HEK293F细胞瞬时表达PDGFR-β/Fc蛋白的条件优化

为优化HEK293F细胞瞬时转染条件,提高PDGFR-β的蛋白表达量,采用聚乙烯亚胺(Polyetherimide,PEI)为转染试剂,将质粒p XLG-PDGFR-β/Fc与PEI混匀聚合后加入到细胞悬液,37℃,φ=6%CO2,180 r/min悬浮振荡培养,培养7 d后收集样品,ELISA检测PDGFR-β蛋白的浓度。对细胞密度、DNA浓度和m(DNA):m(PEI)、聚合时间以及添加物(丙戊酸钠、葡萄糖和蛋白胨)进行优化。结果显示,HEK293F细胞瞬时转染的最佳条件为:细胞密度4×106cells/m L、DNA浓度2.0μg/106cells、m(DNA):m(PEI)为1:2、聚合时间5 min。同时,48 h内添加3 mmol/L丙戊酸钠,第3天补加葡萄糖和1 g/L的蛋白胨TN1可使PDGFR-β/Fc的蛋白表达量明显提高。实验表明,经过对HEK293F细胞瞬时表达PDGFR-β的转染条件的优化,蛋白表达量可达55 mg/L,为更大规模瞬时转染生产PDGFR-β/Fc蛋白奠定了基础。     

大鼠谷氨酰胺转运蛋白EGFP-SNAT3融合蛋白的表达与鉴定

SLC38基因家族编码的Na+偶联的中性氨基酸转运蛋白3(SNAT3)是System N中的一员.它在大脑谷氨酸-谷氨酰胺循环以及肝细胞质膜的谷氨酰胺转运等生理过程中发挥着重要作用.为了方便检测SNAT3在细胞膜上的表达与定位,本研究采用PCR扩增和酶切连接技术将增强型绿色荧光蛋白(EGFP)与SNAT3的N末端连接,通过菌液PCR、酶切和DNA测序验证得到pBK-CMV(Δ[1098-1300])-EGFP-SNAT3重组真核表达质粒.用脂质体转染法将构建好的质粒瞬时转染进入人体胚肾细胞(HEK293T cells),利用激光扫描共聚焦显微镜和Western blot技术检测EGFP-SNAT3融合蛋白的表达和亚细胞定位.结果表明,EGFPSNAT3重组质粒在细胞中正确表达并定位于细胞膜上.EGFP-SNAT3重组质粒的成功构建将有助于日后进一步研究SNAT3的结构和功能.     

重组人凝血因子Ⅶ在HEK293细胞中的瞬时表达

[目的]在HEK293细胞中表达人凝血因子Ⅶ(human coagulation factor,hFⅦ)蛋白。[方法]通过PCR分别扩增与hFⅦ羧基化有关的酶(γ-谷氨酰基羧化酶(GGCX)和维生素K环氧化物还原酶复合体亚单位1(VKORC1))基因序列,与hFⅦ基因片段构建真核表达载体p CAEVKORC1-GGCX-hFⅦ,利用脂质体将表达载体转入HEK293细胞,采用Western blotting和ELISA方法检测细胞上清中hFⅦ的表达水平,凝血因子Ⅶ检测试剂盒测定hFⅦ的促凝血活性。[结果]Western blotting检测细胞上清中含有hFⅦ蛋白,经ELISA检测表达量为12 mg/L,凝血因子Ⅶ检测试剂盒测定hFⅦ的促凝血相对比活性为612%。[结论]该表达载体成功在HEK293细胞中瞬时表达hFⅦ蛋白,为进一步深入研究hFⅦ的生物学特性奠定了基础。     

LC3真核表达载体构建及其在293T细胞中自噬诱导研究

【目的】构建pEGFP-N1-LC3真核表达载体,并将其转染进人胚肾细胞293T,通过Earle's盐平衡液(Balanced salt solution,EBSS)饥饿诱导观察细胞自噬现象。【方法】RT-PCR扩增LC3基因,并将其插入pEGFP-N1真核表达载体构建重组质粒。将重组质粒转染至人胚肾细胞293T,显微镜观察、Western blot检测GFP-LC3融合蛋白表达情况。对转染细胞进行Earle's盐平衡液饥饿诱导,通过Western blot验证自噬指标,激光共聚焦显微镜观察自噬泡形成。【结果】成功构建pEGFP-N1-LC3真核表达载体,并在293T细胞中成功表达目的蛋白,在进行Earle's盐平衡液饥饿诱导后观察到自噬泡的形成,Western blot检测到LC3-Ⅰ向LC3-Ⅱ的转化。【结论】本实验为研究自噬在癌细胞病理进程中的机制提供了实验素材。     

HIV-1病毒样颗粒真核表达系统的建立

目的 利用哺乳动物细胞表达HIV-1病毒样颗粒,为HIV-1病毒的生物学研究和进一步设计HIV-1中和优势表位预防性疫苗奠定基础.方法 以293T细胞作为宿主细胞,利用磷酸钙沉淀法将带有HIV-1病毒被膜蛋白gp160基因的pcDNA3.1/BaL gp160真核表达载体和带有HIV-1核心蛋白(gag)的pVRC3900真核表达载体共转染至293T细胞中,收集培养上清,经蔗糖不连续梯度离心,收集病毒样颗粒,经磷钨酸负染,透射电镜观察结果 .结果 以磷酸钙沉淀DNA转移技术,EGFP真核表达质粒为靶基因,293T细胞为宿主细胞,最佳转染效率达30%以上;将peDt NA3.1/BaL gp160(env)和pVRC3900(gag)真核表达质粒共转染,宿主细胞成功表达目的 蛋白,转染细胞培养上清经蔗糖密度梯度离心,电镜观察可见自行装配的HIV病毒样颗粒.结论 在真核细胞中表达HIV-1病毒样颗粒.     

靶向树突状细胞的呼吸道合胞病毒F重组蛋白的构建与体外活性分析

分析以人呼吸道合胞病毒(Human respiratory syncytial virus,RSV)融合糖蛋白(fusion glycoprotein,F)为抗原靶向DEC205/CD205受体策略对重组F蛋白表达及活性的影响.F蛋白是RSV的重要中和抗原,克隆RSV F蛋白胞外区的编码基因至可识别鼠树突状细胞(Dendritic cells,DCs)DEC205受体的单链抗体(single chain antibody of anti-DEC205,scDEC)的C端,构建可表达重组F蛋白(scDECF)的质粒pVAX1/scDECF,Western blot方法检测scDECF的表达,免疫荧光法和流式细胞术检测表达的scDECF与DEC205受体的结合活性.经Western blot证实在pVAX1/scDECF转染的293T细胞成功表达了scDECF.将所获得的细胞培养上清与表达鼠DEC205受体的细胞CHOmDEC205孵育,用免疫荧光和流式细胞术证实:与作为对照的重组F蛋白scISOF相比,所获得的scDECF与CHOmDEC205细胞呈现明显的结合.本研究成功表达了重组蛋白scDECF,且所获得的重组蛋白scDECF具有与表达DEC205受体的细胞特异性结合的活性.     

大鼠中性氨基酸转运蛋白HA-SNAT3融合蛋白的构建和鉴定(英文)

钠离子依赖的中性氨基酸转运蛋白SNAT3是SLC38基因家族N系统的成员之一,主要在脑部和视网膜的星形胶质细胞中表达,负责转运谷氨酰胺,在脑部和肝脏的谷氨酸-谷氨酰胺循环中发挥重要作用.为了方便检测SNAT3在细胞膜上的表达和定位,本研究采用PCR扩增和酶切连接的方法将HA标签连接到质粒pBK-CMVΔ(1098-1300)-SNAT3中大鼠SNAT3的N端,构建了真核生物表达载体pBK-CMVΔ-SNAT3.用脂质体转染法将该表达载体瞬时转染进人胚肾细胞(HEK293T cells),通过Western blotting检测HA-SNAT3融合蛋白的表达.结果表明,HA-SNAT3能够正确在细胞膜上表达.pBK-CMVΔ-SNAT3表达载体的成功构建对于进一步研究SNAT3的结构和功能提供了有效方法.     

LMP3-EGFP融合蛋白真核表达载体的构建及其在HEK293细胞中的表达

为构建人LMP3-EGFP融合蛋白真核表达载体,并检测其在HEK293细胞中的表达及定位,通过基因重组的方法构建LMP3／pEGFP-N3重组真核表达载体,并通过酶切和基因测序鉴定。脂质体法转染HEK293细胞,用倒置荧光显微镜检测、分析其在HEK293细胞表达及定位。经酶切和基因测序鉴定LMP3／pEGFP-N3重组真核表达载体构建成功。转染HEK293细胞后,荧光显微镜检测显示融合蛋白仅在细胞浆中表达。说明基因重组技术可成功构建LMP3／pEGFP-N3重组体真核表达载体,重组表达的融合蛋白仅存在于细胞浆内。     

表达大鼠FoxA1的慢病毒制备和鉴定

通过PCR扩增获得大鼠FoxA1的cDNA,构建慢病毒重组载体plv-rFoxA1-IRES-EGFP,并瞬时转染293T细胞观察绿色荧光蛋白(GFP)的表达及Western blot检测FoxA1的表达.通过钙转将该重组载体与辅助质粒△8.91,pVSV-G共转染293T细胞制备慢病毒.研究结果表明,大鼠FoxA1慢病毒质粒成功构建,并且证实所制备的慢病毒能感染细胞,使细胞有效表达FoxA1蛋白,为FoxA1的功能研究奠定了材料基础.     

脑心肌炎病毒pCMV-HA-VP2表达载体的构建及在HEK293细胞中的表达

目的:构建脑心肌炎病毒(Encephalomyocarditis Virus,EMCV)衣壳蛋白VP2基因的真核表达载体pCMV-HA-VP2,并在HEK293细胞中表达.方法:提取EMCV的总RNA,RT-PCR扩增VP2基因,酶切后构建带HA标签的真核表达质粒pCMV-HA-VP2,运用脂质体介导法将其转染至HEK293细胞中,分别进行过表达检测、Westernblotting分析及IFA检测来验证VP2基因的转录及表达情况.结果:重组表达载体pCMV-HA-VP2构建成功,转染至HEK293细胞中,VP2蛋白和HA标签融合表达成功.结论:EMCV衣壳蛋白VP2基因的真核表达载体pCMV-HA-VP2在HEK293细胞中的成功表达,为EMCV衣壳蛋白的功能研究提供理想的实验材料,同时也为EMCV感染机制及其受体研究奠定基础.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the