噬菌体展示肽库技术淘选蚕丝纤维蛋白连结短肽的实验研究

采用噬菌体随机肽库展示技术研究与蚕丝纤维蛋白连结的功能性短肽的淘选方法.实验结果显示,淘选的与蚕丝纤维蛋白连结的功能性短肽都包含有一个相同的氨基酸残基序列QSWS.噬菌体与蚕丝蛋白的连结试验和合成肽与蚕丝蛋白的连结试验都证实了QSWS序列与蚕丝蛋白连结的重要性.随着对淘选方法进一步改进和优化,这些功能性短肽将有助于对蚕丝进行功能化改造,可拓宽蚕丝在生物材料领域中的应用.     

小鼠噬菌体抗体库的构建和N-肽结合单链抗体的筛选

成功构建一库容量为1.7×10⁸的小鼠噬菌体抗体库,并从中淘选出对N-肽有结合活性的单链抗体。首先从未免疫小鼠的脾脏中提取总RNA,分离出mRNA,经逆转录合成其总cDNA。随后通过PCR分别扩增出抗体重链和轻链可变区V_H、V_L的基因片断,再经重组PCR将两片断由一编码(Gly₄Ser)₃十五肽的接头连在一起,并克隆到噬菌质粒pCANTAB 5E中,电击转化大肠杆菌TG1。经辅助噬菌体M13KO7超感染回收全部重组噬菌体,此即噬菌体抗体库。N-肽是一种新发现的神经肽,其N端与阿片肽高度同源,可与阿片肽受体相互作用。对其研究可能有助于了解成瘾机制和有临床应用价值。将生物素化的N-肽与抗体库相互作用,用偶联有链霉亲和素的磁珠富集与N-肽结合的重组噬菌体,经四轮淘选,得到亲和力较高的单链抗体。     

肿瘤靶向多肽生物淘选技术研究进展

生物淘选肿瘤或癌细胞的各种特异性靶向多肽是探索肿瘤早期诊断和治疗方法的有效途径.特异性靶向多肽既可用于探测肿瘤细胞表型特征,又可将其与抗癌药物结合进行靶向治疗,同时还可作为体内肿瘤的成像制剂,用于肿瘤及肿瘤细胞微转移的早期探测.噬菌体展示肽库技术能够有效地进行生物淘选或识别出与癌或肿瘤细胞某一靶点连结的,具有特异性、高亲和性的多肽.近年来,利用体内或体外噬菌体展示肽库技术已成功地淘选或识别出一些癌细胞的靶向多肽.本文就这些方面的研究进展进行了简要阐述,重点介绍了癌或肿瘤细胞靶向多肽的体外和体内生物淘选最新技术和临床应用.     

从七肽噬菌体展示库中筛选蛋白质配基

为了研究噬菌体展示技术的应用，以溶菌酶为靶分子从七肽噬菌体展示库中筛选蛋白质的高亲和力噬菌体配体，所筛选的亲和力最高的噬菌体的ELISA检测值A405nm可达0．634．通过比较亲和性噬菌体外源插入肽的DNA序列，认为基元HWWW是肽段与酶分子发生亲和的必需序列．此外，由于靶分子和高亲和性展示肽的等电点分别为11．2和6．74，因此在亲和环境中携带异种电荷，利于亲和吸附的发生，而此时低亲和性展示肽与靶分子携带同种电荷，阻碍了亲和吸附．同时，高亲和性肽段HWWPAS和与其有较高同源性的肽段HWTWWNL都有适中的疏水性，这有利于肽与靶分子表面的疏水位点相互作用从而产生亲和吸附．     

尿激酶短肽抑制剂的初步研究

以尿激酶为目标蛋白， 在噬菌体表面展示六肽库中对尿激酶的短肽类抑制剂进行了三轮特异性筛选. 提高噬菌体与尿激酶的比例及缩短作用时间从而提高筛选压力后， 与尿激酶亲和结合的噬菌体得到富集. 通过对第三轮筛选到的重组噬菌体的DNA序列分析， 获得一组相对保守的肽序列. 相应的合成短肽 NEPKAN 和VSPKVL 对尿激酶的抑制常数分别为32.5 μmol/L和88.6 μmol/L.     

利用十二肽库筛选心肌型脂肪酸结合蛋白特异性的亲和配体

采用噬菌体表面展示十二肽库对心肌型脂肪酸结合蛋白（H FABP）特异性亲和配体进行筛选, 经3轮筛选及序列比对后得到一个酶联免疫测定分析 (ELISA)检测阳性特征序列： W P N H H M L H K R W P. 对此序列进行肽合成, 并标记上荧光标记物芘, 经高效液相纯化、 冻干及质谱确定其分子量后制成荧光肽探针检测急性心肌梗塞病人血样, 结果均呈阳性. 结果表明, 所获得的肽探针具有较好的临床应用效果.心肌型脂肪酸结合蛋白; 噬菌体表面展示十二肽库; 亲和配体; 酶联免疫测定分析     

噬菌体展示肽库技术及其在分子病原细菌学研究中的应用

从噬菌体展示技术的基本原理、肽库的构建、噬菌体肽库的分类、噬菌体肽库的筛选方法等方面,综述了噬菌体展示肽库技术;从抗原表位研究、免疫诊断研究、基因疫苗研究、抗菌药物的靶向投递等方面,阐述了噬菌体展示肽库技术在分子病原细菌学中的应用;并对今后的研究方向进行了展望.     

抗癌胚抗原纳米抗体展示文库的构建与筛选

利用噬菌体展示技术进行纳米抗体库的构建和筛选,获得抗癌胚抗原(CEACAM5)的高亲和力、强特异性纳米抗体,为相关癌症诊断及靶向治疗的应用奠定基础。使用重组CEACAM5抗原免疫羊驼,分离免疫后羊驼的外周血淋巴细胞,提取总RNA后通过RT-PCR技术扩增羊驼重链抗体可变区(VHH)片段,构建纳米抗体文库。采用噬菌体展示技术和固相淘选方法,筛选得到强阳性克隆,经大肠杆菌表达和镍离子亲和层析获得纳米抗体,最终利用Biacore分析其亲和力和特异性。通过3轮的淘选,获得一株纳米抗体亲和力达到2.6×10-10mol·L-1,对同源性蛋白CEACAM-1、-3、-6、-8及肿瘤蛋白AFP均无交叉反应性。利用噬菌体展示技术成功获得了抗癌胚抗原(CEACAM5)的高亲和力、强特异性纳米抗体,可用于后续相关癌症诊断和靶向治疗。     

噬菌体展示肽技术及其应用

综述了噬菌体展示肽技术的基本原理，肽库构建和筛选的基本方法以及噬菌体展示肽库的应用现状和前景。     

在肽库中筛选β2糖蛋白Ⅰ的小肽配体

以β2GPⅠ为目标分子, 在噬菌体表面展示肽库中进行亲和性筛选, 经过4轮筛选后, 噬菌体的收率从2.4×10-5%提高到1.1×10-3%. 随机挑取噬菌体克隆, 测定其与β2GPⅠ的结合活性, 选取其中结合力较强的克隆进行DNA序列测定, 得到一组保守序列(YFSAF), 经与人凝血酶受体前体序列(271～278)比较, 发现它们具有明显的相似性. 经竞争性ELISA分析实验, 含有该序列的噬菌体克隆能够抑制β2GPⅠ与抗磷脂抗体的结合, 抑制率可达20%左右.     

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.     

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.     

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).     

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.