Probe Real-time PCR Research Articles

Rapid identification of Atractylodes macrocephala Koidz., Atractylodes lancea (Thunb.) DC. and hybrids with MLPA-qPCR based on nuclear genome

Atractylodes macrocephala and A. lancea are traditional medicinal herbs with a long history in the treatment of diseases. Although A. macrocephala and A. lancea have similar chemical components, their efficacies are different. Confusion of A. macrocephala and A. lancea is one of the hidden dangers of drug safety. Besides, the hybrids of A. macrocephala and A. lancea were bred and sold for bigger rhizomes, grow faster and cheaper prices. which is harmful to correct breeding and market regulation of medicinal materials. In order to correctly identify A. macrocephala, A. lancea and their hybrids, a molecular method combining multiplex ligation-dependent probe amplification and Real-time Quantitative PCR had been established in this study. Highly species-specific MLPA probes were designed based on ITS2 region within nuclear genome without cross-reaction, and three species could be distinguished according to the melting curve within 3 h. This study suggests that MLPA-qPCR is an accurate, feasible and high-throughput method for the identification of A. macrocephala, A. lancea and hybrids, and provides a reference for identification of species and even hybrids.

OralDisk: A Chair-Side Compatible Molecular Platform Using Whole Saliva for Monitoring Oral Health at the Dental Practice.

Periodontitis and dental caries are two major bacterially induced, non-communicable diseases that cause the deterioration of oral health, with implications in patients’ general health. Early, precise diagnosis and personalized monitoring are essential for the efficient prevention and management of these diseases. Here, we present a disk-shaped microfluidic platform (OralDisk) compatible with chair-side use that enables analysis of non-invasively collected whole saliva samples and molecular-based detection of ten bacteria: seven periodontitis-associated (Aggregatibacter actinomycetemcomitans, Campylobacter rectus, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola) and three caries-associated (oral Lactobacilli, Streptococcus mutans, Streptococcus sobrinus). Each OralDisk test required 400 µL of homogenized whole saliva. The automated workflow included bacterial DNA extraction, purification and hydrolysis probe real-time PCR detection of the target pathogens. All reagents were pre-stored within the disk and sample-to-answer processing took < 3 h using a compact, customized processing device. A technical feasibility study (25 OralDisks) was conducted using samples from healthy, periodontitis and caries patients. The comparison of the OralDisk with a lab-based reference method revealed a ~90% agreement amongst targets detected as positive and negative. This shows the OralDisk’s potential and suitability for inclusion in larger prospective implementation studies in dental care settings.

Study on the Effective Material Basis and Mechanism of Traditional Chinese Medicine Prescription (QJC) Against Stress Diarrhea in Mice.

Stress diarrhea is a major challenge for weaned piglets and restricts pig production efficiency and incurs massive economic losses. A traditional Chinese medicine prescription (QJC) composed of Astragalus propinquus Schischkin (HQ), Zingiber officinale Roscoe (SJ), and Plantago asiatica L. (CQC) has been developed by our laboratory and shows marked anti-stress diarrhea effect. However, the active compounds, potential targets, and mechanism of this effect remain unclear and warrant further investigation. In our study, we verified the bioactive compounds of QJC and relevant mechanisms underlying the anti-stress diarrhea effect through network pharmacology and in vivo experimental studies. After establishing a successful stress-induced diarrhea model, histomorphology of intestinal mucosa was studied, and Quantitative real-time PCR (RT-qPCR) probe was used for the phosphoinositide 3-kinase (PI3K)–Akt signaling pathway to verify the therapeutic effect of QJC on diarrhea. First, using the network pharmacology approach, we identified 35 active components and 130 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in QJC. From among these, we speculated that quercetin, luteolin, kaempferol, scutellarein, and stigmasterol were the main bioactive compounds and assumed that the anti-diarrhea effect of QJC was related to the PI3K–Akt signaling pathway. The RT-qPCR indicated that QJC and its bioactive components increased the expression levels of PI3K and Akt, inhibited the expression of phosphatase and tensin homolog (PTEN), and activated the PI3K–Akt signaling pathway to relieve stress-induced diarrhea. Furthermore, we found that QJC alleviated the pathological condition of small intestine tissue and improved the integrity of the intestinal barrier. Taken together, our study showed that the traditional Chinese medicine QJC, quercetin, luteolin, kaempferol, scutellarein, and stigmasterol alleviated the pathological condition of small intestine tissue and relieved stress-induced diarrhea by increasing the expression levels of PI3K and Akt and inhibiting the expression levels of PTEN.

Canine parvovirus is shed infrequently by cats without diarrhoea in multi-cat environments

Whether subclinical shedding of canine parvovirus (CPV) by cats might contribute to the epidemiology of canine CPV infections, particularly in facilities housing both cats and dogs, requires clarification. Conflicting results are reported to date. Using conventional PCR (cPCR) to amplify the VP2 gene, shedding of the CPV variants (CPV-2a, 2b, 2c) by healthy cats in multi-cat environments was reportedly common in Europe but rare in Australia. The aim of this study was to determine whether low-level faecal CPV shedding occurs in multi-cat environments in Australia and Italy using a TaqMan real-time PCR to detect Carnivore protoparvovirus 1 (CPV and feline parvovirus, FPV) DNA, and minor-groove binder probe real-time PCR assay to differentiate FPV and CPV types and to characterize CPV variants. In total, 741 non-diarrhoeic faecal samples from shelters in Australia (n = 263) and from shelters or cat colonies in Italy (n = 478) were tested. Overall, Carnivore protoparvovirus 1 DNA was detected in 49 of 741 (6.61 %) samples. Differentiation was possible for 31 positive samples. FPV was most common among positive samples (28/31, 90.3 %). CPV was detected in 4/31 samples (12.9 %) including CPV-2a in one sample, CPV-2b in another and co-infections of FPV/CPV-2b and CPV-2a/CPV-2b in the remaining two samples. A high rate of subclinical FPV infection was detected in one shelter during an outbreak of feline panleukopenia, during which 21 of 22 asymptomatic cats (95.5 %) sampled were shedding FPV. Faecal shedding of CPV by cats in multi-cat environments is uncommon suggesting that domestic cats are not significant reservoirs of CPV.

Association of Polymorphic and Haplotype Variants of the MSX1 Gene and the Impacted Teeth Phenomenon.

It is known that genetic factors determine odontogenesis; furthermore, studies have revealed that various genes in humans can regulate the development of different types and generations of teeth. In this study it has been assumed that tooth impaction—at least to some extent—also depends on the presence of specific genetic markers, especially allelic variants of the MSX1 gene. The primary objective of the study was to evaluate the suitability of selected molecular markers located within the MSX1 gene for the determination of the risk of tooth impaction in particular patients. The study participants were divided into two groups: (1) the study group—at least one secondary tooth was impacted in the jaws; (2) the control group—no impacted tooth in the jaws. Real-Time PCR and TaqMan probes were used to detect selected polymorphisms in the analyzed genes. Two single nucleotide polymorphisms of MSX1 were analyzed. After the two subgroups of patients were distinguished in the study group based on the number of impacted teeth, statistically significant differences in the frequency of genotypes described for rs12532 in the MSX1 gene were found.

Development of cycling probe based real-time PCR methodology for influenza A viruses possessing the PA/I38T amino acid substitution associated with reduced baloxavir susceptibility

Baloxavir marboxil has been used for influenza treatment since March 2018 in Japan. After baloxavir treatment, the most frequently detected substitution is Ile38Thr in polymerase acidic protein (PA/I38T), and this substitution reduces baloxavir susceptibility in influenza A viruses. To rapidly investigate the frequency of PA/I38T in influenza A (H1N1)pdm09 and A (H3N2) viruses in clinical samples, we established a rapid real-time system to detect single nucleotide polymorphisms in PA, using cycling probe real-time PCR. We designed two sets of probes that were labeled with either 6-carboxyfluorescein (FAM) or 6-carboxy-X-rhodamine (ROX) to identify PA/I38 (wild type strain) or PA/I38T, respectively. The established cycling probe real-time PCR system showed a dynamic linear range of 101 to 106 copies with high sensitivity in plasmid DNA controls. This real-time PCR system discriminated between PA/I38T and wild type viruses well. During the 2018/19 season, 377 influenza A-positive clinical samples were collected in Japan before antiviral treatment. Using our cycling probe real-time PCR system, we detected no (0/129, 0.0%) influenza A (H1N1)pdm09 viruses with PA/I38T substitutions and four A (H3N2) (4/229, 1.7%) with PA/I38T substitution prior to treatment. In addition, we found PA/I38T variant in siblings who did not received baloxavir treatment during an infection caused by A (H3N2) that afflicted the entire family. Although human-to-human transmission of PA/I38T variant may have occurred in a closed environment, the prevalence of this variant in influenza A viruses was still limited. Our cycling probe-PCR system is thus useful for antiviral surveillance of influenza A viruses possessing PA/I38T.

Evaluation of the prevalence of Echinococcus multilocularis in dogs that visit off-leash dog parks in southern Ontario, Canada.

Prior to 2012, Echinococcus multilocularis was not known to occur in any host in Ontario, Canada. However, since that year, five cases of alveolar echinococcosis have been diagnosed in dogs that resided at the western end of Lake Ontario. In addition, E.multilocularis has been shown to be a common infection in wild canids (i.e. coyotes and foxes) across southern Ontario with a high-risk infection cluster in the area surrounding the western shores of Lake Ontario and northern shores of Lake Erie. In regions endemic for E.multilocularis, dog ownership is considered a risk factor for human alveolar echinococcosis. A study was therefore carried out to determine the prevalence of E.multilocularis intestinal infections in dogs within the high-risk infection cluster. From May to November 2018, faecal samples were collected from 477 dogs aged ≥6months that visited 12 off-leash dog parks in the Halton, Hamilton and Niagara public health units. Faecal samples were analysed via a magnetic capture probe DNA extraction and real-time PCR method for E.multilocularis DNA. Overall, 0% (97.5% CI: 0%-0.80%) of samples tested positive. This result informs preventive recommendations for E.multilocularis infections in dogs in this region.

The Study of a Novel Nucleic Acid Detection Technology by Double-stranded Probe Real-time PCR

The Study of a Novel Nucleic Acid Detection Technology by Double-stranded Probe Real-time PCR

Noninvasive Fetal Sex Determination by Real-Time PCR and TaqMan Probes.

Noninvasive fetal sex determination by analyzing Y chromosome-specific sequences is very useful in the management of cases related to sex-linked genetic diseases. The aim of this study was to establish a non-invasive fetal sex determination test using Real-Time PCR and specific probes. The study was a prospective observational cohort study conducted from August 2018 to September 2019. Venous blood samples were collected from 25 Iranian pregnant women at weeks 7 to 25 of gestation. Cell-free DNA (cfDNA) was isolated from the plasma of samples and fetal sex was determined by SRY gene analysis using the Real-Time PCR technique. In the absence of SRY detection, the presence of fetal DNA was investigated using cfDNA treated with BstUI enzyme and PCR for the epigenetic marker RASSF1A. Of the total samples analyzed, 48% were male and 52% female. The RASSF1A assay performed on SRY negative cases also confirmed the presence of cell-free fetal DNA. Genotype results were in full agreement with neonate gender, and the accuracy of noninvasive fetal sex determination was 100%. Fetal sex determination using the strategy applied in this study is noninvasive and highly accurate and can be exploited in the management of sex-linked genetic diseases.

Molecular detection of important abortion-causing microorganisms in preputial swab of breeding bucks using PCR-based assays.

Infectious diseases and aetiological agents related to female reproductive systems were extensively covered compared to its male counterpart. There needs a proper study to bridge this gap, where microflora and infectious agents of both male and female reproductive are mutually intelligible. With this study, we aimed to evaluate the microbial contamination of the preputial cavity and also screened for abortion-causing agents which are zoonotic as well. In goats, such types of abortions are caused by Brucella melitensis, Chlamydophila, Campylobacter and Coxiella etc. One of the major sources of contamination of semen is the preputial cavity, which is exposed to the external environment leading to spread of infection into the female via semen straws or by natural service. In the current study, good quality bucks (n=32, Barbari=12, Jamunapari=10, Jakhrana=10) which were routinely used for semen collection were screened for their preputial swabs, for the presence of the above pathogens. For detection of Brucella melitensis, OMP31 based TaqMan® probe real-time PCR assay was used, and for Chlamydia, 16srRNA gene based SYBR® green real-time PCR assay was employed for detection of Chlamydophila abortus. While for Campylobacter spp. and Coxiella burnetii, 16srRNA gene based conventional PCR and Trans-PCR were used, respectively. In the current study, of the screened preputial swabs, none of them showed positive for Brucella and Coxiella, but of the screened 32 samples 17 showed positive for Chlamydia (53.13%) and two (6.25%) showed positive for Campylobacter spp. The current study emphasizes on the farms and laboratories which were regularly involved in screening of brucellosis also often overlook the other potential non-brucella pathogens, causing abortions eventually incurring severe economic losses to the goat keepers.

Molecular characterisation and phylogenetic analysis of Marek’s disease virus in Turkish layer chickens

ABSTRACT 1. There is no current data about the genotypes of Marek’s disease virus (MDV) in Turkish poultry flocks; hence, this study was performed to analyse CVI988/Rispens, turkey herpesvirus (HVT) vaccine viruses and MDV field viruses as well as to perform phylogenetic analysis of MDV in Turkish layer chickens. 2. In 2017 and 2018, a total of 602 spleen samples from 49 layer flocks were collected from the Marmara, West Black Sea and Aegean regions. DNA was extracted from the spleen samples and the samples were analysed by real-time PCR probe assay to detect CVI988/Rispens and HVT vaccine viruses and MDV field strains. Samples found positive for MDV by real-time PCR were subjected to PCR using the Meq gene primers for phylogenetic analysis. 3. Amongst 49 flocks, virulent MDV was detected in nine flocks. CVI988/Rispens and HVT vaccine strains were detected in 47 flocks and HVT in all 49 flocks. Splenomegaly, hepatomegaly and tumours in the oviduct were observed in chickens of affected flocks. Virulent MDV was detected in 120 out of 602 spleen samples. Sequencing and phylogenetic analyses showed that MDVs detected in this study were closely related to MDV strains from Italy, Poland, Saudi Arabia, Iraq, India and China but showed diversity with MDV strains from Egypt and Hungary. Multiple sequence analysis of the Meq protein revealed several point mutations in deduced amino acid sequences. Interestingly, CVI988/Rispens vaccine virus from China (AF493555) showed mutations at position 66 (G66R) and 71 (S66A) along with two other vaccine strains from China (GU354326.1) and Russia (EU032468.1), in comparison with the other vaccine strain CVI988/Rispens (DQ534538). The molecular analyses of the Meq gene suggested that Turkish field strains of MDV are in the class of virulent or very virulent pathotypes. 4. The results have shown that MDV still affects poultry health, and the phylogenetic and amino acid variation data obtained will help in vaccination and control strategies.

Synthesis of Dihydroquinoline-Based Derivatives of Fluorescent Rhodamine Dyes for Nucleic Acid Analysis by a Real-Time Polymerase Chain Reaction

An optimized synthesis scheme for the dihydroquinoline-based derivatives of xanthene fluorescent dye has been developed. For the first time, their use as effective fluorophores in hybridization probes for real-time PCR has been demonstrated with the detection on an individual spectral channel.

GoPrime: Development of an In Silico Framework to Predict the Performance of Real-Time PCR Primers and Probes Using Foot-and-Mouth Disease Virus as a Model.

Real-time PCR (rPCR) is a widely accepted diagnostic tool for the detection and quantification of nucleic acid targets. In order for these assays to achieve high sensitivity and specificity, primer and probe-template complementarity is essential; however, mismatches are often unavoidable and can result in false-negative results and errors in quantifying target sequences. Primer and probe sequences therefore require continual evaluation to ensure they remain fit for purpose. This paper describes the development of a linear model and associated computational tool (GoPrime) designed to predict the performance of rPCR primers and probes across multiple sequence data. Empirical data were generated using DNA oligonucleotides (n = 90) that systematically introduced variation in the primer and probe target regions of a diagnostic assay routinely used to detect foot-and-mouth disease virus (FMDV); an animal virus that exhibits a high degree of sequence variability. These assays revealed consistent impacts of patterns of substitutions in primer and probe-sites on rPCR cycle threshold (CT) and limit of detection (LOD). These data were used to populate GoPrime, which was subsequently used to predict rPCR results for DNA templates (n = 7) representing the natural sequence variability within FMDV. GoPrime was also applicable to other areas of the FMDV genome, with predictions for the likely targets of a FMDV-typing assay consistent with published experimental data. Although further work is required to improve these tools, including assessing the impact of primer-template mismatches in the reverse transcription step and the broader impact of mismatches for other assays, these data support the use of mathematical models for rapidly predicting the performance of rPCR primers and probes in silico.

TaqMan probe qRT-PCR detects bovine parvovirus and applies clinically

The present study aimed to establish a TaqMan probe real-time PCR qRT-PCR for detecting Bovine parvovirus BPV , and to develop a novel diagnostic method of BPV. TaqMan probe and primers were designed and synthesized from the sequences of conserved 5?-untranslated regions 5'-UTR of strain Haden of BPV. Optimum reaction conditions were comparatively selected. The sensitivity, specificity, and reproducibility of TaqMan probe qRT-PCR were measured respectively. Feces specimens collected from diarrhea calves were detected using this assay. The results showed that optimized conditions for the probe qRT-PCR were 0.8 &#956L probes 18.0 &#956mol/L , 0.4 &#956L primers 10.0 &#956mol/L and annealing temperature of 43.2 °C for 40 s. The probe qRT-PCR could specially detect BPV, but not for other viruses JEV, CSF, RABV, BRV, BVDV, and bFMDV . The detection limit was 5.26 copies/&#956L. Both intraassay and interassay VCs were lower than 1.65%. Detection of 308 feces samples showed 36 positives for TaqMan probe qRT-PCR compared to 32 positives of universal PCR. Coincidence rate of the two methods was 88.89%. In conclusion, the established TaqMan probe qRT-PCR could specifically detect BPV. It had excellent sensitivity, specificity, and stability. The detection limit was 5.26 copies/&#956L. Its sensitivity was 10,000-fold over the conventional PCR. TaqMan probe qRT-PCR will help to enhance diagnosis and therapy efficacy of diarrhea calves.

Design and Production of a Chimeric Construct as a Genetically Positive Control for the Detection of Burkholderia and Yellow Fever Virus Using the Real-Time PCR

Background: Burkholderia bacteria are species from protobacter and the pathogens of this species include Burkholderia mallei and pseudomallei causing glanders. The yellow fever virus is a blavovirus that has a single-stranded polyribonucleotide genome (positive strand). Yellow fever is a type of acute viral disease, also called black vomit. Even though considerable advances have been made in the development and use of molecular techniques for the detection of pathogens such as Burkholderia species and yellow fever, a major problem in these techniques is lack of proper positive control. Recently developed genetically modified vectors and simulator construct have provided engineered tools that can be used as a positive control in molecular diagnosis. Methods: In the current study, we first designed and produced chimeric simulator constructs, containing specific genes from Burkholderia mallei, pseudomallei, and yellow fever virus. Then, the operational efficiency of the designed structures was evaluated using a single and dual-mode quantitative (using SYBER Green) and qualitative (using the TaqMan probe) Real-time PCR. Results: The minimum and maximum sensitivity of designed construct for Burkholderia and yellow fever detection was indicated to be 0.1 pg and 10 ng, respectively. Conclusions: Our findings suggest that this positive control constructs can be used for development of new diagnostic kits.

Study of the p.V617F and Exon 12 Mutations in JAK2 Gene Among Iranian Chronic Myeloproliferative Patients

Background: Chronic myeloproliferative disorders (CMPD) occur due toclonal proliferation of the single hematopoietic stem cells and result in an increased number of mature and immature cells in the peripheral blood. The mutations in JAK2 gene are identified in large numbers of CMPD patients. Objectives: The aim of this study was to investigate thep.V617F (c.1849G > T) mutation as well as exon 12 mutations in JAK2 gene in the CMPD patients. Methods: Philadelphia chromosome negative CMPD patients were recruited for this study. In order to study p.V617F and JAK2 exon 12 mutations in JAK2 gene, FRET probe real-time PCR, allele specific PCR and PCR-direct sequencing were utilized. Results: JAK2 p.V617F mutation was found in polycythemia vera, Essential thrombocytosis and idiopathic myelofibrosis (67%, 52% and 50% respectively) but not in idiopathic erythrocytosis patients. Also no mutation was found in JAK2 exon 12 of these patients. Conclusions: Our data regarding p.V617F was in concordance with the previous studies. The absence of any mutation in exon 12 of our patients may be due to extracting DNA from whole blood cells instead of granulocytes, that may impact the detection rate of cycle sequencing method.

Association of Complement Factor D and H Polymorphisms with Recurrent Pregnancy Loss.

Recurrent pregnancy loss (RPL) is defined as two or more consecutive pregnancy losses prior to 20 weeks of gestation, and the incidence of RPL is estimated at 1% of all pregnancies. While the etiologies of RPL are diverse, immune function is considered to be an important cause of RPL. In particular, the complement system is essential for stable development of the placenta and fetus. Moreover, complement factor D (CFD) and complement factor H (CFH) are important regulators of the complement system and are associated with diseases, such as age-related macular degeneration. Therefore, we investigated whether polymorphisms of CFD and CFH are associated with RPL in 412 women with RPL and 384 control women. Genotyping of three polymorphisms (CFD rs2230216, CFH rs1065489, and CFH rs1061170) was performed by TaqMan probe real-time PCR and PCR-restriction fragment length polymorphism. Association of three polymorphisms with RPL was evaluated by statistical analysis. The GT/TC genotype combination of CFH rs1065489 G>T/CFH rs1061170 T>C was associated with a decreased risk of RPL occurrence compared with reference genotypes (adjusted odds ratio [AOR] = 0.439; 95% confidence interval [CI] = 0.238–0.810; p = 0.008), and this association remained significant after adjustment for multiple comparisons using false discovery rate (FDR) correction (p = 0.040). In addition, the CFH rs1065489G>T polymorphism is associated with homocysteine and prolactin level and CFH rs1061170 TC genotype is related to uric acid and triglycerides level in RPL patients. Therefore, those factors could be possible clinical risk factors in RPL patients.

Prevalence of Wolbachia in 10 Tenebrionidae stored-product insects and spatiotemporal infection dynamics in Tribolium confusum (Jaquelin Du Val) (Coleoptera: Tenebrionidae)

Abstract Insect symbionts Wolbachia used for pest population control has focused on vector pest species and agricultural insects while rare reports in Chinese stored-product insect samples. In this paper, we surveyed the prevalence of Wolbachia using a PCR detection method in ten Tenebrionidae stored-product insects. Subsequently, the spatiotemporal Wolbachia infection dynamics in Tribolium confusum and Wolbachia elimination patterns using tetracycline treatment were investigated in detail by TaqMan® probe real-time quantitative PCR, and host reproductive fitness parameters were compared. T. confusum was the only Wolbachia infected species in all the surveyed species. Wolbachia infection density consistently increased with the development of T. confusum and plateaued at 3.7 × 107 wsp copies per individual insect at the young adult stage. Wolbachia densities in females were higher than that in males with a significant difference at the pupae stage and varied among different tissues and organs. Uninfected female beetles were completely incapable of producing mature progenies when crossed with Wolbachia infected males. Embryogenesis and egg hatch rate were specifically inhibited after Wolbachia elimination, while other traits, including the number of eggs, pupation rate and sex ratio, remained unaffected by tetracycline treatment. Our results show that the density of Wolbachia quantified by TaqMan® probe qPCR is a reliable detection method for diagnosis as compared to qualitative detection of wsp gene by PCR and relatively quantified by real-time qPCR. The fitness results indicated that Wolbachia infection was not an obligate symbiont and benefited the host confused flour beetle.

Simultaneous detection of classical PRRSV, highly pathogenic PRRSV and NADC30-like PRRSV by TaqMan probe real-time PCR

Porcine Reproductive and Respiratory Syndrome (PRRS), an acute infectious disease caused by the porcine reproductive and respiratory syndrome virus (PRRSV), is one of the most devastating diseases affecting the global swine industry. In order to establish a multiplex real-time PCR method for the simultaneous detection of the classical PRRSV (C-PRRSV) strain, the highly pathogenic PRRSV (HP-PRRSV) strain and NADC30-like PRRSV (NL-PRRSV) strain, we designed specific primers and TaqMan fluorescent probes based on the Nsp2 target gene sequence of these three different PRRSV strains, and designed American-type PRRSV (PRRSV-U) special primers and probes based on the relatively conserved target gene sequence of ORF7. The method established in this study can quickly and accurately detect and differentiate three types of strains of clinical tissue samples, respectively. This method plays a key role in the rapid diagnosis and determination of PRRSV.

Specific Detection of Bovine Coronavirus N Protein with TaqMan Probe qRT-PCR

Background: Bovine Coronavirus (BCoV) can cause acute diarrhea in newborn calves and adult cattle. BCoV infection may cause losses to production by reduced weight gain, reduced milk yield. Several methods have been applied to detect and diagnose BCoV. However, each assay has its deficiency. Currently, real-time quantitative PCR (qRT-PCR) has been utilized to identify and quantify many viral pathogens since it is a highly sensitive. However, the technical assay varies due to normalization control of the signal with an internal standard, typically a housekeeping gene. The main objective of the present study to establish a novel TaqMan probe real-time PCR (qRT-PCR) for detecting BCoV.Materials, Methods &amp; Results: The present study was aimed to establish a novel TaqMan probe real-time PCR (qRT-PCR) for detecting bovine coronaviruses (BCoV), and also to develop a diagnostic protocol which simplifies sample collection and processing. One pair of specific primers, one pair of universal primers and a TaqMan probe were designed from the known sequences of conserved nucleocapsid (N) protein of BCoV. Reaction systems of TaqMan qRT-PCR were optimized including concentrations of the primers and probe as well as annealing temperatures. Prior to optimizing the assay, the recombinant plasmids of pMD18-T-BCoV-N were successfully constructed to make standard curves. The sensitivity, specificity and reproducibility were evaluated on the TaqMan qRT-PCR, respectively. A total of 321 feces specimens collected from diarrheic calves were detected with this assay. The results showed the optimized reaction conditions for qRT-PCR were 14.5 μM/L primers, 19.5 μM/L probes and 45.0°C annealing temperatures. The established TaqMan qRT-PCR assay could specially detect BCoV without detecting any other viruses. Its minimum detection limit was 4.72 × 101 copies/μL. However, universal PCR could detect only 4.72 × 103 copies/μL. Its sensitivity was 100-fold stronger than universal PCR. In conclusion, this TaqMan qRT-PCR had excellent specificity, sensitivity and stability with a 100-fold sensitivity stronger than universal PCR. Minimum detection limit was 4.72 × 101 copies/μL. This method was a cost-effective method to diagnose diarrhea and distinguish pathogens in dairy farms.Discussion: In this study, the authors developed a quantitative real-time PCR (qRT-PCR) in this study based on the TaqMan probe of BCoV. This TaqMan qRT-PCR assay selected and used one pair of specific primers (BCoV-qF/BCoV-qR) and a specific TaqMan probe (BCoV-probe) targeting the conserved nucleocapsid (N) gene. The specificity of primers and probes was validated with Primer-BLAST. The specificity of the qRT-PCR was confirmed by the negative control and other six viruses. The findings demonstrated that TaqMan qRT-PCR could only detect BCoV. This verified the qRT-PCR had an excellent specificity. It is obvious that this TaqMan qRT-PCR assay can detect only BCoV with stronger sensitivity and reproducibility than other real-time PCR methods. The sensitivity test indicated the minimum detection limit of the TaqMan qRT-PCR was 4.72 × 101copies/μL, or 47.2 copies/μL. Sensitivity of the TaqMan qRT-PCR assay was increased by 100-fold as compared to universal PCR with a good inter-assay and intra-assay reproducibility. Thereby, based on the high sensitivity of the assay of this qRT-PCR assay it may be a cost-effective method to diagnose BCoV infections and indentify the etiologic agents of diarrhea syndrome in the dairy farms.