人呼吸道合胞病毒RNA聚合酶复合体蛋白N、P的表达鉴定

本研究根据编码A亚型人呼吸道合胞病毒(HumanRespiratorySyncytialVirus,HRSV)核壳体蛋白(Nucleocapsidprotein,N)和磷蛋白(phosphoprotein,P)的基因序列,各设计一对特异性的引物,应用RT-PCR技术,从感染HRSV的HEp-2细胞中扩增获得n和p的基因片断,克隆至真核表达载体pcDNA3.1( )。获得的重组质粒通过脂质体Lipofectamine2000转染COS-7细胞,72h后再用Westernblot鉴定蛋白的表达。结果显示真核表达载体pcDNA3.1( )/N和pcDNA3.1( )/P的限制性内切酶分析结果与预期一致,基因序列分析显示没有发生无义突变,利用蛋白印记方法也检测到了N和P的特异性条带。于是我们认为成功构建了含有HRSVN和P编码基因的真核表达载体,在真核细胞内能顺利表达。为进一步开展HRSV反向遗传学等研究奠定了基础。     

人乳头瘤病毒l6型E6-E7融合蛋白真核表达载体的构建与鉴定

目的构建人乳头瘤病毒l6型(HPV16)E6-E7融合蛋白真核表达载体,为研究其基因疫苗免疫活性奠定实验基础。方法 PCR扩增HPV16 E6-E7基因片段,将其连接到真核表达载体pcDNA3.1(+),构建真核表达载体pcDNA3.1(+)/HPV16 E6-E7,双酶切及测序鉴定。将质粒转染HeLa细胞,RT-PCR鉴定E6-E7基因在HeLa细胞中的表达。提取质粒免疫小鼠,利用免疫组化方法检测在其肌肉组织中的表达。结果成功构建了真核表达载体pcDNA3.1(+)/HPV16 E6-E7;在转染pcDNA3.1(+)/HPV16 E6-E7的细胞中检测到HPV16 E6-E7基因。在免疫该质粒的小鼠肌肉组织中可以检测到该质粒的蛋白表达。结论成功的构建的了真核表达载体pcDNA3.1(+)/HPV16 E6-E7,该载体能在HeLa细胞内以及小鼠骨骼肌细胞内有效表达。     

小鼠Oct4基因真核表达载体的构建及表达鉴定

目的:构建小鼠Oct4基因真核表达载体并对其表达进行鉴定.方法:以小鼠胚胎干细胞(mouse embryonic stem cells,mESCs)cDNA为模板克隆Oct4基因编码区序列,将其通过定向克隆插入pcDNA3.1(+)栽体多克隆酶切位点(multiple cloning sites,MCS)中,形成pcDNA3.1(+)/Oct4重组载体.将pcDNA3.1(+)空载体和pcDNA3.1(+)/Oct4重组载体分别转染293T细胞,通过Western Blotting检测Oct4蛋白的表达.结果:成功检测到Oct4蛋白的表达.结论:成功构建了小鼠Oct4基因真核表达载体.     

小鼠Uncv基因克隆及真核表达

目的 克隆小鼠的Uncv基因并在真核细胞表达.方法 采用RT-PCR方法扩增小鼠皮肤组织中Uncv基因编码区,以真核表达质粒pcDNA 3.1-Flag为载体,构建Uncv真核表达质粒,将重组载体转染Hela细胞并用Western blot法检测基因表达.结果 构建Uncv基因真核表达载体pcDNA 3.1-Flag/Unev,重组质粒在Hela细胞中有效表达约95×103的融合蛋白.结论 成功构建真核表达载体pcDNA 3.1-Flag/Uncv,并且在真核细胞中有效表达,为研究Uncv基因生物学功能奠定基础.     

HBV PreS2+S/IFN-α融合基因真核表达载体的构建及其表达

构建含HBV PrdS2+S和IFN-α融合基因的真核表达载体pcDNA3.1.S2S/IFN-α并在真核细胞中进行表达.应用重叠延伸剪切技术(splicing by overlapping extension,简称SOE)经两次PCR获得嵌合基因片段S2S/IFN-α,回收后直接克隆到pcDNA3.1 V5/His TOPO TA克隆载体,得到真核重组载体pcDNA3.1.S2S/IFN-α.然后用脂质体法转染Vero E6细胞.对重组载体进行了限制性酶切及PCR鉴定,证明连接正确;经间接免疫荧光检测证实该重组载体能在真核细胞中表达插入的外源性基因编码的融合蛋白.真核表达载体pcDNA3.1.S2S/IFN-α的成功构建及在Vero E6细胞中的有效表达,为进一步探讨HBV感染的特异性免疫治疗提供了实验依据.     

HBV PreS2 S/IFN-α融合基因真核表达载体的构建及其表达

构建含HBVPrdS2 S和IFN α融合基因的真核表达载体pcDNA3.1.S2S/IFN α并在真核细胞中进行表达。应用重叠延伸剪切技术 (splicingbyoverlappingextension ,简称SOE)经两次PCR获得嵌合基因片段S2S/IFN α ,回收后直接克隆到 pcDNA3.1V5 /HisTOPOTA克隆载体 ,得到真核重组载体pcDNA3.1.S2S/IFN α。然后用脂质体法转染VeroE6细胞。对重组载体进行了限制性酶切及PCR鉴定 ,证明连接正确 ;经间接免疫荧光检测证实该重组载体能在真核细胞中表达插入的外源性基因编码的融合蛋白。真核表达载体pcDNA3.1.S2S/IFN α的成功构建及在VeroE6细胞中的有效表达 ,为进一步探讨HBV感染的特异性免疫治疗提供了实验依据     

hAng-1真核表达载体的构建及其在MSCs中的表达

目的:通过基因重组技术,构建人血管生成素-1(human angiopoietin 1,hAng-1)真核表达载体体系,并将其转染至大鼠的骨髓间充质干细胞(marrow mesenchymal stem cells,MSCs)内进行培养,进而验证hAng-1的表达.方法:将hAng-1编码序列(互补脱氧核糖核酸)通过酶切,插入至pcDNA3.1(+)质粒的多克隆位点,构建质粒pcDNA 3.1 (+)/hAng-1真核表达质粒;重组质粒经脂质体介导转染鼠MSCs.应用逆转录聚合酶联反应(RT-PCR)、蛋白免疫印迹法(Western blot)等方法检测hAng-1的表达情况.结果:pcDNA 3.1 (+)/hAng-1真核表达质粒转染鼠MSCs后,应用流式细胞仪检测,转染效率约为15％.同时应用RT-PCR能够检测出目的基因mRNA,Western blot能够检出hAng-1的蛋白表达.结论:本实验通过基因重组技术,构建的pcDNA3.1 (+)/hAng-1真核表达载体能够在转染的鼠MSCs中表达,且表达较为持续,为hAng-1基因应用于基因治疗的研究奠定了基础.     

小鼠EVL 基因的克隆和真核表达载体的构建

目的:构建小鼠EVL(Ena/VASP like)基因的真核表达载体,为深入研究EVL的功能奠定基础.方法:采用PCR方法,从小鼠cDNA文库中,扩增出1245bp的EVL编码区片段,经电泳、胶回收后连接入pMD- 18T载体中,测序鉴定正确.用BamHI和HincⅡ双酶切,定向克隆EVL编码区片段到真核表达载体pcDNA3.1中,用限制性内切酶酶切鉴定重组质粒正确后.将重组质粒转染入HELA细胞中,以RT-PCR检测EVL的mRNA的表达,以Western Blot检测EVL蛋白的表达.结果:酶切鉴定结果显示小鼠EVL编码区基因被成功克隆入真核表达载体pcDNA3.1中;RT-PCR和Western Blot结果以及免疫荧光染色显示Hela细胞中有EVL的mRNA和蛋白的表达.结论:成功获得pcDNA3.1 -EVL的真核表达载体,为进一步深入研究EVL蛋白的功能奠定了基础.     

人类VIM基因的克隆和真核表达载体的构建

目的:构建VIM(Vimentin)基因的真核表达载体,以深入研究VIM的功能及其在相关疾病中的作用.方法:从人cDNA文库中,以RT-PCR方法扩增出1401bp的VIM编码区片段,胶回收后连接入T.载体,测序鉴定.再用Hind Ⅲ和BamHI双酶切,将VIM编码区片段定向克隆到真核表达载体pcDNA3.1中,酶切鉴定重组质粒.将重组质粒转染NIH3T3细胞,分别以RT-PCR和Western Blot方法检测VIM的mRNA表达和蛋白表达.结果:将人VIM编码区基因成功克隆到真核表达载体pcDNA3.1中;继而转染NIH3T3细胞后,RT-PCR和Western Blot结果显示细胞可以表达VIM的mRNA和蛋白.结论:成功构建pcDNA3.1-VIM的真核表达载体,为进一步研究VIM基因的功能以及其在相关疾病中的作用奠定了基础.     

幽门螺杆菌Lpp20-IL2核酸疫苗免疫活性

【目的】观察pcDNA3.1(+)/Lpp20-IL2免疫C57BL/6小鼠后所产生的体液免疫和细胞免疫应答水平,为研制高效、新型的幽门螺杆菌核酸疫苗提供实验依据。【方法】构建pcDNA3.1(+)/Lpp20-IL2重组载体,并转染HeLa细胞,用Western-blot观察鉴定其在真核细胞得到表达后免疫C57BL/6小鼠,ELISA间接法测定小鼠血清中抗Lpp20IgG抗体水平,ELISA双抗体夹心法检测脾淋巴细胞培养上清中IFN-γ、IL4水平,MTT比色法检测脾淋巴细胞增殖反应,免疫荧光组化法检测Lpp20蛋白在小鼠肌肉组织中的表达情况。【结果】成功构建了pcDNA3.1(+)/Lpp20-IL2真核表达载体,且重组质粒能在HeLa细胞内有效表达目的蛋白;小鼠接种pcDNA3.1(+)/Lpp20-IL2核酸疫苗后能产生特异性IgG抗体,8w后ELISA测定血清抗体A450值明显升高。核酸疫苗pcDNA3.1(+)/Lpp20-IL2免疫组小鼠脾淋巴细胞经特异性抗原刺激后,培养上清中IFN-γ、IL4含量明显升高。pcDNA3.1(+)/Lpp20-IL2和pcDNA3.1(+)/Lpp20核酸疫苗组小鼠脾淋巴细胞经特异性抗原刺激后,刺激指数明显高于空质粒组和PBS组。Lpp20蛋白在小鼠肌肉组织中能够有效表达。【结论】幽门螺杆菌Lpp20-IL2融合基因核酸疫苗和Lpp20单基因核酸疫苗均能刺激机体产生较强细胞免疫应答和体液免疫应答,且前者能诱导更强的细胞免疫应答。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000     

Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin

The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.     

Synthesis of hapten and conjugates of coumestrol and development of immunoassay

3-O-Carboxymethylcoumestrol was prepared as the hapten for immunoassay by a partial alkylation of coumestrol with ethyl chloroacetate in acetone alkalized with potassium carbonate. 3-O-Ethoxycarbonylmethylcoumestrol was separated by column chromatography and finally was hydrolyzed with formic acid. 1H and 13C NMR data (APT, COSY, HMQC, and HMBC) revealed that the reaction was regioselective, as 3-O-ethoxycarboxymethylcoumestrol was the only monosubstituted derivative. The hapten was then conjugated to bovine serum albumin and used for immunization of rabbits. A radioimmunoassay (RIA) system was established based on the polyclonal antiserum and a 125I-labeled hapten-tyrosine methyl ester conjugate as the radioligand. Parameters of the RIA: sensitivity: 12 pg per tube, 50% intercept: 140 pg per tube, working range: 20-4000 pg per tube. The cross-reactivity of a panel isoflavonoid and lignan phytoestrogens was either negligible (e.g. formononetin 0.07%; biochanin A 0.06%) or not detectable at all. The major immunoreactive peak in HPLC fractions from an alfalfa extract had the same retention time as coumestrol standard and represented 94.8% of the signal. The remaining 5.2% of immunoreactivity was distributed between five minor peaks. We conclude that after the validation for particular matrices, the method will be a useful tool for analysis of coumestrol, especially in low volume and low concentration samples.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

放牧对牧草光合作用、呼吸作用和氮、碳吸收与转运的影响

研究放牧对草地植物生理活动的影响,对于揭示草地放牧演替的生理机制有重要意义.大量研究表明,家畜放牧对牧草光合作用、呼吸作用以及C和N吸收与转运的影响,可以分为生理伤害和生理恢复2个阶段.放牧通过改变草地冠层结构影响牧草光合作用,净光合作用速率短期内迅速下降,随着叶面积指数增加又逐渐上升,呼吸作用有相似的变化趋势.牧草放牧后再生长所需的C和N最初主要来自根系和留茬中的贮藏物质,此后随着牧草生长恢复逐渐由同化作用供给,C代谢与土壤N水平负相关.放牧后牧草生理活动变化与牧草遗传特性、种间竞争、家畜放牧特征、非生物环境等因素密切相关.     

Effect of soil salinity and water stresses on growth and content of nitrogen,chloride and phosphate of wheat and triticale

Summary Three wheats and one triticale were grown, up to flowering stage, in pots on calcareous soil adjusted to a range of salinities (S₁=3.5, S₂=6, S₃=8.5, and S₄=11 mmhos/cm, 20°C, soilpaste extract) by adding solution consisting of 3∶2∶1 of Na-, Ca- and Mg chlorides in chemical equivalent amounts. Moisture in the pots was kept at 100% (W₁), 40% (W₂) and 20% (W₃) of the available water. The vegetative growth, nitrogen and phosphate were affected by S and W treatments, chloride was affected only by S. The interaction S×W affected only dry weight. Varietal effect was observed between wheat as a group and triticale. Multiple quadratic regression equations of these properties on salinity and water revealed that the higher the available water the wider the range of tolerable salinity. Triticale was relatively more tolerant to water stress. Salinity increases Cl and decreases N, whereas water stress enhances N accumulation to a certain extent. However, in triticale at S₃ and S₄ the effect of water stress on N was overshadowed by the excessive salinity. This did not occur for the wheat (Florence). P trends were described. R² for P was low (0.7435–0.3603) which made interpretations rather difficult.