荧光定量(PCR)用于乙肝病毒DNA检测的诊断价值

分析荧光定量(PCR)应用于乙肝病毒DNA(HBV-DNA)检测与乙肝病毒标志物(乙肝两对半)化学发光法检测的诊断价值。方法 回顾性分析100例2023年3月至2023年8月我院就诊的乙型肝炎患者HBV-DNA和乙肝两对半结果。乙肝两对半定性检测(血清乙型肝炎病毒标志物)采用磁微粒化学发光法。HBV-DNA则采用荧光定量PCR检测;对两种检测结果进行分析。结果 1(+)、3(+)、5(+)模式(HBsAg、HBeAg、HBcAb同时阳性,即“大三阳”)、1(+)、4(+)、5(+)模式(HBsAg、HBeAb、HBcAb同时阳性,即“小三阳”)分别为30例、39例,占比分别为30.0%、39%。将HBV-DNA表达水平>1*102copies/ml判断为阳性;HBV-DNA定量检测结果显示,全部100例患者中,HBV-DNA检测阳性的患者共有56例,阳性率为56.0%(56/100)。在HBV-DNA阳性率方面,和其他模式相比较,3(+)模式及1(+)、3(+)、5(+)模式均更高(P<0.05),分别为100.0%与96.67%;而在HBV-DNA水平方面,和其他模式相比较,1(+)、3(+)、5(+)模式则更高(P<0.05)。结论 联合HBV-DNA定量检测与乙肝两对半定性检测,能为乙型肝炎的早期诊断及临床用药提供参考。

乙型肝炎病毒SYBR GreenⅠ实时荧光定量PCR方法的建立及临床应用

目的建立 SYBR Green I实时荧光定量 PCR检测乙型肝炎病毒 DNA的快速方法，并探讨其临床应用价值。方法根据GenBank公布的Hepatitis B virus gp1基因序列设计引物，建立SYBR Green I实时荧光定量PCR，并对反应体系和扩增程序进行优化。定量标准品通过基因克隆方法获得，同时以浙江省夸克公司 HBV DNA定量检测试剂盒作对照，应用于随机选取的100份乙型肝炎患者血清检测。结果 SYBR Green I 实时荧光定量 PCR 检出限范围为5＆#215;102 copies／ml～5＆#215;108 copies／ml，HBV DNA浓度与CT值有良好线性关系，无交叉反应，整个过程仅需2.5 h。在随机抽取的100份临床标本应用中，与浙江省夸克公司的 HBV荧光定量 PCR检测试剂相比，建立的 SYBR Green I实时荧光定量PCR体系灵敏度100％，特异度92.5％。结论 SYBR Green实时荧光定量PCR快速、简便、灵敏度高、特异度强，可用于乙型肝炎患者病情监测，有效指导临床用药，准确评价 HBV感染者的病情。

H3、H9亚型禽流感病毒双重荧光定量PCR方法的建立及初步应用

虽然H3、H9亚型禽流感病毒（Avian influenza virus, AIV）是低致病性禽流感病毒，但其具有跨宿主感染哺乳动物的能力，对社会公共卫生安全具有重大的潜在危害，因而对这些亚型病毒的监测极其重要。通过比对GenBank上H3、H9亚型禽流感病毒HA基因序列，设计了分别针对H3 AIV和H9 AIV的特异性探针。特异性试验和标准曲线试验的结果显示，这两个探针仅分别特异性识别H3、H9亚型AIV，且具有较好的扩增效率。通过重组质粒pMD19-T-H3HA和pMD19-T-H9HA 10倍梯度稀释液为模板，进行敏感性实验。结果表明，本研究所建立的荧光定量PCR方法能检测到100个DNA拷贝数H3 AIV和10个DNA拷贝数的H9 AIV，比传统PCR方法敏感性分别提高了100倍和1000倍。此外，本方法还能检测到10 EID50的H3亚型AIV或H9亚型AIV，比传统PCR方法检测敏感性均提高了1000倍。批间和批内试验的变异系数均小于3%，表明本研究建立的方法具有较好的重复性。此外，与传统PCR方法相比，用H3、H9亚型AIV双重荧光定量PCR方法检测人工感染动物的肺组织时，针对H3 AIV的敏感性提高了10~100倍，针对H9 AIV的敏感性提高了100倍。综上所述，本研究所建立的H3、H9亚型禽流感病毒双重荧光定量PCR方法具有较高的特异性和敏感性，对H3、H9亚型禽流感病毒监测具有重要的应用价值。

实时荧光定量PCR检测皱纹盘鲍Δ5脂肪酸去饱和酶基因表达方法的建立及应用

研究以皱纹盘鲍(Haliotis discus hannai Ino)体内存在的2条Δ5 Fad(Hdhfad1和Hdhfad2)为目的基因,β-肌动蛋白(β-actin)和核糖体蛋白S9(Ribosomal protein S9,RPS9)为内参基因,应用2–ΔΔCt方法建立了实时荧光定量PCR(Real-Time quantitative PCR,RT-qPCR)检测体系,并应用此体系分析了鲍鱼肌肉组织Δ5 Fad在不同饲料处理下的表达差异。实验饲料含有不同的脂肪源,分别是棕榈酸甘油酯(Tripalmitin,TP饲料)、富含二十碳四烯酸(Arachidonic acid,ARA)的油脂(AO饲料)和富含二十碳五烯酸(Eicosapentaenoic acid,EPA)的油脂(EO饲料)。结果表明:针对Hdhfad1、Hdhfad2、β-actin和RPS9所设计的引物特异性强。各引物对的PCR扩增效率(Efficiency,E)分别为1.05、0.99、0.97和0.98,满足2–ΔΔCt方法对E的要求。当退火温度为52℃,反应体积为25μL时,RT-qPCR的扩增效果最好。所建立的体系能够准确定量Δ5 Fad的基因表达。利用该方法分析Δ5 Fad在不同饲料处理下的表达结果显示,与TP对照组相比,EO和AO饲料显著降低了鲍鱼肌肉组织Δ5 Fad(Hdhfad1和Hdhfad2)的表达量。

鹿布鲁氏菌实时荧光定量PCR检测方法的建立

本研究依据布鲁氏菌的特异性基因Omp25c的部分片段作为靶基因,设计探针引物,且优化了反应体系,筛选出引物、探针的最优浓度配比。将扩增产物连接到PGEM-T载体上,制备标准品及标准曲线,建立鹿布鲁氏菌荧光定量PCR检测方法,并对其特异性、稳定性、敏感性进行评价。由标准曲线可知该方法的最低检测浓度可达到36拷贝/μL,比常规PCR灵敏度高出很多。

多通道Taqman-探针荧光定量PCR鉴定MRSA方法的建立

目的建立基于mec A／nuc／fem B三基因联合的 Taqman-探针荧光定量 PCR鉴定耐甲氧西林金黄色葡萄球菌（MRSA）的方法。方法以常规检验标本中分离和采用 VITEK 2 Compact微生物分析仪鉴定为凝固酶阳性的 MRSA为研究对象，通过PrimerPremier5.0和Beacon Designer 7软件设计针对mec A／nuc／fem B特异性PCR引物及Taqman荧光探针，荧光探针5’端分别采用 FAM，HEX及 ROX标记，3’端采用BHQ1标记，在荧光定量PCR仪进行检测。结果①1 g／dl凝胶电泳结果显示mec A／nuc／fem B三个基因引物特异性较好，扩增出的条带分子量与预期分子量一致且未见非特异性扩增；②在单管单通道及单管多通道的 PCR检测中 mec A／nuc／fem B均获得特异性扩增，且三个基因在单管多通道的PCR扩增效果与单管单通道的相类似。结论成功建立了多通道 Taqman-探针荧光定量 PCR鉴定 MRSA的方法， mec A／nuc／fem B三种基因联合检测可有效区分凝固酶阴性和阳性的 MRSA，提高鉴定 MRSA的准确率。

不同荧光定量PCR对于HBVcccDNA水平的检测差异对比

目的研究对比不同荧光定量聚合酶链反应PCR对于乙型肝炎病毒HBVccc DNA水平的检测差异。方法选择20例从2007—2008年在广州市第八人民医院接受住院治疗的乙肝患者作为研究对象。提取其血清及肝组织进行实验分析,另取2份不含HBV感染的患者血清和肝组织作阴性对照组。将其中经或未经脱氧核糖核酸酶DNase处理的样本分别使用HBVccc DNA跨单缺口PCR和跨双缺口PCR检测。分析Taq Man探针跨单缺口PCR测定HBVccc DNA的结果,对比跨单、双缺口PCR测定结果以及不同荧光定量PCR的测定结果。分析血清和肝组织中HBVDNA与HBVccc DNA病毒载量的关系。结果血清及肝组织经过DNase消化后的有关拷贝数显著低于未消化者。血清和肝组织跨双缺口PCR测定结果较跨单缺口PCR测定结果均显著降低。血清中的HBVDNA及ccc DNA实验结果均显著低于在肝组织中的测定结果,差异均有统计学意义(均P<0.05)。阴性对照组经四种荧光定量PCR检测后均呈阴性。20例E抗原呈阳性的乙肝病人,其机体病毒载量总体趋势为血清HBVDNA的载量较肝组织更低,差异显著。结论 DNase可有效减少HBVccc DNA在检测过程中的假阳性情况,经DNase处理后的跨双缺口PCR检测特异性最高。同时,血清中基本不含ccc DNA。

荧光定量PCR检测志贺菌方法的建立

目的：建立一种检测志贺菌属快速敏感的荧光定量PCR方法．方法：根据志贺菌属侵袭性质粒抗原H （ipaH）编码基因序列，设计1对PCR引物特异性靶基因片段，通过检测3株志贺菌属菌株和9株非志贺菌属菌株来评价该方法的特异性；对福氏志贺菌菌液做一系列10倍稀释后进行荧光定量PCR分析敏感性，PCR 扩增产物经电泳和测序鉴定．结果：3株志贺菌属菌株出现特定大小的目的条带，9株非志贺菌属菌株未出现目的条带；测序也证实了PCR产物的特异性；荧光定量PCR检测福氏志贺菌ipaH基因的下限为200拷贝/mL．结论：本研究建立的方法快速、特异、敏感．

荧光定量PCR测定HBV DNA测量不确定度的评定与应用探讨

目的探讨荧光定量聚合酶链式反应(PCR)测定乙型肝炎病毒核酸(HBV DNA)测量不确定度的评定与临床应用价值。方法采用批内不精密度和批间不精密度数据评定A类不确定度,采用参加卫生部临床检验中心的室间质评(EQA)数据评定B类不确定度;根据A类和B类不确定度结果确定合成不确定度和扩展不确定度;利用不确定度进行HBV DNA检测结果的比较,并建立不确定度报告模型。结果采用EQA靶值评定偏移引入的不确定度Ubias,以偏移与偏移的标准差评定偏移的不确定度,扩展不确定度U1(k=1.96,n=2)在检测值为103和106 IU/ml时分别为0.330 2和0.249 6,而以方法和实验室偏移评定偏移的不确定度,扩展不确定度U2分别为0.307 6和0.239 4;采用同方法组均值评定Ubias,U1分别为0.315 9和0.230 4,U2分别为0.292 2和0.219 3。如前后两次检测结果均在本实验室测量,取U为0.330 2,两者差值≥0.46(LOG值),差异具有统计学意义。结论荧光定量PCR测定HBV DNA引入扩展不确定度使结果具有可比性,有助于临床对患者体内病毒复制水平及抗病毒疗效的评价。

实时荧光定量PCR在食品致病菌及转基因成分检测中应用

与传统定性PCR技术相比,实时荧光定量PCR有更多的优点,其速度快,特异性更强、灵敏度更高、无污染性、自动化水平高等,且能对DNA模板进行定量。本文综述了实时荧光定量PCR技术原理、分类及其应用,并对其存在的问题和发展前景进行了展望。

应用荧光定量RT-PCR检测J亚群禽白血病病毒

针对J亚群禽白血病病毒(ALV-J)基因序列保守区域设计一对特异性引物和一条特异性探针,通过构建重组阳性标准质粒作为阳性标准品,建立了检测ALV-J核酸的荧光定量PCR方法。优化反应体系和条件后进行特异性、敏感性、重复性试验。结果显示,该检测方法特异性强,与其它禽源病毒如A亚群禽白血病病毒(ALV-A)、B亚群禽白血病病毒(ALV-B)、新城疫病毒(NDV)、禽流感病毒(AIV)、鸡传染性贫血病毒(CIAV)和马立克病病毒(MDV)均不发生交叉反应;该方法可检测到3.2×102拷贝/μL的病毒核酸,与常规RT-PCR相比,敏感性高100倍;重复性试验的变异系数小于2%。研究结果表明,建立的Real-time RT-PCR检测方法特异性强、灵敏度高、可重复性好,可用于ALV-J的定量检测。

用荧光定量PCR及金标法检测不孕妇女生殖道沙眼衣原体感染的比较

目的检测73例不孕妇女宫颈分泌物中沙眼衣原体感染情况。方法应用荧光定量PCR及金标法并将两种方法作比较。结果表明用荧光定量PCR法检测不孕的沙眼衣原体阳性为41例(56.1%),阴性32例(43.9%),金标法检测阳性为19例(26.0%),阴性54例(74.0%),荧光定量PCR检测的阳性率明显高于金标法检测(P <0.01)。结论荧光定量PCR法在检测沙眼体较金标法更敏感、快速,是早期诊断生殖道沙眼衣原体感染的一种极有价值的方法。

实时荧光PCR技术快速检测食品中的蜡样芽孢杆菌

以蜡样芽孢杆菌gyrB基因作为目标基因并设计特异性引物,用95℃预变性5 min、95℃变性15 s、50℃复性30 s、72℃延伸30 s,反应45个循环为反应程序,以蜡样芽孢杆菌DNA为模板进行荧光定量聚合酶链式反应(PCR),提出了食品中蜡样芽孢杆菌快速检测的方法,并对该方法特异性、蜡样芽孢杆菌DNA灵敏度以及活菌检出限进行验证。结果表明,该引物在分段扩增中可以实现对蜡样芽孢杆菌的快速检测,而且重复性好;以3种非蜡样芽孢杆菌和蜡样芽孢杆菌进行特异性试验,非蜡样芽孢杆菌均没有扩增出曲线,仅蜡样芽孢杆菌扩增出特异性曲线;蜡样芽孢杆菌DNA按10倍稀释法进行灵敏度检测,可达0.01 mg·L^(-1),活菌检出限为8.9×10^(2)CFU·mL^(-1)。

急性心肌梗死患者血浆游离线粒体DNA拷贝数定量分析及临床意义

目的探究急性心肌梗死(AMI)后血浆游离线粒体DNA拷贝数变化及其临床意义。方法采集50例健康体检者血浆标本为对照组,50例AMI患者为AMI组,应用荧光定量PCR法测定其循环游离线粒体DNA拷贝数。结果对照组血浆游离线粒体DNA拷贝数为4×10~4(2.5×10~4,9.5×10~4)copies/mL;AMI组血浆游离线粒体DNA拷贝数为2.2×10~5(4.9×10~5,0.8×10~5)copies/mL,差异有统计学意义(P<0.05)。结论 AMI患者血浆游离线粒体DNA拷贝数升高,血浆游离线粒体DNA拷贝数检测可能成为辅助诊断心肌梗死的生物学标志。

Development of TaqMan-based Real-time PCR Assay for Detecting Transmissible Gastroenteritis Virus and Its Application in Vaccine Evaluation

[Objective] This study aimed to establish a TaqMan-based real-time PCR assay for detecting transmissible gastroenteritis virus （TGEV）. [Method] Primers and a probe were designed according to the conserved sequence of N gene in TGEV genome. After gradient dilution, the recombinant plasmid harboring the N gene was used as a standard for real-time PCR assay to establish the standard curve. [Re- sult] The results showed that the established real-time PCR assay exhibited a good linear relationship within the range of 102-10^10 copies/ul; the correlation coefficient was above 0.99 and the amplification efficiency ranged from 90% to 110%. The de- tection limit of real-time PCR assay for TGEV was 10 copies/μl, suggesting a high sensitivity; there was no cross reaction with other porcine viruses, indicating a good specificity; coefficients of variation within and among batches were lower than 3%, suggesting a good repeatability. The established real-time PCR method could be ap- plied in quantitative analysis and evaluation of the immune efficacy of TGEV vac- cines and detection of TGEV in clinical samples. [Conclusion] The TaqMan-based real-time PCR assay established in this study is highly sensitive and specific, which can provide technical means for the epidemiological survey of TGEV, development of TGEV vaccines and investigation of the pathogenesis of TGE.

A Method for Detecting Adhesive Related-Factors of Streptococcus suis Serotype 2 by Real-time PCR

[Objective] This study aimed to establish a method for quantitative detection of mRNA transcriptional level of SS2 adhesive related-factors of Streptococcus suis serotype 2 （SS2） by fluorescent quantitative PCR. []Vlethod] The gene fragments en- coding SS2 adhesive related-factors MRP, FBPS and CPS2J and a housekeeping gene aroA were amplified by reverse transcription PCR from the total RNA of SS2, cloned, and sequenced. The recombinant plasmids containing the target genes were constructed, and used as templates in Real-time PCR. [Result] Dynamic curves, stan- dard curves and melting curves of the adhesive related-factors and aroA were ob- tained by the optimized Real-time PCR system. The standard curves showed a good linear relationship between template copy number and circulation number, and the correlation coefficients （FF） of the standard curves were over 0.995. Also, these as- says were highly specific a^d there was single specific melting peak for every gene. Moreover, the assays were highly sensitive and had a detection limit of 1.0×102 copies in 1 μl of initial templates. Finally, it was highly repeatable and had a coeffi- cient of variation less than 2% for intra-assay. [Conclusion] This study will provide a way to reveal the adhesion mechanism of SS2 to different host cells at molecular level.

From Phenotypes to Molecules: Revolutionizing Gut Microbiota Identification Methods

The gut microbiota is a complex ecosystem composed of many bacteria and their metabolites.It plays an irreplaceable role in human digestion,nutrient absorption,energy supply,fat metabolism,immune regulation,and many other aspects.Exploring the structure and function of the gut microbiota,as well as their key genes and metabolites,will enable the early diagnosis and auxiliary diagnosis of diseases,new treatment methods,better effects of drug treatments,and better guidance in the use of antibiotics.The identification of gut microbiota plays an important role in clinical diagnosis and treatment,as well as in drug research and development.Therefore,it is necessary to conduct a comprehensive review of this rapidly evolving topic.Traditional identification methods cannot comprehensively capture the diversity of gut microbiota.Currently,with the rapid development of molecular biology,the classification and identification methods for gut microbiota have evolved from the initial phenotypic and chemical identification to identification at the molecular level.This review integrates the main methods of gut microbiota identification and evaluates their application.We pay special attention to the research progress on molecular biological methods and focus on the application of high-throughput sequencing technology in the identification of gut microbiota.This revolutionary method for intestinal flora identification heralds a new chapter in our understanding of the microbial world.

Application of Real-time Fluorescent Quantitative PCR in Plant

Real-time fluorescent quantitative PCR （RQ-PCR） is a detection method by adding fluorescent dye or fluorescent probe into the PCR reaction system, using fluorescent signal accumulation to monitor amplification reactions of PCR reaction process, and finally the unknown template can be quantitatively analyzed through the standard curve. So the detection level of PCR has improved from the qualitative to the quantitative. In order to provide a theoretical reference for further application, the principle, classification, advantages and disadvantages of RQ-PCR were intro- duced, and its application and progress in plants in recent years were reviewed.

Establishment and Application of a Real-time PCR Method for Detecting stx2 Gene in Shiga Toxin-producing Escherichia coli(STEC)

[Objective] This study aimed to establish a real-time PCR method for de- tecting stx2 gene in Shiga toxin-producing E. coli （STEC）. [Method] According to the known STEC stx2 gene sequences published in GenBank, PCR primers and probes were designed based on the conserved region to construct recombinant plasmid as a positive template, thus optimizing the reaction conditions and establishing the real- time PCR method. [Result] A standard curve was established based on the opti- mized real-time PCR system, indicting a good linear correlation between the initial template concentration and Ct value, with the correlation coefficient F^e of above 0.995. The established method had a good specificity, without non-specific amplifica- tion for 10 non-STEC intestinal bacterial strains; the detection limit of initial template was 1.0x102 copies/μI, indicating a high sensitivity; furthermore, the coefficients of variation within and among batches were lower than 1% and 5% respectively, sug- gesting a good repeatability. [Conclusion] In this study, a real-time PCR method was successfully established for detecting STEC stx2 gene, which provided technical means for rapid detection of STEC in samples.

Respiratory Virus Multiplex RT-PCR Assay Sensitivities and Influence Factors in Hospitalized Children with Lower Respiratory Tract Infections

Multiplex RT-PCR assays have been widely used tools for detection and differentiation of a panel of respiratory viral pathogens. In this study, we evaluated the Qiagen ResPlex lI V2.0 kit and explored factors influencing its sensitivity. Nasopharyngeal swab （NPS） specimens were prospectively collected from pediatric inpatients with lower respiratory tract infections at the time of admission in the Shenzhen Children＇s Hospital from May 2009 to April 2010. Total nucleic acids were extracted using the EZ1 system （Qiagen, Germany） and 17 respiratory viruses and genotypes including influenza A virus （FluA）, FluB, parainfluenza virus 1 （PIV1）, PIV2, PIV3, PIV4, respiratory syncytial virus （RSV）, human metapneumovirus （hMPV）, rhinoviruses （RhV）, enteroviruses （EnV）, human bocaviruses （hBoV）, adenoviruses （AdV）, four coronaviruses （229E, OC43, NL63 and HKU1）, and FluA 2009 pandemic H1NI（H1NI-p） were detected and identified by the ResPlex II kit. In parallel, 16 real-time TaqMan quantitative RT-PCR assays were used to quantitatively detect each virus except for RhV. Influenza and parainfluenza viral cultures were also performed. Among the total 438 NPS specimens collected during the study period, one or more viral pathogens were detected in 274 （62.6%） and 201（45.9%） specimens by monoplex TaqMan RT-PCR and multiplex ResPlex, respectively. When results from monoplex PCR or cell culture were used as the reference standard, the multiplex PCR possessed specificities of 92.9-100.0%. The sensitivity of multiplex PCR for PIV3, hMPV, PIV1 and BoV were 73.1%, 70%, 66.7% and 55.6%, respectively, while low sensitivities （11.1%-40.0%） were observed for FluA, EnV, OC43, RSV and H1N1. Among the seven viruses/genotypes detected with higher frequencies, multiplex PCR sensitivities were correlated significantly with viral loads determined by the TaqMan RT-PCR in FluA, H 1N 1-p and RSV （p=0.011-0.000） The Qiagen ResPlex II multiplex RT-PCR kit possesses excellent specificity for simultaneous detection of 17 viral pathogens in NPS specimens in pediatric inpatients at the time of admission. The sensitivity of multiplex RT-PCR was influenced by viral loads, specimen process methods, primer and probe design and amplification condition.