简介:Aditerpenoid,neostellerin,wasisolatedfromtherootsofStellerachamaejasmeLtogetherwith4knowncompoundsidentifiedasβ-sitosterol,scopoletin,umbelliferoneanddaucosterol.Thestructureofneostellerin,whichwaselucidatedbyNMR,especially2DNMRanalysis,wasdifferentfromotherdaphnanetypediterpenesisolatedfromthisplant.
简介:目的:以L-半胱氨酸和吲哚为底物,利用色氨酸酶基因工程菌WW-11酶法合成L-色氨酸。方法:以IPTG诱导基因工程菌色氨酸酶表达,将酶活最高时的工程菌游离细胞作为转化反应的酶源,通过纸层析和氨基酸自动分析仪分析并测定转化液中L-色氨酸的含量,结果:80mL反应液(L-半胱氨酸0.75g,吲哚75g)37℃反应48h,可积累L-色氨酸1.18g,L-半腕氨酸转化率为93.2%,吲哚转化率为90.1%,经分离纯化所得的L-色氨酸晶体,在熔点,旋光性和红外吸收光谱等方面与标准品完全一致,结论:色氨酸酶基因工程菌能有效地催化L-半胱氨酸和吲哚合成L-色氨酸,这种酶合成法是工业化生产L-色氨酸较为有效的方法之一。
简介:ChinahasagreatresourceofCannabis.ResearchonthetaxonomyandmorphologyofChineseCannabishasbeencarriedout,butsofarnomoleculargeneticresearchhasbeenpublished.RandomamplifiedpolymorphicDNA(RAPD)isasuitabletechniqueformoleculargeneticresearchonCannabis.Intillsexperiment,usingCannabisherbariumspecimensasasourceofgeneticmaterials,thecorrelativeconditionsofthePolymerasechainreaction(PCR),(i.e.,gradientdensityofMg^2+,dNTPs,TaqDNApolymerase,annealtemperature,annealtimeandreactioncycles)wereexaminedseparately.AneffectiveprocedurefortheRAPDanalysisofCannabiswasobtained.
简介:ObjectiveToinvestigatethealterationsofL-typecalciumcurrent(IcaL)inabdominalaorticligation-inducedhypertrophiedratheartsandtheeffectoflosartanonthesealterations.METHODSCardiachypertrophywasinducedbyabdominalaorticligationinrats.TorecordIcaL,whole-cellpatch-clamptechniquewasused.RESULTSMembranecapacitancewaslargerinhypertrophiedcells(148±29pF)thaninsham-operatedcells(102±14pF,P<0.01)andlosartan-treatedcells(118±27,P<0.01).ThemaximalpeakIcaLWasincreasedfrom-835±124pAinsham-operatedcellsto-1404+_417pAinhypertrophiedcells(P<0.01),thecorrespondingIcaLdensitywasincreasedfrom-7.5±1.8pA.pF^1to-10.5±2.2pA.pF^1(P<0.01),whiletheywerereducedto-956-2:170pF(P<0.01)and-8.2±1.6pA.pF^1(P<0.05)respectivelyinlosartan-treatedcells.Themembranepotentialofhalfmaximalactivationofthehypertrophiedcells(-20.6±1.0mV)shiftedtomorenegativepotentialsthansham-operatedcells(-15.6±1.6mV,P<0.01)andlorsartan-treatedcells(-17.4±1.0mV,P<0.01).Theslopeoftheactivationcurveofhypertrophiedcells(5.7±0.4)wasdecreasedslightlythansham-operatedcells(6.4±0.5,P<0.05).Themembranepotentialofhalfmaximalinactivationofhypertrophiedcells(-27.6±1.9mV)shiftedtomorepositivepotentialsthansham-operatedcells(-31.4±2.2mV,P<0.05).Theslopeofinactivationcurveswerenotdifferentinthethreegroups.
简介:目的初步探讨大剂量L-精氨酸致急性坏死性胰腺炎的发病机制。方法观察大鼠血清,胰腺组织一氧化氮(NO)含量的变化及胰腺组织巯基物质和丙二醛(MDA)的变化,以及黄嘌呤氧化酶抑制剂别嘌呤醇在急性坏死性胰腺炎中的作用。结果血清NO呈先升高后降低再回升趋势,胰腺组织NO则一过性降低;急性坏死性胰腺炎早期大鼠胰腺组织内巯基物质含量明显减法,MDA含量明显增加,而别嘌呤醇可对抗这种变化,并可显著降低急性坏死性胰腺炎大鼠血清淀粉酶的增高程度,减轻胰腺损伤。结论以巯基物质为代表的机体的防御体系与以MDA为代表的损伤体系的失衡可能是大剂量L-精氨酸造成胰腺组织损伤的重要原因,别嘌呤醇能够在一定程度上可以减轻急性坏死性胰腺炎时的胰腺损伤。
简介:RecombinanthumanGABAAreceptorswereinvestigatedinvitrobycoexpressionofcDNAscodingforα1,β2andγ2subunitsinthebaculovirus/Sf-9insectcellsystem,Asingleaminoacidexchangeα1(asparaticacid151toasparaginorα1(threonine149toglutamine)intheN-terminal,extracellularpartoftheα1subunitinducedabout10folddecreaseinanantagonistpitrazepineaffinity.OtherGABAAreceptorligandshadlittledifferenceintheiraffinity.Itwaslikelythat151and149aminoacidresidueswereessentialforthebindingaffinityandefficacyofpitrazepinetoGABAAreceptorcombinationscontainiαααααααααnganα1subunit.
简介:Lactivicin,anovelinhibitorofbacterialcellwallsynthesis,wasisolatedfromtheculturefil-tratesofmicroorganismYK-258andYK-422.Itexhibitsbiologicalactivitiessimilartothoseoftheβ-lactamantibiotics,althoughitdoesnothaveaβ-lactamringinitsmolecule.Sincethediscoveryoflactivicin,hundredsofitsderivativeshavebeensynthesized.Most
简介:以乌拉坦麻醉猫膈神经放电及肋间外肌放电为指标(可分别反映延髓呼吸中枢背侧组DRG和腹外侧组VRG的活动),观察3-(2′,2′,2′-苯基环戊基羟基乙氧基)奎宁环(PCHE)对抗敌敌畏(DDVP)的呼吸中枢抑制作用,椎动脉(iva)注射DDVP2mg,膈神经放电立即被抑制,继之肋间外肌放电也抑制或先短暂兴奋再抑制,再于椎动脉注射阿托品0.2mg,仅少数动物(1/3)的肋间外肌放电开始恢复,当加大剂量至0.25mg时,部分动物的两种放电才恢复(2/6)。注射PCHE0.2mg,可使大部分动物(5/6)的两种放电同时恢复,提示DDVP优势影响DRG,阿托品对VRG的作用要比DRG明显,PCHE对DRG及VRG均有较强的作用;PCHE在低于阿托品剂量就可产生更强的对抗DDVP所致的呼吸中枢抑制作用。
简介:本文报道了C6H12O6(NH4)2SO4C2H5OHH2O(C2H5OH/H2O=0.90)体系在35℃时体系溶解度和饱和溶液的折光指数,并绘出了体系相应的溶度图和饱和溶液的折光指数曲线图。结果表明:所研究的体系为四元体系C6H12O6(NH4)2SO4C2H5OHH2O中的一部分。当溶液中肌醇饱和时,溶度曲线落在约50%的等醇水比面上。当(NH4)2SO4在溶液中达到饱和时,出现共饱点。其组成为(NH4)2SO4:210%,C6H12O6:2.08%,C2H5OH:4475%。同时出现分层,在富醇相随着乙醇浓度的增加,出现肌醇与硫酸铵共饱线。在富水相硫酸铵饱和溶度曲线落在约5%乙醇的等醇水比面上,折光指数曲线由三支组成,其中两条分别与C6H12O6·H2O和(NH4)2SO4相对应,另外一条线与(NH4)2SO4和C6H12O6·H2O的共饱线相对应