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.

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.

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。

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。

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。

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。

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。

Establishment of a new quantitative detection approach to adefovir-resistant HBV and its clinical application

AIM:To establish the more feasible and sensitive assessment approach to the detection of adefovir (ADV) resistance-associated hepatitis B virus (HBV) quasispecies.METHODS: Based on the characteristics of rtA181V/T and rtN236T mutations, a new approach based on real-time fluorescent quantitative polymerase chain reaction (RT-PCR) was established for the detection of ADV-resistant HBV quasispecies, total HBV DNA, rtA181 and rtN236 mutations in blood samples from 32 chronic hepatitis B (CHB) patients with unsatisfactory curative effect on ADV and compared with routine HBV DNA sequencing.RESULTS: Both the sensitivity and specificity of this new detection approach to ADV-resistant HBV quasispecies were 100%, which were much higher than those of direct HBV DNA sequencing. The approach was able to detect 0.1% of mutated strains in a total plasmid population. Among the 32 clinical patients, single rtA181 and rtN236T mutation and double rtA181T and rtN236T mutations were detected in 20 and 8, respectively, while ADV-resistant mutations in 6 (including, rtA181V/T mutation alone in 5 patients) and no associated mutations in 26.CONCLUSION: This new approach is more feasible and efficient to detect ADV-resistant mutants of HBV and ADV-resistant mutations before and during ADV treatment with a specificity of 100% and a sensitivity of 100%.

Influences of bracket bonding on mutans streptococcus in plaque detected by real time fluorescence-quantitative polymerase chain reaction

Background Enamel demineralization occurs frequently during orthodontic treatment. In this study, we evaluated the changes of the density of mutans streptococcus （MS） in plaque after bracket bonding and using fluoride adhesive on maxillary incisors by real time fluorescence-quantitative polymerase chain reaction （RT-FQ PCR）.Methods The study was designed as a self-paired test. Brackets were bonded with fluoride adhesive on the left side, while non-fluoride adhesive on the right side for each patient. Plaque samples were taken from the surfaces around the brackets of four maxillary incisors before brackets bonding and after the bonding 4 weeks later. The amount of MS was measured by RT-FQ PCR. The data obtained were analyzed statistically using the SPSS 11.5 version and the alpha level was set at 0. 05 （ 2-tailed）.Results The amount of MS in plaque increased significantly after bracket bonding （ P 〈 0.01 ）, whereas no significant differences were observed among four maxillary incisors both before and after brackets bonding （P 〉 0. 05 ）, and among the incisors using and not using fluoride adhesive （ P 〉 0. 05 ）.Conclusions The increase of the density of MS in plaque after bracket bonding is one of the etiological factors for enamel demineralization in orthodontic patients. The result of this study did not support what we observed clinically that the incidence of enamel demineralization for lateral incisors was higher than that for central incisors. Using fluoride adhesive for bonding did not affect the amount of MS in plaque in our study. Further study is needed.

综合洗消体系对阻断非洲猪瘟病毒传入猪场的作用

切断非洲猪瘟病毒(ASFV)传播途径是防控非洲猪瘟的有效手段。本试验旨在通过在某种猪场建立综合洗消体系以阻断ASFV传入。对拟进入猪场的车辆在出发前和距猪场1 km处清洗和消毒,在猪场门口进行第3次消毒;人员进入猪场前洗澡和隔离,并将其衣物消毒;输入物资进场前消毒。通过实时荧光定量PCR检测经洗消的车辆、人员、物资和猪场内猪只携带ASFV核酸情况,酶联免疫吸附测定(ELISA)检测猪只的ASFV抗体水平。结果显示,2019、2020、2021和2022年,车辆ASFV检出率分别为2.6%、1.3%、0和0,人员ASFV检出率分别为3.0%、1.1%、0和0.9%,物资ASFV检出率分别为12.5%、0、5.9%和0;4年间,猪场内猪只的ASFV核酸和抗体检测均为阴性。结果表明,通过建立完善的洗消体系并开展ASFV检测,能有效阻断ASFV传入猪场。

饮食习惯与肥胖患儿性早熟的相关性分析

目的探讨饮食习惯与肥胖患儿性早熟的相关性分析。方法选取苏州市吴中人民医院2019年3月至2022年3月期间收治的72例性早熟肥胖患儿作为观察组,另选取同期体检的健康肥胖儿童71例作为常规组。采用实时-逆转录荧光定量聚合酶链反应(RT-qPCR)检测两组外周血miR-125b水平,分析患儿饮食习惯。通过比较两组肥胖儿童的外周血miR-125b、饮食习惯,采用Logistic回归分析法分析外周血miR-125b、饮食习惯与肥胖患儿性早熟的关系。结果观察组外周血miR-125b表达水平高于常规组,差异有统计学意义(P<0.05)。观察组饮食没规律、荤多素少、高添加剂食品占比均高于常规组,差异有统计学意义(P<0.05)。观察组女性患儿、不良饮食习惯占比高于常规组,且经多因素分析显示外周血miR-125b表达水平、女性、不良饮食习惯是肥胖患儿性早熟的独立危险因素,差异有统计学意义(P<0.05)。结论肥胖患儿性早熟外周血miR-125b表达水平高于健康肥胖儿童,不良饮食习惯高于健康肥胖儿童,外周血miR-125b表达水平偏高、不良饮食习惯偏低均为肥胖患儿性早熟的影响因素。

六安市鼠形动物中5种病原体检测结果分析

目的 掌握2021年9月至2023年12月六安市鼠形动物中携带5种病原体的分布情况,为本地鼠传疾病的防控和预警提供科学依据。方法 在六安市的金安区、霍邱县、舒城县选取农村居民区、城镇居民区、重点行业、农田耕地等不同的生境,捕获鼠形动物,无菌解剖后采集肝、脾、肺、肾4种组织样品,用实时荧光定量PCR法检测钩端螺旋体、莫氏立克次体、恙虫病东方体、新型布尼亚病毒和汉坦病毒5种病原体。使用SPSS 26.0软件进行数据分析,阳性率的比较采用χ^(2)检验。结果 共检测502份鼠形动物的组织样本,钩端螺旋体核酸检测阳性率为5.58%(28/502),黑线姬鼠携带钩端螺旋体的阳性率最高,为9.09%(19/209);汉坦病毒阳性率为1.39%(7/502);新型布尼亚病毒、恙虫病东方体和莫氏立克次体未检出。农田耕地中的鼠形动物携带钩端螺旋体和汉坦病毒阳性率均最高,分别为8.96%(19/212)和3.30%(7/212)。雌性鼠形动物携带钩端螺旋体、汉坦病毒阳性率(8.02%、2.47%)均高于雄性鼠形动物(4.41%、0.88%)。结论 六安市鼠形动物中钩端螺旋体和汉坦病毒感染水平较高,黑线姬鼠是钩端螺旋体的主要宿主,农田耕地中鼠形动物钩端螺旋体和汉坦病毒检出率最高。人群中存在感染鼠传疾病的风险,应做好防控工作,以降低人群感染风险。

鸡传染性喉气管炎病毒SYBR Green Ⅰ实时荧光定量PCR检测方法的建立与应用

鸡传染性喉气管炎病毒(Infectious laryngotracheitis virus,ILTV)以往多感染蛋鸡,近年来在蛋种鸡、商品肉鸡中连续多发,表明该病毒感染谱有扩大风险,因此有必要加强对ILTV的监测。为建立高效、灵敏的ILTV检测方法,本研究以ILTV的TK基因为靶基因设计引物,扩增并构建pMD18-T-TK质粒标准品,建立SYBR GreenⅠ实时荧光定量PCR检测方法和标准曲线,对其特异性、敏感性和重复性进行验证,并对临床疑似病例进行检测。结果发现,该检测方法特异性良好,与其他常见症状相似病原无交叉反应;最低检测浓度为1.55拷贝/μL,灵敏度是普通PCR方法的10倍;重复性好,批内、批间变异系数在0.79%~1.83%之间。表明本研究建立的ILTV实时荧光定量PCR方法特异性强、灵敏度高,可为ILTV的临床诊断和流行病学研究等提供有效的检测方法。