Establishment of TaqMan Real-time PCR Assay for Detection of Arcanobacterium pyogenes

The study was aimed to establish a specific and sensitive TaqMan Real-time PCR assay for detection of Arcanobacterium pyogenes (A.pyogenes).Based on the conservative sequence of pyolysin (PLO) gene of A.pyogenes published in GenBank, specific primers and TaqMan probes were designed. The TaqMan Real-time PCR assay was established, and the specificity and sensitivity were tested.The specificity test results showed that only A.pyogenes exhibited typical curves.The detection sensitivity of this assay was 77.6 fg genomic DNA per 20 μL reaction, and 63 CFU/mL for pure cultures.16 out of 23 clinical samples were positive detected by the TaqMan Real-time PCR assay, which were consistent with API Coryne identification.The TaqMan Real-time PCR assay developed in this study was specific and sensitive for detection of A.pyogenes, and it could be used for identification and epidemiological investigation of A.pyogenes.     

鸡传染性贫血病病毒TaqMan实时荧光定量PCR检测方法的建立

根据鸡传染性贫血病病毒(chicken infectious anemia virus,CAV)基因组保守区域设计1对特异性引物和探针,通过优化反应条件,建立了一种快速检测CAV的TaqMan实时荧光定量PCR方法,同时验证其特异性、灵敏性和重复性.本试验建立的TaqMan实时荧光定量PCR方法灵敏度可达1.8×10¹拷贝/μL,远高于常规PCR方法;并与禽类其他病毒性疾病无交叉反应,具有高特异性.用分离的病毒人工感染1日龄SPF雏鸡,14日龄剖检,对感染鸡体内各器官的病毒分布及载量进行检测,结果表明,在脑、心脏、肝脏、脾脏、肺脏、肾脏、胸腺、法氏囊和血清中均可检测到病毒,肝脏、胸腺病毒载量明显高于其他组织.本研究建立的TaqMan实时荧光定量PCR方法特异性强、灵敏度高、重复性好,可同时检测大量临床样品,适用于CAV的诊断与流行病学分析.     

.基于TaqMan探针的牛布氏杆菌实时荧光定量PCR的特异性鉴定

根据牛布氏杆菌BM28保守序列设计引物和探针,建立了一种快速鉴定牛布氏杆菌的TaqMan实时荧光定量PCR方法。以梯度稀释的含有目的扩增片段的重组质粒作为标准品,进行定量PCR反应。结果显示:5.0×105~5.0×101拷贝范围内定量PCR均有"S"型扩增曲线,检测灵敏度为50拷贝每微升。本研究建立的实时荧光定量PCR方法具有灵敏度高、特异性和重复性好、方便经济的特性,在牛布氏杆菌的检测与鉴定中具有良好的应用前景。     

牛源化脓隐秘杆菌的分离鉴定及其PCR检测方法的建立

摘要:为分离鉴定牛源化脓隐秘杆菌(Arcanobacterium pyogenes)并建立其PCR检测方法,本研究从某规模化奶牛场患牛肺组织中分离出两株细菌,根据其形态特征、培养特性及生化特性,结合16S rRNA分析确定分离茵为A.pyogenes.对小鼠致病性试验显示纯培养物对小鼠致死率较高,药敏试验表明分离茵仅对少数种类抗生素如头孢唑啉、氧氟沙星、阿奇霉素等敏感.本研究同时建立了快速检测A.pyogenes溶血素(PLO)基因的PCR方法,敏感性试验显示最低检出菌数为9.2×103 cfu/mL,特异性试验表明与其他细菌如布鲁氏茵、大肠杆菌等无交叉反应,通过对已知临床样本检测评估显示该方法适用于临床感染样品的检测.     

胎儿弯杆菌病TaqMan实时荧光定量PCR检测方法的建立

为建立胎儿弯杆菌(C.fetus)定量检测方法,本研究根据C.fetus毒力因子表面蛋白(SapA)基因序列设计引物和一条特异的TaqMan水解探针,建立了一种敏感、特异、重复性好的快速检测C.fetus的TaqMan荧光定量PCR方法.对该方法的特异性与敏感性研究,结果显示,该方法检测C.fetus结果均为阳性,而非C.fetus均为阴性;对带有SapA基因的阳性质粒的检测敏感性为10~8拷贝～10~2拷贝/μL范围内具有良好的线性关系,可敏感地检测到模板中13个拷贝的细菌DNA,其灵敏度是常规PCR方法的100倍.该方法具有简便、快速、特异性强、敏感性高等特点.该方法为C.fetus快速检测试剂盒的研制打下了良好的基础.     

牛巴贝斯虫TaqMan荧光定量PCR检测方法的建立

为建立一种灵敏、特异、快速的牛巴贝斯虫检测方法,针对牛巴贝斯虫Rap-1a基因设计引物进行PCR扩增,然后构建重组质粒制作标准品,经过优化反应体系、绘制标准曲线,建立了牛巴贝斯虫TaqMan荧光定量PCR方法,并进行灵敏度、特异性及稳定性检测,同时利用该方法对37份田间样品进行检测。结果显示：建立的牛巴贝斯虫TaqMan荧光定量PCR检测方法的标准曲线方程式为y=-3.362×Log（X）+43.32,相关系数R2=0.999,扩增效率为98.4%。该方法的灵敏度为1.0×102 copies/μL,是普通PCR（1.0×104 copies/μL）的100倍。该方法对牛双芽巴贝斯虫、大巴贝斯虫、卵形巴贝斯虫等7种常见的牛梨形虫病检测结果均为阴性,组内和组间重复试验的变异系数均小于2.5%,37份田间样品的阳性检出率为67.5%。结果表明,本试验建立的牛巴贝斯虫TaqMan荧光定量PCR灵敏度高,且特异、稳定,适用于牛巴贝斯虫的诊断,从而为其流行病学调查提供了快速有效的检测方法。     

猪源盖塔病毒TaqMan实时荧光定量PCR检测方法的建立

猪盖塔病毒感染是由盖塔病毒(GETV)引起母猪妊娠初期胎儿死亡、初生仔猪发病的一种繁殖障碍性疾病。猪是自然界中GETV的主要扩增宿主,可以产生足够高的病毒血症滴度来感染叮咬的蚊子并维持GETV的传播周期,所以定期对猪群进行GETV监测对于预防潜在的GETV暴发具有重要意义。本研究通过分析GETV E2蛋白基因特征,设计特异性引物和探针,条件优化后建立检测GETV感染的Taq Man实时荧光定量PCR方法。结果表明：以阳性质粒为标准品建立的标准曲线在1×10²～1×10⁷ copies/μL内呈现良好的线性关系,扩增效率为1.61;该检测方法的最低检出限低至3.16 TCID₅₀/mL,远远低于普通PCR的检测限3.16×10³ TCID₅₀/m L;组内、组间重复性试验的变异系数均小于2%,具有良好的重复性和稳定性。本研究建立的方法能够快速有效的检测和定量GETV,为猪群中GETV监测提供可靠的检测方法。     

鸡毒支原体TaqMan实时荧光定量PCR检测方法的建立

为快速检测鸡毒支原体,根据鸡毒支原体的保守基因设计特异性引物和TaqMan探针,建立鸡毒支原体TaqMan实时荧光定量PCR方法并分析鸡毒支原体培养过程中颜色单位改变法(color change unit, CCU)和荧光定量PCR检测的相关性。结果显示,标准曲线y=-3.646x+44.208,相关系数R²=0.998,最低检测限度为1 copy/μL;与其他菌株等均无交叉反应;组内和组间变异系数均小于3%,表明该方法具有良好的稳定性和可重复性。用建立的实时荧光定量PCR检测方法对26份临床样品进行检测,该方法较普通PCR方法检出率更高。建立的荧光定量PCR与CCU显示鸡毒支原体在对数生长期时,两者具有一定的对应关系。表明建立了鸡毒支原体TaqMan探针实时荧光定量PCR检测方法,可实现对鸡毒支原体的快速检测,为鸡毒支原体感染的防控提供技术基础。     

胞内劳森菌TaqMan实时荧光定量PCR检测方法的建立及应用

为建立用于检测临床粪便样品中胞内劳森菌(Lawsonia intracellularis,L.intracellularis)的TaqMan荧光定量PCR方法,本研究参考GenBank中发表的L.intracellularis PHE/MN1-00株基因组序列设计50对引物,通过SYBR GreenⅠ荧光染料法PCR验证引物的特异性,针对扩增效率最好的特异性上、下游引物合成相应的TaqMan探针,优化反应条件,对其线性范围、敏感性和重复性进行验证,系统的完成了该方法的建立。结果表明,所建立的TaqMan荧光定量PCR方法,特异性强;在靶标核酸为2.95×10¹～2.95×10⁶拷贝/μL区间线性关系良好,相关系数R²=0.998 1,扩增效率为96.51%;最低检测浓度为5拷贝/μL;批间和批内的CV均小于2%,重复性好。使用普通PCR方法与本方法对2020年10月至2021年2月采自江西地区猪场的373份粪便样品进行检测,L.intracellularis的总检出率分别为21.4%(80/373)和27.6%(103/...     

口蹄疫病毒TaqMan荧光定量PCR检测方法的建立

为建立检测口蹄疫病毒(FMDV)的方法,本研究根据GenBank中FMDV的2B基因序列,设计合成一对引物和一条TaqMan探针,将2B基因克隆到pBlueScriptSK(-)载体中,利用T7体外转录试剂盒制备标准品,通过优化反应条件,建立了TaqMan荧光定量PCR检测方法.结果表明,该检测方法的敏感性达到102拷贝/μL;与其它主要相关病毒均不发生交叉反应,批内和批间试验重复性的变异系数(CV)均小于3％.本研究建立的FMDV TaqMan荧光定量PCR方法对FMDV的快速检测具有重要意义.     

Establishment of TaqMan Real-time PCR Method for Detection of Duck Poxvirus

To establishment a TaqMan Real-time PCR method for detection of duck poxvirus (DPV),we cloned the P4b gene of DPV.The specific primers and probe were designed according to the nucleotide sequence of avipoxvirus available in GenBank.Recombinant plasmid pMD-DPV-P4b was employed as positive standard template for Real-time PCR.By optimization of reaction conditions,a TaqMan Real-time PCR method for detection of DPV was established.The results of specificity test proved this method had no cross-react with other waterfowl vial agents and poxviruses including avian influenza virus,duck flavivirus,duck hepatitis virus,Newcastle disease virus,duck entertitis virus,goose parvovirus,goatpox virus and fowlpox virus.The detection limit of the assay was 1.29×10² copies/μL of viral DNA,which was 100 times higher than that of the routine PCR.Reproducibility test showed that the CVs of intra assay and inter assay were both less than 2%.Above results supported that the assay was suitable for the detection of DPV very well.     

鸭痘病毒TaqMan荧光定量PCR检测方法的建立

为建立检测鸭痘病毒的TaqMan荧光定量PCR方法,本试验克隆了鸭痘病毒P4b基因,构建重组质粒pMD-DPV-P4b,并将其作为标准阳性模板。参照GenBank收录的禽痘病毒P4b基因设计合成1对特异性引物及与该引物相匹配的特异探针。以定量的10倍系列稀释的质粒pMD-DPV-P4b为标准品,通过对反应条件进行优化,建立了一种检测鸭痘病毒的TaqMan荧光定量PCR方法。结果显示,该方法与禽流感病毒、鸭黄病毒、鸭肝炎病毒、新城疫病毒、鸭瘟病毒和小鹅瘟病毒等其他水禽病毒,以及山羊痘病毒和鸡痘病毒等其他痘病毒均无交叉反应,特异性好。该方法最低检测限为1.29×10²拷贝/μL,比普通PCR检测方法高100倍。组内和组间变异系数均小于2%。结果表明,本试验所建立方法具有灵敏、特异、安全、快速的特点,适用于鸭痘病毒的检测。     

猪圆环病毒2型TaqMan荧光定量PCR检测方法的建立

采用PCR方法克隆了猪圆环病毒2型 (porcine circovirus 2,PCV2) 衣壳蛋白（capsid protein,CAP）基因,构建了重组质粒p-18T-CAP,并将其作为标准阳性模板。参照GenBank收录的PCV2 ORF2基因设计合成1对特异性的引物和与该引物相匹配的特异探针,通过对反应条件进行优化,以定量的10倍系列稀释的质粒p-18T-CAP为标准品进行TaqMan荧光定量PCR扩增,建立了一种检测PCV2的TaqMan荧光定量PCR方法。试验结果显示,该方法与猪圆环病毒 1 型、猪流感病毒、猪繁殖与呼吸综合征病毒、猪伪狂犬病病毒、猪瘟病毒等均无交叉反应;该方法最低可检测到4.53×10²拷贝/μL,比PCR检测方法高100倍;其标准曲线线性范围是10²～10⁹拷贝/μL,且具有良好的重复性。     

Establishment and Application of A Double TaqMan MGB Real-time PCR Assay for Detection of Canine Distemper Virus and Canine Parvovirus

This study was aimed to establish a double TaqMan MGB Real-time PCR assay to simultaneously and specifically detect canine distemper virus (CDV) and canine parvovirus (CPV) in one reaction.Two pairs of specific primers for CDV and CPV,along with two TaqMan MGB probes for each virus were designed in the assay basing on CDV H gene and CPV VP2 gene sequences.The specificity,sensitivity and repetition of the double TaqMan MGB Real-time PCR assay were tested,and 48 samples taken from clinic suspicious CDV and CPV infected canines had been testified by the established double TaqMan MGB Real-time PCR.The results indicated that the doulde TaqMan MGB Real-time PCR assay was successfully established,and the number of standard curve correlation (R²) of CDV and CPV were 0.997 and 0.993,respectively.The specificity of the double TaqMan MGB Real-time PCR assay revealed that amplifications were showed on CDV and CPV samples,but other pathogens and negative controls had no amplifications;The sensitivity of CDV and CPV were both 10 copies/μL.Meanwhile,14 CDV positive samples,19 CPV positive samples and 4 CDV/CPV double positive samples were detected,which were consistent with the results of the sequencing.Therefore,the established double TaqMan MGB Real-time PCR assay had high sensitivity,specificity and flux accurate quantitative,which could be applied to clinical CDV/CPV infection each periods.     

牛源化脓隐秘杆菌PLO蛋白的原核截短表达及其溶血活性检测

为研究牛源的化脓隐秘杆菌溶血素(PLO)生物学功能,本研究应用PCR方法扩增牛源化脓隐秘杆菌(A.pyogenes)PLO全基因序列,通过生物信息学方法分析其与猪源A.pyogenes的PLO蛋白差异,并构建了溶血功能区重组表达质粒pQE30-PLO585,在E.coli XL1Blue中用IPTG诱导表达。结果表明,扩增到PLO蛋白基因ORF为1 605 bp,编码535个氨基酸,与猪源PLO的核苷酸序列同源性为97.4%,氨基酸同源性为97.2%,在生物学活性功能区没有发生改变。表达的PLO蛋白溶血功能区重组蛋白能够被阳性血清识别,而且具有溶解绵羊红细胞的活性,产生β溶血现象。本研究获得了牛源A.pyogenes截短重组PLO蛋白,并证明PLO具有β溶血功能与较好的抗原性。     

牛支原体、巴氏杆菌A型和化脓隐秘杆菌多重PCR快速检测方法的建立

本试验旨在建立一种可同时鉴别牛支原体、巴氏杆菌A型和化脓隐秘杆菌的多重PCR方法。分别针对多杀性巴氏杆菌A型特异的hyac-hvaD基因区段、化脓隐秘杆菌的16SrRNA基因上保守区段和牛支原体的UvrC基因设计特异性引物,多重PCR的最佳扩增条件确定为：95℃ 10min预变性;95℃ 1min,56℃ 50s,72℃ 1min,循环30次;72℃ 210min延伸。结果表明,该多重PCR方法可同时扩增出以上三种致病菌的特异性片段,不能扩增出其他病原菌的相关片段;对多杀性巴氏杆菌A型、化脓隐秘杆菌和牛支原体的最低检测浓度分别为8×10^5CFU／mL、8×10^5CFU／mL和4×10^6CFU／mL。同时用该方法检测了牛支原体肺炎患牛的鼻拭子与肺组织,发现12h预增菌后,肺组织检测与牛支原体培养的阳性符合率为92％。对临床样本进行牛支原体分离培养需要3-4d时间,而采用多重PCR方法检测12h预增菌则能在24h内出结果。该多重PCR方法显著加快了临床诊断速度,具有推广应用价值。     

Establishment of a Duplex TaqMan Real-time PCR Method for Detection of Bovine Viral Diarrhea Virus Types 1 and 2

【Objective】 This study was aimed to establish a duplex TaqMan Real-time PCR method for rapid detection of Bovine viral diarrhea virus types 1(BVDV1) and 2(BVDV2).【Method】 Specific primers were designed based on the 5'-non-coding region of 95 strains of BVDV1 and BVDV2 in GenBank.The positive plasmids containing the target fragments of BVDV1 and BVDV2 were constructed.The reaction conditions were optimized, the standard curve was constructed, the specificity, sensitivity and reproducibility of the duplex TaqMan Real-time PCR method were tested, and the established duplex TaqMan Real-time PCR assay was used to detect the clinical samples collected from Jilin province.【Result】 The results showed that the optimal annealing temperature of the duplex TaqMan Real-time PCR was 57.0 ℃, the optimum primer concentration was 0.5 μmol/L, and the optimum probe concentration was 0.3 μmol/L.The standard curves of BVDV1 and BVDV2 were Y=-3.54X+37.36 (R²=0.990) and Y=-3.18X+35.95 (R²=0.997), respectively.There was no specific amplification of Infectious bovine rhinotracheitis virus (IBRV), Bovine respiratory syncytial virus (BRSV) and Bovine parainfluenza virus type 3 (BPIV3), with intra- and inter-batch CV less than 3%, and the lower limit of detection was 10 copies/μL.The results of clinical samples showed that the overall positive rate was 23.1% (36/156), of which 17.9% (28/156) were positive for BVDV1 and 5.1% (8/156) were positive for BVDV2.【Conclusion】 In this study, a duplex TaqMan Real-time PCR method was established, which could identify BVDV types 1 and 2 simultaneously, quickly and accurately, and provided technical support for the prevention, control and purification of BVDV.     

流产衣原体TaqMan实时荧光定量PCR 检测方法的建立及初步应用

流产衣原体是导致绵羊地方性流产的主要病原体,给全球畜牧业经济发展构成了巨大威胁。为建立一种灵敏、特异且快速的检测流产衣原体的实时荧光定量PCR方法,依据衣原体蛋白酶样活性因子的基因组序列设计了针对检测流产衣原体的引物和TaqMan探针,对反应体系和反应条件进行了优化,对方法的灵敏度、特异性及重复性进行了评价,并初步应用于临床样本检测。结果显示,该方法的最低检测限为26 copies/μL,灵敏度是普通PCR的10倍;与其他可以引起类似症状的病原体无交叉反应;组内和组间变异系数均小于3%;对156份流产羊拭子的基因组进行检测,检出率为78.21%。研究表明,该方法可以很好的应用于流产衣原体的大规模临床样本检测,为流产衣原体病的高通量检测和流行病学调查提供技术手段。