反转录酶活性检测实时荧光定量PCR方法的建立

目的在传统产物增强性反转录酶（PERT）活性检测方法基础上建立检测反转录酶活性的实时荧光定量PCR方法。方法以噬菌体MS2RNA为模板,设计、合成引物和探针,并分别以连续10倍倍比稀释的AMV反转录酶（1×10-1～1×10-9U/μl）标准品催化体外反转录反应合成相应cDNA。采用实时荧光定量PCR法检测底物cDNA模板量,并获得相应的PCR荧光值曲线,分析AMV反转录酶的相对活性。同时应用传统PERT方法对cDNA进行扩增,测定该方法的灵敏度。结果将AMV反转录酶标准品连续10倍倍比稀释后催化反转录反应,实时荧光定量PCR分析所得的反转录产物cDNA,结果得到与理论值完全相符合的PCR标准荧光值曲线;定量分析结果显示,浓度为1×10-2～1×10-8U/μl的AMV反转录酶均可得到相应的荧光值。不同稀释度的AMV反转录酶,经传统PERT方法扩增后,结果显示浓度为1×10-3～1×10-7U/μl的AMV反转录酶均可见大小为112bp的阳性条带,检测灵敏度达到1×10-7U/μl。结论成功建立了基于实时荧光定量PCR技术的检测反转录酶活性的新方法,实验操作简单,具有高精确性和无污染性,为生物制品外来污染尤其是反转录病毒污染的检测提供了参考指标。     

HBV cccDNA荧光定量检测方法的建立及应用

目的建立一种HBVccc DNA定量检测方法,并定量检测慢性乙型肝炎患者肝组织内的cccDNA。方法分析A-G亚型HBV DNA序列,根据其结构特点,于DNA缺口两侧高度保守区域设计引物和探针,并摸索该方法最佳反应条件,以期实现不同亚型HBV cccDNA的特异性扩增。对该方法进行特异性、敏感性及重复性检测。将扩增产物进行测序以检测方法的特异性。用102~1010拷贝/ml的标准质粒检测方法的敏感度。106拷贝/ml标准质粒30复管,以检测其重复性。取32例慢性乙型肝炎患者抗病毒治疗前后的肝穿组织,提取DNA,用该方法进行cccDNA定量,观察抗病毒治疗前后cccDNA的变化及与总HBV DNA的关系。结果测序结果显示扩增产物为目的片段;该定量方法的敏感度为103~1010拷贝/ml;标准质粒30复管后其Ct值为29.69±0.31,变异系数为1.04%。肝内cccDNA占肝内总HBV DNA的47%~98%,平均81.5%。结论本方法操作简便,特异性高,定量线形范围宽及重复性好,可用于科研中cccDNA的定量检测。     

人线粒体DNA荧光定量PCR检测方法的建立

建立SYBR Green I实时荧光PCR定量检测人线粒体DNA的方法。选取人线粒体DNA高度保守基因片段,将该基因片段与pCF-T载体连接后,转化入E.coli DH5α,提取重组质粒PCR及测序鉴定后,作为阳性模板建立SYBR-Green I荧光定量PCR标准曲线和熔解曲线。结果表明:构建的标准曲线线性关系良好(反应体系中含101~108拷贝时,扩增反应CT值与拷贝数的对数成线性关系),相关系数为0.997。批内和批间重复性测定的变异系数分别为1.23%~3.29%以及3.10%~5.21%。我们成功建立了实时荧光定量PCR检测人线粒体DNA的方法,该方法可作为进一步研究线粒体DNA的方法,在相关疾病诊断和监测中具有一定的应用前景。     

狂犬病病毒实时荧光定量PCR检测方法的建立和阳性对照的制备

目的 建立狂犬病病毒实时荧光定量PCR检测方法,制备狂犬病病毒(rabies virus,RV)的假病毒颗粒阳性对照.方法 在RV的N基因保守区设计引物和探针,建立反转录实时荧光定量PCR检测方法,克隆得到噬菌体MS2的装配蛋白和壳蛋白基因(MS2),将其重组到质粒pET-28b(+)中,再将RV的N基因片段重组到MS2下游,经原核表达得到RV假病毒颗粒.结果 实时荧光定量PCR检测RV重组质粒最低检测限为15拷贝/μl,重组表达质粒经原核表达可形成耐RNase的RV病毒样颗粒.结论 建立了反转录实时荧光定量PCR检测RV核酸的方法,成功构建了可耐受RNase且无传染性的RV阳性对照.     

荧光定量PCR检测沙眼衣原体及临床应用

目的：用荧光定量聚合酶链反应（FQ－PCR）检测沙眼衣原体的含量,探讨FQ－PCR在衣原体性尿道炎诊断中的价值。方法：应用荧光探针标记引物的荧光定量聚合酶链反应对172例疑为沙眼衣原体感染患者标本进行检测,并与常规PCR（电泳－EB染色）进行比较。结果：FQ－PCR阳性率为19．8％,常规PCR法为20．9％,两法符合率为63．9％。女性宫颈分泌物标本FQ－PCR阳性为29．2％,常规PCR法为16．7％;男性分泌物FQ－PCR阳性率为16．9％,常规PCR法为13．8％。FQ－PCR特异性较常规PCR法高。结论;FQ－PCR在扩增中实时在线检测,并选择理想的标准曲线做出较精确的临值分析,具有较高的特异性和敏感性,对病原体的诊断有一定的临床意义。     

实时荧光定量PCR检测常见性传播疾病病原体基因

目的;用实时荧光定量聚合酶链反应(FQ-PCR)技术准确定量检测常见性病病原体基因,为临床治疗提供依据.方法采用实时FQ-PCR技术,检测了临床送检标本3641份.结果淋球菌(NGH)1416份、沙眼衣原体(CT)1165份、解脲支原体(UU)765份,人乳头瘤病毒(HPV6.11)214份、梅毒螺旋体(TP)81份,阳性率分别为26%(368/1416)、27%(315/1165)、36.5%(279/765)、77%(165/214)、21%(17/81).阳性率差异有高度显著性(P＜0.001).NGH、CT、UU、HPV6.11、TP阳性标本DNA平均拷贝数2.3×106、8.5×105、2.4×104、5.6×107、3.8×105.146例治疗后复查,其转阴率为NGH63.9%(39)、CT70%(33)、UU44.7%(17).治疗后复查转阴率差异有显著性(P＜0.05),其DNA拷贝平均数有明显下降.结论实时FQ-PCR技术检测常见性病病原体基因,具有简便、快捷、特异性高、定量准确等优点,对其诊断和治疗有指导意义.     

马尔堡、埃博拉病毒双重荧光定量PCR检测方法的建立

目的 建立一种快速、敏感、特异的双重实时荧光定量PCR方法,可同时检测马尔堡病毒和埃博拉病毒.方法 通过序列比对挑选出两种病毒基因组中高度保守的序列,分别设计引物及Taqman探针,两条探针分别标记FAM和Texas Red荧光报告基因,建立双重实时荧光定量PCR反应体系.结果 双重荧光定量PCR方法检测两种病毒阳性标准品的灵敏度分别为30.5拷贝/μl和28.6拷贝/μl,通过检测日本脑炎病毒、黄热病毒、登革热病毒无交叉反应,有较好的灵敏度和特异性.结论 建立了马尔堡、埃博拉病毒双重荧光定量PCR检测方法,实现了两种病毒同时实时定量检测,在传染病防控领域有较好的应用前景.     

辛德毕斯病毒荧光PCR检测方法的建立

目的建立辛德毕斯病毒核酸的SYBRGREENΙ荧光PCR检测方法。方法根据辛德毕斯病毒基因组核苷酸序列特性设计引物。病毒在BHK21细胞上繁殖扩增后提取RNA和逆转录。以病毒cDNA为模板分别进行SYBRGREENΙ荧光PCR和常规RTPCR扩增,并对SYBRGREENΙPCR法的灵敏性、特异性、重复性等进行分析。结果最适退火温度为55℃,最适引物浓度为0.5μmol/L。用该方法检测2株SIN病毒株YN87448和XJ160结果均为阳性,而对其他虫媒病毒如甲病毒属Geta病毒、乙脑病毒、Batai病毒、Banna病毒、环状病毒及西方马脑炎病毒合成模板检测时结果均为阴性。根据病毒空斑形成实验结果,将YN87448病毒悬液进行连续10倍稀释后分别用常规PCR和SYBRGREENΙ荧光PCR方法进行检测。结果SYBRGREENΙ荧光PCR检测敏感性比常规PCR方法要高近100倍,检出下限可达0.1PFU/ml。对模拟感染的人血清标本检测结果表明人血清中成分对检测体系无明显影响。对151份不明原因发热和病毒性脑炎患者的血清或脑脊液标本进行检测,结果检测到6份标本阳性。结论本实验建立了辛德毕斯病毒特异性核酸的SYBRGREENΙ荧光PCR检测方法,实验结果显示了较好的特异性、广谱性,初步证实可应用于临床标本的检测,为将来用于临床和调查辛德毕斯病毒在我国的流行情况提供了新的技术手段。     

人类疱疹病毒6型荧光定量PCR检测方法的建立和应用

目的 建立人类疱疹病毒6型(HHV-6)荧光定量PCR检测方法,并检测临床样本.方法 根据文献合成HHV-6 U65-66基因片段的特异性引物和TaqMan探针,构建质粒制备标准品,评估该方法的特异性、灵敏度和重复性;并用该方法检测93份临床诊断为病毒性脑炎的脑脊液标本.结果 本实验检测HHV-6的灵敏度为3×10(0)拷贝/μl;标准曲线间线性关系(R2)为0.999,扩增效率为97.9％;同一样本重复检测3次,组内Ct值的变异系数最大为0.61％,组间为3.13％;特异性检测中只有HHV-6阳性标本出现扩增曲线.93份临床标本中检出HHV-6阳性2例,检出率为2.15％.结论 本实验所建立的荧光定量PCR检测HHV-6的方法特异强、灵敏高、重复性好,具有应用于临床检测的潜在价值.     

Development of a quantitative real-time PCR assay for detection of Mycoplasma genitalium

Mycoplasma genitalium is known to cause nonchlamydial, nongonococcal urethritis in men and to be associated with pelvic inflammatory disease in women. Specific and sensitive PCR methods are needed for diagnosis of this bacterium because it is very difficult to culture from patient samples. To determine the bacterial load in patients' specimens, a quantitative real-time LightCycler PCR was developed. The housekeeping gene gap encoding glyceraldehyde-3-phosphate dehydrogenase was chosen as the target gene. The assay could consistently detect five genome copies per reaction. To evaluate the PCR, we tested 246 selected urethral swab samples from men attending a clinic for sexually transmitted diseases. Eighty-two of the samples were found positive for M. genitalium by a conventional 16S rRNA gene PCR assay, whereas 164 samples were randomly chosen among those tested negative. Of the positive samples, 78 (95.1%) were found positive, whereas 6 (3.7%) of the negatives were found positive by the LightCycler assay. The patient samples were also tested with a quantitative TaqMan assay, and the bacterial load was compared to the LightCycler results. A good linear correlation between the LightCycler and the TaqMan assays was found with a correlation coefficient of 0.89 and a slope of 0.99. Significantly more M. genitalium-positive men had urethritis, discharge, and dysuria than had M. genitalium-negative men. The M. genitalium DNA load in samples from patients with urethritis was significantly higher than in samples from those without (61 and 2.9 copies/microl, respectively [P = 0.0005]). This assay may prove useful in the monitoring of treatment and for optimizing sample preparation methods.     

Evaluation of real-time reverse transcriptase PCR and real-time loop-mediated amplification assays for severe acute respiratory syndrome coronavirus detection

We compared the performance of a recently established real-time loop-mediated amplification (LAMP) assay with the one from a highly sensitive quantitative PCR assay. None of these assays produced false-positive results in this study. For samples isolated from patients within the first 3 days of disease onset, the detection rate of the quantitative PCR assay was higher (14 of 15 were positive) than the LAMP assay (9 of 15 were positive). By contrast, the detection rates of these assays toward specimens sampled from patients with more than 3 days of illness were similar (32 of 44 for PCR and 33 of 44 for LAMP were positive). The simpler operation of LAMP might be a possible solution for on-site diagnosis.     

Development of a real-time PCR assay for quantitative detection of Encephalitozoon intestinalis DNA

A new real-time PCR assay for quantitation of Encephalitozoon intestinalis DNA was developed which used a TaqMan fluorescent probe for specific detection. Serial dilutions of E. intestinalis spore suspensions obtained from tissue culture were used as external standards. The detection limit of the technique was 20 spores per ml, with a good interassay reproducibility (coefficient of variation of 7.1% for the suspension containing 20 spores/ml, 5.0% for the suspension containing 75 spores/ml and below 3.5% for higher concentrations). Quantitative detection of E. intestinalis DNA was similar whether the serial dilutions of spores were made in distilled water or in a stool suspension, allowing the use of the assay for stool specimens. The assay was then applied to 14 clinical specimens from 8 immunocompromised patients with proven E. intestinalis infection. The quantitation of the parasitic burden was achieved in stools, blood, urine, tissue biopsies, and bronchopulmonary specimens. The highest parasitic burdens were noted in stools, urine, and bronchopulmonary specimens, reaching 10(5) to 10(6) spores/g or ml. Dissemination of the infection was also evidenced in some patients by demonstration of E. intestinalis DNA in blood and serum. We conclude that real-time PCR is a valuable tool for quantitation of E. intestinalis burden in clinical specimens.