The cloning of non-structural-1 (NS1) gene of H9N2 subtype of avian influenza virus in pGEX-4T-1 and pMAL-c2X plasmids and expression in <i>Escherichia coli</i>DH5<i>α</i>strain

Avian influenza is a viral contagious disease that affects poultry industry and human health. Vaccination has been considered as a preventive tool in the eradication of AI, but it causes some limitations including trade embargoes and interfering with serologic surveillance in differentiation between infected and vaccinated animals (DIVA strategy). Several distinct DIVA strategies have been presented to conquer these limitations. In this study, the open reading frame of NS1 gene of a H9N2 subtype of AI virus was amplified by polymerase chain reaction. After extraction and purification of NS1 gene from agarose gel, it was inserted into two different pGEX-4T-1 and pMAL-c2X plasmids and transferred in DH5α strain of Escherichia coli by using electroporation procedure. The E. coli colonies possessing recombinant NS1 gene were screened using PCR, restriction mapping and sequencing analysis. The expressed rNS1 protein was purified using affinity chromatography based on MBP (pMAL- c2X) and GST (pGEX-4T-1). The MBP-NS1 and GST- NS1 proteins on SDS-PAGE had bands with molecular weight of 68 and 52 kDa respectively. Western blotting with MBP-NS1 protein showed positive reaction using antisera obtained from chickens challenged with a H9N2 subtype strain. But, the most sera prepared from H9N2 vaccinated chickens were negative in WB. These findings indicated that the MBP-rNS1 protein of 26 kDa expressed by pMAL-c2X plasmid can be used in a DIVA for differentiation of AI infected and vaccinated chickens.

Construction and expression of a synthetic gene encoding nonstructural glycoprotein NS1 of dengue 2 virus in Pichia pastoris

To express and characterize NS1 of Indonesian-specific DENV2 virus in Pichia pastoris (P. pastoris).MethodsA codon optimized synthetic gene derived from the DENV-2 NS1 amino acid sequences was synthesized commercially and inserted into the P. pastoris pPICZαA expression vector. The recombinant DENV-2 NS1 protein was purified by Ni-NTA affinity chromatography, and its antigenicity was tested.ResultsThe recombinant DENV-2 NS1 protein was secreted as a protein with a molecular weight of ∼45 kDa, and the optimal expression condition was achieved by induction with 2% (v/v) methanol for 72 h. The purified recombinant DENV-2 NS1 protein was able to interact with a monoclonal antibody of NS1 in a commercial rapid test.ConclusionsThe resulting recombinant DENV-2 NS1 protein produced in P. pastoris KM71 is a potential candidate for use in the development of a dengue diagnostic kit and vaccine.

The Study on The Immune Response Induced by Expressing Recombinant Plasmid of Dengue Virus Type 2 NS3 Protein

The PSV?NS3, an expressing recombinant plasmid of dengue virus type 2 NS3 protein, was injected directly into the quadriceps of Balb/C mice to explore whether it could inducing immune response. The splenic T cell subsets of two groups was analysed by flow cytometry. It was found that the percentage of CD4+ and CD8+ T cells of experimental group were significantly higher than those of the control group. The titer of IgG antibody was as high as 1∶5 120 in experimental group, but it couldn’t be detected in control group by ELISA. The western blot further proved that the IgG antibody was specific for NS3 protein. Those results Suggested that inoculation Balb/C mice with PSV?NS3 could inducing immune response, and the NS3 protein might be used as the candidate protein of DNA vaccine of dengue virus.

环氧合酶-2选择性抑制剂NS-398诱导人肝癌BEL-7402细胞凋亡及其机制探讨

目的:探讨环氧合酶-2(cyclooxygenase-2,COX-2)选择性抑制剂NS-398对人肝癌BEL-7402细胞凋亡及凋亡抑制蛋白survivin、XIAP和c-IAP1表达的调节作用。方法:用不同浓度的NS-398作用BEL-7402细胞后,MTT法测定细胞增殖抑制情况,FCM法和TUNEL法检测细胞凋亡情况,免疫细胞化学法检测COX-2、survivin、XIAP和c-IAP1蛋白的表达情况。结果:NS-398可以显著抑制BEL-7402细胞的增殖,诱导其凋亡。免疫细胞化学法检测结果显示,与未处理组相比,NS-398作用可使BEL-7402细胞中COX-2、survivin、XIAP和c-IAP1蛋白的表达明显下调(P<0.01)。结论:NS-398对人肝癌细胞株BEL-7402有抑制细胞增殖和诱导细胞凋亡的作用,其机制可能与通过下调survivin、XIAP和c-IAP1的表达有关。

登革病毒2型非结构蛋白NS2B的原核表达、纯化及其抗体的制备

目的原核表达登革病毒(Dengue Virus,DV)NS2B蛋白并纯化,制备NS2B的小鼠多克隆抗体。方法RT-PCR扩增DV2全长的NS2B基因序列,构建表达带有6×His标签的NS2B的原核表达载体,进行表达与纯化,免疫Balb/c小鼠,制备NS2B多克隆抗体。采用ELISA检测抗体效价,Western-blot及免疫荧光染色检测其特异性。结果成功构建原核表达载体pQE-31/NS2B,进一步获得相对分子质量为16000的纯化蛋白及多克隆抗体,ELISA显示抗体效价达1∶25600。Western-blot和免疫荧光染色显示多克隆抗体与NS2B蛋白特异性结合。结论本研究获得了纯化的DV2NS2B蛋白,成功地制备了NS2B多克隆抗体,为进一步研究NS2B的作用机制奠定了基础。

三齿NS_2型配体Cu(Ⅱ)配合物的合成、光谱性质及电化学性质

蓝铜蛋白具有特征的光谱性质和异常的电化学性质因而受到人们的广泛重视［１，２］。为了阐述其结构与性质之间的关系，科学家们研究了一系列模型化合物，并且已取得了某些公认的结论［１］。然而，只有很少的配合物模拟了蓝铜蛋白ＥＳＲ谱中较小的超精细裂分Ａ‖值（３０...

S-adenosyl-L-methionine modifies antioxidant-enzymes,glutathione-biosynthesis and methionine adenosyltransferases-1/2 in hepatitis C virus-expressing cells

AIM: To elucidate the mechanism(s) by which S-adenosyl-L-methionine(SAM) decreases hepatitis C virus(HCV) expression.METHODS: We examined the effects of SAM on viral expression using an HCV subgenomic replicon cell culture system. Huh7 HCV-replicon cells were treated with 1 mmol/L SAM for different times(24-72 h), then total RNA and proteins were isolated. c DNA was synthesized and real time-PCR was achieved to quantify HCV-RNA, superoxide dismutase 1 and 2(SOD-1, SOD-2) catalase, thioredoxin 1, methionine adenosyltransferase 1A and 2A(MAT1A, MAT2A) expression, and GAPDH and RPS18 as endogenous genes. Expression of cellular and viral protein was evaluated by western-blot analysis using antibodies vs HCV-NS5 A, SOD-1, SOD-2, catalase, thioredoxin-1, MAT1 A, MAT2 A, GAPDH and actin. Total glutathione levels were measured at different times by Ellman's recycling method(0-24 h). Reactive oxidative species(ROS) levels were quantified by the dichlorofluorescein assay(0-48 h); Pyrrolidin dithiocarbamate(PDTC) was tested as an antioxidant control and H2O2 as a positive oxidant agent.RESULTS: SAM exposition decreased HCV-RNA levels 50%-70% compared to non-treated controls(24-72 h). SAM induced a synergic antiviral effect with standard IFN treatment but it was independent of IFN signaling. In addition, 1 mmol/L SAM exposition did not modify viral RNA stability, but it needs cellular translation machinery in order to decrease HCV expression. Total glutathione levels increased upon SAM treatment in HCV-replicon cells. Transcriptional antioxidant enzyme expression(SOD-1, SOD-2 and thioredoxin-1) was increased at different times but interestingly, there was no significant change in ROS levels upon SAM treatment, contrary to what was detected with PDTC treatment, where an average 40% reduction was observed in exposed cells. There was a turnover from MAT1A/MAT2 A, since MAT1 A expression was increased(2.5 fold-times at 48 h) and MAT2 A was diminished(from 24 h) upon SAM treatment at both the transcriptional and translational level. CONCLUSION: A likely mechanism(s) by which SAM diminish HCV expression could involve modulating antioxidant enzymes, restoring biosynthesis of glutathione and switching MAT1/MAT2 turnover in HCV expressing cells.

Cyclin E、CDK_2和p21^(WAF1)在食管上皮癌变过程中的表达及意义

目的 探讨食管上皮癌变过程中细胞周期调控因子cyclin E、CDK2和p21WAF1的表达状况及其意义。方法 应用免疫组化SP法和原位杂交方法分别检测48例食管癌组织、31例非典型增生组织和17例正常食管粘膜中cyclin E、CDK2和p21WAF1蛋白及mRNA表达。应用半定量RT PCR和Western blot检测22例新鲜食管癌及相应癌旁组织的mRNA和蛋白表达。结果 从食管正常粘膜、非典型增生组织到癌组织,cyclin E和CDK2蛋白和mRNA阳性表达率逐渐上升,差异具有统计学意义(P<0.01或P<0.05)。食管癌组织中cyclin E、CDK2和p21WAF1蛋白及mRNA高表达,与癌旁组织或切缘正常食管粘膜有显著性差异(P<0.01)。cyclin E、CDK2和p21WAF1 基因表达显著正相关(P<0.01 或P<0.05)。结论 食管上皮癌变过程中,细胞周期相关基因cyclin E和CDK2表达逐渐增强。cyclin E基因表达异常是食管癌变过程中的早期事件。p21WAF1 基因在食管癌中高表达,可能与细胞周期调控的反馈机制有关。

Nucleostemin siRNA对肝癌细胞HepG2增殖的影响

Nucleostemin(NS)作为核仁蛋白,在神经干细胞、胚胎干细胞以及某些肿瘤细胞中均高表达,在多种肿瘤细胞增殖和凋亡调控中具有重要作用.本文通过瞬时转染NS siRNA降低NS的表达,以探究NS对HepG2细胞增殖和凋亡的影响.结果显示,下调NS表达使HepG2细胞增殖加快,G1期细胞减少,S期及G2/M期细胞增加,凋亡减少.激光共聚焦实验表明,NS与S期激酶相关蛋白2(S-phase kinase-associated protein 2,Skp2)在HepG2细胞中存在共定位现象;Co-IP实验证明,NS与Skp2能相互作用;NS下调后,Skp2出核仁的数量增加,p27和p53表达降低.总之,下调NS可促进HepG2细胞中Skp2从核仁逸出,p27降解增强,同时p53表达下降,或由此促进HepG2细胞增殖,抑制其凋亡.

Analysis of molecular variation in porcine reproductive and respiratory syndrome virus in China between 2007 and 2012

In the present study, 89 porcine reproductive and respiratory syndrome virus(PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics of these isolates were analyzed based on the sequences of non-struc-tural protein 2(Nsp2) and glycoprotein 5(GP5). The genetic variations of the isolates were also compared with six representative strains. The results showed that a high degree of genetic diversity exists among the PRRSV population in China. Highly pathogenic PRRSV isolates, with a discon-tinuous deletion of a 30 amino acid residue in the Nsp2 region, remained the most dominant virus throughout 2007–2012 in China. Owing to the extensive use of representative vaccine strains, natu-ral recombination events occurred between strains. Three isolates – HH08, DY, and YN-2011 – were more closely related to vaccine strains than the other isolates. Both YN-2011 and DY were the evolu-tionary products of recombination events between strains SP and CH-1R. The results of the present study provide useful information for the epidemiology of PRRSV as well as for vaccine development.

Variation analysis of the severe acute respiratory syndrome coronavirus putative non-structural protein 2 gene and construction of three-dimensional model

Background The rapid transmission and high mortality rate made severe acute respiratory syndrome (SARS) a global threat for which no efficacious therapy is available now. Without sufficient knowledge about the SARS coronavirus (SARS-CoV), it is impossible to define the candidate for the anti-SARS targets. The putative non-structural protein 2 (nsp2) (3CL pro , following the nomenclature by Gao et al, also known as nsp5 in Snidjer et al) of SARS-CoV plays an important role in viral transcription and replication, and is an attractive target for anti-SARS drug development, so we carried on this study to have an insight into putative polymerase nsp2 of SARS-CoV Guangdong (GD) strain. Methods The SARS-CoV strain was isolated from a SARS patient in Guangdong, China, and cultured in Vero E6 cells. The nsp2 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and cloned into eukaryotic expression vector pCI-neo (pCI-neo/nsp2). Then the recombinant eukaryotic expression vector pCI-neo/nsp2 was transfected into COS-7 cells using lipofectin reagent to express the nsp2 protein. The expressive protein of SARS-CoV nsp2 was analyzed by 7% sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). The nucleotide sequence and protein sequence of GD nsp2 were compared with that of other SARS-CoV strains by nucleotide-nucleotide basic local alignment search tool (BLASTN) and protein-protein basic local alignment search tool (BLASTP) to investigate its variance trend during the transmission. The secondary structure of GD strain and that of other strains were predicted by Garnier-Osguthorpe-Robson (GOR) Secondary Structure Prediction. Three-dimensional-PSSM Protein Fold Recognition (Threading) Server was employed to construct the three-dimensional model of the nsp2 protein.Results The putative polymerase nsp2 gene of GD strain was amplified by RT-PCR. The eukaryotic expression vector (pCI-neo/nsp2) was constructed and expressed the protein in COS-7 cells successfully. The result of sequencing and sequence comparison with other SARS-CoV strains showed that nsp2 gene was relatively conservative during the transmission and total five base sites mutated in about 100 strains investigated, three of which in the early and middle phases caused synonymous mutation, and another two base sites variation in the late phase resulted in the amino acid substitutions and secondary structure changes. The three-dimensional structure of the nsp2 protein was successfully constructed. Conclusions The results suggest that polymerase nsp2 is relatively stable during the phase of epidemic. The amino acid and secondary structure change may be important for viral infection. The fact that majority of single nucleotide variations (SNVs) are predicted to cause synonymous, as well as the result of low mutation rate of nsp2 gene in the epidemic variations, indicates that the nsp2 is conservative and could be a target for anti-SARS drugs. The three-dimensional structure result indicates that the nsp2 protein of GD strain is high homologous with 3CL pro of SARS-CoV urbani strain, 3CL pro of transmissible gastroenteritis virus and 3CL pro of human coronavirus 229E strain, which further suggests that nsp2 protein of GD strain possesses the activity of 3CL pro .

Structural Basis for Complementary and Alternative Medicine:Phytochemical Interaction with Non-Structural Protein 2 Protease-A Reverse Engineering Strategy

Objective： To understand the druggability of the bioactive compounds from traditional herbal formulations ＂Nilavembu Kudineer＂ and ＂Swasthya Raksha Amruta Peya＂ to heal chikungunya virus （CHIKV） infection. Methods： The efficiency of twenty novel chemical entities from ＂Nilavembu Kudineer＂ and ＂Swasthya Raksha Amruta Peya＂ to inhibit CHIKV infection in silico were evaluated. Ligands were prepared using Ligprep module of Schr0dinger. Active site was identified using SiteMap program. Grid box was generated using receptor grid generation wizard. Molecular docking was carried out using Grid Based Ligand Docking with Energetics （GLIDE） program. Results： Molecular docking studies showed that among twenty compounds, andrographoside, deoxyandrographoside, neoandrographolide, 14-deoxy-11-oxoandrographolide, butoxone and oleanolic acid showed GLIDE extra precision （XP） score of-9.10,-8.72, -8.25,-7.38,-7.28 and -7.01, respectively which were greater than or comparable with chloroquine （reference compound） XP score （-7.08） and were found to interact with the key residues GLLI 1043, LYS 1045, GLY 1176, LEU 1203, HIS 1222 and LYS 1239 which were characteristic functional unit crucial for replication of CHIKV. Conclusion： The binding affinity and the binding mode of chemical entities taken from herbal formulations with non-structural protein 2 protease were understood and our study provided a novel strategy in the development and design of drugs for CHIKV infection.

Nsp2 and GP5-M of Porcine Reproductive and Respiratory Syndrome Virus Contribute to Targets for Neutralizing Antibodies

Porcine reproductive and respiratory syndrome virus(PRRSV)is characterized by its genetic variation and limited cross protection among heterologous strains.Even though several viral structural proteins have been regarded as inducers of neutralizing antibodies(NAs)against PRRSV,the mechanism underlying limited cross-neutralization among heterologous strains is still controversial.In the present study,examinations of NA cross reaction between a highly pathogenic PRRSV(HP-PRRSV)strain,JXwn06,and a low pathogenic PRRSV(LP-PRRSV)strain,HB-1/3.9,were conducted with viral neutralization assays in MARC-145 cells.None of the JXwn06-hyperimmuned pigs’sera could neutralize HB-1/3.9 in vitro and vice versa.To address the genetic variation between these two viruses that are associated with limited crossneutralization,chimeric viruses with coding regions swapped between these two strains were constructed.Viral neutralization assays indicated that variations in nonstructural protein 2(nsp2)and structural proteins together contribute to weak cross-neutralization activity between JXwn06 and HB-1/3.9.Furthermore,we substituted the nsp2-,glycoprotein2(GP2)-,GP3-,and GP4-coding regions together,or nsp2-,GP5-,and membrane(M)protein-coding regions simultaneously between these two viruses to construct chimeric viruses to test cross-neutralization reactivity with hyperimmunized sera induced by their parental viruses.The results indicated that the swapped nsp2 and GP5-M viruses increased the neutralization reactivity with the donor strain antisera in MARC-145 cells.Taken together,these results show that variations in nsp2 and GP5-M correlate with the limited neutralization reactivity between the heterologous strains HP-PRRSV JXwn06 and LP-PRRSV HB-1/3.9.