The genetic modification of the live attenuated Mycobacterium bovis BCG to deliver a protective Corynebacterium diphtheriae antigen in vivo could be a safer and less costly alternative to the new and more expensive DT...The genetic modification of the live attenuated Mycobacterium bovis BCG to deliver a protective Corynebacterium diphtheriae antigen in vivo could be a safer and less costly alternative to the new and more expensive DTP vaccines available today, in particular to third world-countries. The stability of expression of heterologous antigens in BCG, however, is a major challenge to the use of live recombinant bacteria in vaccine development and appears to be dependent to a certain extent, on a genetic compatibility between the expression cassette within the plasmid construct and the mycobacterium host. In the quest for the best recombinant BCG transformant to express the dtb gene of C. diphtheriae we generated two new rBCG strains by transforming the Moreau substrain of BCG with the mycobacterial expression vectors pUS973 and pUS977, each one carrying a different promoter to drive the expression of the target antigen. After transformation recombinant BCG clones were selected on Middlebrook 7H10 kanamycin Agar plates, expanded in Middlebrook 7H9 kanamycin Broth and analyzed by agarose gel electrophoresis and immunoblotting. rBCGs transformed with the construct carrying the weak PAN promoter from M. paratuberculosis stably expressed the dtb gene. Conversely, rBCGs transformed with the construct carrying the strong mycobacterium hsp60 promoter were unstable and consequently unfit for the expression of the C. diphtheriae gene.展开更多
BACKGROUND: Phage display technology has become a vital tool in studies aimed at identifying molecules binding to a specific target. It enables the rapid generation and selection of high affinity, fully human antibody...BACKGROUND: Phage display technology has become a vital tool in studies aimed at identifying molecules binding to a specific target. It enables the rapid generation and selection of high affinity, fully human antibody product candidates to essentially any disease target appropriate for antibody therapy. In this study, we prepared the recombinant single-chain fragment variable ( ScFv) antibody to hepatitis B virus surface antigen (HBsAg) by the phage display technology for obtaining a virus-targeting mediator. METHODS: mRNA was isolated from B-lymphocytes from a healthy volunteer and converted into cDNA. The fragment variables of heavy and light chain were amplified separately and assembled into ScFv DNA with a specially constructed DNA linker by polymerase chain reaction. The ScFv DNA was ligated into the phagmid vector pCANT-AB5E and the ligated sample was transformed into competent E. coli TG1. The transformed cells were infected with M13K07 helper phage to form a human recombinant phage antibody library. The volume and recombinant rate of the library were evaluated by bacterial colony count and restriction analysis. After two rounds of panning with HBsAg. the phage clones displaying ScFv of the antibody were selected by enzyme-linked immunosorbant assay ( ELISA) from the enriched phage clones. The antigen binding affinity of the positive clone was detected by competition ELISA. HB2151 E. coli was transfected with the positive phage clone demonstrated by competition ELISA for production of a soluble form of the anti-HBsAg ScFv. ELISA assay was used to detect the antigen binding affinity of the soluble anti-HBsAg ScFv. Finally, the relative molecular mass of soluble anti-HBsAg ScFv was measured by SDS-PAGE. RESULTS: The variable heavy ( VH ) and variable light (VL) and ScFv DNAs were about 340bp, 320bp and 750bp, respectively. The volume of the library was up to 2 × 106 and 8 of 10 random clones were recombinants. Two phage clones could strongly compete with the original HBsAb for binding to HBsAg. Within 2 strong positive phage clones, the soluble anti-HBsAg ScFv from one clone was found to have the binding activity with HBsAg. SDS-PAGE showed that the relative molecular weight of soluble anti-HBsAg ScFv was 32 kDa. CONCLUSION: The anti-HBsAg ScFv successfully produced by phage antibody technology may be useful for broadening the scope of application of the antibody.展开更多
AIM: To develop a Fok-I nested polymerase chain reaction(PCR)-restriction fragment length polymorphism analysis(PRA) method for the detection of hepatitis B virus X region(HBx) V5 M mutation.METHODS: Nested PCR was ap...AIM: To develop a Fok-I nested polymerase chain reaction(PCR)-restriction fragment length polymorphism analysis(PRA) method for the detection of hepatitis B virus X region(HBx) V5 M mutation.METHODS: Nested PCR was applied into DNAs from 198 chronic patients at 2 different stages [121 patients with hepatocellular carcinoma(HCC) and 77 carrier patients]. To identify V5 M mutants, digestion of nested PCR amplicons by the restriction enzyme Fok-I(GGA TGN9↓) was done. For size comparison, the enzymetreated products were analyzed by electrophoresis on 2.5% agarose gels, stained with ethidium bromide, and visualized on a UV transilluminator.RESULTS: The assay enabled the identification of 69 patients(sensitivity of 34.8%; 46 HCC patients and 23 carrier patients). Our data also showed that V5 M prevalence in HCC patients was significantly higher than in carrier patients(47.8%, 22/46 patients vs 0%, 0/23 patients, P < 0.001), suggesting that HBx Ag V5 M mutation may play a pivotal role in HCC generation in chronic patients with genotype C infections.CONCLUSION: The Fok-I nested PRA developed in this study is a reliable and cost-effective method to detect HBx Ag V5 M mutation in chronic patients with genotype C2 infection.展开更多
[Objective] The aim was to investigate the possibility to analyze the genetic diversity of Eriocheir sinensis and Eriocheir hepuensis by using the technique denaturing gradient gel electrophoresis（DGGE）.[Method] Mit...[Objective] The aim was to investigate the possibility to analyze the genetic diversity of Eriocheir sinensis and Eriocheir hepuensis by using the technique denaturing gradient gel electrophoresis（DGGE）.[Method] Mitochondrial cyt b gene fragment was amplified from 180 individuals of five populations of E.sinensis and a population of E.hepuensis and then analyzed by using DGGE.[Result] All PCR products showed two kinds of electrophoretic mobility on DGGE.The PCR products of all individuals from E.hepuensis showed the same mobility with that of the individuals from 46.7% of Jiangdu population,23.3% of Yizheng population and 20.0% of Wenzhou population of E.sinensis,while the rest of the individuals from the three populations of E.sinensis mentioned above as well as all the individuals of Nanjing and Panjin populations showed the same mobility,which was higher compared with that of E.hepuensis.The results indicated that there was the same genetic marker in E.sinensis populations as that of E.hepuensis population,which was consistent with previous studies.[Conclusion] DGGE technique could be used to analyze the genetic diversity of Chinese mitten crab.展开更多
目的:探讨载脂蛋白A1、B基因多态性对非创伤性股骨头坏死(avascular necrosis of the femoral head,ANFH)发生的影响。方法:应用聚合酶链反应对中国北方汉族143例ANFH患者和92例正常人分别扩增含ApoA1基因启动子-75bp和第一内含子+83bp...目的:探讨载脂蛋白A1、B基因多态性对非创伤性股骨头坏死(avascular necrosis of the femoral head,ANFH)发生的影响。方法:应用聚合酶链反应对中国北方汉族143例ANFH患者和92例正常人分别扩增含ApoA1基因启动子-75bp和第一内含子+83bp及ApoB基因EcoRI、XbaI和3'!VNTR的DNA片段,限制性内切酶酶切扩增产物,琼脂糖凝胶电泳分离基因多态性。结果:ApoA1基因启动子-75bp处,ANFH患者中A/A基因型频率明显高于正常组(P<0.01),而G/A基因型频率明显低于正常组(P<0.01)。ApoA1内含子+83bp位点,ApoB基因EcoRI、XbaI位点和3'!VNTR区域ANFH患者组和正常组基因型及等位基因频率分布无统计学差异。结论:ApoA1基因启动子区域-75bp位点A/A型可能是非创伤性股骨头坏死易感基因之一,但未能发现ApoA1第一内含子+83bp位点及ApoB基因EcoRI、XbaI和3'!VNTR位点多态性与非创伤性股骨头坏死发生有明显的关系。展开更多
基金Research supported by Bio-Manguinhos/FIOCRUZ,PAPES II/FIOCRUZ,FAPERJ,CNPq,CAPES,Programa de Núcleo de Excelencia(PRONEX/MCT/CNPq).
文摘The genetic modification of the live attenuated Mycobacterium bovis BCG to deliver a protective Corynebacterium diphtheriae antigen in vivo could be a safer and less costly alternative to the new and more expensive DTP vaccines available today, in particular to third world-countries. The stability of expression of heterologous antigens in BCG, however, is a major challenge to the use of live recombinant bacteria in vaccine development and appears to be dependent to a certain extent, on a genetic compatibility between the expression cassette within the plasmid construct and the mycobacterium host. In the quest for the best recombinant BCG transformant to express the dtb gene of C. diphtheriae we generated two new rBCG strains by transforming the Moreau substrain of BCG with the mycobacterial expression vectors pUS973 and pUS977, each one carrying a different promoter to drive the expression of the target antigen. After transformation recombinant BCG clones were selected on Middlebrook 7H10 kanamycin Agar plates, expanded in Middlebrook 7H9 kanamycin Broth and analyzed by agarose gel electrophoresis and immunoblotting. rBCGs transformed with the construct carrying the weak PAN promoter from M. paratuberculosis stably expressed the dtb gene. Conversely, rBCGs transformed with the construct carrying the strong mycobacterium hsp60 promoter were unstable and consequently unfit for the expression of the C. diphtheriae gene.
基金This study was supported by grants from the National Natural Science Foundation of China (No. 30572213)and Student Innovation Program of Shanxi Medical University (No.200404).
文摘BACKGROUND: Phage display technology has become a vital tool in studies aimed at identifying molecules binding to a specific target. It enables the rapid generation and selection of high affinity, fully human antibody product candidates to essentially any disease target appropriate for antibody therapy. In this study, we prepared the recombinant single-chain fragment variable ( ScFv) antibody to hepatitis B virus surface antigen (HBsAg) by the phage display technology for obtaining a virus-targeting mediator. METHODS: mRNA was isolated from B-lymphocytes from a healthy volunteer and converted into cDNA. The fragment variables of heavy and light chain were amplified separately and assembled into ScFv DNA with a specially constructed DNA linker by polymerase chain reaction. The ScFv DNA was ligated into the phagmid vector pCANT-AB5E and the ligated sample was transformed into competent E. coli TG1. The transformed cells were infected with M13K07 helper phage to form a human recombinant phage antibody library. The volume and recombinant rate of the library were evaluated by bacterial colony count and restriction analysis. After two rounds of panning with HBsAg. the phage clones displaying ScFv of the antibody were selected by enzyme-linked immunosorbant assay ( ELISA) from the enriched phage clones. The antigen binding affinity of the positive clone was detected by competition ELISA. HB2151 E. coli was transfected with the positive phage clone demonstrated by competition ELISA for production of a soluble form of the anti-HBsAg ScFv. ELISA assay was used to detect the antigen binding affinity of the soluble anti-HBsAg ScFv. Finally, the relative molecular mass of soluble anti-HBsAg ScFv was measured by SDS-PAGE. RESULTS: The variable heavy ( VH ) and variable light (VL) and ScFv DNAs were about 340bp, 320bp and 750bp, respectively. The volume of the library was up to 2 × 106 and 8 of 10 random clones were recombinants. Two phage clones could strongly compete with the original HBsAb for binding to HBsAg. Within 2 strong positive phage clones, the soluble anti-HBsAg ScFv from one clone was found to have the binding activity with HBsAg. SDS-PAGE showed that the relative molecular weight of soluble anti-HBsAg ScFv was 32 kDa. CONCLUSION: The anti-HBsAg ScFv successfully produced by phage antibody technology may be useful for broadening the scope of application of the antibody.
基金Supported by a National Research Foundation(NRF)of Korea grant funded by the Korean government(Ministry of EducationScience+2 种基金and TechnologyMEST)Grant No.2013-005810
文摘AIM: To develop a Fok-I nested polymerase chain reaction(PCR)-restriction fragment length polymorphism analysis(PRA) method for the detection of hepatitis B virus X region(HBx) V5 M mutation.METHODS: Nested PCR was applied into DNAs from 198 chronic patients at 2 different stages [121 patients with hepatocellular carcinoma(HCC) and 77 carrier patients]. To identify V5 M mutants, digestion of nested PCR amplicons by the restriction enzyme Fok-I(GGA TGN9↓) was done. For size comparison, the enzymetreated products were analyzed by electrophoresis on 2.5% agarose gels, stained with ethidium bromide, and visualized on a UV transilluminator.RESULTS: The assay enabled the identification of 69 patients(sensitivity of 34.8%; 46 HCC patients and 23 carrier patients). Our data also showed that V5 M prevalence in HCC patients was significantly higher than in carrier patients(47.8%, 22/46 patients vs 0%, 0/23 patients, P < 0.001), suggesting that HBx Ag V5 M mutation may play a pivotal role in HCC generation in chronic patients with genotype C infections.CONCLUSION: The Fok-I nested PRA developed in this study is a reliable and cost-effective method to detect HBx Ag V5 M mutation in chronic patients with genotype C2 infection.
基金Supported by Application Basic Research Foundation of TianjinInternational Cooperation Fund(033803511,033803511G)the Tianjin Higher Education Science and Technology Development Fund(2004BA31)~~
文摘[Objective] The aim was to investigate the possibility to analyze the genetic diversity of Eriocheir sinensis and Eriocheir hepuensis by using the technique denaturing gradient gel electrophoresis（DGGE）.[Method] Mitochondrial cyt b gene fragment was amplified from 180 individuals of five populations of E.sinensis and a population of E.hepuensis and then analyzed by using DGGE.[Result] All PCR products showed two kinds of electrophoretic mobility on DGGE.The PCR products of all individuals from E.hepuensis showed the same mobility with that of the individuals from 46.7% of Jiangdu population,23.3% of Yizheng population and 20.0% of Wenzhou population of E.sinensis,while the rest of the individuals from the three populations of E.sinensis mentioned above as well as all the individuals of Nanjing and Panjin populations showed the same mobility,which was higher compared with that of E.hepuensis.The results indicated that there was the same genetic marker in E.sinensis populations as that of E.hepuensis population,which was consistent with previous studies.[Conclusion] DGGE technique could be used to analyze the genetic diversity of Chinese mitten crab.
文摘目的:探讨载脂蛋白A1、B基因多态性对非创伤性股骨头坏死(avascular necrosis of the femoral head,ANFH)发生的影响。方法:应用聚合酶链反应对中国北方汉族143例ANFH患者和92例正常人分别扩增含ApoA1基因启动子-75bp和第一内含子+83bp及ApoB基因EcoRI、XbaI和3'!VNTR的DNA片段,限制性内切酶酶切扩增产物,琼脂糖凝胶电泳分离基因多态性。结果:ApoA1基因启动子-75bp处,ANFH患者中A/A基因型频率明显高于正常组(P<0.01),而G/A基因型频率明显低于正常组(P<0.01)。ApoA1内含子+83bp位点,ApoB基因EcoRI、XbaI位点和3'!VNTR区域ANFH患者组和正常组基因型及等位基因频率分布无统计学差异。结论:ApoA1基因启动子区域-75bp位点A/A型可能是非创伤性股骨头坏死易感基因之一,但未能发现ApoA1第一内含子+83bp位点及ApoB基因EcoRI、XbaI和3'!VNTR位点多态性与非创伤性股骨头坏死发生有明显的关系。
