蜜蜂克什米尔病毒实时荧光RT-PCR检测方法的建立和评价

蜜蜂克什米尔病毒(Kashmir bee virus,KBV)是一种高毒力的急性蜜蜂病毒,可以引起蜜蜂的死亡和蜂群崩溃.本研究旨在建立一种灵敏、快速检测KBV的TaqMan实时荧光RT-PCR检测方法.参照GenBank中polymerase polyprotein有关基因序列,设计一组特异性引物和探针,并通过体外转录法制备RNA标准品作为阳性模板.在对反应体系进行优化的基础上,建立了 KBV的实时荧光RT-PCR检测方法并进行了特异性试验、敏感性试验、重复性试验和临床样本验证.结果显示:该方法能有效扩增8×100拷贝/μL～8×107拷贝/μL 的KBV标准品,建立的标准曲线呈现良好的线性关系.该方法的检测灵敏度为8拷贝/μL,对其他蜜蜂病毒不发生交叉反应,具有很好的特异性;重复性试验结果显示组内和组间的变异系数分别低于1％和2％,重复性良好.应用本研究建立方法与常规RT-PCR方法对样品进行检测,TaqMan实时荧光RT-PCR检测方法的特异性优于常规RT-PCR.本研究建立的实时荧光RT-PCR检测具有良好的敏感性、特异性和重复性,为KBV的检测和流行病学调查提供技术支持.     

中国蓝舌病病毒流行株血清型实时荧光定量RT-PCR检测方法的建立与应用

[背景]蓝舌病病毒(Bluetongue virus,BTV)是一种严重危害反刍动物的虫媒病毒,我国存在12种血清型BTV (BTV-l、-2、-3、-4、-5、-7、-9、-12、-15、-16、-21和-24)的流行.[目的]建立12种血清型BTV的RT-qPCR定型方法,为BTV的诊断与流行病学研究提供技术保障....     

检测蜜蜂急性麻痹病毒TaqMan实时荧光RT-PCR方法的建立和初步应用

[背景] 蜜蜂急性麻痹病毒（Acute Bee Paralysis Virus,ABPV）是一种高毒力的蜜蜂病毒,可以引起蜜蜂的大批死亡和蜂群衰竭。[目的] 建立一种快速、灵敏的ABPV实时荧光RT-PCR检测方法。[方法] 根据ABPV衣壳蛋白基因保守序列设计引物和探针,通过对引物、探针浓度和退火温度等反应条件进行优化,建立基于TaqMan探针检测ABPV的实时荧光RT-PCR方法,并对方法的灵敏性、特异性和稳定性进行验证。[结果] ABPV实时荧光RT-PCR检测方法在9.8×10¹-9.8×10⁸ copies/μL之间呈现良好的线性关系,线性相关系数R²为0.998,扩增效率为103.8%。该方法的检测灵敏度为9.8 copies/μL;对其他蜜蜂病毒不发生交叉反应,具有良好的特异性;重复性试验结果显示组内和组间的变异系数分别为0.19%-0.80%和0.57%-1.07%,重复性良好。对2018年-2019年在福建地区采集的70份蜜蜂样品进行ABPV检测,阳性率为2.86%。[结论] 建立的ABPV实时荧光RT-PCR检测方法能用于该病的实验室检测、流行病学调查和疫情监测。     

北美洲流行汉坦病毒多重荧光定量RT-PCR检测方法的建立

为了建立牛轭湖病毒(Bayou virus,BAYV)、纽约病毒(New York virus,NYV)、厄尼诺洛峡谷病毒(El Moro Canyon virus,ELMCV)以及岛景病毒(Isla Vista virus,ISLAV)四种病毒快速筛查、诊断的核酸检测技术,本研究选用上述四种病毒的N蛋白基因作为靶标区域设计四组特异性引物探针,建立四重实时荧光定量RT-PCR检测方法。用四种病毒体外转录RNA进行灵敏度和重复性验证,并使用其他病毒细胞培养物及体外转录RNA进行特异性验证。结果显示,四重实时荧光定量PCR扩增效率均可达到95%以上,四种病毒体外转录RNA灵敏度介于1～10拷贝/μL,与单重检测方法无明显差异,且与其他病毒无交叉反应。稳定性评价结果显示,批内、批间变异系数均在3%以内。本研究所建立的检测方法具有良好的敏感性、特异性和重复性,可用于相关样本的诊断与筛查。     

禽流感和新城疫病毒二重荧光定量RT-PCR检测方法的建立

目的：建立二重荧光定量RT-PCR方法,用于禽流感病毒（AIV）和新城疫病毒（NDV）的检测。方法：根据AIV和NDV的基因保守序列,设计了AIV和NDV的2对特异性引物和2条用不同荧光基团标记的TaqMan探针;对反应条件和试剂浓度进行优化,建立了能够同时检测AIV和NDV的Z-重荧光定量RT-PCR方法。结果：所建方法特异性好,对AIV和NDV的检测敏感性均达到2000个模板拷贝数,比常规RT-PCR敏感性高100倍;抗干扰能力强,对AIV和NDV不同模板浓度进行组合,仍可有效地同时检测2种病毒。对保存的AIV或NDV鸡胚尿囊液及临床病料进行二重荧光定量RT-PCR检测,结果尿囊液检测的拷贝数均达到10^10/μL以上,临床病料的拷贝数为2．13x10^8-6．52x10^4／μL。结论：建立了用于检测AIV和NDV的二重荧光定量RT-PCR法,该方法特异、敏感、快速、可定量,对AIV和NDV的防制有重要意义。     

琉球病毒、索尔韦齐病毒、苏里斯病毒等三种沙粒病毒实时荧光RT-PCR检测方法研究

建立可检测琉球病毒(Ryukyu virus,RYKV),索尔韦齐病毒(Solwezi virus,SOLV)以及苏里斯病毒(Souris virus,SOUV)等三种沙粒病毒的实时荧光定量RT-PCR检测方法.分析三种病毒流行病学分布特征,从国际公共数据库搜索下载基因组序列,进行比对分析,确定检测靶标,借助primer premier 6.0生物信息学软件,设计引物和探针,建立实时荧光定量RT-PCR检测方法,利用化学合成和体外转录方法制备模拟样本,比较评价三种方法的检测限、特异性、重复性特征.所建实时荧光定量RT-PCR检测方法均可有效扩增检测病毒RNA靶标,检测限分别为40拷贝/μL、7拷贝/μL和15拷贝/μL,检测汉城病毒、汉滩病毒、登革病毒Ⅰ～Ⅳ型分离株、发热伴血小板减少综合病毒及30份健康人血清样本无非特异性扩增,三种病毒相互间以及其他8种出血热相关沙粒病毒RNA间无交叉反应,重复性比较分析显示变异系数均在2％以内.本研究建立的检测RYKV、SOLV和SOUV三种沙粒病毒的实时荧光RT-PCR方法具备用于相关疑似感染者临床样本、宿主动物标本以及进出口物品的筛查检测的潜力,但因未经基于实际病毒感染样本的比较评价,检测结果的解释仍具有一定的局限性.     

SYBR Green Ⅰ荧光定量RT-PCR检测埃博拉病毒方法的建立

为了建立一种快速准确的检测埃博拉病毒(EBOV)亚型的方法。本研究根据GenBank中公布的EBOV NP基因序列,通过设计引物和优化反应条件,建立了一种SYBR GreenⅠ荧光定量RT-PCR检测方法检测EBOV。以体外转录的EBOV RNA为模板进行试验,该方法检测的灵敏度可以达到1.0×102个拷贝/μL,检测范围达到9个数量级为102～1010,可检测5种亚型EBOV。建立的方法对马尔堡病毒(MARV)、登革病毒(DENV)、新疆出血热病毒(XHFV)、乙型脑炎病毒(JEV)、流感病毒(H1N1和H3N2)和猪繁殖和呼吸综合征病毒(PRRSV)E基因组RNA无非特异性扩增。本文将荧光定量RT-PCR技术用于埃博拉病毒的定量检测中,并且建立了EBOV SYBRGreenⅠ荧光定量RT-PCR检测方法。     

小反刍兽疫病毒(PPRV)与蓝舌病病毒(BTV)双重荧光RT-PCR快速检测方法的建立

为了研制小反刍兽疫病毒(PPRV)与蓝舌病病毒(BTV)双重荧光RT-PCR快速检测试剂盒,根据GenBank公布的小反刍兽疫病毒、蓝舌病病毒的基因序列,设计两套特异性的引物和探针,建立基于Taqman探针的双重荧光RT-PCR快速检测小反刍兽疫病毒与蓝舌病病毒的方法。实验结果表明,该方法特异性好、灵敏度高,检测最低浓度为10拷贝/μL数量级阳性标准品。通过对临床样品的检测,证实本研究建立的检测方法具有较好的临床应用价值。     

SYBR Green Ⅰ实时荧光定量RT-PCR测定猴免疫缺陷病毒RNA拷贝数方法的建立

目的 建立SYBR Green Ⅰ荧光染料实时定量RT-PCR方法,测定猴免疫缺陷病毒(SIV)RNA拷贝数.方法 巢式RT-PCR扩增SIV病毒RNA gag基因上1360-1837之间的长度为477 bp的片段,将该片段克隆到pGEM T载体上,构建pGEM-SIVgag477质粒.该质粒经限制性内切酶Not I酶切后,进行体外转录,转录出的RNA产物(RS)纯化后10倍系列稀释,作出标准曲线,作为SIV病毒RNA荧光定量检测的外标准品.结果 应用Qiagen公司QuantiTect SYBR GREEN RT-PCR Kit,该标准品可精确定量到100 copies/μL.结论 制备的RS外标准品纯度高,SYBR Green Ⅰ荧光染料实时定量RT-PCR法特异性、敏感性高,稳定性好,可用于定量测定猴免疫缺陷病毒(SIV)RNA拷贝数.     

TaqMan 荧光定量RT-PCR 检测犬瘟热病毒方法的建立与初步应用

犬瘟热（Canine distemper,CD）是由犬瘟热病毒（Canine distemper virus,CDV）感染引起的一种急性、高度接触性、致死性传染病.CDV属副粘病毒科麻疹病毒属成员,宿主谱很广,可感染犬（Canis familiaris）、狐狸（Vulpes vulpes）、貉（Ussuriensis）、狼（Canis lupus）、雪貂（Lepus zibellina）、虎（Panthera tigris）、狮（Panthera leo）、大熊猫（Ailuropoda melanoleuca）、小熊猫（Ailures fulgens）、黑熊（Selenarctas thibetanus）等动物,严重危害养犬业、经济动物养殖业的健康发展以及野生动物的生存.     

Morphology and Development of Bovine Ephemeral Fever Virus

The development of the virus of bovine ephemeral fever in mouse brain has been studied by electron microscopy. The virus particles are bullet-shaped, 70 by 145 nm, and slightly tapered toward the rounded end. The outer envelope is closely apposed to an electron-dense shell, about 12 nm thick, but no other internal structure is visible. The virus strains studied bud from the marginal membranes of neurones, but intracytoplasmic development, possibly aberrant, was also observed with one strain. Ephemeral fever virus is thus obviously a rhabdovirus, with points of resemblance to vesicular stomatitis, Flanders-Hart Park, and Kern Canyon viruses on the one hand, and to rabies virus on the other, but is structurally distinct from any of these.     

Double Strandedness of Ribonucleic Acid of Bovine Ephemeral Fever Virus

Virus labeled with ³H-uridine or ³²P-orthophosphate was purified by CsCl equilibrium centrifugation of concentrated virus materials from infectious BHK21-WI2 cell culture fluids. A single clearly visible band formed in the gradient coinciding with a sharp peak of radioactivity having a buoyant density of 1.19 g/ml. Infectivity exhibited a broader distribution with a peak coinciding with the visible band, in which numerous virions of the virus were observed with the aid of an electron microscope using the phosphotungstic negative staining technique. Ribonucleic acid (RNA) extracted from the purified virus by the phenol method exhibited a rather broad distribution of radioactivity with a major peak at about 12 S when analyzed by the sucrose density gradient centrifugation technique. Viral RNA centrifuged in the gradient after ribonuclcase (RNase) treatment showed a single sharp peak at about 12 S. These findings seemed to indicate that the virion of this virus contained double-stranded RNA. Double strandedness of the viral RNA was further corroborated by an examination of the base composition, reduced resistance to RNase in low salt concentration and a sharp thermal transition with a relatively high melting temperature of 85 C. The virus could not be classified either in the rhabdovirus group, although the shape of the virion resembled that of the rhabdoviruses, or in the reovirus group since the virus was ether-sensitive. It seemed necessary to create a new genus for this virus.     

牛流行热病毒糖蛋白G1抗原表位在毕赤酵母中的表达和抗原性鉴定

从包含牛流行热病毒G蛋白基因的质粒pMD-G中克隆G1抗原表位区基因,亚克隆进表达载体pPIC9K,构建重组载体pPIC9K-G1,线性化后电转化毕赤酵母GS115,通过G418压力和PCR法筛选阳性重组酵母进行诱导表达。经SDS-PAGE、脱糖基化分析、Western blot、ELISA、兔体免疫实验和特异性分析,表明该基因在GS115中表达并进行了适度的糖基化,表达蛋白有良好的生物学活性和特异性,可作为包被抗原,开发ELISA诊断试剂盒。     

口蹄疫病毒RT-LAMP检测方法的建立

利用逆转录环介导等温核酸扩增技术(RT-LAMP),建立了口蹄疫病毒快速检测方法,同时评价了该方法的灵敏性和特异性。结果表明,根据口蹄疫病毒多聚蛋白基因保守区段设计的LAMP引物能够在65℃下,1 h内实现目标核酸区段的大量扩增,检测结果可直接用肉眼判断。该检测体系具有极高的特异性,只能检测到目标病毒,与其他类似病毒如猪水泡病病毒、猪瘟病毒、猪细小病毒等无交叉反应,可检测到10-5稀释度的目标病毒核酸量,比普通RT-PCR的灵敏性高100倍,比荧光PCR高10倍。     

Expression and Antigenic Characterization of the Epitope-G1 of the Bovine Ephemeral Fever Virus Glycoprotein in Pichia pastoris

The epitope-G1 gene of Bovine ephemeral fever virus(BEFV) glycoprotein was synthesised by PCR and cloned into expression vector pPIC9K to construct recombinant plasmid pPIC9K-G1.Then the pPIC9K-G1 was linearized and transformed into Pichia pastoris GS115.The recombinant P.pastoris strains were selected by a G418 transformation screen and confirmed by PCR.After being induced with methanol,an expressed protein with 26 kDa molecular weight was obtained,which was much bigger than the predicted size(15.54 kDa).Deglycosylation analysis indicated the recombinant G1 was glycosylated.Western blot and ELISA tests,as well as rabbit immunization and specificity experiments indicated that the target protein had both higher reaction activity and higher immunocompetence and specificity.The recombinant G1 protein could be used as a coating antigen to develop an ELISA kit for bovine ephemeral fever diagnosis.     

牛病毒性腹泻病毒RT-LAMP检测方法的建立

目的:建立牛病毒性腹泻病毒(BVDv)的环介导体外等温扩增(LAMP)快速检测方法。方法:根据BVDv的5'端非编码区序列,在保守区的8个位点设计LAMP特异性引物(2对特异性引物和1对环引物),对反应条件和试剂浓度进行优化,建立恒温(63.5℃)、快速(65min)的检测方法。结果:建立的方法特异性好,检测其他对照病毒均为阴性;灵敏度高,最低可检测到1个拷贝的阳性质粒,可通过观察浑浊度或加入染料后直接判定扩增结果。结论:建立了用于检测BVDv的LAMP方法,该方法简便、快速、特异性好、灵敏度高,适合基层和现场检测。     

荧光定量PCR检测土拨鼠肝炎病毒核酸方法的建立

目的建立土拨鼠肝炎病毒（woodchuck hepatitis virus,WHV）核酸的荧光定量PCR（Real-time PCR）检测方法,应用于土拨鼠肝炎病毒模型的研究。方法分别根据土拨鼠肝炎病毒核心抗原（WHcAg）和表面抗原（WHsAg）的DNA序列设计13对扩增引物,从中筛选无非特异性扩增及引物二聚体且灵敏度高的引物,用于土拨鼠血清中WHV DNA的Real-time PCR检测。建立感染土拨鼠肝炎病毒的土拨鼠血清中WHV核酸的Real-timePCR检测方法。结果根据WHsAg基因的5＇端设计的一对引物WHVSF1与WHVSR1,检测灵敏度可达1×101拷贝/μL,病毒拷贝数与Real-time PCR Ct值的标准曲线的R2值为0.997,且电泳未见明显非特异性条带及引物二聚体。结论建立了土拨鼠血清中WHV DNA的Real-time PCR检测方法,该方法为进一步研究土拨鼠肝炎病毒模型奠定了基础。     

Rapid Molecular Assays for the Detection of Yellow Fever Virus in Low-Resource Settings

Background

Yellow fever (YF) is an acute viral hemorrhagic disease transmitted by Aedes mosquitoes. The causative agent, the yellow fever virus (YFV), is found in tropical and subtropical areas of South America and Africa. Although a vaccine is available since the 1930s, YF still causes thousands of deaths and several outbreaks have recently occurred in Africa. Therefore, rapid and reliable diagnostic methods easy to perform in low-resources settings could have a major impact on early detection of outbreaks and implementation of appropriate response strategies such as vaccination and/or vector control.

Methodology

The aim of this study was to develop a YFV nucleic acid detection method applicable in outbreak investigations and surveillance studies in low-resource and field settings. The method should be simple, robust, rapid and reliable. Therefore, we adopted an isothermal approach and developed a recombinase polymerase amplification (RPA) assay which can be performed with a small portable instrument and easy-to-use lyophilized reagents. The assay was developed in three different formats (real-time with or without microfluidic semi-automated system and lateral-flow assay) to evaluate their application for different purposes. Analytical specificity and sensitivity were evaluated with a wide panel of viruses and serial dilutions of YFV RNA. Mosquito pools and spiked human plasma samples were also tested for assay validation. Finally, real-time RPA in portable format was tested under field conditions in Senegal.

Conclusion/Significance

The assay was able to detect 20 different YFV strains and demonstrated no cross-reactions with closely related viruses. The RPA assay proved to be a robust, portable method with a low detection limit (<21 genome equivalent copies per reaction) and rapid processing time (<20 min). Results from real-time RPA field testing were comparable to results obtained in the laboratory, thus confirming our method is suitable for YFV detection in low-resource settings.     

鉴别检测非洲猪瘟野毒株和基因缺失疫苗株的三重荧光PCR的建立

非洲猪瘟是由非洲猪瘟病毒(African swine fever,ASFV)引起的猪的一种急性、高度接触性传染病.本研究根据ASFV B646L、MGF360-14L和CD2v基因设计了 3套引物和探针,建立了可同时鉴别检测ASFV野毒株和基因缺失疫苗株的三重荧光PCR方法.结果表明,该法特异性强,可同时检测ASFV B646L、MGF360-14L和CD2v基因,与猪圆环病毒2型、猪瘟病毒、猪繁殖与呼吸综合征病毒、口蹄疫病毒、猪A型塞内卡病毒等无交叉反应;两份ASFV MGF360-505R与CD2v基因联合缺失疫苗株DNA三重荧光PCR法检测结果都仅出现一条B646L扩增曲线,与预期一致;灵敏度高,该法对重组质粒pUC-B646L、pUC-360-14L和pUC-CD2v的检出限分别为1.572×103拷贝/mL、1.934×103拷贝/mL 和 1.929×103拷贝/mL,灵敏度比世界动物卫生组织(World organization for animal health,OIE)推荐的荧光PCR高10倍;重复性好,对三种重组质粒检测的Ct值批内和批间变异系数均小于2％;应用该法及OIE推荐的荧光PCR对1 215份样品进行平行检测,结果显示23份样品为阳性,1 192份样品为阴性,两种方法检测结果一致.本研究建立的方法能鉴别检测ASFV野毒株和基因缺失疫苗株(缺失MGF360-505R和/或CD2v基因),对将来基因缺失疫苗的推广应用及ASF疫情防控具有重要的意义.