用差异显示技术分离空心莲子草抗旱相关基因

采用mRNA差异显示技术,分离空心莲子草在干旱胁迫1 d后差异表达的基因,获得139个基因片段.经过Reverse Northern检测,初步证实有两个片段受干旱诱导表达上调.对其中一个片断克隆测序并进行核甘酸序列比对,显示与其他基因同源性都很低,表明可能是新的基因.半定量PCR技术证实该基因受干旱诱导表达上调.     

麻疯树干旱诱导差异表达基因片段的分离与功能分析

运用mRNA差异显示技术(DDRT-PCR),并结合反向Northern杂交筛选麻疯树(Jatropha.curcus)干旱胁迫下差异表达基因,最终从麻疯树叶片中分离出8条干旱胁迫诱导下表达上调的差异片段.经克隆、测序和基因信息分析后发现其中4个片段与GenBank中已知序列有较高同源性.对这4个差异表达片段的序列分析表明:JcDD-3和JcDD-13分别与1-磷酸-肌醇合成酶(MIPS)基因及甜菜碱醛脱氢酶(BADH)基因序列有较高同源性;JcDD-16与白杨中度抗旱叶片中提取的表达序列标签(CU230383)核酸序列同源;JcDD-25与植物富含亮氨酸重复序列型类受体蛋白激酶(LRR-RLK)基因序列同源.     

一个麻疯树C2H2型锌指蛋白基因JcZFP1的克隆与表达分析

从麻疯树胚乳cDNA文库中克隆得到一个C2H2型锌指蛋白基因,JcZFP1,全长931bp,开放阅读框全长735bp,编码244个氨基酸残基,等电点pI=7.0,分子量PA=27.38kD.C2H2型锌指结构位于第81至103个氨基酸残基中,包括植物锌指蛋白特有的保守氨基酸序列QALGGH.在该基因的顺式作用元件上发现了与生长发育和逆境胁迫相关的启动元件.荧光定量PCR(qPCR)检测发现,JcZFP1基因在麻疯树各器官中的表达量依次为:绿果皮花叶根茎种仁,且幼嫩器官表达量高于成熟器官;对麻疯树幼苗进行低温、干旱胁迫时,JcZFP1基因的表达量明显增加,表明该基因可能在麻疯树的生长发育及逆境胁迫应答过程中起重要作用.     

佛手GRAS基因的克隆及表达分析

利用抑制消减杂交法从芸香科柑橘属不耐寒植物佛手中分离得到了一个表达序列标签(EST)片段,结合RACE技术克隆获得该基因的1 669 bp序列,编码区长1 236 bp,编码413个氨基酸.通过Blastn同源序列比对分析,结果显示该基因与拟南芥已知的GRAS基因同源性较高;与GenBank数据库比对分析,表明该基因具有GRAS特有的保守结构域.因此,命名该基因为:CmsGRAS(GenBank登录号:JF440647).用荧光定量聚合酶链式反应(qPCR)的方法研究了该基因在低温胁迫处理下的表达特性,结果显示该基因在低温胁迫后的表达量有明显的变化.     

马尾松PmCBL3基因的克隆及其表达分析

【目的】为明确马尾松(Pinus massoniana)CBL基因结构特征及干旱胁迫下的表达特性,探讨该基因在马尾松抗旱调控过程中的生物学功能。【方法】以马尾松优良家系为试材,采用RT-PCR和RACE方法克隆马尾松CBL基因全长cDNA,运用生物信息学方法,分析其蛋白质性质和亲缘关系,利用荧光定量PCR分析干旱胁迫下的基因表达特性。【结果】获得马尾松的一个CBL同源基因,命名为PmCBL3,该基因cDNA序列全长1 035 bp,包括681 bp的完整开放阅读框,编码226个氨基酸。PmCBL3蛋白含4个EF-hand功能域,且相邻EF-hand功能域之间的氨基酸数目非常保守,属于EFh家族蛋白。系统进化分析表明:该蛋白与其他植物CBL同源性达62%～98%,其中与北美云杉(Picea sitchensis)CBL亲缘关系最近。qRT-PCR结果显示,PmCBL3在马尾松根中表达量最高,茎和叶次之; 干旱第15天表达量最大,随干旱胁迫加剧,表达量逐渐降低。【结论】PmCBL3基因属于CBLs家族,与北美云杉亲缘关系最近。该基因响应干旱胁迫,推测其可能参与马尾松干旱逆境的应答调控。     

甘蓝型油菜BnDHAR基因的克隆及表达分析

在甘蓝型油菜矮化突变体与其高秆亲本构建的消减杂交文库中,得到一长约230bp与编码脱氢抗坏血酸还原酶的DHAR基因核苷酸序列相似的DNA片段.采用同源克隆技术,在甘蓝型油菜中获得该基因的全长cDNA序列,命名为BnDHAR.BnDHAR与已公布的甘蓝型油菜基因组中的该基因核苷酸序列完全一致.对BnDHAR基因不同发育时期组织的表达分析的结果显示,BnDHAR基因在高秆油菜苗期的叶中表达量最高,是矮化突变体的5倍,在根、茎中表达极低,具有组织特异性.非生物胁迫显著影响BnDHAR表达,高温胁迫使其表达升高,盐胁迫处理9h时达最高,而干旱胁迫时表达量在处理12h时才达最高.     

油菜一个WRKY基因对盐胁迫和干旱胁迫的表达响应

以抗性不同的3个油菜品系为材料,半定量RT_RCR方法检测油菜叶片WRKY转录因子家族的BnD11基因在高盐和干旱胁迫下的表达情况.高盐和干旱胁迫6 h后BnD11基因表达量即有明显调高,在抗性最强的‘862'品系中表达量增加幅度最高,而在抗性最弱的‘1821'品系中表达量增加幅度最少.结果表明BnD11基因表达量与油菜品系抗性强度具有明显正相关性,可能在油菜抗(耐)盐和干旱的生理过程中具有重要作用.     

棉花耐旱相关基因的cDNA-AFLP差异显示

为鉴定棉花干旱胁迫响应基因,应用cDNA-AFLP技术,以棉花耐旱品种晋棉13号幼苗为研究对象,对干旱胁迫早期叶片基因表达进行了mRNA指纹分析。通过64对引物组合的筛选,共分离得到232个差异表达的转录衍生片段(TDFs),对其中102个TDFs进行了克隆、测序和序列分析。结果表明:45个TDFs与NCBI中已有序列同源,功能涉及信号传导、转录调控以及逆境诱导蛋白等,另有57个TDFs无同源序列或同源性低,预测其为是一些未知功能基因。     

干旱胁迫下中国沙棘HB15基因的时空表达模式

中国沙棘是西北高寒干旱区的抗旱型植物,HB类转录因子是参与植物干旱胁迫的重要基因。为发掘沙棘抗旱相关基因,文中以转录组测序获得的HD-Zip家族的中国沙棘转录因子HB15基因为研究对象,采用qRT-PCR技术研究中国沙棘HB15基因在干旱胁迫下的时空表达模式。结果表明:随着干旱胁迫程度增强,HB15基因的表达量在干旱胁迫的中国沙棘的根、茎、叶3个部位均呈现先增加后降低的趋势,并于复水后急剧降低,且3个部位均为上调表达,但表达情况又有所差异。研究结果说明中国沙棘HB15基因受干旱胁迫的诱导表达。     

马铃薯乙醇酸氧化酶StGLO1对模拟水分胁迫的响应

为了解乙醇酸氧化酶在调控植物生长代谢及生物与非生物胁迫过程中发挥的作用。本研究以‘青薯9号’马铃薯为材料克隆乙醇酸氧化酶基因StGLO1,构建过表达载体并转化烟草,观察在干旱胁迫处理下转基因烟草和野生型烟草的长势,并测定了叶片中的游离脯氨酸、CAT、POD的含量以及转基因根茎叶中StGLO1基因的表达量变化,验证过表达StGLO1烟草在干旱胁迫下的响应。结果表明:StGLO1(GenBank登录号XM_006348318.2)基因CDS为1 116 bp,编码371个氨基酸;干旱胁迫下,转StGLO1基因烟草的生长优于野生型,转基因烟草StGLO1基因的表达量在叶片中最高;转基因烟草中的游离脯氨酸、CAT、POD的含量高于野生型,达到差异显著水平(P0.05)。该结果为进一步研究马铃薯干旱胁迫响应机制有一定参考价值,也丰富了马铃薯抗旱育种的基因资源。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

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 Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that