedtobevitaltolifeonthisplanet.8-oxo-7,8-dihydro-2deoxyguanosine(=8-OHdG),isprobablythemostimportantproductof"oxidativestress”inDNA.ItsconcentrationinDNAis,infact.aquantitativeanalysisofthedegreeofDNAdamagethatanorganismhasundergone.Duetotheimportanceof8-OHdGofnucleicacidginmutagenesis,carcinogenesisandaging,numerouschemicalandbiologicalinvestigationshavebeenmadeonthissubjectinthepasttime.Kuchinoandco-workershavefoundthat8-OHdGresidueinDNAismisreadingduringtheprocessofDNAreplication.Recently,somereportshavebeenpresentedonhigh8-OHdGlevelsinpatientssufferingfromvariousdiseasessuchaschronichepatitis,Fanconisanemia,diabetesmellitusandHelicobacterpyloriinfections.Asaresult,8-OHdGisausefulmarkerforthestudyofDNAdamagearisingfromreactiveoxygenspeciesandisofgreatsignificanceforcancerresearch.The8-OHdGlevelsinDNAcanhelpunderstandthemechanismofcarcinogensandleadtomoreeffectivetreatmentsformanydifferenttypesofcancer.Forthesereasons,ananalysisof8-OHdGwithquickness,lowcostandhighaccuracyisrequired.

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简介：Thedye-dopedsilicananoparticlescanbeusedasnanobiosensorsthatareabletorecognizeanddetectspecificDNAsequence.Inthispaper,sphericalnanosizedluminol/SiO2compositeparticleshavebeensynthesizedwithreversemicellsviahydrolysisoftetraethylorthosilicate(TEOS)inthemicroemulsion.ThenanoparticlesweremodifiedwithchitosanandusedtolabelDNA,formingtheDNAprobewhichwasusedtohybridizewithtargetDNAimmobilizedonaPPymodifiedPtelectrode.Thehybridizationeventswereevaluatedbyelectrogeneratedchemiluminescence(ECL)measurementsandonlythecomplementarysequencecouldformadouble-strandedDNA(dsDNA)withDNAprobeandgivestrongECLsignals.Athreebasemismatchsequenceandanon-complementarysequencehadalmostnegligibleresponses.Duetothelargenumberofluminolmoleculesinsidesilicananoparticles,theassayallowsdetectionatlevelsaslowas2.0×10^-12mol/LofthetargetDNA.TheintensityofECLwaslinearlyrelatedtotheconcentrationofthecomplementarysequenceintherangeof5.0×10^-12—1.0×10^-9mol/L.

简介：Hereinwedemonstratetheconstructionofthreetypesofparallelgoldnanorod(AuNR)clustersusingaDNAorigamirod(DOR)asthetemplate.BasedontheprecisecontroloverthepositionofcapturestrandsonDOR,numberandorientationoftheAuNRclusterscanbewellengineered,asevidencedbybiologicaltransmissionelectronmicroscope(TEM).Importantly,theAuNRclustersexhibitchiropticalresponseswhicharestronglyaffectedbythenumberofAuNRonrod-likeDNAorigami.

简介：新奇建筑群[公司(phen)2HPlP]Cl3[phen=phenanethroline，HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][l，10]phenanethroline]被元素的分析综合了，在结构上描绘了，紫外，红外和1HNMR光谱学。有小牛胸腺DNA(CTDNA)的建筑群的相互作用被学习了使用吸收和排放光谱学，DNA融化技术和周期的voltammetry。混合物看吸收hypochromicity，荧光改进和DNA融化温度增长是否有约束力到CTDNA。CV测量与DNA的增加在山峰电流在减小潜力和一个变化显示出移动。这些结果证明混合物插入到DNA基础对的地席。山峰潜力的移动显示在建筑群和DNA之间的离子相互作用模式。到DNA的混合物的有约束力的常数是4.37灳慬瑮?郥誸???蚰铧?髧??螻?趤??藥???藥薗郧芀漀椭吗？？

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简介：由石油化工研究院大庆化工研究中心编制完成的一项评价塑料抗氧化性的国家标准，目前通过了塑料标准化技术委员会塑料树脂产品分会的审查验收，经呈送国家质量监督检验检疫总局批准，即将在全国发布实施。

简介：采用荧光光谱法和紫外-可见分光光谱法,在生理条件下(含0.1mol/LNaCl的Tris-HCl缓冲溶液,pH=7.40)研究了紫杉醇与生物大分子DNA的相互作用方式.结果表明DNA引起紫杉醇的紫外吸收光谱明显的红移和增色,并导致紫杉醇的荧光猝灭;测定不同温度下紫杉醇与DNA的荧光动态猝灭常数,结果显示K27℃=10266,K37℃=8755,K47℃=5788,即K27℃>K37℃>K47℃,说明动态猝灭常数随着温度升高而减小.同时考察了离子强度、磷酸根浓度及猝灭剂KI对紫杉醇与DNA相互作用的荧光强度的影响,三者对紫杉醇与DNA相互作用都无明显影响.表明DNA对紫杉醇的荧光猝灭类型是静态猝灭,紫杉醇与DNA的相互作用方式是嵌插作用.