环丙沙星与Fe^3＋及DNA相互作用的光谱研究

用荧光光谱法研究了环丙沙星(CPFX)与Fe3+及其鲱鱼精DNA的相互作用.结果表明,Fe3+和鲱鱼精DNA均可使环丙沙星的荧光强度发生猝灭.在Fe3+存在下,鲱鱼精DNA对环丙沙星的荧光猝灭作用显著增强,并用荧光法测定了CPFX-Fe3+和CPFX-DNA二元络合物的组成和结合常数.CPFX-DNA的光谱图在有Fe3+存在时,发生了明显的变化,表明能够形成CPFX-Fe3+-DNA三元络合物.研究表明在一定的浓度范围内,三元络合物的荧光强度与天然DNA的浓度成线性关系.讨论了反应的最佳条件,初步探讨了环丙沙星与Fe3+和DNA的结合机理.     

Water Soluble Polyphenylenepyridyl Dendrimers.Interpolyele ctrolyte Complexes Formed by DNA and Dendrimers

1 Results Recently[1] we synthesized rigid polypyridylphenylene dendrimers (PPD) of different generations. The rigidity endows the dendrimers with shape persistence and well ordered 3D structure that allows one to control the arrangement of functional (pyridine) groups in the molecule. The arrangement can be freely varied from practically uniform distribution through the molecule to a pronounced localization either on the periphery or in the interior of the dendrimer. The desirable distribution can be r...     

以DNA为模板Pd纳米线的电化学制备及其性质

以DNA为模板,采用电化学方法制备出Pd纳米线,通过透射电镜(TEM)和X-射线衍射(XRD)对产物进行了表征,得到粒径大约50nm、长度3.0 um的Pd纳米线.同时讨论了不同实验条件对纳米线结构的影响,并对所制备出的纳米线的电化学性质进行了探讨,对H2O2具有催化响应.     

人类神经Tau具有提高DNA熔链温度的作用

在小牛胸腺ＤＮＡ溶液中加入基因重组人类神经Ｔａｎ，观察ＤＮＡ热变性时的增色效应显示：人类神经Ｔａｕ具有提高ＤＮＡ熔链温度（Ｔ_ｍ）的作用，可将Ｔｍ由 ６７℃提高至 ８１℃；并将质粒ｐＢｌｕｅｓｃｒｉｐｔ Ⅱ ＳＫ的熔链温度由７５℃提高到８５℃．动力学实验表明，Ｔａｕ蛋白能明显减慢ＤＮＡ在热变性时的动力学过程．以上结果提示， Ｔａｕ蛋白可能具有稳定 ＤＮＡ双螺旋空间结构的作用．     

运用RAPD技术鉴定澳大利亚油橄榄品种的研究

由于早期引种记录的丢失、栽培品种的错命名和重命名、品种间的杂交等原因，澳洲现有的油橄榄品种形态变化较大，同名异物和同物异名现象比较普遍，使品种间的鉴定十分困难．运用随机扩增多态DNA技术，在筛选引物的基础上，分别对2种待鉴定样品和9个已知油橄榄品种的RAPD指纹进行比较分析，经UPG—MA聚类分析，在鉴定待测样品上取得了理想效果．     

Chromatin assembly during S phase: contributions from histone deposition, DNA replication and the cell division cycle

During S phase of the eukaryotic cell division cycle, newly replicated DNA is rapidly assembled into chromatin. Newly synthesised histones form complexes with chromatin assembly factors, mediating their deposition onto nascent DNA and their assembly into nucleosomes. Chromatin assembly factor 1, CAF-1, is a specialised assembly factor that targets these histones to replicating DNA by association with the replication fork associated protein, proliferating cell nuclear antigen, PCNA. Nucleosomes are further organised into ordered arrays along the DNA by the activity of ATP-dependent chromatin assembly and spacing factors such as ATP-utilising chromatin assembly and remodelling factor ACF. An additional level of controlling chromatin assembly pathways has become apparent by the observation of functional requirements for cyclin-dependent protein kinases, casein kinase II and protein phosphatases. In this review, we will discuss replication-associated histone deposition and nucleosome assembly pathways, and we will focus in particular on how nucleosome assembly is linked to DNA replication and how it may be regulated by the cell cycle control machinery.     

RNA二级结构预测算法及图形表示

在生物大分子ＲＡＮ序二级结构预测的算法中使用了溯算法，并对ＲＮＡ二级结构预测的结果实现图形表示。     

PAC克隆DNA制备方法的改进

为了解决PAC克隆DNA制备中存在的若干问题，我们探索了几种改进方法，使提取的PAC克隆DNA质量明显改进，能较好地满足我们对儿童急性淋巴细胞白血病6q21缺失区抑癌基因克隆的研究目的。     

The role of CopG mediated DNA bending on the regulation of the σ^54-dependent promoters in E. coli

In prokaryotic cells, although the σ54 RNA poly- merase can stably bind to the σ54-dependent promoter without the enhancer-binding proteins (EBPs), it re- mains as a closed complex which is silent for transcrip- tion[1]. When binding to the enhancer-lik…     

Molecular diversity of the 5S rRNA gene in cultivated and wild rice species

We have used the polymerase chain reaction to analyze variation in the size of 5S ribosomal gene spacer sequence. Eighty accessions, including 65 cultivated rice and 15 wild rice, were analyzed. Among them seven size classes of 5S DNA spacer were observed. Classification asindica orjaponica on the basis of 5S DNA spacer patterns generally agrees with classification based on morphological studies, indicating that the length polymorphism of 5S DNA spacer could be used as a molecular marker for taxonomic and phylogenetic analysis. Supported by the National Natural Science Fundation of China Yi Qingming: born in Apr. 1938, Professor