恩替卡韦4′-氨基酸酯化衍生物的合成及生物活性评价

恩替卡韦是一种常用的治疗乙型肝炎病毒的拟核苷类药物,可以显著的抑制病毒HBV-DNA在人体内的复制水平,降低HBV-DNA在人体血浆中的含量;但临床实验表明恩替卡韦在人体中的口服生物利用度偏低,稳定性不好。选择性的合成了8种恩替卡韦4'-氨基酸酯化衍生物,以期提高其在体内的吸收效率;并保留其抗HBV活性。所有的化合物之前均未见报道,其结构经ESI-MS和1HNMR确证,同时其对于Caco-2细胞的膜渗透活性及其在HepG 2.2.15细胞中的抗HBV活性都在体外进行了进一步的评价。结果表明与恩替卡韦相比,所有的4'-氨基酸酯化衍生物的膜渗透活性都有一定程度的提高,同时化合物5c还表现出了与恩替卡韦相接近的抗HBV活性。     

苯乙酰异谷氨酰胺类化合物合成及抗肿瘤活性

苯乙酰异谷酰胺作为抗癌酮（Antineoplaston A10）在体内的一种降解产物，具有一定程度的抗肿瘤活性。为此设计并合成了一些新的苯乙酰异谷氨酰胺类化合物以测试其抗肿瘤活性。合成中采用在酸性条件下，先选择性地对L－谷氨酸γ位羧基进行酯化，再进一步合成目标化合物，反应条件温和，收率好。所合成化合物结构经IR、^1HNMR及元素分析鉴定，对所合成的目标化合物的抗肿瘤活性采用MTT法对体外培养的乳腺癌细胞成活率进行了测试，初步结果显示有一定抑制肿瘤细胞存活的作用。     

抗癌药物放线菌素D及其新类似物体外DNA结合特性研究

以 CD及 UV光谱研究了放线菌素 D及新合成的两个新类似物体外与小牛胸腺 DNA的结合特性 ,并与以往报道的 3种化合物抗肿瘤活性研究结果进行了比较 .结果显示 ,测试的 3种化合物体外与 DNA结合能力的大小与体内抗肿瘤活性之间存在平行关系 .     

植物液泡膜Na~+/H~+逆向转运蛋白的研究与应用

液泡膜Na~+/H~+逆向转运蛋白是植物体内广泛存在的一种跨膜转运蛋白,负责植物体内Na~+、H~+的交换。本文对Na~+/H~+逆向转运蛋白的克隆、分子结构、功能及应用等方面展开论述,旨在为研究者系统的理解Na~+/H~+逆向转运蛋白的研究进展,为调控该蛋白的表达来改进植物的生长发育及抗盐胁迫能力等方面的应用提供参考。     

benztropine类多巴胺转运蛋白配体的QSAR研究

利用Hansch方法，研究了37种benztropine类化合物diphenylmethoxy部位苯环取代基结构与其活性的定量关系，结果表明：苯环取代基的电性和体积等均是影响该类化合物与多巴胺转运蛋白亲和力的重要因素，所得到的benztropine类化合物diphenylmethoxy部位取代基的综合结构效应，对进一步研究该部位与多巴胺转运蛋白相互作用的电性和立体性质及设计新的多巴胺转运蛋白配体具有指导意义。     

转运葡萄糖苷类化合物的Caco-2细胞模型建立

建立转运葡萄糖苷类化合物的Caco-2细胞模型,为葡萄糖及葡萄糖苷类化合物肠道吸收研究提供基础。通过对Caco-2细胞最适培养基的选择、单层致密性的测定、单层通透性和细胞两侧碱性磷酸酶活性比的测定、单层亚显微结构的观察、细胞葡萄糖转运蛋白SGLT1和GLUT2的mRNA及蛋白表达水平的分析,建立可靠的细胞模型。研究表明:Caco-2细胞的最适培养基为添加体积分数15%血清的DMEM低糖培养基;Caco-2细胞在14～17d的跨膜电阻趋于稳定,苯酚红的表观渗透系数达到0.49×10-6~0.51×10-6cm·s-1,微绒毛分化成熟,细胞两侧碱性磷酸酶比值达到2.0以上。葡萄糖转运载体SGLT1的mRNA表达在14d时显著高于17d和21d,葡萄糖转运载体SGLT1和GLUT2的蛋白表达在14、17、21d无显著差异(P<0.05)。Caco-2细胞培养14～17d即可建立可靠的肠细胞吸收模型,用于葡萄糖及葡萄糖苷类化合物吸收的体外研究。     

拟南芥中一个镍离子转运蛋白的亚细胞定位

离子的跨膜转运是细胞获取养分的重要环节，亦是植物在组织和器官水平上进行养分吸收运移的基础．在植物中镍（Ni）元素主要以Ni^2＋的形式存在，并通过Ni^2＋转运蛋白将其跨膜转运至相应的组织器官，参与氢酶和脲酶的合成．生物信息学分析表明，拟南芥中一个Ni^2＋转运蛋白AT2G16800含有叶绿体定位信息．克隆该基因5’端编码转运肽的272bp片段，与绿色荧光蛋白（GFP）基因融合后，在拟南芥中高效表达，对其进行了亚细胞定位的研究．转基因植株通过共聚焦扫描显微镜的观察，发现GFP荧光信号只存在于叶绿体中，该结果表明A他G16800为叶绿体蛋白．     

体外消化对大豆多肽性质和ACE抑制活性的影响

为了验证大豆多肽血管紧张素转换酶(ACE)抑制活性的生物可获得性,采用Alcalase蛋白酶催化大豆蛋白水解获得了3种水解程度不同的大豆多肽,再应用摸拟体外消化方法处理大豆蛋白及其水解产物,并进一步分析了摸拟消化前后大豆多肽结构、性质和ACE抑制活性的变化.结果显示:3个大豆多肽的相对分子质量均小于16000,且水解度越高,TCA可溶性蛋白含量就越高;经过摸拟体外消化,大豆蛋白出现降解,其分子大小和性质与大豆多肽趋于一致,大豆多肽则进一步降解;3种大豆多肽的ACE抑制活性在经过摸拟体外消化后显著下降,大豆蛋白的ACE抑制活性则显著上升,两者之间没有显著差异,表明虽然Alcalase对大豆蛋白的酶促处理能够释放降血压肽,但经过模拟体外消化后其ACE抑制活性又会下降,而直接口服大豆蛋白有可能获得同样的降血压效果.     

凋亡素融合蛋白的基因克隆、表达与体外活性分析

来源于HIV-1病毒(47~57位氨基酸)的TAT小肽具有跨膜功能,可以将外源蛋白进行跨膜转运。通过聚合酶链反应(PCR)的方法扩增了TAT-凋亡蛋白序列,与载体pET-28b连接后在大肠杆菌BL21(DE3)中获得了高表达,以包涵体形式表达的TAT-凋亡蛋白在变性条件下进行了Ni-NTA纯化,纯化的蛋白经MTT法证明具有诱导HeLa细胞凋亡的能力。     

肽树枝状化合物在生物学中的应用

肽树枝状化合物是一类含有肽键或表面接枝肽的树枝状化合物,在生物技术及生物化学领域具有广泛的应用。作者就该类化合物在基因转运、作为蛋白质类似物及在催化剂载体方面的研究进展进行讨论。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.