阴道毛滴虫铁氧还蛋白基因真核表达质粒的构建

作者用螯合树脂(Chelex-100)提取阴道毛滴虫基因组DNA,PCR扩增出阴道毛滴虫铁氧还蛋白(ferredoxin,Fd)基因,克隆入pMD-18T载体,亚克隆至pcDNA3.1(+)真核表达质粒。经PCR及酶切鉴定,Fd基因体外扩增产物为306bp,与已知序列吻合。成功构建了Fd基因的真核表达质粒。     

重组超抗原金黄色葡萄球菌肠毒素B基因的克隆和序列分析

目的　采用基因工程技术制备金黄色葡萄球菌B型肠毒素 (SEB)。方法　根据SEB已知序列 ,设计一对引物 ,用PCR方法从金黄色葡萄球菌染色体DNA上扩增出基因片段 ,克隆到原核表达质粒 pET32a上 ,转化大肠埃希菌JM10 9感受态细胞 ,经酶切和PCR鉴定 ,然后进行测序。结果　PCR扩增产物大小为 74 0bp ,重组质粒经双酶切PCR鉴定表明已正确重组 ,测序结果与已知序列基本吻合。结论　成功地克隆了金黄色葡萄球菌B型肠毒素 ,为下一步研究发病机制奠定基础。     

副溶血弧菌tlh基因的克隆及序列分析

目的　构建副溶血弧菌不耐热性溶血毒素 (thermolabilehemolysin ,TLH)tlh基因重组质粒。方法　根据已知GenBank中的tlh基因序列 ,设计合成一对引物 ,用PCR方法从副溶血弧菌基因组DNA中扩增编码TLH的基因片段 ,克隆至pET32a+ 质粒 ,转化大肠杆菌DH5感受态细胞 ,经酶切及PCR鉴定 ,而后进行测序。结果　tlh基因体外扩增产物大小约1 30 0bp ,重组质粒经酶切及PCR鉴定表明获得正确重组子 ,测序结果与已知序列基本吻合。 结论　在国内首次克隆了副溶血弧菌tlh基因 ,为研究TLH的功能和探讨TLH作为作为特异性诊断靶抗原的研究奠定了基础     

阴道毛滴虫ap33基因克隆及其表达载体的构建

目的 研究阴道毛滴虫粘附蛋白AP33的基因结构特点并构建其表达载体。方法 提取阴道毛滴虫mRNA,逆转录合成cDNA,PCR得到阳性克隆,将其亚克隆到pLICm-T载体中进行PCR、酶切及测序分析,并与CenBank中核苷酸序列进行同源性分析。再将亚克隆与表达载体分别酶切并连接。结果 阳性克隆经酶切鉴定,目的基因片段长度为927bp,,ap33与国外已报道的3株T.vaginalis的ap33基因分别具99％、97％、94％的同源性。结论 成功克隆出阴道毛滴虫ap33基因序列,与已公布的ap33序列有很高的同源性。构建获得PET-32a(+)-ap33重组质粒,可在原核中进一步表达特异性蛋白。     

乙型肝炎病毒S基因的克隆

目的:对乙型肝炎病毒S基因进行克隆。方法:依据S基因两侧序列设计引物并引入酶切位点;聚合酶链式反应(PCR)扩增目的基因;对PCR产物和载体质粒pCMV-tag2B分别作EcoRⅠ和HindⅢ双酶切后,T4连接酶连接;将连接产物转化为大肠杆菌DH5α;增菌培养后提取重组质粒;对重组质粒作PCR、酶切及测序鉴定。结果:PCR扩增出目的基因片段;目的片段与载体连接后成功;获得含重组质粒的DH5α阳性克隆;经鉴定和测序,重组质粒含有完整正确的S基因序列。结论:成功构建了S基因的克隆载体,获得大量S基因片段,为研究S基因对HBsAg检测的影响奠定了基础。     

苏云金杆菌cryIVD基因的克隆及序列分析

目的　克隆苏云金杆菌 ( B.t.i) cry IVD基因并测定其序列。　方法　根据 B.t.i cry IVD已知序列 ,设计合成 1对引物 ,应用 PCR技术扩增 cry IVD基因 ,克隆入 p UC18载体 ,阳性克隆的重组质粒经酶切、电泳鉴定后进行序列测定。　结果　 PCR扩增得到特异的 2 .0 kb基因片段。重组质粒经酶切后得到预期大小的基因片段。序列分析证明目的基因被完整且正向克隆。　结论　 B.t.i cry IVD基因被成功克隆。     

苏云金芽孢杆菌以色列亚种毒性蛋白基因的克隆及其原核表达

目的从苏云金芽孢杆菌（Bacillus thuringiensis,Bti）以色列亚种中获得cry4B、cry11A和cyt1A3种主要杀蚊幼虫蛋白的基因,并进行克隆和原核表达。方法根据GenBank上3种基因的已知序列设计合成引物,应用PCR技术扩增目的基因,克隆入pUC19质粒,阳性克隆质粒经酶切和测序鉴定。将测序鉴定的3种蛋白基因克隆入原核表达载体（pET32c）进行原核表达。结果PCR扩增获得特异性的基因片段,重组质粒经酶切后获得预计大小的基因片段,并测序鉴定。序列结果与已知序列一致。原核表达载体经ITPG诱导,获得预计大小的目的蛋白。结论成功克隆了苏云金芽孢杆菌以色列亚种的3个主要杀蚊幼虫蛋白的基因,并进行原核表达。     

白纹伊蚊乙酰胆碱酯酶基因片段克隆及鉴定

目的　从白纹伊蚊中分离、克隆及鉴定乙酰胆碱酯酶 (ACh E)基因片段。　方法　根据已知的果蝇和斯氏按蚊 ACh E氨基酸序列保守区域设计简并引物 ,对白纹伊蚊 ACh E基因片段进行扩增 ,将凝胶回收的 PCR产物经与 T-载体质粒连接进行 T/ A克隆 ,用α互补筛选法筛选重组质粒克隆 ,用碱裂解法提取重组质粒 DNA并对重组质粒进行酶切鉴定和 PCR鉴定。　结果与结论　获得与设计相符的白纹伊蚊 ACh E基因片段 PCR扩增产物并对其作出鉴定     

微小隐孢子虫LDH基因的克隆与序列分析

目的克隆微小隐孢子虫(Cryptosporidium parvum,Cp)南京株(NJ)乳酸脱氢酶(lactate dehydrogenase,LDH)基因,测序并分析微小隐孢子虫NJ株CpLDH与其他隐孢子虫分离株LDH基因序列的差异。方法根据微小隐孢子虫已知LDH 基因序列设计合成2对引物, 应用巢式PCR 技术从微小隐孢子虫NJ株基因组DNA 中扩增LDH 基因, 并将其克隆到pMD18 T 载体上,阳性克隆的重组质粒经PCR及双酶切鉴定后, 用双脱氧链终止法对重组质粒中的插入序列进行测序,应用生物信息学方法分析 CpLDH 基因序列和其他物种LDH序列的同源性。结果巢式PCR 扩增得到特异的CpLDH 基因序列,经PCR及双酶切鉴定获得了正确的pMD18 T CpLDH 重组质粒。测序表明, NJ株微小隐孢子虫LDH 基因全长966 bp, 编码322个氨基酸,该基因序列已登录GenBank,登录号为 HM001298。序列分析表明, 我国微小隐孢子虫NJ株与国外分离的Iowa II株 LDH基因编码的氨基酸序列具有98%的同源性。结论成功克隆了微小隐孢子虫NJ株LDH 基因;序列测定及同源性分析表明, 微小隐孢子虫NJ株在LDH酶关键结构位点存在突变。     

苏云金杆菌cryIVD基因的克隆及序列分析

目的 克隆苏云金杆菌（B.t.i)cryIVD基因并测定其序列。方法 根据B.t.i cryIVD已知序列，设计合成了1对引物，应用PCR技术扩增cryIVD基因，克隆入pUC18载体，阳性克隆的重组质粒经酶切，电泳鉴定后进行序列测定。结果 PCR扩增得到特异的2.0kb基因片段。重组质粒经酶切后得到预期大小的基因片段。序列分析证明目的基因被完整且正向克隆。结论 B.t.icryIVD基因被成功克隆。     

阴道毛滴虫TPI基因克隆及原核表达

目的构建阴道毛滴虫TPI基因原核表达载体,并在大肠埃希菌BL21(DE3)中表达。方法根据阴道毛滴虫TPI基因开放阅读框设计并合成特异性引物,以阴道毛滴虫总cDNA为模板PCR扩增目的片段,与pMD-18-T连接构建克隆载体pMD-TPI,经双酶切回收目的片段,与表达载体pGEX-T连接,构建原核表达载体pGEX-TPI,经IPTG诱导后通过SDS-PAGE及Western blot鉴定表达产物。结果成功构建了阴道毛滴虫TPI基因原核表达载体pGEX-TPI;SDS-PAGE电泳显示,在IPTG诱导下重组质粒转化菌高效表达分子质量单位为27.5ku的蛋白质;Western blot显示表达产物可被抗阴道毛滴虫的多克隆血清识别。结论成功构建了TPI基因原核表达载体,并在大肠埃希菌BL21(DE3)中高效表达,为进一步研究阴道毛滴虫TPI基因功能奠定了基础。     

粉尘螨Ⅰ类变应原的cDNA克隆测序及亚克隆

目的　获得粉尘螨I类变应原(Derf1)cDNA克隆及亚克隆,并进行测序。　方法　设计合成引物,从粉尘螨体内提取RNA,经逆转录聚合酶链反应(RTPCR)获得cDNA,PCR扩增目的片段经纯化回收后克隆至pMD18T,转化大肠埃希菌(E.coli)JM109,经PCR初筛挑选阳性克隆并测序,将PCR筛检阳性重组子及pET32a(+)表达载体分别用BamHⅠ和SacⅠ双酶切,连接转化至E.coli感受态细胞JM10 9中过夜培养,挑选菌落进行酶切鉴定。　结果　从粉尘螨基因组RNA中扩增出Derf1基因,获得pET32a(+)Derf1亚克隆,酶切产物的大小与预期相符。　结论　对粉尘螨Derf1基因进行体外扩增并获得pET32a(+)Derf1亚克隆。     

阴道毛滴虫病毒衣壳蛋白基因cap2037的克隆与表达

目的对阴道毛滴虫病毒衣壳蛋白基因的克隆与原核表达。方法提取阴道毛滴虫总核酸为模板，根据所克隆的阴道毛滴虫病毒部分序列和GenBank中发表的阴道毛滴虫病毒TvV—T1序列设计一对引物，经RT—PCR得到与预计大小一致的PCR特异性产物，将其克隆到pMD-18T载体后测序，并与GenBank中核苷酸序列进行同源性搜索与分析，再将其克隆至表达载体pET28a。并以异丙基-β-D-硫代半乳糖苷（IPTG）诱导表达。结果目的基因片段长度为2037bp，与阴道毛滴虫病毒T1株（U08999）的同源性最高为82．9％，构建原核表达载体pET—Cap2037；IPTG诱导后，SDS—PAGE显示表达产物的大小约75kDa。结论成功克隆出阴道毛滴虫病毒衣壳蛋白基因序列，与TVV—T1株序列有82．9％的同源性，经IPTG诱导，SDS-PAGE分析表明，75kDa蛋白基因在大肠杆菌BL21（DE3）中得到高效表达。     

细粒棘球蚴95(Eg95)抗原基因的克隆及真核表达质粒的构建

目的　克隆Eg95抗原基因 ,构建携带目的基因的真核表达载体 ,为细粒棘球蚴DNA疫苗的研究提供材料。方法　应用PCR方法从细粒棘球蚴cDNA文库中克隆获得Eg95抗原基因 ,将其克隆至 pUCm -T载体 ,测序确定其正确性。利用定向克隆技术将Eg95抗原基因片段克隆至真核表达质粒pcDNA3上 ,根据选择标记的氨苄抗性基因筛选到阳性克隆 ,通过酶切分析和PCR鉴定筛选出阳性克隆 ,测序确定序列。结果　测序表明所选 pcDNA3-Eg95阳性克隆均为正确连接Eg95抗原基因的重组质粒 ,可以作为DNA疫苗作进一步的研究。结论　成功构建真核细胞表达载体 pcDNA3-Eg95。     

Cloning and sequencing of cagA gene fragment of Helicobacter pylori with coccoid form

AIM: To clone and sequence the cagA gene fragment of Helicobacter pylori (H pylori) with coccoid form. METHODS: H pylori strain NCTC11637 were transformed to coccoid form by exposure to antibiotics in subinhibitory concentrations. The coccoid H pylori was collected. cagA gene of the coccoid H pylori strain was amplified by PCR. After purified, the target fragment was cloned into plasmid pMD-18T. The recombinant plasmid pMD-18T-cagA was transformed into E.coli JM109. Positive clones were screened and identified by PCR and digestion with restriction endonucleases. The sequence of inserted fragment was then analysed. RESULTS: cagA gene of 3,444 bp was obtained from the coccoid H pylori genome DNA. The recombinant plasmid pMD-18T-cagA was constructed, then it was digested by BamH I+Sac I, and the product of digestion was identical with the predicted one. Sequence analysis showed that the homology of coccoid and the reported original sequence H pylori was 99.7%. CONCLUSION: The recombinant plasmid containing cagA gene from coccoid H pylori has been constructed successfully. The coccoid H pylori contain completed cagA gene, which may be related to pathogenicity of them.     

Cloning and sequencing of cagA gene fragment of Helicobacter pylori with coccoid form

AIM:To clone and sequence the cagA gene fragment ofHelicobacter pylori(H pylon)with coccoid form.METHODS:Hpyloristrain NCTC11637 were transformedto coccoid form by exposure to antibiotics in subinhibitoryconcentrations.The coccoid Hpyloriwas collected,cagAgene of the coccoid Hpyloristrain was amplified by PCR.After purified,the target fragment was cloned into plasmidpMD-18T.The recombinant plasmid pMD-18T-cagA wastransformed into E.coli JM109.Positive clones were screenedand identified by PCR and digestion with restrictionendonucleases.The sequence of inserted fragment wasthen analysed.RESULTS:cagA gene of 3 444 bp was obtained from thecoccoid Hpylori genome DNA.The recombinant plasmidpMD-18T-cagA was constructed,then it was digested byBamH I Sac I,and the product of digestion was identicalwith the predicted one.Sequence analysis showed that thehomology of coccoid and the reported original sequenceH pylori was 99.7%.CONCLUSION:The recombinant plasmid containing cagAgene from coccoid H pylorihas been constructed successfully.The coccoid H pylori contain completed cagA gene,whichmay be related to pathogenicity of them.     

Construction of a recombinant attenuated Salmonella typhimurium DNA vaccine carrying Helicobacter pylori hpaA

AIM: To construct a recombinant attenuated Salmonella typhimurium DNA vaccine carrying Helicobacter pylori hpaA gene and to detect its immunogenicity. METHODS: Genomic DNA of the standard H pylori strain 17 874 was isolated as the template, hpaA gene fragment was amplified by polymerase chain reaction (PCR) and cloned into pUCmT vector. DNA sequence of the amplified hpaA gene was assayed, then doned into the eukaryotic expression vector pIRES through enzyme digestion and ligation reactions. The recombinant plasmid was used to transform competent Escherichia coliDH5α, and the positive clones were screened by PCR and restriction enzyme digestion. Then, the recombinant pIRES-hpaA was used to transform LB5000 and the recombinant plasmid isolated from LB5000 was finally used to transform SL7207. After that, the recombinant strain was grown in vitro repeatedly. In order to identify the immunogenicity of the vaccine in vitro, the recombinant pIRES-hpaA was transfected to COS-7 cells using Lipofectamine~(TM)2000, the immunogenicity of expressed HpaA protein was detected with SDS-PAGE and Western blot. RESULTS: The 750-base pair hpaA gene fragment was amplified from the genomic DNA and was consistent with the sequence of H pylori hpaA by sequence analysis. It was confirmed by PCR and restriction enzyme digestion that H pylori hpaA gene was inserted into the eukaryotic expression vector pIRES and a stable recombinant live attenuated Salmonella typhimurium DNA vaccine carrying H pylori hpaA gene was successfully constructed and the specific strip of HpaA expressed by pIRES-hpaA was detected through Western blot. CONCLUSION: The recombinant attenuated Salmonella typhimurium DNA vaccine strain expressing HpaA protein with immunogenicity can be constructed and it may be helpful for further investigating the immune action of DNA vaccine in vivo.