耐热性重组Taq DNA酶的制备及鉴定

利用含Taq DNA聚合酶基因的pTaq表达质粒转化大肠杆菌E.coli菌株,用异丙基硫代-β-D-乳糖苷(IPTG)诱导10～12h表达耐热Taq DNA聚合酶;然后溶菌酶、NP40裂解细菌;硫酸铵沉淀、4℃下透析;SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)、考马斯亮蓝法和PCR分析其纯度、浓度和活性。结果表明分离纯化制备的耐热性Taq DNA聚合酶,其纯度、浓度和活性均可与同类产品相比,比活性达20000U/mg,能有效扩增出DNA片段。     

Left-handed DNA in restriction fragments and a recombinant plasmid

Circular dichroism and 31P-NMR on synthetic oligomers of (dC-dG) inserted within DNA restriction fragments indicate that the right-handed B-structure can exist in close proximity to the left-handed Z-structure. Also, this salt-induced transition to Z-form in a small (dC-dG) segment (1.3%) of a recombinant plasmid markedly influenced the supercoil of the plasmid. These observations have implications for the postulated role of naturally occurring related simple sequences in the regulation of gene activity.     

CC-NUMA结构计算机含错技术研究

主要研究CC-NUMA结构计算机的主存共享状态下含错技术问题。本文对主存共享、含错区域划分进行了说明，并深入分析了在主存共享状态下的含错区域划分、乱写防护等含错技术支持和保障。     

Expression of active human factor VIII from recombinant DNA clones

DNA clones encoding the complete 2,351 amino acid sequence for human factor VIII have been isolated and used to produce biologically active factor VIII in cultured mammalian cells. The recombinant protein corrects the clotting time of plasma from haemophiliacs and has many of the biochemical and immunological characteristics of serum-derived factor VIII.     

理性看待特许经营

目前，国内许多企业为了在较短的时间内迅速扩大规模，纷纷采取特许经营模式，有些已经取得了较大的进展，但其中也不乏盲目跟刚才是，文章从国内特许经营存在的问题入手，指出了特许经营中的陷阱及对策。     

Construction and analysis of recombinant DNA for human chorionic somatomammotropin

DNA complementary to mRNA coding for the human polypeptide hormone, chorionic somatomammotropin, has been purified by specific restriction endonuclease digestion and religation before cloning into bacterial plasmids. The primary structure of a major portion of this mRNA species is deduced from the nucleotide sequence of the recombinant DNA.     

Active gamma-carboxylated human factor IX expressed using recombinant DNA techniques

Factor IX (Christmas factor), a vitamin K-dependent plasma protein made in the liver, functions in the middle phase of the intrinsic pathway of blood coagulation. A functional deficiency of factor IX underlies haemophilia B, a chromosome X-linked recessive disease for which the major therapeutic approach is replacement treatment using factor IX concentrates. The cloning and characterization of the gene for human factor IX would mean that human factor IX could be produced in greater yield and purity through using recombinant DNA techniques. We have now used a human factor IX cDNA clone, inserted into a vaccinia virus-derived vector, to infect human hepatoma cells which normally produce no factor IX, and mouse fibroblasts. Fully active factor IX was produced by the hepatoma cells, whereas the fibroblasts produced a protein less active than natural factor IX, even in the presence of high levels of vitamin K. Human factor IX is extensively post-translationally modified, and thus represents probably the most complex protein produced in active form by recombinant DNA techniques to date. Our study also illustrates the potential of vaccinia virus-based vectors for expressing significant amounts of complex, clinically useful proteins in eukaryotic cells, in addition to its already demonstrated usefulness for producing live recombinant vaccines.     

Expected change: U.S. recombinant DNA guidelines

Continuing the trend towards relaxing controls on recombinant DNA research, the National Institutes of Health published revised guidelines in the Federal Register of 21 April 1982. Although the existing system of mandatory controls and institutional biosafety committees is retained, no class of experiments will be totally prohibited, and the guidelines dealing with containment levels have been greatly simplified.     

有理簇和拟有理簇

投影空间是最基本的代数簇，而有理簇与它有着极紧密的关系，特别在应用中（如丢番图方程，计算机辅助几何设计）是一个重要的例子。本书综合使用经典的和现代的方法处理有理性的基本问题，按研究生可接受的水平讲述了有理簇和拟有理簇的现代理论。本书源于第一作者1996年8月在匈亚利的Eger举办的欧洲数学会夏季数学学校上所作的讲座，正式成书时由其他作者整理加工，并增补了大量的例子和习题，补齐了文献，并注意将读者引向研究前沿，特别着重于一些困难的基本问题即非有理性判定。     

遏制大学生论文抄袭现象之我见

毕业论文的写作过程是一种创新性活动。本文针对当前大学生、研究生毕业论文写作中抄袭、剽窃等突出问题,强调加强学生基本功的训练,着重从论文结构、材料、主题三方面培养和提高学生创新精神和创新思维作粗浅探析。     

关于创新教育的理性思考

创新教育主要是为了培养学生的创新素质而进行的素质教育 ,包括培养学生的创新意识、创新精神、创新能力、创新人格等创新素质 .在实施创新教育中教师要发挥好关键作用 .     

关于有理小数的一个注记

给出了十进制小数δ=0.(1α)(2α)…(nα)…是有理数的一个必要条件,并由此改进了一个已知结果.     

城市垃圾填埋场地下环境污染及控制对策

对城市垃圾填埋场渗滤液及其污染特性进行了分析,对我国城市垃圾填埋造成的土地、地下水污染现状进行了3个实例分析。通过实验室模拟实验研究渗滤液中污染物在地下环境中迁移转化作用,实验结果表明,垃圾渗滤液在地下出现了4个顺序氧化还原带,分别为产甲烷带、Fe(III)还原带、NO-3还原带和氧还原带,微生物在每个带利用的最终电子受体是不同的。最后以北天堂垃圾填埋场为例,建立地下水污染物运移的数值模型,对垃圾渗滤液污染的控制方案进行了模拟研究,模拟计算表明,北天堂垃圾填埋场顶部防护层的设置,必须使外部水进入垃圾场的入渗量控制在小于36 mm/a,才能有效控制渗滤液的污染。     

关于从机制创新上治理腐败的思考

反腐倡廉要标本兼治,重在治本。如何从源头治理腐败,本文从机制创新上做了一些探讨。意在通过创新监督制约机制、权力运行机制、公开透明机制、公务消费机制、保障调节机制,按照市场经济规律,制定既有利于市场经济竞争又有利于反腐倡廉的运行机制,从源头上遏制腐败的产生、发展和蔓延。     

关于从机制创新上治理腐败的思考

反腐倡廉要标本兼治，重在治本。如何从源头治理腐败，本文从机制创新上做了一些探讨。意在通过创新监督制约机制、权力运行机制、公开透明机制、公务消费机制、保障调节机制，按照市场经济规律，制定既有利于市场经济竞争又有利于反腐倡廉的运行机制，从源头上遏制腐败的产生、发展和蔓延。     

美国重组DNA咨询委员会的演变史

 重组DNA技术于1972年诞生于美国高校实验室。重组DNA咨询委员会（简称RAC）问世于1974年,并于2019年退出历史舞台,为美国基因操作技术的风险规制立下了汗马功劳。RAC在美国基因操作技术风险规制中跌宕起伏的演变史,是美国基因操作技术的风险规制由稚嫩逐步走向成熟的印证。通过探究RAC及其监管权是在哪些力量的作用下问世,还原RAC在基因操作技术风险阴霾笼罩下被政府当局质疑能力的历史图景,呈现美国基因治疗的基本规制路径,描述RAC审批首次基因治疗的经过以及RAC在首次基因治疗致死事件中的应对表现,阐述RAC退出历史舞台的过程和缘由,从而描摹一幅美国重组DNA咨询委员会演变历程的脉络图。