MicroRNA特征与功能

通过分析总结现代分子生物学国际前沿microRNA(miRNA)领域的研究文献，整理出miRNA研究的基本脉络和走向。miRNA是一类长度～22nt的非编码小分子RNA，在包括线虫、果绳、家鼠、人体以及拟南芥等生物中普遍存在；它在调节基因转录与表达，调控生物体正常发育等生理过程中扮演重要角色。从比较的角度出发，揭示了miRNA与小干扰RNA在其代谢与功能方面共用某些途径，相互交叉与替代，可能同属一个更广范围的小分子RNA介导的生理调控机制。miRNA的研究可能对新一代基因药物的开发具有深远意义。     

MicroRNA的生物合成及作用机制

MicroRNA(miRNA)是真核生物中一类长度约为22个核苷酸的非编码小分子RNA。它们能够通过与靶mRNA特异性结合引起靶mRNA的降解或者抑制其翻译而在动植物基因表达调控中扮演重要角色。本文主要就miRNA的生物学特征、生物合成、作用机理及其功能等方面进行综述。     

MiRdetector：一个预测与搜寻miRNA基因的计算工具

MicroRNA（miRNA）是一类内源性的长约21～24 nucleotide(nt)的非编码小分子RNA,能够调节其它基因的表达活性,在生物体的发育过程中发挥重要的作用.每种生物体中miRNA的基因总数还未知,生物信息学分析手段为发现新的miRNA基因提供了有效的方法.作者开发了一个预测与搜寻miRNA基因的完全自动化系统“MiRdetector”.MiRdetector系统是基于计算机比对和miRNA前体茎环结构判断的.用水稻miRNA基因对系统的预测精度进行了检验,系统正确识别了155个样本中的140个,预测精度达到90.32％,并且搜寻到了95个可能的水稻miRNA基因.由于系统的假阳性率较低,因此能够为进一步证实miRNA基因的实验研究提供高质量的数据集.     

microRNA与宫颈癌关系的研究

MicroRNA（miRNA,微小RNA）是一大家族小分子非编码单链RNA,长约19~25个碱基。最新研究表明miRNA可参与多种调节途径,包括细胞增殖凋亡、细胞分化、生殖以及肿瘤发病机制等。实验证据表明,miRNA可通过调控其靶基因参与的多种信号通路,影响宫颈癌的发生发展,为宫颈癌发病机制的研究和诊断治疗提供了新的思路。本文就近年来miRNA与宫颈癌发生发展、诊断治疗的相关研究进展作一综述。     

微RNA在非小细胞肺癌中的研究进展

微RNA(miRNA)是一类内源性、非编码的单链小分子RNA,作用广泛,参与生命活动中的一系列重要进程,并与肿瘤的发生、发展密切相关。大量研究表明,微RNA参与肺癌的发生、发展和预后,具有与原癌基因或肿瘤抑制基因相似的作用。在肺癌组织中微RNA有特定的表达谱,参与调节肿瘤血管生成等多个过程,并可作为生物标志物用以早期诊断,靶向治疗及临床预后。作为一类新的分子靶标,微RNA为肺癌的诊断和治疗提供了新的方向。     

miRNA传感检测技术的研究进展

微小RNA（miRNA）是一类新发现的长度为21-25个核苷酸的RNA,它在转录后水平调节靶基因表达．已有研究表明,miRNA在发育、细胞增殖、凋亡、脂类代谢、激素分泌及肿瘤发生等多种生理和病理过程中发挥重要作用．针对miRNA的检测技术的研究主要包括2大类：一是以传统实验技术方法为基础建立起来miRNA特有的技术方法,二是已成熟应用的生物传感技术．综述了2大类miRNA的检测技术,并对现有的检测技术的特点进行分析．     

MicroRNA在白血病中的研究新进展

微小RNA(microRNA,miRNA)是在真核生物中发现的一类内源性非编码RNA,其长度为21 ～ 25个核苷酸大小.miRNA在基因表达调控中发挥了重要作用.miRNA不仅在白血病中存在明显的表达失调,而且与白血病的诊断和预后有关.本文着重综述了白血病中急性髓系白血病(AML),急性淋巴细胞性白血病(ALL)和慢...     

Sigma因子6促进拟南芥MIRNA基因转录

本研究在筛选拟南芥miRNA水平异常的突变体的过程中,分离得到了一个新的突变体m112,随后通过图位克隆结合基因组测序发现M112的突变基因编码Sigma因子6(SIG6).通过Northern blot和小分子RNA测序,明确了sig6突变体中成熟miRNA的累积下调;通过荧光定量PCR检测pri-miRNA的表达,发现sig6突变体中pri-miRNA水平下调;进一步的MIRNA基因的启动子融合报告基因GUS染色结果显示在sig6突变体中,MIRNA基因启动子的活性减弱.这些实验结果表明SIG6通过影响MIRNA基因的转录参与了miRNA的生物合成,为人们进一步了解miRNA的生物合成途径提供了帮助.     

子痫前期患者胎盘组织中miR-411表达的研究

研究miR-411在子痫前期患者和正常产妇胎盘组织中的表达差异,探讨微小RNA(miRNA)对子痫发病所起到的作用,收集子痫前期患者胎盘组织和正常产妇胎盘组织,并从中提取RNA;采用miRNA特异RT引物进行反转录; 最后用荧光实时定量PCR(Real Time PCR)的方法检测基因的表达量.结果 miR-411在子痫前期患者胎盘组织中表达降低.表明此次实验阐明了子痫前期患者胎盘组织中存在特异miRNA的差异表达,子痫前期发病可能受到miRNA的调控.     

miRNA在肿瘤转移中的研究进展

microRNA(miRNA)是近几年发现的一类高度保守的、长度为20～25 nt的非蛋白质编码的单链小分子RNA。miRNA广泛地存在于多种真核生物中,其主要功能是通过两种方式调控其靶基因的表达:诱导靶向mRNA的降解或者抑制靶向mRNA的翻译。miRNA除了在机体的正常生长发育等生理过程发挥作用外,还在多种病理过程尤其是肿瘤的发生、发展和转移中扮演重要的角色。肿瘤转移的本质是宿主与肿瘤细胞之间一系列复杂的、多因素的相互作用的结果,是恶性肿瘤的重要生物学特征之一。现已有大量研究表明,诸如miR-21、let-7、miR-224和miR-10b等miRNA与消化系统肿瘤、呼吸系统肿瘤、泌尿系统肿瘤和乳腺癌等的转移有关。除此以外,miR-200也与肿瘤转移的EMT(上皮-间质转化)理论密切相关。这些miRNA具体的调控、靶基因的预测和被调控通路虽有大量研究,但机制尚不完全清楚。随着今后相关研究的深入,miRNA可为诊断肿瘤的早期转移和预后检测带来广阔的前景,也会作为新的生物学标记参与肿瘤的治疗。     

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).     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.