Effects of Different Temperature and Time Durations of Virus Inactivation on Results of Real-time Fluorescence PCR Testing of COVID-19 Viruses

Summary:The novel coronavirus SARS-CoV-2 caused an outbreak of pneumonia in Wuhan,Hubei province of China in January 2020.This study aims to investigate the effects of different temperature and time durations of virus inactivation on the results of PCR testing for SARS-CoV-2.Twelve patients at the Renmin Hospital of Wuhan University suspected of being infected with SARS-CoV-2 were selected on February 13,2020 and throat swabs were taken.The swabs were stored at room tempcrature(20-25℃),then divided into aliquots and subjected to different temperature for different periods in order to inactivate the viruses(56℃for 30,45,60 min;65,70,80℃for 10,15,20 min).Control aliquots were stored at room temperature for 60 min.Then all aliquots were tested in a real-time fluorescence PCR using primers against SARS-CoV-2.Regardless of inactivation temperature and time,7 of 12 cases(58.3%)tested were positive for SARS-CoV-2 by PCR,and cycle threshold values were similar.These results suggest that virus inactivation parameters exert minimal infuence on PCR test results.Inactivation at 65℃for 10 min may be sufficient to ensure safe,reliable testing.

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.

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 fluorescent quantitative PCR非特异性扩增的研究进展

Real-time fluorescent quantitative PCR(RT-qPCR)因其高效快速、操作简便、高度敏感等优点获得广泛应用,但因其强大的放大功能而容易出现非特异性扩增的问题,尤其是荧光染料法中更加明显。文章对RT-qPCR的原理、非特异性扩增的发生因素、解决方案及该技术的应用前景进行了综述。

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.

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.

Development of Real-Time Fluorescent PCR for Rapid Detection of Haempohlius parasuis

[ Objective] To develop a real-time fluorescent PCR assay for rapid detection of Haempohlius parasuis （HPS）. [ Method] According to the conservative sequences of 16 S rRNA genes of HPS published in GenBank, a pair of specific primers was designed. The real-time fluorescent PCR was developed by optimizing primer concentration and annealing temperature. And its specificity and reproducibility were evaluated. Ten HPS- suspected samples were detected by the developed method. [ Result] The lowest detection limit of the developed real-time fluorescent PCR was 50 copies/μl. This method had good reproducibility, and its coefficient of variation was lower than 2%. Only HPS rather than Streptococcus suis type 2, Staphylococcus aureus, E. coli DH5 alpha, and swine Salmonella typhi could be detected by the developed real-time fluorescent PCR. The HPS-pesitive samples detected by this method were also positive when they were detected by isolation of bacteria or conventional PCR. [ Conclusion] The developed real-time fluorescent PCR is rapid, sensitive, specific and highly reproducible; thus, it can be used for rapid detection of HPS.

Synchronously Detecting Allergenic Ingredients of Peanut and Sesame in Food by Real-time Fluorescent PCR

Peanut,sesame and other raw materials of food are allergens for special populations.In this study,specific primers and TaqMan probes labeled by different fluorescences were designed targeting Ara h 2 gene of peanut and Ses i 1 gene of sesame.After the optimization of reaction conditions,a real-time fluorescent PCR method was established for simultaneous detection of allergenic ingredients of peanut and sesame in food.Genomic DNA samples of peanut,sesame,rice,wheat,barley,soybean,celery,maize,potato,tomato,walnut,groundnut in shell,cashew nut,sunflower seed,almond,apple,pear and strawberry,pork,beef,mutton and fish were used as templates for PCR amplification with deionized water as negative control template.Results indicated that the established real-time fluorescent PCR method could specifically identify allergenic ingredients of peanut and sesame simultaneously.Sensitivity test showed that the minimum detection limit of this method was 0.01%.Therefore,the established real-time fluorescent PCR method is a specific,sensitive and effective assay for simultaneously detecting allergenic ingredients of peanut and sesame in food.

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.

PCR技术在食品微生物检测中的应用研究

PCR技术因具有高灵敏度、高特异性和快速性的特点,在食品微生物检测领域广泛使用。本文阐述食品中常见的致病微生物、PCR技术的基本原理、食品中常见致病微生物的PCR检测方法,探讨PCR技术在食品微生物检测中的应用,并介绍PCR技术在食品微生物检测中的发展趋势。

应用TaqMan-MGB探针实时荧光定量PCR技术快速检测青海省海西州鼠疫自然疫源地鼠疫耶尔森菌耐链霉素基因

目的 应用TaqMan-MGB探针实时荧光定量PCR技术快速检测青海省海西州鼠疫自然疫源地鼠疫菌耐链霉素基因,为今后该地区突发人间鼠疫的精准临床用药提供理论依据。方法 分离培养海西地区1957—2009年间取自鼠疫患者、媒介昆虫及中间宿主的代表性鼠疫菌110株,提取其DNA,针对我国链霉素耐药基因rpsl基因设计引物P-F和P-R和TaqMan-MGB探针Probe1 [FAM]和Probe2[VIC],利用荧光定量PCR技术,进行耐药rpsl基因筛查。结果 110株被试菌株中FAM检测均为阳性(RFU峰值>2000);VIC阳性的为0株(RFU峰值<200)。阳性对照和空白对照成立。结论 实时荧光定量PCR结果显示,该地区未检测出耐链霉素菌株。

Diagnosis of Mycobacterium tuberculosis using molecular biology technology

Objective:To present an integrated molecular biology dedicated system for tuberculosis diagnosis.Methods:One hundred and five sputum specimens from patients strongly suspected by clinical parameters of tuberculosis were studied by Ziehl-Neelsen staining,by cultivation on solid medium and by a balanced hemincsted fluorometric PCR system(Orange C3TB) that could preserve worker safety and produce a rather pure material free of potential inhibitors. DNA amplification was performed in a low cost tuberculosis termocycler-fluorotneter.Produced double stranded DNA was flurometrically detected.The whole reaction was conducted in one single tube which would not be opened after adding the processed sample in order to minimize the risk of cross contamination with amplicons.Results:The assay was able to delect 30 bacillus per sample mL with 99.8%interassay variation coefficient.PCR was positive in 23(21.9%) tested samples(21 of them were smear negative).In our study it showed a preliminary sensitivity of 94.5%for sputum and an overall specificity of 98.7%.Conclusions:Total run time of the test is 4 h with 2.5 real working time.All PCR positive samples are also positive by microbiological culture and clinical criteria.Results show that it could be a very useful tool to increase detection efficiency of tuberculosis disease in low bacilus load samples.Furthermore,its low cost and friendly using make it feasible to run in poor regions.

荧光定量PCR技术与酶联免疫法在手足口病肠道病毒检测中的应用价值比较

目的探讨荧光定量PCR技术(FQ-PCR)与酶联免疫法(ELISA)在手足口病肠道病毒检测中的应用价值。方法选取2021年1月至2022年12月就诊于广东省江门市妇幼保健院的疑似238例手足口病患儿,均行FQ-PCR检测与ELISA检测,统计FQ-PCR与ELISA病毒阳性检出率,以病毒分离培养及临床表现、血清实验室综合诊断结果为金标准,对比FQ-PCR与ELISA检测敏感度与特异度、准确度及检测窗口期。结果238例患儿中137例(57.56%)最终确诊为手足口病。FQ-PCR检测敏感度与特异度、准确度均高于ELISA,差异有统计学意义(P<0.05);FQ-PCR病毒阳性检出率较ELISA高,差异有统计学意义(P<0.05);FQ-PCR对通用型肠道病毒、Cox A16、EV71检测窗口期均短于ELISA检测,差异有统计学意义(P<0.05)。结论与ELISA相比,FQ-PCR在手足口病肠道病毒检测中具有更高的特异度、敏感度,可提高阳性检出率,且检测窗口期更短,利于临床早期实施治疗。

实时荧光PCR技术在高危型人乳头瘤病毒检测中的价值

目的 分析实时荧光PCR技术在高危型人乳头瘤病毒(HPV)检测中的价值。方法 选取本院行病理诊断检查的66例高危型HPV感染者及68例健康女性为研究对象,均实施实时荧光PCR技术和第二代杂交捕获试验(HC-Ⅱ)技术行HPV检测,比较两种检测技术的诊断效能。结果 以病理检验结果为金标准,实时荧光PCR技术的准确度、灵敏度、特异度、阳性预测值、阴性预测值、诊断符合率分别为94.03%、96.97%、91.18%、91.43%、96.88%、94.03%,高于HC-Ⅱ技术的76.12%、81.82%、70.59%、72.97%、80.00%、76.12%,差异有统计学意义(P<0.05)。结论 高危型HPV检测中应用实时荧光PCR技术,能够保证疾病检测结果的准确性和可靠性,进而为后续的临床治疗提供支持,应用价值较高。

利用重组PCR技术构建适合真菌ATMT转化的GFP基因表达载体

[目的]构建适合真菌ATMT转化的GFP基因表达载体。[方法]利用含有GFP基因和Nos终止子的A2GFP质粒和含有普遍适于真菌基因表达的构巢曲霉启动子(Ptrpc)的pUCATPH质粒,通过重组PCR技术构建Ptrpc-GFP-Nos重组基因,然后插入到农杆菌质粒pCAMBIA 1300的多克隆位点,构建适合真菌ATMT转化的GFP基因表达载体,并对其进行酶切和测序鉴定。[结果]通过重组PCR技术,仅通过Ptrpc启动子基因扩增、GFP-Nos基因扩增、Ptrpc-GFP-Nos重组基因扩增、1次双酶切、1次连接和转化,就成功地构建了适合真菌ATMT转化的GFP基因的表达载体pCAMBIA 1300-PGN,不需要构建中间载体,并大大简化了连接步骤。该载体经过PCR、酶切和测序鉴定,结构正确,连接准确,序列无误。[结论]该研究为真菌ATMT突变体的构建和快速检测奠定了基础。

实时荧光PCR在乙肝病毒DNA检测中的临床意义

目的用实时荧光定量PCR检测乙型肝炎患者HBV DNA结果进行分析,以探讨其临床诊疗意义。方法对630例血清标本用时间分辨荧光免疫技术定量测定乙肝炎病毒血清学指标,用荧光定量PCR法检测血标本中的HBVDNA,并依据乙肝两对半结果进行归类分组。结果 630份标本中,大三阳206例标本中有173份HBV-DNA为阳性,阳性率为84.0%,其PCR定量拷贝数为(2.13±0.72)×107/ml;小三阳211例中有64份HBV-DNA阳性,阳性率达到30.3%,PCR定量拷贝数为(1.61±0.85)×106/ml;69份HBs Ab(+)、HBe Ab(+)、HBc Ab(+)标本有33份HBV-DNA阳性,阳性率47.8%;27份HBs Ag(+)、HBc Ab(+)标本中有8份HBV-DNA为阳性,阳性率为29.6%;22份HBe Ab(+)、HBc Ab(+)标本有3份PCR HBV-DNA阳性,阳性率13.6%;20份HBs Ag(+)、HBs Ab(+)、HBe Ag(+)、HBc Ab(+)标本中有17份HBV-DNA为阳性,阳性率为85.0%;17份HBs Ab(+)、HBe Ab(+)阳性标本有3份PCR HBV-DNA阳性,阳性率为17.6%;13份HBs Ab(+)、HBc Ab(+)标本有1份HBV-DNA阳性,阳性率7.7%;12份HBc Ab(+)标本有5份PCR HBV-DNA阳性,阳性率为41.7%;2份HBs Ab(+)的标本HBV-DNA均为阴性,PCR定量拷贝数为<1.00E×103;1份HBs Ag(+)标本HBV-DNA均为阳性,阳性率为100%;其余30例全阴性结果和各少见模式基本未见有HBV-DNA的检出。结论 PCR定量测定HBV-DNA可以真实反映体内乙肝病毒感染和复制及病毒载量情况,更有利于临床治疗和疗效观察。

Validation of Molecular Detection Methods for Gluten Allergens in Infant Formula

[Objectives]To verify the specificity,sensitivity,precision and negative-positive deviation of the foodproof gluten component de-tection kit for the detection of gluten allergens in milk powder matrix,and to establish a real-time fluorescent PCR legal method for the detec-tion of gluten allergens in milk powder.[Methods]The specificity,sensitivity,precision and negative-positive deviation of the detection method of foodproof gluten component detection kit(PCR-probe method)were verified by artificially adding different concentrations of wheat bran and extracting sample DNA by kit method,and applied to sample detection.[Results] The specific detection results of two kinds of milk powder with wheat bran and buckwheat added showed that the foodproof gluten component detection kit(PCR-probe method)had good speci-ficity for wheat gluten.The results of artificially added wheat bran positive samples showed that the false positive rate and false negative rate of the kit in the milk powder matrix were O,and the sensitivity and precision were high.[Conclusions]The kit is simple to operate and has high accuracy,which is suitable for the detection of gluten allergen components in milk powder.

荧光定量PCR技术在环境微生物检测中的应用

阐述了实时荧光定量PCR技术的原理、特点及其在环境微生物检测中的应用与研究进展,分析了该技术在环境微生物检测中存在的问题,并探讨了存在的问题,以及其发展和应用前景。

实时荧光PCR技术检测妊娠晚期孕妇B族链球菌(GBS)感染的临床效能

目的分析妊娠晚期孕妇B族链球菌(GBS)感染接受实时荧光PCR技术检测的效能。方法以2017年10月—2018年12月该院6710例妊娠晚期孕妇为对象,通过PCR-荧光探针法、细菌培养法、基因测序法实施B族链球菌(GBS)检测,分析检测结果。结果实时荧光PCR筛查GBS感染的灵敏度为97.62%,特异度为99.68%,准确度为99.55%,阳性预测值为95.35%,阴性预测值为99.84%;实时荧光PCR检出GBS阳性率为6.41%,细菌培养法检出GBS阳性率为5.37%(χ^2=6.590,P<0.05)。结论实时荧光PCR技术检测能够较为准确筛查出妊娠晚期孕妇B族链球菌感染,具备较高准确度、特异度及灵敏度,能够指导临床积极采取干预措施。

高灵敏荧光定量PCR技术在乙肝患者中的应用分析

目的研究高灵敏荧光定量PCR技术在乙肝患者中的应用效果。方法现研究选取的研究对象为2016年10月—2017年6月在我院进行治疗的乙肝患者923例和同期在本院进行体检的健康体检者200例。使用高灵敏荧光定量PCR技术检测两组受检者。结果不同血清标志物阳性乙肝患者的HBV-DNA拷贝数差异存在统计学意义(P<0.05),阳性率分别为35.97%、57.96%、6.07%,乙肝患者间进行比较差异具有统计学意义(P<0.05)。结论采用高灵敏荧光定量PCR技术可较好的诊出乙肝,还可监测治疗过程及评价药效。