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141.
用生物活性法和双抗体夹心桥联酶免疫吸附(ELISA)法检测了人类疱疹病素6型(HHV-6)GS株和南京地方株CN5,8,10感染的淋巴细胞培养上清中的肿瘤坏死因子(TNF)的水平,发现培养24h即可检出高水平的TNF,48~72h述到峰值,此后逐渐下降,与未感染耐照组比较有及其显著的差异(P<0.001)。GS株与地方株同诱生TNF水平无儿著性差异(P>0.1),三株地方株诱生TNF也无显著性差异(P>0.05)。TNF-α单抗可以完全中和培养上清中TNF的活性,证实上清中有TNF-α。与LPS比较,HHV-6诱生TNF-α的能力要强得多。 相似文献
142.
采用逆转录聚合酶链反应(RT-PCR)从广东省一例慢性丙型肝炎病人血清中获得丙型肝炎病毒(HCV)5'端非编码区(5'NCR)302bp的cDNA片段,经补齐和提纯后插入pUC19质粒,获得的重组体pUN进行序列测定。将pUN的目的基因亚克隆进体外转录载体pSPORTI多克隆位点的EooRI和PstI切点之间,所得重组体pSN线性化后由T_7RNA多聚酶及SP6RNA多聚酶引导体外转录反应,产物经凝胶电泳及特异引物RT-PCR,证实SP6引导的是正义RNA,T7合成的是反义RNA,其大小分别力429bp和362bp。并证实所得RNA力HCV5'NCRcDNA转录而来。获得的HCV5'NCRcDNA和RNA在常规逆转录和PCR步骤中用于设立有效的模板对照,对消除假用性及评估试剂有重要意义。同时,HCV5'NCR体外转录载体的构建可用于制各RNA探针和反义RNA,改进后还可作为定量PCR的竞争性模板。 相似文献
143.
用Aedans标记肌动蛋白单体G-Actin上Cys374残基作为探针,研究了稀土离子Ce~(3+)与G-Actin的结合及引起的微构象变化。Ce~(3+)在低浓度(Ce~(3+)/Actin摩尔比<1)和Ca~(2+)竞争G-Actin上二价离子的高亲合位点。Ce~(3+)取代Ca~(2+)引起Aedans荧光强度增强与Mg~(2+)取代Ca~(2+)的结果相同。Ce~(3+)/Actin>l则导致Aedans荧光强度下降。说明Ce~(3+)在高低两种浓度条件下结合的位点及对Cvs374的微构象的影响不同。时间分辩测得的Aedans荧光寿命也支持这一结论。CD谱结果表明Ce~(3+)/Actin<0.4,Actin的二级结构增加,大于0.4又导致其失去。Ce~(3+)-Actin在有/无游离ATP时用聚合液诱导的聚合结果表明,无游离ATP时,极低浓度Ce~(3+)促进聚合,高浓度虽有促进但有所减弱;有游离ATP时,Ce~(3+)/Actin在实验范围内促进聚合。 相似文献
144.
中药固真方对一些与细胞增殖有关基因表达的影响姚明忠,顾文聪,丁卫,韩志芬,杜国光(上海中医药大学生物化学教研室,上海200032)(北京医科大学生物化学与分子生物学系,北京100083)中药固真方(VRF)具有补肾益精、延缓衰老的作用[1].能提高成... 相似文献
145.
146.
To provide further understanding of the biotransformation of benzaldehyde to L-phenylacetyl carbinol (L-PAC), an intermediate in L-ephedrine production, a kinetic model has been developed for the deactivation of pyruvate decarboxylase (PDC) by benzaldehyde. The model confirms that deactivation is first order with respect to benzaldehyde concentration and exhibits a square root dependency on time. The model covers the range of benzaldehyde concentrations 100–300 mM, as it has been shown previously that 200 mM benzaldehyde can produce L-PAC concentrations up to 190 mM (28.6 g/L) using partially purified PDC from Candida utilis. 相似文献
147.
Zhao Yan-Xiu Philip J. C. Harris Yao Dun-Yi 《Plant Cell, Tissue and Organ Culture》1995,40(2):119-123
Protoplasts were isolated from cotyledons of Sesbania bispinosa (Jacq.) W.F. Wight. In a liquid-over-agar culture system with Murashige and Skoog (MS) medium supplemented with 1 mg l-1 2,4-dichlorophenoxyacetic acid (2,4-d, 2 mg l-1 benzyladenine (BA), 1 mg l-1 glutamine and 0.5 and formed callus. The first division occurred after 3–4 days. Callus formed from the protoplasts differentiated shoots by organogenesis on MS medium with 1 mg l-1 indolebutyric acid (IBA) and 1 mg l-1 BA. These shoots developed into complete plantlets when excised and cultured on MS medium with 0.5 mg l-1 IBA. 相似文献
148.
An intramolecular recombination mechanism for the formation of the rRNA gene palindrome of Tetrahymena thermophila. 总被引:1,自引:0,他引:1 下载免费PDF全文
Large palindromic DNAs are found in a wide variety of eukaryotic cells. In Tetrahymena thermophila, a large palindrome is formed from a single rRNA gene (rDNA) during nuclear differentiation. We present evidence that a key step in the formation of the rDNA palindrome of T. thermophila involves homologous intramolecular recombination. Heteroduplex micronuclear rDNA molecules were constructed in vitro and microinjected into developing macronuclei, where they formed palindromes. Analysis of the resulting palindromes indicated that both strands of the microinjected rDNA are used to form the same palindrome. This study, together with a previous study (L. F. Yasuda and M.-C. Yao, Cell 67:505-516, 1991), is the first to define a molecular pathway of palindrome formation. The process is initiated by chromosome breakage at sites flanking the micronuclear rDNA. An intramolecular recombination reaction, guided by a pair of short inverted repeats located at the 5' end of the excised rDNA, covalently joins the two strands of micronuclear rDNA in a giant hairpin molecule. Bidirectional DNA replication converts the giant hairpin molecule to a palindrome. We suggest that the general features of this pathway are applicable to palindrome formation in other cell types. 相似文献
149.
Summary Insitu perfusion of rat liver was performed with a medium containing glucose-cysteine adduct [2-(D-gluco-pentahydroxypentyl) thiazolidine-4-carboxylic acid, glc-cys] and its effect on glutathione (GSH) and ATP levels and bile production was examined. The GSH content in the liver was maintained at the original level during perfusion with 1 mM glc-cys for 2h, while it decreased significantly in the absence of glc-cys. After 4h of perfusion without glc-cys, ATP content and bile production decreased significantly besides the decrease in GSH content, but they were maintained at the original levels with glc-cys. When the perfusion was performed with the liver of rats injected with diethyl maleate (DEM), the GSH level, which was decreased to 6.0% of the control by DEM injection, was restored to 22.6% of the original level by perfusion with 2mM glc-cys for 30 min. Data indicate that glccys is a cysteine prodrug with protective action on the liver. 相似文献
150.
Summary Effect of intraperitoneal administration (5 mmol/kg of body weight) of glucose- cysteine adduct (glc-cys) as a cysteine prodrug in rat tissues was studied. Cysteine levels in liver and kidney increased to 1.08 and 1.98mol per g or ml, respectively, at 2h after the administration. GSH levels did not change substantially. However, when glc-cys was injected to rats treated with diethyl maleate, a GSH-depleting agent, the decreased GSH levels were restored rapidly. The recoveries in liver and kidney were 72% at 1h and 66% at 2h, respectively, after glc-cys administration. Metabolism of glc-cys was assessed by urinary excretion of glc-cys, sulfate and taurine. Average excretion of glc-cys was 2.86mmol/kg/24h after glc-cys administration. Increased excretions of sulfate and taurine were 0.77 and 0.14mmol/kg/24h, respectively. Data show that, although glc-cys excretion was relatively rapid, glc-cys was effectively utilized for GSH synthesis in GSH-depleted tissues. 相似文献