罗勒毛状根培养体系的优化

为寻找最佳罗勒毛状根培养体系优化方案,用四种发根农杆菌A4,R1601,C58C1,15834诱导药用植物罗勒外植体产生毛状根.实验从外植体、菌株、侵染时间、共培养四个因素优化罗勒毛状根培养体系.结果表明,用发根农杆菌R1601诱导罗勒叶片,预培养时间48h、共培养时间48h、侵染时间6min时,出根效果最好;用1/2MS液体培养基继代培养30d最佳.     

丹参毛状根诱导条件的优化

以发根农杆菌C58C1，A4，R1601为试验菌株，叶片、叶柄、茎段为外植体，研究了菌液浓度、共培养时间和乙酰丁香酮（AS）等因素对丹参毛状根转化频率的影响，并用PCR对诱导出的毛状根进行了阳性鉴定．试验结果表明：菌株和外植体类型对丹参毛状根诱导率存在着显著的差异；最佳共培养时间为3—4d，乙酰丁香酮（AS）浓度为400μmol／L有利于促进毛状根的产生．为进一步利用基因工程技术进行中药丹参的品质改良奠定了基础．     

超声波辅助的发根农杆菌对黄瓜的遗传转化

由于超声波处理可在外植体上产生许多微小伤口,从而提高农杆菌与外植体之间的接触面积,提高农杆菌对外植体的转化频率。用野生型发根农杆菌（Agrobacterium rhizogenes)A4菌株感染黄瓜（Cucumis sativus L.) 无菌苗的子叶和下胚轴,建立了黄瓜的发根遗传转化体系。同时,对超声波处理时间、外植体放置方向、预培养时间、外植体类型、乙酰丁香酮的添加与否等影响因素进行了研究。结果表明,采用外植体在添加0．5mg/L NAA和2mg/L 6-BA的MS培养基上预培养4d,超声波处理2s,共培养3d,在预培养共培养期间子叶上表皮向下可以取得最佳的转化效果,发根诱导率为94．7％。乙酰丁香酮对发根诱导频率影响不明显。冠瘿碱检测表明,发根确定能合成农杆碱。     

发根农杆菌介导云南萝芙木的遗传转化

用发根农杆菌A4分别感染云南萝芙木幼嫩的真叶和茎段,诱导出毛状根,并对毛状根进行了离体培养, PCR检测转基因毛状根和HPLC检测毛状根中利血平的含量．结果表明:这两种外植体的转化频率及诱导出的毛状根差异极大,幼嫩的真叶叶片比茎段更适合作转化外植体用．PCR检测结果表明,诱导毛状根的基因rolB和 rolC整合到云南萝芙木基因组中,HPLC含量检测表明毛状根中利血平的含量比自然根中利血平的含量有显著的增加,因此可以作为利血平来源生产的有效途径之一．     

怀牛膝毛状根诱导及培养体系的建立

以牛膝叶片为外植体,研究了不同发根农杆菌、培养基、乙酰丁香酮(AS)对毛状根诱导率及其生长的影响.结果表明,发根农杆菌不同菌种对牛膝叶片转化率有显著影响,3个供试菌种中ATCC15834菌株诱导率最高;在1/2MS无激素固体培养基上毛状根的诱导率及生长状况均优于MS培养基;100μmol·L-1 AS可以有效提高毛状根诱导率.毛状根从叶片形态学下端中脉切口处形成的愈伤组织上产生,能在无外源激素的培养基上自主生长.PCR扩增结果显示发根农杆菌Ri质粒的rolB基因已在牛膝毛状根基因组中插入、整合并得到表达.建立了牛膝毛状根诱导培养体系,为利用毛状根大规模生产药用成分奠定了基础.     

盾叶薯蓣毛状根的诱导与薯蓣皂甙元的生产

报道盾叶薯蓣形成毛状根诱导的方法及不同毛状根系间生长速率与薯蓣皂甙元含量的差异．结果表明，盾叶薯蓣的幼叶和茎段难被R1601、A4和LBA9402等发根农杆菌菌株诱导出毛状根，但愈伤组织则比较容易；34%的被R1601菌株感染、并在添加200μmol／L乙酰丁香酮的共培养基上培养3d的愈伤可以在30d内形成毛状根；不同的毛状根系在生长速率与薯蓣皂甙元含量方面存在显著差异．     

龙胆毛状根的诱导培养

发根农杆菌（Ａ．ｒｈｉｚｏｇｅｎｅｓ）Ｒ１５００感染龙胆茎段、叶片外植体，１５ｄ后可诱导出毛状根。茎段诱导率高于叶片，可达４２．３％。毛状根的诱导与温度和光照有关。转化根具有抗卡那霉素的特征，在不含激素的ＭＳ培养基上培养，筛选出了生长正常的毛状根系。     

影响农杆菌介导的辣椒基因转化因素的研究

试验设置农杆菌类型、辣椒基因型、外植体、vir基因活化培养基、方法5个因素，研究了利用根癌农杆菌介导法辣椒遗传转化的效果。以获得Km抗性芽外植体频率为指标，发现农杆菌菌株类型和辣椒基因型对转化效率都有较大影响，直接影响着转化效率。采用预培养2d的子叶外植体，用农杆菌侵染5～7min，可获得最高的转化效率。     

银杏毛状根的诱导和培养

利用３个发根农杆菌菌株：Ｒ１５８３４,Ｒ１０００和Ａ４分别对银杏幼叶、幼芽和幼茎外植体进行成功的转化：除Ａ４外,均诱导获得了毛状根。通过对毛状根中冠瘿碱的检测,农杆菌Ｒｉ质粒的Ｔ－ＤＮＡ部分已整合到银杏细胞的基因组中。     

地黄毛状根的培养研究

发根农杆菌是一种革兰氏阴性菌,能侵染大多数的双子叶植物,诱发被感染植物的受伤部位长出毛状根.本实验用发根农杆菌感染地黄外植体诱导其产生毛状根,并加以培养,为今后选择合适的培养方式,大规模培养毛状根来生产地黄的次生物质奠定基础.     

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.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

Features of Women''s language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme