利用SYBR Green real-time PCR方法监控鸡外周血淋巴细胞中马立克病毒的载量

建立基于SYBR Green Ⅰ的real-time FQ-PCR方法检测并定量鸡外周血淋巴细胞(peripheral blood leukocytes,PBLs)中马立克病毒(Marek's disease virus,MDV)的载量(以meq基因为定量标准),并将此技术的敏感性与标准PCR方法进行对比.应用PCR技术从MDV-1攻毒后的霞烟鸡PBLs中扩增MDV meq基因的部分片段,纯化上述基因的DNA扩增产物,然后克隆到pGM-T载体,重组质粒通过PCR和EcoR Ⅰ酶切及测序分析进行确认;将浓度梯度的meq基因的重组标准品质粒DNA进行real-time FQ-PCR,建立其相应的标准曲线.同样以质粒DNA为模板,real-time FQ-PCR方法的最低检出率为10拷贝,而标准PCR的最低检出率则为32拷贝.结果表明,在检测MDV时,real-time FQ-PCR敏感度比标准PCR要高.     

Clinical, haematological and biochemical findings in foals with neonatal Equine herpesvirus-1 infection compared with septic and premature foals.

A retrospective multicentre study comparing historical, clinical, haematological, acid-base and biochemical findings of foals with Equine herpesvirus-1 (EHV-1) infection, septicaemia or prematurity was performed to determine if early diagnosis of EHV-1 foals was possible. Fifty-three foals were studied and were assigned to one of 2 groups: herpes positive (n = 14) or herpes negative (n = 39). The latter group included 20 septic, 11 premature, and 8 premature and septic foals. The presence of herpes antigen was confirmed by immunoperoxidase histochemical staining of tissues from necropsied foals. A nonparametric statistical analysis followed by a backwards elimination logistic regression was performed to establish a model at a P value of <0.05. All herpes positive foals died, while 47% (9/19) of the septic foals survived. Based upon our analysis, herpes positive foals were more likely to have total white blood cell counts less than 3 x 10(9)/l and to be icteric as compared to the septic and premature foals. Despite profound hepatic necrosis in the herpes positive foals, liver enzymes were not elevated and were not significantly different from the controls.     

Detection of equine herpesvirus-1 in nasal swabs of horses by quantitative real-time PCR

Background: Early identification of inhalation-transmitted equine herpesvirus type 1 (EHV-1) infections has been facilitated by the availability of a number of real-time quantitative PCR (qPCR) tests. A direct comparison between nasal swab qPCR and traditional virus isolation (VI) requires a method for normalizing the qPCR samples and controlling for PCR inhibitors present in some clinical samples.
Objectives: To quantify EHV-1 shedding in viral swabs using an internal control and to compare fast qPCR to VI for the detection of EHV-1 in nasal swabs from horses.
Animals: Fifteen horses experimentally infected with EHV-1.
Methods: Experimental study : Nasal swab samples were collected daily after experimental infection for up to 21 days. VI was performed by conventional methods. The DNA was prepared for qPCR with the addition of a known quantity DNA of Marek's disease virus as an internal control. qPCR was performed.
Results: The qPCR method detected virus up to day 21 after challenge, whereas VI detected virus only to day 5. The median Kaplan-Meier estimates for EHV-1 detection were 12 days for qPCR and 2 days for VI ( P < .0001). When compared with VI, the sensitivity and specificity of qPCR were 97 (95% CI: 86–100) and 27% (95% CI: 20–35).
Conclusions and Clinical Importance: We conclude that fast qPCR of nasal swab samples should be chosen for diagnosis and monitoring of herpesvirus-induced disease in horses. Recommended reference ranges of C _T values are provided as well as justification of a minimum 10-day quarantine period.     

基于胞内劳森菌16S rDNA基因的TaqMan荧光定量PCR检测方法的建立与应用

参考GenBank发表的胞内劳森菌(Lawsonia intracellularis,L.intracellularis)基因组16SrDNA序列,设计1对特异性引物和1条TaqMan探针,以L.intracellularis疫苗核酸为模板,建立L.intracellularis TaqMan实时荧光定量PCR检测方法。对该检测法制作了标准曲线,并进行了特异性、敏感性和重复性试验,并将其应用于猪增生性肠炎诊断。结果表明,所建立的TaqMan实时荧光定量方法特异性强,仅对含有L.intracellularis扩增出S型荧光曲线,而对大肠杆菌、沙门菌、金黄色葡萄球菌、副猪嗜血杆菌等均无扩增;该方法在1.2×102¹.2×108 copies/μL有良好的线性关系,相关系数为0.972;最低检测浓度为10copies/μL,重复性良好。对79份临床样品检测表明,该方法灵敏度高于普通PCR方法,可用于猪增生性肠炎的临床诊断。     

Detection of elephant endotheliotropic herpesvirus type 1 in asymptomatic elephants using TaqMan real-time PCR

This study assessed the feasibility of identifying asymptomatic viral shedders using a novel TaqMan real-time PCR on trunk washes and swabs from the conjunctiva, palate and vulva of elephants. Six elephants from a UK collection were sampled weekly over a period of 11 weeks for this study. The herd prevalence of elephant endotheliotropic herpesvirus-1 (EEHV-1) was 100 per cent by PCR. The virus DNA was detected in all the sampling sites; however, the prevalence of virus DNA in the conjunctiva swabs was higher. In addition, Asian elephants from two continental European collections were sampled once and one animal tested positive on a trunk wash. The virus from this animal was phylogenetically typed as EEHV-1A based on 231 nucleotides of the terminase gene.     

牛传染性鼻气管炎gB基因TaqMan探针及SYBR Green 1荧光定量PCR方法的建立与比较

为建立牛传染性鼻气管炎病毒(IBRV)荧光定量PCR检测方法,本研究利用IBRV g B基因序列设计引物及相应探针,分别建立Taq Man探针与SYBR Green 1荧光定量PCR方法,并对两种方法的敏感性等综合比较。结果显示,SYBR Green 1荧光定量PCR方法的相关系数(R2)为0.998,扩增效率(E)为95.7%;Taq Man探针荧光定量PCR方法的R2为0.999,E为108.3%;两种方法的敏感性均为0.2 TCID50,变异系数均小于3%。综合结果显示,两种检测方法无显著差异。最后,本研究成功建立了检测IBRV的荧光定量PCR,将为IBRV的临床检测提供方法。     

Rapidly quantitative detection of Nosema ceranae in honeybees using ultra-rapid real-time quantitative PCR

BackgroundThe microsporidian parasite Nosema ceranae is a global problem in honeybee populations and is known to cause winter mortality. A sensitive and rapid tool for stable quantitative detection is necessary to establish further research related to the diagnosis, prevention, and treatment of this pathogen.ObjectivesThe present study aimed to develop a quantitative method that incorporates ultra-rapid real-time quantitative polymerase chain reaction (UR-qPCR) for the rapid enumeration of N. ceranae in infected bees.MethodsA procedure for UR-qPCR detection of N. ceranae was developed, and the advantages of molecular detection were evaluated in comparison with microscopic enumeration.ResultsUR-qPCR was more sensitive than microscopic enumeration for detecting two copies of N. ceranae DNA and 24 spores per bee. Meanwhile, the limit of detection by microscopy was 2.40 × 10⁴ spores/bee, and the stable detection level was ≥ 2.40 × 10⁵ spores/bee. The results of N. ceranae calculations from the infected honeybees and purified spores by UR-qPCR showed that the DNA copy number was approximately 8-fold higher than the spore count. Additionally, honeybees infected with N. ceranae with 2.74 × 10⁴ copies of N. ceranae DNA were incapable of detection by microscopy. The results of quantitative analysis using UR-qPCR were accomplished within 20 min.ConclusionsUR-qPCR is expected to be the most rapid molecular method for Nosema detection and has been developed for diagnosing nosemosis at low levels of infection.     

鸭呼肠孤病毒TaqMan与SYBR Green荧光定量检测方法的建立及比较

本研究旨在针对新型鸭呼肠孤病毒(NDRV)建立两种快速、敏感、特异的荧光定量PCR诊断方法并对其临床实用性进行比较。试验根据呼肠孤病毒S1基因序列设计合成1对特异性引物和1条MGB探针,分别建立TaqMan和SYBR GreenⅠ两种荧光定量PCR检测方法,并对两种方法的特异性、灵敏性、重复性进行比较。结果显示,两种检测方法标准曲线的相关系数均为0.999,对鸭细小病毒(DPV)、A型鸭甲肝病毒(DHV-1)、C型鸭甲肝病毒(DHV-3)、鸭传染性支气管炎(IBV)、鸭坦布苏病毒(DTMUV)、鹅星状病毒(JSHV)的检测结果均为阴性,特异性良好。SYBR GreenⅠ法的最低检测限度为10⁰拷贝/μL,TaqMan法的最低检测限度为10¹拷贝/μL,前者的灵敏度比后者高10倍。SYBR GreenⅠ法和TaqMan法重复性试验的组内和组间变异系数均分别小于2.1%和1.8%。利用这两种方法对临床30份疑似病料进行检测,其中TaqMan法检出29份,SYBR GreenⅠ法检出30份,符合率为97%。综上,两种荧光定量方法均可用于临床NDRV...     

Equine herpesvirus-1-specific interferon gamma (IFNgamma) synthesis by peripheral blood mononuclear cells in thoroughbred horses

REASONS FOR PERFORMING STUDY: An assay has been developed that measures EHV-1 specific interferon gamma synthesis (IFNgamma), a cytokine produced following the activation of memory T lymphocytes and therefore a measure of cell mediated immunity. The method requires validation in the field. OBJECTIVES: To measure the frequency of EHV-1 specific, IFNgamma synthesising peripheral blood mononuclear cells (PBMC) in a population of Thoroughbred horses, and examine its relationship with age, gender, premises and history of vaccination or field infection with EHV-1. METHODS: Lymphocytes from 200 Thoroughbred horses were stimulated with EHV-1 in vitro, and IFNgamma detected using a monoclonal antibody and indirect immunofluorescence. Percent positive cells were enumerated by flow cytometric analysis and the results described and compared statistically between groups. RESULTS: The frequency of IFNgamma+ PBMC was significantly higher in animals age >5 years compared with 2-4 years, in females vs. males, on stud farms vs. training yards and following vaccination of 2-year-olds with inactivated virus compared with nonvaccinates. Age strongly confounded all these associations and care must therefore be taken interpreting these results. Mares exposed to a field infection with EHV-1 also had higher frequencies of IFNgamma+ PBMC than other vaccinated horses. CONCLUSIONS: The frequency of EHV-1 specific, IFNgama+ PBMC among the sample Thoroughbred population was diverse but lowest in young, unvaccinated horses-in-training. POTENTIAL RELEVANCE: The frequency of EHV-1 specific lymphocytes synthesising IFNgamma in this population may be associated with its susceptibility to infection with this virus. This easy technique may be applied to monitor the antigenicity of vaccines and their effectiveness at stimulating cellular immunity.     

猪瘟病毒野毒株与疫苗株E2基因双重TaqMan real-time PCR鉴别检测方法的建立

为建立猪瘟病毒(CSFV)野毒株和疫苗株快速定量鉴别检测方法,根据CSFV野毒株和疫苗株E2基因序列差异,设计了2对特异性引物及1条Taq Man探针,以含CSFV HB株和C-株E2基因的重组质粒p BS-E2C和p BS-E2作为标准品,建立了能同时检测CSFV野毒株和疫苗株的双重Taq Man real-time PCR鉴别检测方法。结果表明,建立的CSFV双重Taq Man real-time PCR标准曲线Ct值与1×101~1×106copies/μL之间的E2基因拷贝数呈良好的线性关系,灵敏度达10 copies/μL,且特异性和重复性很好。综上,本试验建立的Taq Man real-time PCR检测方法可用于CSFV野毒株和疫苗株的鉴别诊断及病原定量分析。     

Cytochemical demonstration of esterases in peripheral blood leukocytes.

Cytochemical methods for alpha naphthyl acetate esterase and chloroacetate esterase have been used to identify human monocytes and granulocytes. In this study, a standard procedure for staining alpha naphthyl acetate and chloroacetate esterase activities was modified by extending the range of pH of the incubation mixture and the duration of staining and was applied to cat, dog, goat, guinea pig, hamster, human, pig, rabbit, rat, and sheep leukocytes. The results for both enzymes showed (1) incubation time and pH had discrete effects on staining and (2) species differences for in vitro conditions to demonstrate esterase activity were pronounced.     

Replication kinetics of duck virus enteritis vaccine virus in ducklings immunized by the mucosal or systemic route using real-time quantitative PCR

A chicken embryo-adapted duck enteritis virus (DEV) strain is the most widely used vaccine against duck virus enteritis (DVE) infection. The kinetics of attenuated DEV vaccine was examined in tissues of ducklings vaccinated by the mucosal or systemic route at 20 days of age and sampled regularly up to 60 days post-vaccination (p.v.). Significant numbers of virus genomes in the lymphoid and other parenchymatous organs were first detected at 60 min p.v., and subsequently rose to peak levels during 90 min to 1 day p.v. independent of the route of vaccine administration. The peak level of vaccine virus in the individual parenchymatous organs of subcutaneously immunized ducklings was significantly higher than that of orally or nasally immunized ducklings. The route of vaccine administration had significant effect on the initial tissue distribution of vaccine virus in respiratory and digestive tracts. Vaccine viruses spread to digestive tract and trachea tissues by mucosal route, i.e. oral and nasal administration, early than that by subcutaneous route. The rapid early increase of vaccine virus levels in all samples examined followed by a steady decline from 90 min to 6 days p.v. The real-time PCR analysis of a variety of tissues is significant for further investigation of the mechanism of vaccinal protection, and the optimization of vaccination regimes.     

发生马铃薯立枯病土壤中立枯丝核菌的荧光定量PCR快速检测

连作马铃薯根际土壤中立枯丝核菌的大量累积可能是导致马铃薯连作障碍发生的主要原因之一。为了解根际土壤中土传病害病原菌的积累与连作障碍之间的关系,进一步寻求缓解和克服马铃薯连作障碍土传病害的有效途径,本研究建立优化了荧光定量PCR(real-time PCR)方法,对引起马铃薯立枯病的病原菌立枯丝核菌进行了快速监测和绝对定量,对马铃薯连作1～5年根际土壤立枯丝核菌的动态变化趋势进行了检测分析。结果显示,研究建立优化的荧光定量PCR检测方法,可直接应用土壤DNA进行病原菌的定量检测,能检测到土壤中浓度为1×10²个拷贝/g土的马铃薯立枯丝核菌,扩增效率为1.04,具有检出限低、扩增效率高的特点,实现了不通过病土分离培养方法,就可掌握病原菌在根际土壤中的累积状况;在马铃薯立枯病发病严重的连作根际土壤中,立枯丝核菌的累积数量随连作年限的递增呈上升趋势;病原菌的累积随生育进程的推进呈下降趋势;病原菌累积量最大的是连作5年的播前土壤,每g土壤达3.75×10⁷个拷贝数,由此可见,连作导致了土壤微生物种群结构发生改变,土壤致病真菌数量增加,相应地也增加了马铃薯立枯病的初侵染机率。     

猪链球菌通用及2型TaqMan荧光PCR检测技术建立与应用

在对设计合成的引物和6-carboxy-fluorescein(6-FAM)荧光素标记的TaqMan水解探针进行筛选的基础上,通过反应体系优化,建立了检测猪链球菌通用和2型的2种荧光PCR检测技术,实现了对猪链球菌的快速检测和定型。敏感性、特异性、重复性、感染组织模拟试验及临床样品的检测结果均表明建立的方法快速、特异、灵敏,整个检测过程(包括样品的前处理时间)可在1.5 h内完成,检测培养物和模拟组织样品的灵敏度可达10 CFU～100 CFU。     

Cross-sectional study of Brucella spp. using real-time PCR from bovine whole blood in Colombia

Veterinary Research Communications - A cross-sectional study was conducted in Colombia to recover Brucella spp. DNA from bovine whole-blood samples through probe-based real-time PCR (qPCR). By an...     

猪JAK-1、JAK-2、STAT-1和STAT-2TaqMan荧光定量RT-PCR检测方法的建立及应用

为建立定量检测猪Janus激酶(JAK)和信号转导和转录激活因子(STAT) mRNA的TaqMan荧光定量PCR检测方法,本研究针对猪JAK-1,JAK-2,STAT-1、STAT-2及管家基因β-actin的序列设计了特异性的引物和探针,分别构建了各自的阳性重组质粒,建立了TaqMan荧光定量PCR方法.结果表明:所建立的检测方法荧光定量PCR扩增均无非特异性产物的产生;检测下限均达1.0×101 copies/μL;批内及批间变异系数均小于2％.利用该方法对猪细小病毒(PPV)感染ST细胞48 h后JAK-1、JAK-2、STAT-1和STAT-2 mRNA的转录水平进行了检测,结果表明:JAK-1和JAK-2转录水平显著上调,STAT-1和STAT-2转录水平呈现下调趋势,本研究建立的TaqMan荧光定量PCR方法特异性强、敏感性高、重复性好,适于猪细胞传导因子JAK和STAT的定量检测.