简介：通过对香蕉枯萎病菌4号小种致病突变体B1233的进一步研究，分离了被突变的致病相关基因foABC1，同源性分析及保守结构预测该基因编码一类ABC转运蛋白，其功能可能同稻瘟病菌的ABC转运蛋白一样，负责真菌毒素的泵出，或是像其他真菌的ABC转运蛋白，在病原菌侵染寄主植物时能忍耐植物因防卫反应所释放的植保素或抗毒素类物质。

简介：Glucosetransporter4(GLUT4)isresponsibleforinsulin-stimulatedglucosetransportingintotheinsulin-sensitivefatandmusclecells.ThedynamicsofGLUT4storagevesicles(GSVs)remainstobeexploredanditisunclearhowGSVsarearrangedbasedontheirmobility.Weexaminedthisissuein3T3-L1cellsviainvestigatingthethree-dimensionalmobilityofsingleGSVlabeledwithEGFP-fusedGLUT4.Athinlayerofcytosolrightadjacenttotheplasmamembranewasilluminatedandsuccessivelyimagedat5Hzunderatotalinternalreflectionfluorescencemicroscopewithapenetrationdepthof136nm.Employingsingleparticletracking,thethree-dimensionalsubpixeldisplacementofsingleGSVwastrackedataspatialprecisionof22nm.Boththemeansquaredisplacementandthediffusioncoefficientwerecalculatedforeachvesicle.Trackingresultsrevealedthatvesiclesmovedasifrestrictedwithinacagethathasameanradiusof160nm,suggestingthepresenceofsomeintracellulartetheringmatrix.ByconstructingthehistogramofthediffusioncoefficientsofGSVs,weobservedasmoothdistributioninsteadoftheexistenceofdistinctgroups.TheresultindicatesthatGSVsaredynamicallyretainedinacontinuousandwiderangeofmobilityratherthanintoseparateclasses.

简介：TheE(envelope)proteinisthesmalleststructuralproteininallcoronavirusesandistheonlyviralstructuralproteininwhichnovariationhasbeendetected.WeconductedgenomesequencingandphylogeneticanalysesofSARS-CoV.Basedongenomesequencing,wepredictedtheEproteinisatransmembrane(TM)pro-teincharacterizedbyaTMregionwithstronghydrophobicityandα-helixcon-formation.Weidentifiedasegment(NH2-_L-Cys-A-Y-Cys-Cys-N_-COOH)inthecarboxyl-terminalregionoftheEproteinthatappearstoformthreedisulfidebondswithanothersegmentofcorrespondingcysteinesinthecarboxyl-terminusoftheS(spike)protein.ThesebondspointtoapossiblestructuralassociationbetweentheEandSproteins.OurphylogeneticanalysesoftheEproteinsequencesinallpub-lishedcoronavirusesplaceSARS-CoVinanindependentgroupinCoronaviridaeandsuggestanon-humananimalorigin.

简介：WestudiedstructuralandimmunologicalpropertiesoftheSARS-CoVM(mem-brane)protein,basedoncomparativeanalysesofsequencefeatures,phylogeneticinvestigation,andexperimentalresults.TheMproteinispredictedtocontainatriple-spanningtransmembrane(TM)region,asingleN-glycosylationsitenearitsN-terminusthatisintheexteriorofthevirion,andalongC-terminalregionintheinterior.TheMproteinharborsahighersubstitutionrate(0.6%correlatedtoitssize)amongviralopenreadingframes(ORFs)frompublisheddata.ThefoursubstitutionsdetectedintheMprotein,whichcausenon-synonymouschanges,canbeclassifiedintothreetypes.OneofthemresultsinchangesofpI(isoelectricpoint)andcharge,affectingantigenicity.ThesecondchangeshydrophobicityoftheTMregion,andthethirdonerelatestohydrophilicityoftheinteriorstructure.PhylogenetictreebuildingbasedonthevariationsoftheMproteinappearstosupportthenon-humanoriginofSARS-CoV.Toinvestigateitsimmunogenicity,wesynthesizedeightoligopeptidescovering69.2%oftheentireORFandscreenedthembyusingELISA(enzyme-linkedimmunosorbentassay)withserafromSARSpatients.Theresultsconfirmedourpredictionsonantigenicsites.

简介：竞争性寡聚脱氧核糖核酸识别转录因子的DNA结合域,抑制了转录因子对基因的转录调控,转录因子E2F作为潜在的治疗靶点,可以用于抑制肾小球系膜细胞和血管内皮细胞的增生,在部分异常增生的疾病中显示了一定的应用前景.

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简介：利用构建的犬2型腺病毒E3区缺失质粒pBE3L分别构建了含有和不含外源性启动子的绿色荧光蛋白(GFP)基因和狂犬病病毒糖蛋白(Rgp)基因的重组表达质粒pBE3LGFP、pBE3LCGFP、pBE3LRgp和pBE3LCRgp,并分别对DK细胞进行了转染实验,以检测其表达,结果显示,pBE3LCGFP质粒在转染DK细胞后,于36h即可观察到荧光,72～96h无明显差别,传3代后仍可见表达荧光的细胞,pBE3LCRgp质粒转染DK细胞后,于48～96h用间接免疫荧光染色可检测到糖蛋白的表达,而pBE3LGFP和pBE3Rgp质粒转染DK细胞后经检测均无表达,表明构建的E3区缺失性载体不能利用E3区自身的启动子进行目的基因的表达,但利用外源性启动子可使外源基因获得良好表达.

简介：Mammaliancelltotipotencyisasubjectthathasfascinatedscientistsforgenerations.AlonglastingquestionwhethersomeofthesomaticcellsretainstotipotencywasansweredbythecloningofDollyattheendofthe20thcentury.Thedawnofthe218thasbroughtforwardgreatexpectationsinharnessingthepoweroftotipotentcyinmedicine.Throughstemcellbiology,itispossibletogenerateanypartsofthehumanbodybystemcellengineering.Considerableresourceswillbedevotedtoharnesstheuntappedpotentialsofstemcellsintheforeseeablefuturewhichmaytransformmedicineasweknowtoday.Atthemolecularlevel,totipotencyhasbeenlinkedtoasingulartranscriptionfactoranditsexpressionappearstodefinewhetheracellshouldbetotipotent.NamedOct4,itcanactivateorrepresstheexpressionofvariousgenes.Curiously,verylittleisknownaboutOct4beyonditsabilitytoregulategeneexpression.ThemechanismbywhichOct4specifiestotipotencyremainsentirelyunresolved.Inthisreview,wesummarizerethestructureandfunctionofOct4andaddresstoOct4functioninmaintainingtotipotencyorpluripotencyofembryonicstemcels.

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简介：InteractionbetweencytotoxicTlymphocyte-associatedantigen-4(CTLA4,CD152)andB7molecules(B7-1andB7-2)isofimportanceinthecellulareventsoflymphocyte,includingantigen-specificT-cellactivationandinductionofautoreactiveT-cell.WedescribehaerethefirstintroductionofamurinesolubleCTLA4gene,CTLA4Ig,toMm1cells,amacrophagiccellline.CTLA4IgwassuccessfullyexpressedonMm1cellsandtheexpressedCTLA4IgwasfoundtobefunctionallyactiveintheirbindingtoB7moleculesbyflowcytometryandimmunofluorescencestudies.ThebiologicalactivityofCTLA4IgfromthetransfectedMm1cellswasstudiedandshowedinhibitoryactivityonmixedlymphocyteculture.AhighCTLA4Igproducingmacrophagiccelllinewasobtained.AsMm1cellswereregardedasdifficultforgenetransfectionandtherehassofarbeennoreportonexpressionofCTLA4IggeneonMm1cells,theseresultssuggestedthattheCELA4IgexpressingMm1cellscouldbeusefulforanalysisofCTLA4andB8moleculeinteractioninbothmacrophageandT-cell.

简介：Trichosanthin(TCS)isapotentallergentomice.Accordingtoourpreviousexperiments,itcouldbringouttheIgEresponsetoovabumin(OVA)ifTCSwasgivenonedaybeforeOVAimmunization,whileOVAalonecouldnotinduceIgEtoit.Inthiswork,thekineticsofinterleukin4(IL-4)andinterferonγ(IFN-γ)geneexpressioninthemesentericlymphnode(MLN)ofTCS-immunizedmicewasinvestigatedusingasemi-quantitativeRT-PCRmethod.ItindicatedthatTCSinducedsignificantIL-4geneexpressionandthepeaksofIL4geneexpressionwereondayoneafterTCSimmunizationinbothprimaryandsecondaryresponse.Incontrast,theIFN-γgeneexpressionwassuppressed.Furthermor,theIL-4geneexpressioninthesecondaryresponsewaslowerthanthatintheprimaryresponse.ThusthepresenceofIgEmemoryBcellswerestudied.ResultsshowedthattheamountofmatureIgEmRNAarosesignificantlyandrapidlyonedayafterTCSrestimulation,whileintheMLNofthemiceprimed30daysbeforeandwithoutboost,itwasalmostasthesameamountoftheunimmunizedcontrol.ThesefindingssuggesttheexistenceoftheIgEmemoryBcellsinthemiceaftertheprimaryTCSimmunization.

简介：Asimplemethodtocreateachromosome-specificDNAlibrqaryofrice,includingmicrodissection,amplification,charterizationandcloning,isdescribed.Ricechromosome4fromametaphasecellhasbeenisolatedandamplifiedbytheLinkerAdapterPCR(LA-PCR).ThePCRproductswerelabeledasprobeswithDIG-11-dUTPusingtherandomprimingmethod.SouthernblotanalysiswithricegenomicDNAandspecificRFLPmarkersdemonstratedthatthePCRproductswerederivedfromricechromosome4.Alargelibrarycomprisingover100,000recombinantplasmidmicroclonesfromricechromosome4wasconstructed.Colonyhybridizationshowedthat58%oftheclonescontainedsingleorlow-copysequencesand42%containedrepetitivesequences.ThesizeofinsertsgeneratedbyPCRrangedfrom140bpto500bp.ThismethodwillfacilitatecloningofthespecificchromosomeDNAmarkersandimportantgenesofrice.

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简介：维生素E是人和动物必需维生素.本文以20份向日葵种质资源为实验材料,通过对维生素E含量、含油率、皮壳率以及百粒重的测定及统计分析,试图了解向日葵种质资源中维生素E含量变异及相关数据.结果表明,在20份向日葵种质资源中,油葵的维生素E含量和含油率明显高于食葵;含油率与维生素E含量在0.01水平呈极显著正相关,含油率与百粒重在0.05水平呈显著负相关;百粒重与皮壳率在0.01水平呈极显著负相关.通过初步评价,发现3份富含天然维生素E的向日葵种质资源.

简介：Changesinthedistributionof1P1-antigeninthedevelopingchickretinahavebeenexaminedbyindriectimmunofluorescencestainingtechniqueusingthenovelmonoclonalantibody(MAb)1P1.Expressionofthe1P1antigenwasfoundtoberegulatedinradialaswellasintangentialdimensionoftheretina,beingpreferentiallyorexclusivelylocatedintheinnerandouterplexiformlayersoftheneuralretinadependingonthestagesofdevelopment,Withtheonsetoftheformationoftheinnerplexiformlayer1P1antigenbecomesexpressedintheretina.Withprogressingdifferentiationoftheinnerplexiformlayer1P1immunofluorescencerevealed2subbandsatE9and6subandsatE18,Atpostnatalstages(afterP3)immunoreactivitywasreducedinaninside-outsidesequenceleadingtothecompleteabsenceofthe1P1antigeninadulthood.1P1antigenexpressionintheouterplexiformlayerwasalsosubjecttodevelopmentalregulation.Thespation-temporalpatternof1P1antigenexpressionwascorrelatedwiththetimecourseofhistologicaldifferentationofchickretina,namelythesynapserichplexiformlayers.Whetherthe1P1antigenwasfunctionallyinvolvedindendriteextensionandsynapseformationwasdiscussed.

简介：白细胞介素4(IL-4)是一种由TH2细胞分泌的具有多种生物学活性的细胞因子,是机体免疫系统的重要成员,在参与机体免疫调节方面有重要作用。据文献报道,IL-4在临床上与过敏性哮喘、皮炎等疾病有关,美国Genzyme公司已研制开发ELISA试剂盒检测IL-4水平,但价格昂贵。本实验制备rhIL-4抗血清以应用于IL-4的生物学活性研究及临床检测IL-4水平等方面。

简介：为研究人血小板因子4(hPF4)的生物学性能和用于肿瘤生物治疗的可能性,运用反转录聚合酶链反应(RTPCR)从人红白血病细胞系HEL细胞总RNA中扩增出hPF4基因cDNA序列,将其克隆至pUC18载体中.序列分析证实克隆片段与文献报道的hPF4基因cDNA序列完全一致,说明已成功克隆到hPF4基因cDNA.

简介：CTLA4Ig是人CTLA4胞外区与人免疫球蛋白铰链区、CH2区、CH3区组成的融合蛋白，可以与B7结合，通过阻断B7与CD28的结合，从而阻断B7介导的T细胞活化必需的共刺激信号，可作为免疫抑制剂用于器官移植。将CTLA4Ig融合分子克隆到真核表达载体pCI-dhfr，并用脂质体方法转染到COS7和CHO-dhfr-细胞中，用氨甲喋呤筛选转染的CHO-dhfr-细胞。用RT-PCR、ELISA、细胞免疫荧光染色和Western-blot鉴定重组蛋白的表达。采用A蛋白纯化重组蛋白。

简介：Interleukin-4isacytokineproducedbyactivatedTcells,mastcells,andbasophilsthatelicitsmanyimportantbiologicalresponses[1](seeTab1).TheseresponsesrangefromtheregulationofhelperTcelldifferentiation[2]andtheproductionofIgE[3]totheregulationoftheadhesivepropertiesofendothelialcellsviaVCAM-1[4],Inkeepingwiththesediversebiologicaleffects,high-affinitybindingsitesforIL-4(Kd20to300pM)havebeendetectedonmanyhematopoieticandnon-hematopoieticcelltypesatlevelsrangingfrom50to5000sitespercell[5].ThisreviewwillfocusonthediscretesignaltransductionpathwaysactivatedbytheIL-4recxeptorandthecoordinationoftheseindividualpathwaysintheregulationofafinalbiologicaloutcome.

简介：Arabidopsisthaliana嘘一deacetylase1(AtHD1或AtHDA19)，酵母RPD3的一个相当或相同的事物，是在植物的许多生理、发展的过程的一个全球管理者。尽管有为在植物基因规定和开发的AtHD1的一个角色的基因证据，AtHD1的生物化学、细胞的性质糟糕被理解。这里，我们在vivo报导AtHD1的细胞的本地化模式并且嘘在vitro的一项deacetylase活动。绿荧光灯的蛋白质(GFP)的短暂、稳定的表示在洋葱房间标注了AtHD1并且分别地，在转基因的Arabidopsis的根，种子和叶子表明AtHD1在euchromatic区域大概在原子核是局部性的并且从核排除。AtHD1的本地化模式与涉及核形成和transgenes的silencing并且分别地重复了DNA元素的AtHD2和AtHDA6的那些不同。另外，一hist一deacetylase活动试金证明在细菌生产的recombinantAtHD1示威了一特定嘘在vitro的一项deacetylase活动。数据建议AtHD1是原子蛋白质并且拥有嘘为对植物生长和开发重要的全球transcriptional规定负责的一项deacetylase活动。