Expression of Human Chorionic Gonadotropin β （hCGβ） in Lactobacillus Casei

Objective To construct a recombinant lactobacillus (Lb.) strain excreting the human chorionic gonadotropin beta~subunit (hCGβ) Methods The hCGβ cDNA was ligated to the signal peptide sequence of S-layer protein from Lb. brevis and then cloned into down-stream of lactose-inducible promoter of an integrative plasmid, pIlac. After electroporation into Lb. casei CECT5276, PCR using the genomic DNA of the recombinant lactobacillus as template was performed to confirm whether the hCGfl gene had been integrated into the genome. Radioimmunoassay (RIA) was used to determine the level of hCGfl in the supernatant and the cell lysate. Results The hCGβ was integrated into the genome of Lb. casei CECT5276. The highest concentration of hCGβ in the culture supernatant amounted to 440 mlU/mL 21 h after lactose induction. About 2/3 of the objective proteins were excreted into the supernatant. Conclusion We have obtained stable and efficient hCGβ excretion in Lb. casei, which was inducible by lactose.     

RelationshipBetween Serum DNAReplication,Clinicopathological Characteristics andPrognosis ofHepatitis BVirus-associated Glomerulonephritis withSevereProteinuria byLamivudinePlus Adefovir Dipivoxil Combination Therapy

ObjectiveTo explore the relationship between HBV DNA and the clinical manifestations, pathological types, injury severity, and prognosis with HBV-GN. Methods102 patients with HBV-GN were divided into 3 groups, according to the serum titer of the HBV DNA. 24-h urine protein excretion, and other parameters were measured.Renal biopsy were performed. The association between HBV DNA and the pathological stage of membranous nephropathy was analyzed in 78 patients with HBV-MN. 24-h urine protein excretion was used for the evaluation of the prognosis, and the relationship between HBV DNA and prognosis were analyzed. ResultsSeveral findings were demonstrated with the increase of serum HBV DNA: 24-hurine protein excretion, plasma cholesterol, and triglycerides increased significantly (P<0.05), while the plasma level of albumindecreased significantly (P<0.05); The changes of serum creatinine, C3 and C4 were found but no statistical significance. Glomerular deposition of HBVAg increased, and the pathological injury was more severe. The clinical remission rate was lower in the high replication group after treatment as compared with the low replication group (P<0.01). ConclusionWith the increase of serum HBV DNA, the urine protein excretion and the kidney injury were more severe, and the clinical remission rate was decreased.     

A study on the Appearance of HBV DNA in the Liver and Serum of Patients with HDV/HBV Infection

The appearance of HBV DNA in the liver and serum of 15 patients with hepatitisB conifected with HDV was observed and compared with that of 13 HDV-negative cases.Itwas found that HBsAg titer was lower than or equal to 1:4 in 8 HDV-positive patients,inwhom it was temporally negative in 5,and negative during the,two-day hospitalization in 1.No similar result could be observed in the HDV-negative cases.The detection rate of HBVDNA in both the HDV positive and negative groups was 20.0％ (3/15) and 25％ (3.12) in se-rum,and 46.7％ (7/15) and 61.5％ (8/13) in the liver rcspectively.There was no signif-icant statistical difference between the 2 groups.The HBV DNA grains detected with in situ hybridization,with biotinylated HBV DNAprobe were demonstrated in the sparse type of distribution in 3 cases and lightly stained in 2.Itis believed that HBV DNA replication activity might be suppressed by HDV.However activeHRV DNA replication was also present in some HDV-positive patients and HBV DNA was posi-tive in both the liver and serum in 3 such patients.It was concluded that the difference of the detection rate of HBV DNA in HDV-positivepatients might be related to the different stages of HDV infection.     

Expression of cyclooxygenase-2 mRNA in drug-sensitive cell and drugresistant strains of ovarian cancer cell lines

Objective： To investigate the expression of cyclooxygenase-2 （COX-2） mRNA in drug-sensitive cell and drugresistant clones of ovarian cancer cell lines. Methods： RT-PCR and immunocytochemistry were used to investigate the expression of cyclooxygenase-2 in 3 clones drug-sensitive and 5 clones drug-resistant ovarian cancer cell. Results： Strong COX-2 mRNA expressions were detected in 3 clones of drug-sensitive cell and weak expressions were detected in 5 clones of drug-resistant cell. The protein expression of COX-2 in drug-sensitive cell was strongly positive reaction in immunocytochemistry stain and there was a weak positive reaction in 5 clones of drug-resistant cell. Conclusion： The expression of COX-2 mRNA in drug-sensitive cell strains is much higher than that in drugresistant strains of ovarian cancer cell lines, providing a basis of the chemoprevention for ovarian cancer.     

Construction of Recombinant Plasmid Harboring APP717 Mutation and Preliminary Study of APP Proteolysis

In order to investigate the pathogenesis of Alzheimer disease （AD） and study the enzymatic progress of amyloid precursor protein （APP）, the fluorescent eukaryotic expression plasmid of C99 was constructed containing APP717 mutation. The fragment encoding the last 99-aa of APP （which was named C99 containing APP717 mutation）, together with the fragment encoding yellow fluorescence protein （which was named YFP） were amplified by PCR. The two fragments （YFP and C99） were inserted into the vector pcDNA3.0. The recombinant plasmid pcDNA3.0-YFP-C99 was accomplished and its authenticity was confirmed by enzyme digestion and sequencing. Then SH-SY5Y cells were transiently transfected with the recombinant plasmid pcDNA3.0-YFP-C99. The expression of the fusion gene was detected by laser confocalmicroscopy. Amyloid-β （Aβ） was detected by both microscopy and immunochemistry. The authenticity of the construct was confirmed by the endonuclease digestion and DNA sequencing. The YFP fluorescence could be seen and proved the expression of fusion gene. Aβ labeled by YFP was detected by confocalmicroscopy and confirmed by immunocytochemistry. It was found that Aβ accumulated and deposited in the intracytoplasm, membrane and outside of the cell. Furthermore, Aβ accumulated mainly within the cell ahead of the deposition in the cell space and the cell shape was rough. It was suggested that Aβ could be generated within the cells. Aβ accumulated in the cell at the early stage before the deposition outside of the cells Intracellular Aβ accumulation induced the secondary damage to the cells and caused the cell shape rough. Taken together, the recombinant plasmid, pcDNA3.0-YFP-C99 could be a useful tool to further study the cleavage mechanism of APP and to explore the pathogenesis of AD.     

HBV PreS1蛋白酵母双杂交诱饵表达载体的构建及其毒性和自激活效应

目的 利用Sos招募系统(SRS),构建含HBV PreS1基因的酵母双杂交诱饵质粒,并检测其表达产物对cdc25酵母细胞有无毒性作用及对报告基因有无激活作用.方法 聚合酶链反应(PCR)扩增HBV PreS1基因的编码序列,定向克隆到酵母表达载体pSos中,构建诱饵重组质粒pSos-PreS1.经测序正确后其将转化酵母菌cdc25感受态细胞,检测其表达产物对酵母细胞有无毒性作用及对报告基因有无自激活作用.结果 序列测定证实重组诱饵质粒pSos-PreS1构建成功.重组质粒转化入酵母细胞后,经检测其表达产物对cdc25酵母细胞无毒性作用,对报告基因亦无自激活作用.结论 可以利用SRS来研究与HBV PreS1蛋白相互作用的蛋白,为进一步研究乙型肝炎病毒的致病机制奠定了基础.

Abstract：

Objective To construct a yeast expression vector of hepatitis B virus (HBV) PreS1 gene using the Sos-recruitment system (SRS), and evaluate the effect of the expression product on the growth of the yeast cells and activation of the reporter gene. Methods The coding sequence of HBV preS1 was amplified by PCR and cloned into the yeast expression plasmid pSos. The recombinant bait plasmid pSos- PreS1 was verified by sequencing before transformation into competent yeast cells. The effects of the expression product on the yeast cell growth and activation of the reporter gene were evaluated. Results The yeast expression vector of HBV PreS1 gene was constructed sucessfully. The recombinant bait plasmid showed no toxic effect on yeast cdc25H cells without a self-activation of the reporter gene. Conclusion The SRS can be used to study the proteins interacting with HBV PreS1 protein and provides a means for obtaining insight into the pathogenic mechanism of HBV.     

Preliminary Studies of in situ Hybridization in Routine Paraffin Embedded Liver Tissue Sections with iotinylated HBV DNA Probe:Localization and Morphology of HBV DNA in Various Types of Liver Diseases

The in situ hybridization of HBV DNA with biotinylated probe informalin-fixed and paraffin-embedded liver tissue sections was performed and thelocalization and morphology of HBV DNA in various types of chronic liver diseases wereobserved.25 out of the 75 cases studied were HBV DNA positive (33.3%).HBV DNA inhepatocytes was demonstrated as numerous coarse grains in cytoplasm and occasionally afew grains in individual nuclei.The distribution of the HBV DNA positive hepatocytes inthe sections was in 3 types,i.e.,the diffuse type (Type I,4/25,16%),the focal type (Type Ⅱ,20/25,80%),and the scattered type (Type Ⅲ,1/25,4%).The HBV DNA grains incytoplasm might be condensed (Type a) or sparsed (Type b) depending on the number of theHBV DNA grains.The different distribution patterns and the amount of HBV DNAgrains might be a reflection of the replication activity and the state of infectivity of HBV.HBV DNA positive hepatocytes were found only in the tissues contiguous to the cancertissue in cases with hepatocellular carcinoma with cirrhosis.     

Detection of HBV and HCV Coinfection by TEM with Au Nanoparticle Gene Probes

Gold(Au) nanoparticle HBV DNA or HCV cDNA gene probes were prepared and were used to detect HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection directly by transmission electron microscopy(TEM).PCR identifying HBV and HCV in serum of patients with HBV and HCV coinfection was established.Alkanethiol-modified oligonucleotide was bound with self-made Au nanoparticles to form nanoparticle HBV DNA or HCV cDNA gene probes through covalent binding of Au-S.HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection was added to the detection system composed of nanoparticle HBV DNA and(or) HCV cDNA gene probes.The results showed that HBV DNA and HCV RNA could be specifically amplified by PCR.The zones of DNA amplification appeared in 431 bp and 323 bp respectively.When HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection were added to the detection system,TEM displayed the nanoparticles self-assembled into large network aggregates.It was concluded that the detection of HBV and HCV coinfection by TEM was convenient and efficient with high specificity and sensitivity.     

Construction of retrovirus vector with HBV Pol gene and its expression invitro

Objective: To construct retroviral vector with HBV Pol gene and study its expression in vitrn. Methods: The recombinant plasmid HBV2/pBR322 containing 2 copies of HBV full-length gene was provided as the amplification template. The PCR product was cloned into pMD 18-T and subeloned into pMSCVneo and pLNCX2 to construct the recombinantret roviral vectors with HBV Pol gene named by HBV P/pMSCVneo and HBV P/pLNCX2. HBV Pol gene was detected by RTPCR after transfecting the recombinant plasmids into SMMC7721 cells with liposome and G418 selection. Results: The retroviral vector with HBV Pol gene was successfully constructed and the expression of HBV Pol gene in vitro was detected by RTPCR. Conclusion: The retroviral vector with HBV Pol gene can be obtained, which will provide a new insight on the function of HBV Pol gene.     

HBV全基因C区突变株在永生化B淋巴母细胞系中的稳定表达

目的 构建携带V60、G87和L97突变位点的HBV全基因组真核表达载体，转染慢性HBV感染者永生化B淋巴母细胞系（LCLs）。方法 用定点突变技术将HBVp3．8Ⅱ质粒C基因区3个氨基酸V60、G87、L97进行突变（p3．8Ⅱ-V60，G87，L97），转化E．coli．XL1-Blue感受态细胞扩增筛选，用限制性内切酶Sac I和Kpn I分别将野生型和突变型p3．8Ⅱ质粒进行双酶切，插入EBV-plpp真核细胞表达载体，转染LCLs，潮霉素稳定筛选后，鉴定目的基因在转染细胞能够稳定表达。结果与结论 DNA序列分析表明，野型HBV DNA核心区第60、87、97位氨基酸发生了预期的突变，Western Blotting和微粒子免疫荧光法证明转染的LCLs能稳定表达HBV抗原，证实成功构建了预期细胞模型。     

反义基因转移表达及抗乙型肝炎病毒的作用

目的观察重组逆转录病毒载体－包装细胞系统介导反义基因转移表达和抗乙型肝炎病毒（ＨＢＶ）的作用。方法将ＨＢＶａｙｗ１４０２－２９０６片段和２８３９－１９８６片段反向插入重组逆转录病毒载体质粒，分别转染ＰＡ３１７包装细胞，分别感染ＮＩＨ３Ｔ３细胞和２．２．１５细胞。结果转导的ＮＩＨ３Ｔ３细胞内有ＨＢＶ反义ＲＮＡ转录表达。ＨＢＶ反义基因重组逆转录病毒感染２．２．１５细胞后第３天，表面抗原（ＨＢｓＡｇ）和ｅ抗原（ＨＢｅＡｇ）表达量减少，感染后第５天，ＨＢＶ抗原表达抑制率达高峰。ｐｒｅＳ／Ｓ片段反义基因转移后，ＨＢｓＡｇ表达抑制率为７１％，ＨＢｅＡｇ抑制率为２３％；ｐｒｅＣ／Ｃ片段反义基因转移后，ＨＢ－ｓＡｇ表达抑制率为２３％，ＨＢｅＡｇ抑制率为５９％。结论逆转录病毒载体－包装细胞系统能够介导ＨＢＶ反义基因在真核细胞内转移和表达，并对ＨＢＶ复制和表达均有抑制作用。     

APOBEC3G真核表达载体构建及抗HBV复制的初步研究

目的构建人载脂蛋白B mRNA编辑酶催化多肽样蛋白3G（APOBEC3G）真核表达载体,并探讨其抗乙型肝炎病毒（HBV）复制的作用。方法采用RT-PCR法从健康人外周血单个核细胞中克隆APOBEC3G基因编码区片段,构建pcDNA3.1-A3G真核表达载体,利用脂质体转染法将pcDNA3.1-A3G转染HepG2.2.15细胞,分别于转染后第24、48、72 h收集细胞培养上清液和细胞总蛋白,Western blot检测HBx蛋白表达情况,ELISA法检测细胞上清液中HBsAg和HBeAg表达情况。结果测序结果显示pcDNA3.1-A3G真核表达载体中APOBEC3G编码区序列存在1处碱基同义突变;HepG2.2.15细胞经APOBEC3G蛋白干扰后,HBx、HBsAg和HBeAg表达量逐渐降低,于72h表达量显著降低。结论成功构建了APOBEC3G真核表达载体pcDNA3.1-A3G;APOBEC3G在体外可以抑制HBV复制,为深入研究APOBEC3G作为抗HBV药物提供了实验基础。     

RNA干涉对乙型肝炎病毒复制和表达的影响

目的：观察HBV S区和C区特异性的小发夹RNA（shRNA）表达载体对HepG2.2.15细胞中HBV复制和表达的影响。方法：采用含有pol Ⅲ启动子的真核表达载体pSilenceCircle-U6构建针对HBV S区和C区的特异性shRNA表达质粒SC-S和SC-C。实验设立SC-S组、SC-C组、无关对照SC-N组和空白对照组,采用不同浓度的重组载体转染HepG2.2.15细胞,并作用不同时间。应用ELISA方法检测细胞上清液中的HBeAg和HBsAg,用斑点杂交方法检测细胞上清中的HBV DNA。结果：成功构建了含目的序列的重组质粒SC-S和SC-C。SC-S对HBeAg和HBsAg表达的抑制率明显高于SC-C;随着给药浓度的增加,SC-S对HBeAg和HBsAg表达的抑制率逐渐增强;SC-S转染HepG2.2.15细胞后第3天产生明显抑制效应,对HBeAg及HBsAg表达的抑制率在第6天达高峰,第9天抑制率仍较高。斑点杂交结果显示,SC-S对HBV复制的抑制效应强于SC-C。结论：构建的HBV S区和C区特异性shRNA表达质粒有明显、高效抑制HBV复制和表达的作用。     

HBV全基因真核细胞表达载体的构建及表达

目的：构建全基因HBV真核细胞表达载体,并对其在细胞内的复制、转录、翻译进行研究。方法：采用分子亚克隆技术,将长约3.2Kb的HBV全基因克隆到真核细胞表达载体pBK-CMV折EcoPI位点,构建的pKB-HBV经FUGENE^TM6导入人肝癌细胞系SMMC－7721细胞中。结果：经PCR、RT－PCR验证pBK-HBV能够在SMMC－7721细胞中有效复制和转录。固相放免法显示HBV转染细胞内的HBsAg、HBeAg的合成和分泌。免疫组化法证明,胸内浆型分布为主的HBcAg的表达。结论：HBV全基因真核细胞表达载体pBK-HBV能够在SMMC－7721细胞中有效复制、转录及表达。     

抑制HBV复制的小干扰RNA的重组腺病毒构建与鉴定

目的构建可同时表达绿荧光蛋白（GFP）和针对HBVS区基因的小干扰RNA（siRNA）的重组腺病毒,并研究该siRNA在体外对HBV的抑制作用。方法采用PCR技术自质粒pEGFP-C1中扩增含CMV启动子的GFP表达框,自质粒pAVU6＋4sh579中扩增含U6启动子的针对HBV S 区579-597位基因的siRNA表达框,分别将两个表达框克隆至穿梭载体质粒pShuttle内,与质粒pADEasy-1在大肠杆菌BJ5183内进行同源重组,将阳性重组体DNA转染至人胚肾细胞株HEK293细胞中进行包装、扩增,并在HepG2.2.15细胞中初步观察其对HBV复制的抑制疗效。结果构建了可同时表达GFP和siRNA的重组腺病毒,其可在HEK293细胞中进行包装、扩增,并在HepG2.2.15细胞中对HBV-DNA、HBsAg和HBeAg的表达具有抑制作用。结论成功构建了可同时表达GFP和针对HBV的siRNA的重组腺病毒,并在体外实验中证实了其对HBV复制具有抑制作用。     

乙型肝炎病毒表面抗原单链抗体细胞内免疫抗乙型肝炎病毒基因治疗研究

目的 :研究乙型肝炎病毒表面抗原 (HBsAg)人源单链可变区抗体 (ScFv)细胞内免疫抗乙型肝炎病毒(HBV)基因治疗的作用。方法 :用噬菌体表面展示技术筛选特异性的HBsAg人源单链可变区抗体 ,聚合酶链反应(PCR)法扩增HBsAg单链抗体基因 ,并构建表达HBsAgScFv基因的重组逆转录病毒载体pLXSN HBsAgScFv,转染PA317细胞 ,将转染细胞分泌的假病毒颗粒感染 2 2 15细胞 ,酶联免疫吸附法 (ELISA)检测其上清HBsAg和HBeAg ,定量检测HBVDNA。结果 :成功筛选出HBsAgScFv ,PCR扩增出 75 0bp的全基因 ,构建HBsAgScFv基因的逆转录病毒载体 ,转染PA317细胞 ,在上清中检测出含HBsAgScFv假病毒颗粒的存在 ,上清感染 2 2 15细胞后第 3、5、7、14天 ,HBsAg、HBeAg逐渐下降 ,到第 14天时HBsAg已变为阴性 ,DNA定量检测无明显变化。结论 :HBsAgScFv能成功地在逆转录病毒载体中表达 ,并有抑制HBsAg、HBeAg表达的作用     

利用重叠延伸PCR快速构建中国株乙型肝炎病毒的感染性克隆

目的：体外扩增中国株乙型肝炎病毒（hepatitis B virus,HBV）的基因组全长序列,快速构建中国株HBV感染性克隆,建立中国株HBV体外复制细胞模型。方法：设计保守引物,扩增HBV全长基因组序列。对扩增到的HBV基因组进行DNA测序及计算机辅助分析,确定病毒的基因型。通过重叠延伸PCR（splicing by overlap extension PCR,SOE-PCR）技术,构建1.3倍基因组长度的HBV感染性克隆质粒pHBV1.3。将pHBV1.3质粒转染人肝癌细胞系HepG2,采用Western Blot、酶联免疫吸附试验及Real-PCR检测病毒复制及表达情况。检测该感染性克隆对临床抗病毒药物阿德福韦的敏感性。结果：成功扩增到1株C基因型HBV全长基因组,其GenBank登陆号为KF495606。构建了中国株HBV感染性克隆pHBV1.3（C）质粒,该质粒能在肝癌细胞株中进行有效的复制、转录和表达。阿德福韦能在体外抑制该HBV感染性克隆的复制,抑制程度依赖于药物浓度。结论：利用SOE-PCR可快速构建HBV感染性克隆,所构建的感染性克隆能介导高水平病毒复制,可用于HBV复制机制和抗病毒等方面的研究。     

以S区为靶位的小干扰RNA抗乙型肝炎病毒的实验研究

目的以乙型肝炎病毒（HBV）S基因区为靶位,构建表达siRNA的质粒载体pSilencer3．1-H1hygro,体外观察siRNA抗HBV的效果。方法以HepG2．2．15细胞为靶细胞,利用脂质体Metafectene转染表达siRNA的质粒载体pSilencer3．1-H1hygro于细胞中,用时间分辨免疫荧光分析法（IFMA法）检测细胞上清中HBsAg和HBeAg,用定量聚合酶链反应（FQ—PCR）检测细胞上清DNA,用逆转录（RT）-PCR检测HBV mRNA。结果成功构建了表达siRNA的转录质粒载体,siRNA可抑制HBV的抗原表达和病毒复制,1、2、4μgsiRNA对HBsAg的抑制率分别为75％、82％、89％;对HBeAg的抑制率分别为32％、38％、43％;对HBVDNA的抑制率分别为30％、43％、49％;对HBVRNA的抑制率分别为30％、70％、90％。结论靶向HBVS区的siRNA能抑制HBV的抗原表达和复制;siRNA抑制作用呈剂量依赖性和序列特异性。     

HBx基因缺失突变对HBV复制和转录的影响

目的构建HBx基因缺失突变质粒pUC-HBV1.0.X7,研究HBx缺失对HBV复制和转录的影响。方法以包含HBV全长基因组的野生型质粒pUC-HBV1.0为模板,用定点突变技术构建HBx基因缺失突变质粒pUC-HBV1.0.X7,并酶切和DNA测序鉴定。用SapⅠ单酶切这两种质粒,获得线性的野生型和HBx缺失突变型HBV基因组,经转染试剂PolyJetTMReagent介导分别瞬时转染到HepG2细胞中。在转染后各时间点Western blot检测HBx蛋白的表达,Southern blot和Real-time PCR同时检测细胞质DNA复制和细胞核cccDNA的合成,Real-time PCR分析定量HBV前基因组RNA(pgRNA)的转录。结果在野生组中可检测到HBx蛋白的表达,而在HBx突变组中HBx蛋白的表达低于Western blot的检测范围。两组中各时间点合成的cccDNA水平无统计学差异(P>0.05)。而在转染后96 hHBx突变组中细胞质DNA的复制和pgRNA的转录都分别比野生组减少50%～70%(P<0.05)。结论 HBx缺失虽然不影响细胞核HBV cccDNA的合成,但是它能下调细胞质HBV DNA的复制和pgRNA的转录。