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。     

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.     

脂质体转染人肝星状细胞和肝细胞条件优化

利用Lipofectamine 2000(Lipo)介导LacZ及EGFP基因转染人肝星状细胞系LX-2和人肝细胞系Chang Liver,探讨Lipo用量、质粒用量、转染时间、细胞初始接种密度及不同启动子驱动对转染效率的影响.结果显示,两种细胞均能得到高效转染,Chang Liver细胞转染效率(80%)高于LX-2细胞(60%).Lipo用量为每孔2μL,转染后6 h换液,LX-2细胞应用质粒DNA为每孔0.45μg,Chang Liver细胞应用质粒DNA为每孔0.30~0.45μg,此时转染效率最高.巨细胞病毒(CMV)启动子驱动LacZ转染效率与CMV早期增强子/鸡β肌动蛋白(CAG)启动子驱动增强型绿色荧光蛋白(EGFP)转染效率无显著差异;细胞初始接种密度对转染效率无显著影响.     

磷酸钙法将MMP-2，MMP-3双基因干扰载体转入HEK293T细胞的效率观察

检测用磷酸钙法能否将修饰后用于沉默MMP-2,MMP-3基因的慢病毒载体有效地转入到HEK293T细胞。利用磷酸钙法,MMP-2,MMP-3双基因干扰载体（MMP组）与对照质粒（对照组）被分别转染HEK293T细胞,在转染后的第24,48及72h,通过计算绿色荧光蛋白（GFP）阳性细胞数的百分比来判断转染效率。转染24h后,两组细胞均生长状况良好,荧光显微镜下观察,已有大量绿色荧光出现,计算MMP组转染效率为（91．5±6．2）％,对照组转染效率为（80．3±4．7）％;转染后48—72h,两组感染效率均未见明显下降。与对照相比,插入了MMP-2,MMP-3 shRNA模板序列的慢病毒载体没有降低磷酸钙法转染HEK293T细胞效率,反而有所增高。     

抗人PD-L1单克隆抗体的瞬转表达

利用HEK293 6E细胞瞬转表达抗人PD L1单克隆抗体. 将HEK293 6E细胞无血清悬浮培养, 筛选最佳生长培养基; 考察HEK293 6E细胞的筛选表达培养基、 DNA和PEI质量比及转染时细胞密度等转染条件, 并对收获的抗体进行SDS PAGE和ELISA鉴定. 结果表明: 在A无血清表达培养基中, 以2×106个/mL的细胞密度和m(DNA)∶m(PEI)=1的条件转染, 第4天收获抗体的产量最高, 为170.9 μg/mL; 收获PD-L1抗体的重链分子量约为50 000, 轻链分子量约为25 000.     

HEK293 PEAK瞬转快速表达抗体蛋白平台的建立

将HEK293 PEAK细胞用Gibco FreeStyleTM293表达培养液进行无血清悬浮驯化培养,获得无血清悬浮培养的HEK293 PEAK细胞,并经有限稀释法获得细胞亚克隆,建立抗体瞬转表达的工程细胞株.用转染试剂PEI将质粒转入该细胞株中表达抗体.通过优化质粒DNA与转染试剂PEI的比例,质粒与转染试剂的比例为1∶2时,转染效率最佳,并对瞬转表达抗体进行鉴定和活性分析,确认获得具有生物活性的抗体(Herceptin),抗体分子量约150 kD,结果表明已成功建立了以无血清悬浮培养的HEK293 PEAK细胞为宿主细胞的瞬转快速表达抗体蛋白平台.     

人乳头瘤病毒假病毒制备方法的优化

人乳头瘤病毒假病毒可广泛应用于中和抗体鉴定和疫苗免疫性评估等研究.本研究对多质粒共转染293FT细胞生产HPV假病毒的方法进行了深入优化,结果显示不同的HPV结构蛋白表达质粒转染比例对于假病毒生产效率有显著的影响,HPV主要结构蛋白L1的表达水平是影响生产效率的主要因素,L2表达质粒的用量过高或过低均不利于假病毒的生产,而报告质粒的用量对假病毒生产效率的影响相对较小.综合比较显示,在该体系中L1和L2表达质粒和报告质粒以合适比例(如1:1/10:1/2)进行共转染可获得更为理想的生产效率.本研究同时也在293FT细胞中对磷酸钙转染方法进行了优化,通过磷酸钙与质粒用量的交叉配比试验获得了较优的转染条件.通过优化,建立了更为高效的HPV假病毒大量制备方法,在HPV16、HPV18、HPV6、HPV11假病毒生产中的应用结果显示较原方法可显著提高生产效率.本研究为HPV假病毒中和实验的规模化应用提供了有利条件.     

构建逆转录病毒PBabepuro-Bcl-2表达质粒及稳定转染细胞株

目的:构建pBabepuro-Bcl-2逆转录病毒表达质粒,鉴定表达,在小鼠胚胎成纤维细胞NIH3T3中建立过表达Bcl-2稳定转染细胞。方法:以人上皮细胞的cDNA为模板,利用X-tremeGENE HP(Roche)转染293T细胞,蛋白质免疫印迹法在蛋白水平检测表达,利用逆转录病毒感染NIH3T3细胞。结果:成功构建了逆转录病毒表达质粒pBabepuro-BCl-2,蛋白水平检测证实其在293T细胞可以有效地表达,成功建立了过表达Bcl-2的NIH3T3稳定转染细胞。结论:通过构建pBabepuro表达质粒及在NIH3T3建立过表达Bcl-2稳定转染细胞,为进一步研究Bcl-2的功能调控奠定了基础。     

293T细胞转染表达ARG1及其对砷代谢的影响

研究含有ARGI基因的真核表达载体PcDNA3.1-IE-ARG1转染真核细胞后,在细胞中的表达及对细胞砷代谢的影响。由脂质体介导将PcDNA3.1-IE-ARG1转染入293T中,用real-timePCR方法检测ARG1基因的表达,用原子吸收分光光度法测定24h砷染毒后细胞内砷含量及细胞排砷量。重组质粒成功转入293T细胞中且表达良好;与转染前细胞比较,转染重组质粒的细胞在不同浓度砷染毒下细胞内砷含量明显降低(P0.05),并且细胞的排砷量也高于转染前的;此外,转染表达ARGI基因的细胞在砷染毒48h后其内GSH及GST的含量高于转染前细胞。这些表明,ARG1基因在真核细胞中相对高表达后在砷代谢排出中发挥了一定的作用。     

PEI介导pCEP4/EGFP瞬时转染293-F细胞条件优化

为构建真核表达载体pCEP4/EGFP,PEI介导瞬时转染293-F细胞,观察转染效率,优化转染条件.通过NotI和Hind III酶切位点将增强型绿色荧光蛋白基因(EGFP)插入真核表达载体p CEP4中,并转化Trans5α感受态细胞,氨苄青霉素筛选培养,挑取阳性克隆扩增后提取质粒,酶切鉴定正确后,PEI介导转染293-F细胞,流式细胞仪检测转染效率.实验结果表明,成功构建了真核表达载体pCEP4/EGFP,当N/P(PEI/DNA)为25,悬浮培养模式下转染293-F细胞,48 h转染效率为77.57%,重组载体p CEP4瞬时转染293-F细胞,可获得理想转染效果.     

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.     

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…     

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     

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.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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。     

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.     

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