人ERCC1在大肠杆菌中表达研究

人ERCC1基因是与核苷酸切除修复有关的基因。为了对其结构和功能进行进一步研究，将ERCC1基因放入大肠杆菌中进行表达。试验中发现表达产物大多以包涵体的形式存在为了提高表达产物的可溶性表达，实验了3种方法：将ERCC1与GROES/EL共表达，将ERCC1与PDI共表达及在低温下进行ERCC1的表达，最终发现低温表达使可溶性表达显著上升。     

3个甘蔗品种（系）响应低温胁迫的转录组分析

权重基因共表达网络分析( weighted gene co-expression network analysis， WGCNA) 可通过聚类鉴定共表达的基因模块来研究生物学数据与相应性状之间的关系。为了挖掘甘蔗响应低温的特异基因，揭示甘蔗响应低温的分子调控机理，本研究以3个耐寒能力不同的甘蔗品种作为试验材料，利用转录组测序技术分析不同抗性甘蔗品种在低温胁迫（4℃）下基因表达。研究结果表明，WGCNA鉴定出13个基因共表达模块，通过相关性分析筛选到blue和yellow模块作为甘蔗抗寒机理研究的目标模块。基于blue和yellow模块中筛选关键基因，以及筛选抗寒品种中特异表达基因，最终筛选出13个基因可能与甘蔗抗寒能力密切相关，为后续选育耐寒性强的优良甘蔗新品种提供理论依据和技术支撑。     

人源化IGF-Ⅰ基因的人工合成、重组与表达

为了实现人源化胰岛素样生长因子Ⅰ(human insulin-like growth factors-Ⅰ,hIGF-Ⅰ)基因在大肠杆菌中的高效表达,了解IGF-Ⅰ基因结构与功能的关系,探索人工制备的hIGF-Ⅰ在临床治疗疾病上的应用,实验参照GenBank中人IGF-Ⅰ氨基酸序列并进行密码子优化,然后人工合成这条基因并将克隆至pUC57载体上.构建重组表达载体pGEX-6P-1-hIGF-Ⅰ,转化大肠杆菌BL21菌株,进行不同诱导条件的优化,SDS-PAGE电泳确定最佳诱导条件,并利用建立hIGF-Ⅰ的间接ELISA检测方法分析表达产物活性.结果表明,获得重组表达载体pGEX-6P-1-hIGF-Ⅰ,并在大肠杆菌中实现与GST蛋白的融合可溶性表达.最佳诱导条件OD600值为0.8、IPTG浓度为0.5 mmol/L,表达蛋白的浓度为2.811 mg/mL,且产物具有抗原活性.说明人工制备的hIGF-Ⅰ与天然的hIGF-Ⅰ生物活性有部分相同,在基础研究和药物开发方面可作为替代物进行研究.     

嗜酸乳杆菌亚油酸异构酶基因的克隆与表达

利用分子生物学方法对嗜酸乳杆菌AS1.1854菌株的亚油酸异构酶基因进行克隆与表达.培养菌体后提取总DNA,用PCR法扩增其亚油酸异构酶基因,再将其克隆到pET30a载体上,转入到大肠杆菌BL21株中表达,在低温下诱导表达出重组蛋白,并用Ni2 金属鳌合层析对重组蛋白进行分离和纯化.通过实验,得到了亚油酸异构酶的基因,成功转入到载体中,表达出了可溶性的重组蛋白,并对其进行了纯化.实验表明,在原核细胞中可以表达出可溶性重组亚油酸异构酶,以200 mmol/L的咪唑洗脱液进行洗脱可以获得目标蛋白.     

扁豆几丁质酶基因的克隆及表达

以扁豆总RNA为模板,通过RT-PCR技术扩增到长度为885 bp的扁豆几丁质酶基因cDNA,其编码294个氨基酸,目的蛋白的分子量为28.429 kDa.以该基因构建pET-21a-chi表达载体并在E.coli BL21(DE3)中表达.30℃下,用0.1 mmol.L-1IPTG,诱导5 h,表达产物的酶活力为36.25 U.mL-1.通过常压Sephadex G-50凝胶过滤色谱,DEAE-650C常压与高效离子交换色谱对表达产物进行纯化.目标蛋白达到电泳纯(SDS电泳一条带),几丁质酶的比活力108.42 U.mg-1.表达的蛋白质产物主要以可溶性形式存在.     

HIV-1外膜蛋白原核表达载体的构建与表达

为原核表达免疫缺陷病毒(human immunodeficiency virus,HIV)外膜蛋白,对HIV-1外膜蛋白的基因进行了修饰,并利用PCR技术克隆env基因,将env基因克隆到原核表达载体中,利用大肠杆菌表达系统表达外膜蛋白,应用Western blotting检测其表达情况.结果表明:酶切鉴定证实正确地构建了pRSETB表达质粒,Western blotting和SDS-PAGE试验检测结果表明,构建后的env基因能在低温诱导的条件下表达.产物的相对分子质量为50000和33000,表达的env蛋白具有较好的免疫原性.     

大鼠再生肝8种细胞的基因转录谱预示BE115434和X76129参与凝血反应

为了解新基因BE115434和X76129与大鼠再生肝的凝血反应相关性,按张丽君[1]等方法分离大鼠再生肝8种细胞、检测它们的基因表达变化,分析新基因的序列同源性、共表达关系及参与的生理活动.结果表明,X76129与纤溶酶原激活酶基因plaur同源和共表达,BE115434与纤维蛋白活化因子抑制蛋白serpind1同源和共表达.它们的表达变化预示X76129和BE115434参与大鼠再生肝的凝血反应.     

BpMYB4基因在白桦中的遗传转化及低温胁迫应答反应

【目的】为了研究BpMYB4基因在冷胁迫反应中的功能,对其进行了白桦转化试验。【方法】采用定量PCR技术对BpMYB4基因在白桦的根、茎、叶、木质部、芽、茎段等18个组织部位的表达模式进行分析,然后克隆构建PGWB2-BpMYB4植物过表达载体,通过农杆菌介导法进行白桦合子胚的遗传转化,采用PCR和荧光定量PCR技术检测转基因白桦株系中BpMYB4基因的相对表达量,最后采用分光光度计法对BpMYB4转基因白桦进行了8项生理指标的测定。【结果】相对于芽的表达量,BpMYB4基因在第3片叶的叶脉和第1片叶与第2片叶之间嫩茎的表达量最高; 白桦的遗传转化总共获得了13个过表达株系,且BpMYB4基因已经成功整合到白桦基因组上,定量结果发现MYB-8、MYB-11、MYB-12转基因白桦中BpMYB4基因的表达量相对于非转基因对照株系(NT)上调幅度最大; 在低温胁迫下,过量表达BpMYB4基因提高了白桦的超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、花青素(OPC)含量、过氧化氢酶活性(CAT)、可溶性糖含量、可溶性蛋白含量和脯氨酸(PRO)含量,同时降低了转基因白桦的丙二醛(MDA)的含量。【结论】BpMYB4转基因白桦在低温胁迫下能够产生具有保护作用的物质,具有一定的抵抗低温的能力,因此,可以将其培育成抗冻优选株系。     

pap和ipt共表达与提高转基因烟草抗病性的初步研究

通过构建pap与ipt共表达的双元载体,利用农杆菌介导,将pap与ipt共表达基因导入烟草K326品种的叶肉细胞,经过抗性筛选和鉴定,获得高表达的转基因植株,并对其进行了攻毒实验.结果表明:pap与ipt共表达基因转化烟草的转化率明显提高(25%),证实转基因细胞中ipt基因表达可降低PAP细胞毒性;接种烟草花叶病毒(TMV)后,pap高表达的转基因植株出现病症的时间延迟20 d,叶片失绿程度较轻,表明该转基因植株对病毒的抗性有一定程度的提高.     

ARID1A对结肠癌细胞迁移的调控作用

为研究ARID1A对结肠癌细胞迁移的影响,并进一步分析ARID1A调控细胞迁移的机制,本文通过在结肠癌细胞系HCT116中过表达和干扰ARID1A基因,观察细胞迁移率的变化,通过比较HCT116与正常组织中的基因表达数据,筛选出ARID1A共表达基因,进行GO和KEGG分析.结果显示,过表达ARID1A后,细胞迁移率降低,而干扰ARID1A则与之相反.在1212个相关系数大于0.9的ARID1A共表达基因中,仅有4个基因参与细胞增殖,29个基因参与细胞迁移,涉及趋化因子信号通路、细胞因子受体相互作用等多个信号通路.以上结果说明ARID1A抑制细胞迁移,并可能通过多个信号通路调控细胞迁移.     

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