Rapid detection of the hepatitis B virus YMDD mutant using TaqMan-minor groove binder probes

BACKGROUND: TaqMan-minor groove binder (MGB) probes were used in a real-time PCR-based assay for the rapid and accurate detection of hepatitis B virus (HBV) YMDD mutants. METHODS: TaqMan-MGB probes were designed to distinguish between wild-type (YMDD) and mutant (YVDD and YIDD) strains of HBV. The detection limit and sensitivity of the assay were determined using a dilution series of a mixture of wild-type and mutant plasmids. Serum samples collected from four patients with chronic mutant HBV infections during lamivudine therapy were analyzed using this method. RESULTS: The detection limit for YVDD and YIDD was 10 and 50 copies, respectively, whereas the sensitivity was 10% within a mixed virus population. In the clinical samples, mutant strains of HBV could be detected at levels <2.6 log copies/ml of HBV DNA. While 15 of the 21 samples tested by this method were positive for the YMDD mutant, direct sequencing and a reverse hybridization line probe assay (INNO-LiPA HBV DR v2) detected the mutant strain in only 11 and 9 samples, respectively. Moreover, the data for 6 samples analyzed by TA cloning were fully consistent with our TaqMan PCR results. CONCLUSIONS: We successfully established a sensitive and accurate assay for the YMDD mutant of HBV. This method may be useful for monitoring patients treated with lamivudine.     

IL-34在表皮生长因子受体突变肺腺癌中的表达及其预后评估价值

目的检测白介素34(interleukin-34,IL-34)在表皮生长因子受体（epidermal growth factor receptor,EGFR）突变的肺腺癌患者中的表达水平,探讨其对该类肺腺癌患者预后的评估价值。方法 收集2015年7月至2017年12月在复旦大学附属中山医院诊治的144例术前未接受抗肿瘤治疗的EGFR突变肺腺癌患者的手术切除标本及其临床资料。通过免疫组织化学染色,检测IL-34在肺癌组织及正常肺组织中的表达情况。用Kaplan-Meier生存曲线及Cox比例风险模型分析IL-34与患者预后的关系。结果 IL-34在EGFR突变的肺腺癌患者的肿瘤组织中相对高表达,在正常肺组织中低表达。随访64(42, 73)个月,IL-34高表达组患者（n=93）总生存率低于低表达组（n=51,P=0.006）,累积复发率高于低表达组（P=0.011）。Cox比例风险模型示,IL-34表达为患者总生存（HR=2.218, P=0.015）及复发的独立预测因素（HR=2.486, P=0.018）。结论 IL-34升高可能提示EGFR突变肺腺癌患者术后预后较差。     

肿瘤坏死因子突变体对胃癌细胞肿瘤坏死因子受体的调节

本文采用放射配基结合分析法和蛋白合成抑制试验研究了肿瘤坏死因子突变体（ＴＮＦ－ｍ）对ＳＧＣ７９０１细胞ＴＮＦ受体的影响。结果表明，ＴＮＦ－ｍ可显著降低ＳＧＣ７９０１细胞表面ＴＮＦ受体数目并呈剂量、时间、温度依赖关系，对受体亲和力无影响，ＴＮＦ－ｍ可使胞浆ＴＮＦ受体数目增加，去除ＴＮＦ－ｍ３ｈ后，膜ＴＮＦ受体大约可恢复６０％，显著高于胰蛋白酶处理组ＴＮＦ受体的恢复率，放线菌素Ｄ对ＴＮＦ－ｍ处理的细胞ＴＮＦ受体的抑制作用显著低于对照组，且ＴＮＦ受体的半衰期约为９０ｍｉｎ．据此认为，ＴＮＦ－ｍ通过介导ＴＮＦ受体的内化从而使膜ＴＮＦ受体数降低。     

A mating deficient and temperature-sensitive lethal mutant of Schizosaccharomyces pombe defines a new fertility locus

Summary A recessive mutant allele, mef1-84, of a novel locus mapping on the left arm of chromosome I, between ade3 and ura1, 5 cM apart from lys5, confers temperature-sensitive growth and mating deficiency at the nonrestrictive temperatures for growth. Two other mutations suppress the phenotype conferred by mef1-84: sts1-1 suppresses the temperature-sensitive growth only, and smd1-35 suppresses both temperature-sensitive growth and mating deficiency.     

Construction and expression of eukaryotic plasmids containing lamivudine-resistant or wild-type strains of Hepatitis B Virus genotype C

AIM： To construct eukaryotic expression plasmids of full-length Hepatitis B Virus （HBV） genotype C genome, which contain lamivudine-resistant mutants （YIDD, YVDD） or wild-type strain （YMDD）, and to observe the expression of HBV DNA and antigens [hepatitis B surface antigen （HBsAg） and hepatitis B e antigen （HBeAg）] of the recombinant plasmids in HepG2 cells. METHODS： Three HBV full-length genomes were amplified from the plasmids pMD18T-HBV/YIDD, pMD18T-HBV/YVDD and pMD18T-HBV/YMDD, using PCR. Three recombinant plasmids were generated by inserting each of the PCR products into the eukaryotic expression vector pcDNA3.1 （＋）, between the EcoRI and HindⅢ sites. After being characterized by restriction endonuclease digestion, and DNA sequence analysis, the recombinant plasmids were transfected into HepG2 cells. At 48 and 72 h post-transfection, the levels of intracellular viral DNA replication were detected by real-time PCR, and the expression of HBsAg and HBeAg in the cell culture supernatant was determined by ELISA.
RESULTS： Restriction endonuclease digestion and DNA sequence analysis confirmed that the three recombinant plasmids were correctly constructed. After transfecting the plasmids into HepG2 cells, high levels of intracellular viral DNA replication were observed, and HBsAg and HBeAg were secreted into the cell culture supernatant.
CONCLUSION： Eukaryotic expression plasmids pcDNA3.1 （＋）-HBV/YIDD, pcDNA3.1 （＋）-HBV/YVDD or pcDNA3.1 （＋）-HBV/YMDD, which contained HBV genotype C full-length genome, were successfully constructed. After transfection into HepG2 cells, the recombinant plasmids efficiently expressed HBV DNA, HBsAg and HBeAg. Our results provide an experimental basis for the further study of HBV lamivudine-resistant mutants.     

C基因截短突变体抗乙型肝炎病毒作用机制的研究

目的 探讨C基因截短突变体抗乙型肝炎病毒(HBV)的作用机制。方法 构建C基因截短的真核表达载体pcDNA3-△C及野生型C基因真核表达载体pcDNA3-C，瞬时转染HepG2细胞，用SDSPAGE western blot检测pcDNA3-△C、pcDNA3-C的蛋白表达。pcDNA3-△C与adwR9共转染HepG2细胞，以pcDNA3与adwR9为对照，用荧光定量PCR检测培养上清液及细胞内病毒量，用Native western blot分析C基因截短蛋白干扰核心颗粒形成。结果重组载体pcDNA3-△C、pcDNA3-C均可表达，DcDNA3-△C与adwR9共转染组上清液和细胞内病毒量较对照组降低，pcDNA3-△C和pcDNA3-C共转染组Native western blot条带与pcDNA3和pcDNA3-C共转染组条带相比较明显淡。结论 C基因截短突变体可干扰核心颗粒的形成，导致HBV复制下降。