新型类嘌呤脱氧核糖核苷类化合物的抗乙型肝炎病毒体外活性实验研究

探讨新型类嘌呤脱氧核糖核苷类化合物体外抗乙型肝炎病毒(HBV)的作用,为了将新型类嘌呤脱氧核糖核苷类化合物作用于以Hep G2.2.15细胞系,通过四甲基偶氮唑盐(MTT)比色法检测样品对Hep G2.2.15细胞的毒性,采用酶联免疫吸附测定技术(ELISA)检测细胞上清中HBsAg和HBeAg的变化.结果显示,新型类嘌呤脱氧核糖核苷类化合物在第9天时,浓度为10μmol/L,对HBsAg和HBeAg的抑制率都较高,化合物的毒性也较低.体外细胞培养表明,新型类嘌呤脱氧核糖核苷类化合物在体外有一定的抗乙型肝炎病毒作用.     

中间体苯腙类化合物的合成

利用Japp-Klingemann反应,可较为方便地制备苯腙类化合物,由Fischer吲哚合成法,可进一步合成5-取代吲哚衍生物。机理见文献[3]。 反应中通常使用的α-活泼氢化合物为乙酰乙酸乙酯及乙酰丙酮等的衍生物,它们与重氮盐偶合后一般都转变成苯腙类化合物。当我们使用α-氰乙基丙二酸二乙酯仿照文献[5]进行反应时,得到的是偶氮酯类而非苯腙类化全物,即:α-(4—苄氧基苯偶氮基)-α-氰乙基丙二酸二乙酯(Ⅰ),经碱处理时,该偶氮酯可转变成苯腙类化合物(Ⅱ)。这两个化合物均未见文献报道,经核磁、红外等方法证实。     

化学发光标记技术

化学发光标记(Chemiluminescence labeling,CLL)及发光免疫分析(Luminescent Im-munoassy,LIA)是一种灵敏度高,特异性强、检测快速、无放射危害的分析技术,本文综述了该项技术的机理、实验技术及应用.常用的化学发光特质有:鲁米诺(Luminol)和异鲁米诺(Isoluminol)及其衍生物(如:AE-BI);咪唑类(如:咯粉碱);吖啶酯类(如:光泽精);苯酚类化合物(如:焦性没食子酸)及芳基草酸酯类(如:TCPO,DNPO),近年来提出了高量子效率、高稳定性的化学发光剂:1,2-二氧化环乙烷衍生物(如:AMPPD).     

5′-脱氧-5′-取代嘧啶氨基核苷类似物的合成及抗肿瘤活性

通过微波促进的一锅法反应合成了一系列C-5′羟基取代的嘧啶基核苷类衍生物,化合物结构经NMR和HRMS等表征.利用MTT法研究了合成化合物的抗肿瘤活性,二甲氨基修饰的嘧啶基5-甲基尿苷衍生物3a和肌苷衍生物4a显示了好的活性,IC50值分别为10.73和10.99μmol/L.而合成的其他核苷类衍生物在测试的细胞株中没有活性,说明环状氨基修饰的嘧啶基显著降低合成的核苷类衍生物的活性.     

阿魏酸及阿魏酸乙酯的合成

综述了合成阿魏酸及其酯类的研究状况,并通过对阿魏酸及阿魏酸乙酯合成方法的改进,考察了阿魏酸及其酯类衍生物的合成新工艺.     

水杨酸类试剂在稀土荧光分析法中的应用

对水杨酸、水杨酸苯环上的取代衍生物、水杨酸酯类及其它衍生物等四部分总结了荧光分析法测定稀土元素的研究现状,并对水杨酸类试剂在稀土荧光分析中的应用前景作了评述和展望。     

核苷二苯基磷酸酯的合成及大鼠体内药物动力学

AZT的5'-二苯基系列磷酸酯衍生物在体外抗病毒实验中显示了良好的抗HIV病毒活性,具有开发为新型核苷类抗病毒药物的潜力.本文采用PCl3-锅法合成了系列核苷二苯基磷酸酯,并对其纯化后的化合物进行大鼠体内药物动力学规律评价.结果显示该系列衍生物的动力学表现和苯基上取代基的性质有直接联系,且均能改善对AZT的释放,有作为临床抗艾滋病治疗剂的可能.     

核苷类似物的设计合成及其抗肿瘤活性

以氨基葡萄糖盐酸盐为原料,在碱性水溶液中与1,3-二羰基化合物反应得到吡咯衍生物,进而设计合成了6个核苷类似物.所合成的化合物经IR,NMR及HRMS对其结构进行了表征,并对合成的核苷类似物进行了初步的生物活性测试.     

阿魏酸的合成及其分子改造研究进展

本综述了合成阿魏酸及其酯类，酰胺类，酮类和醚类等衍生物的研究状况。鉴于阿魏酸及其衍生物的用途广泛，生物活性高而且低毒性，深入开展对阿魏酸及其分子改造的研究具有重要意义。     

长花马先蒿核苷类万分研究

从长花马先蒿全草乙醇提取物中的进一步分离出２个核苷类化合物，经ＵＶ，ＩＲ，＾１ＨＮＭＲ，＾１３ＣＮＭＲ，ＤＥＰＴ，ＥＩＭＳ和ＦＡＢＭＳ现代波谱技术，鉴定它们为６－肌苷和腺嘌呤核苷，其中６－肌苷为新化合物。     

3-O-甲基-4，6-O-苯亚甲基-N-（2-吡啶基）-α-D-葡萄糖的合成研究

研究了以α-D-葡萄糖为原料，经异丙叉基保护、甲基化、苯亚甲基化等步骤合成了3-O-甲基-4，6-O-苯亚甲基-N-（2-吡啶基）-α-D-葡萄糖，产物经质谱、核磁共振谱及红外光谱对其进行了结构表征分析。N-杂环取代的糖类化合物是一种重要的医药和有机合成中间体，该类化合物将在合成糖基、核苷类似物、杂环化合物、糖多肽等具有潜在药理活性的化合物中具有广阔的应用前景．     

Three-dimensional structure of hyper-modified nucleoside Q located in the wobbling position of tRNA.

The hyper-modified nucleoside Q (queuosine) is exclusively located in the wobbling position of anticodons of tRNATyr tRNAHis, tRNAAsn and tRNAAsp that recognise codons NAUC (ref. 1). Queuosine and its hexose-containing derivatives are widely distributed in microorganisms, animals and plants. We confirm here the chemical structure of queuosine as 7-(3, 4-trans-4, 5-cis-dihydroxy-1-cyclopenten-3-ylaminomethyl)-7-deazaguanosine (Fig. 1). The unique structural features of Q are the unusual cyclopentenediol side chain and the 7-deazaguanine ring. Queuosine is one of the most complicated modified nucleosides found thus far.     

酞菁铜硅胶固定相上分离嘧啶核苷

利用合成的磺化酞菁铜硅胶固定相,在反相ＨＰＬＣ条件下对３种结构极为相似的嘧啶核苷进行分离。同时研究了酸、有机修饰剂用量、流动相流速等对分离效果的影响。     

离子液体中核苷类似物的合成

核苷类似物因其特殊的结构和良好的生物活性,在药物化学领域中占有重要的地位.核苷类似物的高效和绿色合成是有机化学和药物化学的重要研究内容,本文着重介绍了在离子液体中具有重要生物活性的几种核苷类似物,如D4T,BVDU等的合成研究,并与经典的合成方法作了对比分析,结果表明用离子液体作介质的合成反应具有独特的优势.     

Crystal structure of a concentrative nucleoside transporter from Vibrio cholerae at 2.4 Å

Nucleosides are required for DNA and RNA synthesis, and the nucleoside adenosine has a function in a variety of signalling processes. Transport of nucleosides across cell membranes provides the major source of nucleosides in many cell types and is also responsible for the termination of adenosine signalling. As a result of their hydrophilic nature, nucleosides require a specialized class of integral membrane proteins, known as nucleoside transporters (NTs), for specific transport across cell membranes. In addition to nucleosides, NTs are important determinants for the transport of nucleoside-derived drugs across cell membranes. A wide range of nucleoside-derived drugs, including anticancer drugs (such as Ara-C and gemcitabine) and antiviral drugs (such as zidovudine and ribavirin), have been shown to depend, at least in part, on NTs for transport across cell membranes. Concentrative nucleoside transporters, members of the solute carrier transporter superfamily SLC28, use an ion gradient in the active transport of both nucleosides and nucleoside-derived drugs against their chemical gradients. The structural basis for selective ion-coupled nucleoside transport by concentrative nucleoside transporters is unknown. Here we present the crystal structure of a concentrative nucleoside transporter from Vibrio cholerae in complex with uridine at 2.4??. Our functional data show that, like its human orthologues, the transporter uses a sodium-ion gradient for nucleoside transport. The structure reveals the overall architecture of this class of transporter, unravels the molecular determinants for nucleoside and sodium binding, and provides a framework for understanding the mechanism of nucleoside and nucleoside drug transport across cell membranes.     

The Biochemical and Cytochemical Study of 5-nucleotldase Activity in Chilling-sensitive and Chilling-tolerant Rice Plasmalemma

5-nucleotidase (EC 3.1.3.5) can catalyze the hydrolysis of most ribonucleoside 5-monophosphates and deoxynucleoside 5-monophosphates to the corresponding nucleosides and orthophosphates. It is localized predominantly in the plasma membranes of human and animal tissues,and often used as a marker enzyme for plasma membranes in     

DNA microarray synthesis by using PDMS molecular stamps (Ⅲ)—— Optimization for the reaction conditions

Optimization for the technological processes of fabricating oligonucleotide microarray by the molecular stamping method is studied in this note. Three factors that affect the pressing coupling reactions of the nucleosides are focused on: the stability of the chemical activities of the reaction solutions, the contamination of the remain of the reactive nucleotides among the different spots on the chip, and the influence of the capping reaction on the hybridization result. The experiments show that the acetonitrile solution of tetrazole and nucleoside monomer could maintain sufficient reactive activity for more than 10 h. An effective method has been used and proved to eliminate the residual reactive nucleosides on chip with small molecules containing hydroxyl group. Finally, the capping step—a regular step in the conventional DNA chemical synthesis can be neglected in our on-chip DNA synthetic process, which would not affect its hybridization results.     

DNA microarray synthesis by using PDMS molecular stamps (Ⅲ)-- Optimization for the reaction conditions

Optimization for the technological processes of fabricating oligonucleotide microarray by the molecular stamping method is studied in this note. Three factors that affect the pressing coupling reactions of the nucleosides are focused on: the stability of the chemical activities of the reaction solutions, the contamination of the remain of the reactive nucleotides among the different spots on the chip, and the influence of the capping reaction on the hybridization result. The experiments show that the acetonitrile solution of tetrazole and nucleoside monomer could maintain sufficient reactive activity for more than 10 h. An effective method has been used and proved to eliminate the residual reactive nucleosides on chip with small molecules containing hydroxyl group. Finally, the capping step-- a regular step in the conventional DNA chemical synthesis can be neglected in our on-chip DNA synthetic process, which would not affect its hybridization results.     

核酸光化学研究进展

讨论了近年来紫外光诱导的ＤＮＡ碱基主要光化学反应及其进展,其中包括嘧啶环丁烷二聚体、「６－４」光加成产物、光水合产物、ＤＮＡ－蛋白质光交联产物的形成以及在和嘌呤碱基之间的光化学反应,这些光反应及春产物是导致核酸光损的主要原因。     

Fluorescence quenching and the binding interaction of lumichrome with nucleic acids

The interaction of lumichrome (LC) as an endogenous fluorescence probe with nucleobases, nucleosides and nucleic acids has been studied by UV-visible absorption, fluorescence spectroscopy, polarized fluorescence and viscosity. The fluorescence of LC was strongly quenched by a series of nucleic acids and their precursors. The influences of the medium, temperature and salt effects on LC-nucleobase and LC-nucleic acid complexes were investigated. The influences of polarized fluorescence, thermal denaturation and viscosity on LC-ctDNA interaction were examined. The results demonstrate that the main binding model of LC-ctDNA includes strong intercalating into the DNA helix chain.