Detection of Lactobacillus acidophilus in Fermented Material by Real-time Fluorescent Quantitative PCR

The species distinctive PCR primer of Lactobacillus acidophilus （ L. acidophilus） was designed according to 16S rRNA gene sequences of conunon Lac- tobacillus species in fermented material. Bacterial genome DNA of separated L. acidophilus in fermented sample was taken as template, and L. acidophilus in fer- mented material was conducted the quantitative determination by real-time quantitative PCR （RT-PCR）. Analysis on RT-PCR results shown that contents of L. aci- dophilus in the test sample reached 1.5 billion CFU / g. Test results shown that contents of L. acidophilus in fermented material could be detected accurately by the established RT-PCR method in the test. indicating that the established RT-PCR method could be aookued to the detection of L. acidophilus in fermented material.

Real-time fluorescent quantitative immuno-PCR method for determination of fluoranthene in water samples with a molecular beacon

A reliable and sensitive competitive real-time fluorescent quantitative immuno-PCR （RTFQ-IPCR） assay using a molecular beacon was developed for the determination of trace fluoranthene （FL） in the environment.Under optimized assay conditions,FL can be determined in the concentration range from 1 fg/mL to 100 ng/mL,with y=0.194x ＋ 7.859,and a correlation coefficient of 0.967 was identified,with a detection limit of 0.6 fg/mL.Environmental water samples were successfully analyzed,recovery was between 90% and 116%,with intra-day relative standard deviation （RSD） of 6.7%-12.8% and inter-day RSD of 8.4%-15.2%.The results obtained from RTFQ-IPCR were confirmed by ELISA,showing good accuracy and suitability to analyze FL in field samples.As a highly sensitive method,the molecular beacon-based RTFQ-IPCR is acceptable and promising for providing reliable test results to make environmental decisions.

Application of Real-time Fluorescent Quantitative PCR in Studies on Plants

Real-Lime fluorescent quantitative PCR is a method for quantitative analysis of gene expression developed in recent years, which has been widely used in various fields such as basic scientific research, clinical diagnosis, disease study, drug research and development since its appearance. It starts relatively late in study on plants, but has already been used for analysis of gene expression in plants and gene identification of exogenous genes. The principles or advantages and dis- advantages of real-time fluorescent quantitative PCR, or its potential problems and condition optimizations in tests were introduced in this study, and then the appli- cation and prospect of real-time fluorescent quantitative PCR in study on plants were also been discussed.

Establishment of a Real-time Fluorescent Quantitative PCR Assay for Detection of Genetically Modified Maize Line MON88017

In order to improve the standardized technical systems of quantitative analyses for genetically modified organisms （GMOs） and products, ensure bio-safety and reduce ecological risk in China, a real-time fluorescent quantitative PCR assay was established for detection of genetically modified maize line MON88017. The established method was evaluated based on the specificity, sensitivity, accuracy and measurement uncertainty. The results showed that the established method had strong specificity in detection of genetically modified maize line MON88017. 1.50% MON88017 sample was detected with 29 replica- tions. The average measured value （ 1. 541% ） was close to the actual value （ 1.50% ） and the relative deviation was 2.70%. The variation coefficient of the measured value was 0.110 g ; the recovery was 100.00% and the measurement uncertainty was 0. 096. The limit of detection for genetically modified maize line MON88017 with the established method was 5 copies at the 97.5% confidence level. Thus, the real-time fluorescent quantitative PCR assay established in this study exhibited high specificity, accuracy and sensitivity, which could provide technical support for the safety supervision of genetically modified organ- isms and products in China.

Detection of Ratoon Stunting Disease in Virus-free Seedcane via Real-time Fluorescence Quantitative PCR

This study was to develop the real-time fluorescence quantitative PCR technique for detecting the ratoon stunting disease （RSD） in virus-free seedcane seedlings. Healthy tissue culture seedlings were obtained from six plants of sugarcane ROC22, which had been confirmed RSD-positive by detecting the sugarcane juice, by employing the sugarcane seedlings production protocol. Real-time fluorescence quantitative PCR was used to detect RSD pathogens in tissue culture sam- pies. The results showed that target fragment of RSD pathogens was not found in all 10 samples in real-time fluorescence quantitative PCR, with the Ct values of 37 - 39. The healthy tissue culture sugarcane seedlings do not carry RSD pathogens, indicating that adopting healthy seedcane seedlings production technique could thoroughly get rid of RSD pathogens.

Synchronous Detection of DNA/RNA of Four Shrimp Viruses by Real-time Fluorescence Quantitative RT-PCR

[ Objective] This study aimed to establish a simultaneous detection method of shrimp viruses by real-time fluorescence quantitative RT-PCR, to improve the efficiency of inspection and quarantine. [ Method] A novel real-time fluorescence quantitative RT-PCR assay was established and optimized for simultaneously detecting DNA/RNA of four shrimp viruses （WSSV, IHHNV, TSV and YHV ）. [ Result] The optimized real-time fluorescence quantitative RT-PCR system gener- ated typical amplification curves with high amplification efficiencies （E = 1.06, 1.07, 0.92 and 0.92, respectively）, good hnear relationship （ r = 1 ）, uniform repeatability （ standard deviation = 0.05 - 0.46 ; variation coefficient = 0.26% - 1.62% ） and high sensitivity, exhibiting no significant differences compared with re- al-time fluorescence quantitative PCR （average error of Ct value = 0.04 -0.40; T = 0.53 -2.50; P 〉 0.05 ）. The total detection time was about 1 h. [ Conclusion] The optimized real-time fluorescence quantitative RT-PCR system can be used for rapid detection of WSSV, IHHNV, TSV and YHV.

Detection and clinical significance of multidrug resistance-1 mRNA in bone marrow cells in children with acute lymphoblastic leukemia by real-time fluorescence quantitative RT-PCR

Objective： Multidrug resistance（MDR） is one of the most important reasons for treatment failure and recurrence of acute leukemia. Its manifestations are different in children with acute lymphoblastic leukemia（ALL） which may be due to different detection methods. This study was to detect the expression of MDR1 mRNA in bone marrow cells of children with ALL by real-time fluorescence- quantitative reverse transcription polymerase-chain reaction（FQ-RT-PCR）, and combine minimal residual desease（MRD） detection by flow cytometry（FCM） and to study their relationship with treatment response and prognosis of ALL. Methods：The MDR1 mRNA levels in bone marrow cells from 67 children with ALL[28 had newly diagnosed disease, 27 had achieved complete remission（CR）, 12 recurrent] and 22 children without leukemia were detected by FQ-RT-PCR. MRD was detected by FCM. The patients were observed for 9-101 months, with a median of 64 months. Results：Standard curves of human MDR1 and GAPDH genes were constructed successfully. MDR1 mRNA was detected in all children with a positive rate of 100%. The mRNA level of MDR1 was similar among the newly diagnosed ALL group, CR group, and control group（P 〉 0.05）, but significantly higher in the recurrence group than that in newly diagnosed disease group and control group（0.50 ± 0.55 vs. 0.09 ± 0.26 and 0.12 ± 0.23, P〈 0.05）. 54 ALL patients were followed up, and it was found that MDR1 mRNA level was significantly higher in ALL patients within 3 years duration than that of ALL patients with 3-6 years and over 6 years duration（0.63 ± 0.56 vs. 0.11 ± 0.12 and 0.04 ± 0.06, P〈 0.01）. For the 28 children with newly diagnosed disease, the MDR1 mRNA level was similar between WBC 〉 50 ~ 109 group and WBC〈50 × 10^9 group（P〉 0.05）. In the 33 CR patients, the MDR1 mRNA level was significantly higher in MRD〉10a group than that in MRD〈10a group（0.39 ± 0.47 vs. 0.03 ± 0.03, P 〈 0.05）. Conclusion：The sensitivity and specificity of FQ-RT-PCR in detecting MDR1 mRNA in bone marrowy cells of children with ALL patients are high. MDR1 mRNA is expressed in children with and without leukemia. MDR1 mRNA is highly expressed in the CR ALL patients with high MRD, recurrence and short duration（within 3 years）. Monitoring MRD and the MDR1 mRNA level might be helpful for individual treatment.

Development and Preliminary Application of SYBR Green I Real-Time Fluorescence Quantitative PCR Method for Detecting Porcine Parvovirus Virus

According to VP2 gene sequence of the porcine parvovirus virus strain NADL-2 （NC001718） available in GenBank （NC_001718）, a pair of specific primer was designed, and the target fragment of 431 bp was obtained by PCR amplification. The products were ligated with pMD18- T vector and then transformed into bacteria DH5α for recombinant plasmid extraction. After PCR identification and sequencing, recombinant plasmid was used as a standard template to establish the standard curve of SYBR Green I fluorescence quantitative PCR. Sensitivity test, specificity test and repeatability test were also determined. The results indicated that there was a good linear relationship between threshold cycle of the standard curve and template concentration, R2 =0.997 6. Tm ranged from 82.3 to 82.9 ℃, while the sensitivity was 72.1 copies/μl with good specificity and repeatability. The developed SYBR Green I real-time quantitative PCR method to detect PPV VP2 gene laid the basis for further studies on patho- oenesis, early clinical diaonosis of this virus and quantitative analysis of PPV infection.

Real-Time PCR探针法定量检测沙门菌方法的建立及应用

目的建立快速、特异性好、灵敏度高的Real-Time PCR方法定量检测沙门菌。方法根据编码沙门菌肠毒素基因stn的核苷酸序列,设计荧光探针和一对引物,通过对荧光定量PCR反应体系和反应条件的摸索,建立定量检测沙门菌的方法。结果建立的Real-Ti me PCR方法有很好的特异性与敏感性,所检测沙门菌结果均为阳性,而非沙门菌均为阴性;标准曲线相关系数为R2=0.993,其敏感性为5CFU。运用该方法对108份鸡粪便、50份鸡肉以及58份水样进行检测,阳性率分别为3.7%(6/108)、4%(2/50)和3.4%(2/58),与传统细菌分离检测结果相符。结论结果表明该方法具有简便、快速、特异性强、敏感性高等特点,此研究为环境及疾病诊断中沙门菌快速检测提供了新方法。

Real-time TaqMan RT-PCR快速检测犬瘟热病毒方法的研究

按照犬瘟热(CDV)N基因序列,设计合成了特异性引物和探针,经各反应条件的优化,建立了Real-time荧光定量RT-PCR技术,对细胞培养物、肝脏、肺脏、脑、脾脏、淋巴结以及鼻腔拭子等组织病料中的CDV进行了特异性检测和敏感性试验。同时,利用建立的Real-time荧光定量RT-PCR方法与常规RT-PCR以及韩国BIOINDIST生产的BIT RAPID CDV检测试剂盒对57份临床样品进行了检测。结果:用20pmol/mL的引物浓度各1uL和20pmol/mL的探针浓度0．3uL,获得的荧光信号最强,曲线平滑。敏感性高,可检测到1．24×10—3ng/uL的病毒RNA;特异性强,与NDV、AIV、NiPV等RNA病毒不发生交叉反应。试验重复性的变异系数(CV)分别为2．3%、2．5%和4．2%;与常规RT-PCR和BIOINDIST生产的BIT RAPID CDV检测试剂盒相比较,该方法具有快速、特异、敏感、可定量,并可同时检测大量样品等优点。

3种猪繁殖障碍性病毒Real-time PCR快速检测方法的建立

【目的】建立可同时检测猪伪狂犬病毒(PRV)、猪细小病毒(PPV)和猪圆环病毒Ⅱ型(PCV2)的多重实时荧光定量PCR方法。【方法】根据GenBank数据库中PRV、PPV和PCV2的核苷酸序列,设计3对特异性引物和探针,以10倍系列稀释的阳性质粒为模板,优化反应条件,建立检测PRV、PPV和PCV2的多重Real-time PCR方法,并对其敏感性、重复性和特异性进行检验;分别采用单项和多重Real-time PCR方法,对临床收集的42份疑似病料进行检测,比较2种方法的符合率。【结果】特异性和灵敏度试验表明,建立的多重Real-time PCR检测方法具有高度特异性,与其他病原无明显交叉反应;检测灵敏度高,可检出1.0×101拷贝/μL的阳性质粒或1TCID50/mL的病毒样品。用多重Real-time PCR对42份临床疑似病料进行检测,其检测结果与单重Real-time PCR结果完全一致,表明多重Real-time PCR方法是可行的。【结论】建立了可同时检测PRV、PPV和PCV2的多重Real-time PCR方法,该法具有快速、灵敏、特异和重复性好等优点。

犬冠状病毒和犬细小病毒双重TaqMan荧光定量PCR检测方法的建立

旨在建立犬冠状病毒(CCoV)和犬细小病毒(CPV)双重TaqMan荧光定量PCR检测方法。针对CCoV的3′UTR与CPV的VP2设计引物与探针,通过对反应体系与条件进行优化,建立了CCoV与CPV的双重荧光定量PCR检测方法,并对该方法进行敏感性、特异性、重复性验证与临床样品检验。结果:CCoV与CPV阳性参考质粒浓度在10^(2)~10^(7) copies/μL,CCoV与CPV的标准曲线R^(2)分别为0.999与0.996,线性关系良好,CCoV与CPV的最低检测限均为5 copies/μL,与其他病原无交叉反应,组内与组间的变异系数均小于1.38%,说明该方法灵敏度高、特异性强、重复性良好;对113份临床样本进行检测,与普通PCR比较,该方法对CCoV和CPV的检出率较高,分别为37.2%和40.7%。研究表明,本试验建立的CCoV和CPV双重荧光定量PCR方法检测效果良好,为相关疾病的临床诊断、流行病调查等提供了有力工具。

牦牛源牛肠道病毒实时荧光定量PCR检测方法的建立及应用

为了快速、准确地检测牦牛源牛肠道病毒(Bovine enterovirus,BEV),试验根据GenBank中牦牛源BEV-NH2株3D基因序列(登录号为PP746571)设计可用于检测青海牦牛源BEV的实时荧光定量PCR特异性引物,通过构建标准质粒和绘制标准曲线建立牦牛源BEV实时荧光定量PCR检测方法,对该方法进行特异性、敏感性和重复性试验,并分别应用该方法及普通RT-PCR方法对青海省海北地区6个牦牛繁育基地的286份腹泻牦牛粪便样品进行检测,计算两种方法的符合率。结果表明:建立的牦牛源BEV实时荧光定量PCR检测方法扩增产物的熔解曲线单一,Tm值在85.6~85.8℃之间,无引物二聚体和非特异性扩增;质粒浓度在3×10^(2)~3×10^(8)copies/μL范围内时标准曲线的线性关系良好,Ct值在10.88~29.63之间,回归方程为y=-3.16x+38.01,R^(2)=0.9964;仅可检测到牦牛源BEV-NH2株,检测不到牛病毒性腹泻病毒(Bovine viral diarrhea virus,BVDV)MY01株、牛轮状病毒(Bovine rotavirus,BRV)MY20株和牛冠状病毒(Bovine coronavirus,BcoV)QL21株;对牦牛源BEV的最低检测限为3×10^(2)copies/μL;当模板浓度为3×10^(2)copies/μL、3×10^(3)copies/μL和3×10^(7)copies/μL时,Ct值的变异系数分别为1.28%、1.74%和0.15%,均在1.80%以下。286份牦牛粪便样品中,采用建立的实时荧光定量PCR检测方法检出BEV阳性样品182份,阳性率为63.64%;采用普通RT-PCR方法检出BEV阳性样品114份,阳性率为39.86%;两种方法的符合率为76.22%。说明本研究建立的牦牛源BEV实时荧光定量PCR检测方法特异性强、敏感性高、重复性好,可用于牦牛腹泻临床样本的BEV检测。

鸽圆环病毒荧光定量PCR检测方法的建立及应用

为实现对鸽圆环病毒(pigeon circovirus, PiCV)的快速检测,建立了针对Cap基因的PiCV荧光定量PCR检测方法,并应用该方法进行PiCV分子流行病学调查。本研究针对PiCV核衣壳蛋白Cap基因的保守序列设计一对特异性引物,并通过优化反应条件,成功建立了荧光定量PCR检测方法。此外,还对该方法的灵敏度、特异性、重复性进行了全面评估。利用建立的荧光定量PCR方法对华北和西北部分地区147份临床样本进行检测,并对阳性代表样本的Cap全长序列进行遗传演化分析。结果表明,所建立的荧光定量PCR方法在1×10^(4)至1×10^(8)拷贝·μL^(-1)范围内显示出良好的线性关系,最低检测限达到1×10^(1)拷贝·μL^(-1),显著高于传统PCR方法。此方法具有良好的重复性,且不与其他常见鸽病病原产生交叉反应。采用本试验方法检测的147份华北和西北部分地区肉鸽和信鸽临床样本PiCV阳性率为85.0%,阳性样本的Cap全长序列分析及遗传演化分析结果显示,6株分离株相似性在89.8%~97.5%之间,与PiCV HeBeiTS2021株在同一个分支,亲缘关系较近。建立的PiCV荧光定量PCR方法具备灵敏、特异和稳定等优点,可用于PiCV的快速检测,同时流行病学调查结果表明,2022—2023年华北和西北部分地区PiCV感染率较高,为我国PiCV的防控研究提供数据支撑。

兔源支气管败血波氏杆菌荧光定量PCR检测方法的建立

【目的】建立兔源支气管败血波氏杆菌(Bb)的快速检测方法,用于兔波氏杆菌病的诊断。【方法】以Bb的fimX基因为靶基因,设计特异性引物并构建质粒标准品。在此基础上建立检测兔源Bb的SYBR GreenⅠ荧光定量PCR方法,对该方法的特异性、敏感性和重复性进行评价,并将该方法初步应用于临床样品的检测。【结果】荧光定量PCR方法仅对兔源Bb的检测结果呈阳性,对其他常见兔源病原菌的检测结果均呈阴性;对质粒标准品的最低检测限为13.8拷贝·μL^(-1),敏感性是普通PCR方法的10倍;批内重复性试验的变异系数小于2%,批间重复性试验的变异系数小于3%;对68份临床样品进行检测,阳性检出率为39.71%,比普通PCR方法的高2.95%。【结论】建立的SYBR GreenⅠ荧光定量PCR方法特异性强、敏感性高、重复性好,且对临床样品的阳性检出率比普通PCR方法高,为兔源Bb的快速检测和防控提供了技术支持。

Real-time PCR检测大豆CONSTANS基因在不同光照条件下的表达

采用实时荧光定量PCR方法检测了不同感光大豆品种的CO(CONSTANS)基因在不同光照条件下的mRNA水平变化。结果表明:早熟品种东农49和晚熟品种东农42各自在短日照(8h/16h光/暗)下会比长日照(16 h/8 h光/暗)下表达有所增强,同时东农49中CO基因的表达要高于东农42,它们的表达峰值均出现在光暗交界处。东农42由长日照或短日照移入完全光或完全暗条件时,暗下CO基因的表达量剧增,并且大致维持之前长日照和短日照的表达规律。CO基因的表达有很强的昼夜节律性,暗下利于其表达,并且在不同感光品种中表达有所不同。

Real-time PCR方法检测高脂饲喂小鼠肝脏CYP2A5的表达

为了建立非酒精性脂肪肝(NAFLD)模型小鼠肝组织中CYP2A5表达的实时荧光定量PCR(real-time fluorescence quantitative PCR,qRT-PCR)方法。高脂饮食诱导小鼠至8周,采用qRT-PCR方法检测小鼠肝脏中CYP2A5的表达水平,同时评价该方法的特异性。建立了小鼠肝组织中CYP2A5的SYBR Green实时荧光定量PCR检测方法,结果显示,该方法的溶解曲线为单峰,同时核酸电泳显示一条特异性条带。检测结果表明,高脂诱导的NAFLD小鼠肝组织中CYP2A5的表达水平极明显高于正常对照组(P<0.01)。表明该实时荧光定量PCR方法,特异性好、灵敏度强,为进一步研究小鼠CYP2A5的表达提供了试验基础。

微小隐孢子虫和安氏隐孢子虫SYBR Green real time PCR检测方法的建立

根据GenBank中登录的隐孢子虫小亚基rRNA基因序列设计1对引物,并以标准基因组DNA为模板,初步建立了检测乳牛微小隐孢子虫和安氏隐孢子虫的SYBR Green real time PCR方法,并对乳牛微小隐孢子虫和安氏隐孢子虫阳性样品和上海40份乳牛粪便进行了检测。结果表明,此次建立的real timePCR对微小隐孢子虫和安氏隐孢子虫均能扩增出曲线,且其他寄生虫(鸡贝氏隐孢子虫、刚地弓形虫、犬新孢子虫)和大肠杆菌均未检测到;标准基因组DNA的检测阈值达到5个拷贝,牛粪中卵囊的最低检测量为每克粪便5个卵囊,乳牛粪便阳性率为15%(6/40)。表明,建立的荧光定量PCR快速、特异、敏感,可用于乳牛隐孢子虫病的流行病学调查。

Rea1-time qPCR检测安氏隐孢子虫卵囊方法的建立及应用

根据GenBank公布的安氏隐孢子虫SSU rRNA基因序列设计1对引物和TaqMan探针,建立了基于Taq-Man探针检测安氏隐孢子虫的实时荧光定量PCR方法,并对奶牛粪便进行了检测。结果显示,设计的探针对检测安氏隐孢子虫具有很高的特异性;质粒DNA和卵囊的检测阈值分别达到5个拷贝和10个卵囊,奶牛粪便阳性率为21.15%(11/52)。建立的安氏隐孢子虫TaqMan荧光定量PCR检测方法简便、快速,特异性强,敏感度高,可用于安氏隐孢子虫的快速定量检测。

马铃薯病毒病实时荧光定量PCR检测技术

【目的】鉴定马铃薯主要病毒病病原,为马铃薯病毒病的科学防治提供科学依据。【方法】根据Gen-Bank数据库注册序列设计马铃薯Y病毒(Potato virus Y,PVY)、马铃薯S病毒(Potato virus S,PVS)、马铃薯卷叶病毒(Potato leaf roll virus,PLRV)的检测引物,完成引物浓度及系统优化。【结果】建立3种马铃薯病毒病的实时荧光定量PCR检测技术体系(real-time fluorescent quantitative RT-PCR,RT-qPCR),其标准曲线循环阈值与模板浓度呈良好的线性关系,相关系数为99.42%以上,扩增效率均为84.48%以上,可快速、准确检测出3种马铃薯病毒。【结论】实时荧光定量PCR检测技术是一种高灵敏度、特异性强的检测方法,可实时监测马铃薯生产中病毒病的感染情况。