Early and simultaneous detection ofNosema bombycis(Microsporidia: Nosematidae), nucleopolyhedrovirus (Baculoviridae), and densovirus (Parvoviridae) by multiplex real-time polymerase chain reaction inBombyx mori(Lepidoptera: Bombycidae)

2017 ◽  
Vol 149 (2) ◽  
pp. 265-275
Author(s):  
Shan Wu ◽  
Yong-Qiang He ◽  
Xing-Meng Lu ◽  
Xiao-Feng Zhang ◽  
Jiang-Bing Shuai ◽  
...  

AbstractAn effective multiplex real-time polymerase chain reaction (PCR) assay for the simultaneous detection of three major pathogens,Nosema bombycisNägeli (Microsporidia: Nosematidae),Bombyx morinucleopolyhedrovirus (Baculoviridae: genusAlphabaculovirus) (NPV), andBombyx moridensovirus (Parvoviridae: genusIteravirus) (DNV), in silkworms (Bombyx mori(Linnaeus); Lepidoptera: Bombycidae) was developed in this study. Polymerase chain reaction and real-time PCR tests and basic local alignment search tool searches revealed that the primers and probes used in this study had high specificities for their target species. The ability of each primer/probe set to detect pure pathogen DNA was determined using a plasmid dilution panel, in which under optimal conditions the multiplex real-time PCR assay showed high efficiency in the detection of three mixed target plasmids with a detection limit of 8.5×103copies forN. bombycisandBombyx moriNPV (BmNPV) and 8.5×104copies forBombyx moriDNV (BmDNV). When the ability to detect these three pathogens was examined in artificially inoculated silkworms, our method presented a number of advantages over traditional microscopy, including specificity, sensitivity, and high-throughput capabilities. Under the optimal volume ratio for the three primer/probe sets (3:2:2=N. bombycis:BmNPV:BmDNV), the multiplex real-time PCR assay showed early detection of BmNPV and BmDNV by day 1 post inoculation using DNA templates of the three pathogens in various combinations from individually infected silkworms; the early detection ofN. bombyciswas possible by day 3 post inoculation using the DNA isolated from the midgut ofN. bombycis-infected silkworms.

2021 ◽  
Author(s):  
Yang Pan ◽  
Jing Chen ◽  
Junhuang Wu ◽  
Yongxia Wang ◽  
Junwei Zou ◽  
...  

Abstract Background: Canine Kobuvirus (CaKoV) and Canine Circovirus (CaCV) are viruses that infect dogs causing diarrheal symptoms that are very similar. However, there is no clinical method to detect a co-infection of these two viruses.Results: In this study, a duplex SYBR Green I-based quantitative real-time polymerase chain reaction (PCR) assay for the rapid and simultaneous detection of CaKoV and CaCV was established. CaKoV and CaCV were distinguished by their different melting temperature which was 86℃ for CaKoV and 78℃ for CaCV. The assay was highly specific, with no cross-reactivity with other common canine viruses and demonstrated high sensitivity. The detection limits of CaKoV and CaCV were 8.924 × 101 copies/μL and 3.841 × 101 copies/μL, respectively. The highest intra- and inter-assay Ct value variation coefficients (CV) of CaKoV were 0.40% and 0.96%, respectively. For CaCV, the highest intra- and inter-assay Ct value variation coefficients were 0.26% and 0.70%, respectively. In 57 clinical samples, positive detection rates of CaKoV and CaCV were 8.77% (7/57) and 15.79% (9/57), respectively. The co-infection rate was 7.02% (4/57). Conclusions: The duplex SYBR Green I-based real-time PCR assay established in this study is a fast, efficient, and sensitive method for the simultaneous detection of the two viruses and provides a powerful tool for the rapid detection of CaKoV and CaCV in clinical practice.


2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Iman Rezaee Azhar ◽  
Minoo Mohraz ◽  
Masoud Mardani ◽  
Mohammad Ali Tavakoli ◽  
Amin Ehteshami Afshar ◽  
...  

The introduction of polymerase chain reaction (PCR) techniques has improved the detection of respiratory viruses, particularly with the use of multiplex real-time technique with the capability of simultaneous detection of various pathogens in a single reaction. The aim of this study was to apply the above technology for the diagnosis of influenza infections and at the same time to differentiate between common flu species between hospitalized patients in Laleh hospital (Iran) between two flu seasons (2016- 2017 and 2017-2018). Different respiratory specimens were collected from 540 patients from a period of December 2016 to May 2018 and were sent to the laboratory for molecular diagnosis. RNAs were extracted and subsequently, a multiplex real time PCR identifying flu A, flu B and typing flu A (H1N1) was carried out. The mean age of patients was 47.54±23.96. 216 (40%) and 321 (60%) of subjects were male and female, respectively. 219 out of 540 (40.5%) were positive for influenza infection including flu A (n=97, 44.3%), flu A (H1N1) (n=45, 20.7%) and flu B (n=77, 35%). Flu A was the dominant species on 2016-2017 and flu B was the major species on 2017-2018. Flu A (H1N1) was comparable in both time periods. Flu infections were most frequently diagnosed in age groups 21-40. Flu-positive patients suffered more from body pain and sore throat than flunegative patients with significant statistical difference (P values <0.001). The mean duration of hospitalization was shorter for flu-positive patients (P value = 0.016). Application of multiplex real time PCR could facilitate the influenza diagnosis in a short period of time, benefiting patients from exclusion of bacterial infections and avoiding unnecessary antibiotic therapy. Influenza diagnosis was not achieved in up to 60% of flu-like respiratory infections, suggesting the potential benefit of adopting the same methodology for assessing the involvement of other viral or/and bacterial pathogens in those patients.


2006 ◽  
Vol 96 (11) ◽  
pp. 1255-1262 ◽  
Author(s):  
C. Zijlstra ◽  
R. A. Van Hoof

This study describes a multiplex real-time polymerase chain reaction (PCR) approach for the simultaneous detection of Meloidogyne chitwoodi and M. fallax in a single assay. The approach uses three fluorogenic minor groove binding (MGB) TaqMan probes: one FAM-labeled to detect M. chitwoodi, one VIC-labeled to detect M. fallax, and one NED-labeled to detect the internal amplification control (IAC) to monitor false negative results. One common primer set is used for the amplification of part of the internal transcribed spacer (ITS) region of M. chitwoodi and M. fallax and one primer set for the amplification of the IAC. The test enabled detection of M. chitwoodi and/or M. fallax in DNA samples extracted from batches of juveniles, from single juveniles, and from infected plant material. Compared with current assays to detect M. chitwoodi and M. fallax, the multiplex real-time PCR offers the following advantages: it is faster because the test can simultaneously detect both quarantine species without the need for post-PCR processing; and it is at least 10 times more sensitive than a comparable regular PCR also targeting the ITS sequence. Inclusion of the IAC facilitates the interpretation of the FAM and VIC cycle threshold (Ct) values and can prevent the scoring of false negative results when FAM, VIC, and NED Ct values are high. The test allows precise quantification when only one of the two species is present in the sample. However, experiments with mixtures of genomic DNA of M. chitwoodi and M. fallax revealed that the ability of the multiplex real-time PCR assay to detect small quantities of DNA of one species is reduced when large quantities of DNA of the other species are present.


2007 ◽  
Vol 53 (3) ◽  
pp. 391-397 ◽  
Author(s):  
Gehua Wang ◽  
Erin Becker ◽  
Christine Mesa

The optimal 6-carboxy-X-rhodamine (ROX) concentration, which is used as a passive reference dye for real-time quantitative polymerase chain reaction (PCR) with molecular beacon chemistry, was determined with the Mx4000™ Multiplex Quantitative PCR System. Additionally, the effects of changing ROX concentrations on PCR reproducibility, Ct values, and efficiency were investigated with this system by using the PCR data obtained from amplification of the Escherichia coli shiga toxin 2 (stx2) gene and the Campylobacter jejuni luxS gene. This study indicated that different ROX concentrations influence many aspects of the real-time PCR reaction. ROX concentration variation could have consequences in the analysis of quantitative data and may lead to erroneous results. This study further indicated that the optimal ROX concentration is 60 nmol/L for real-time PCR, using molecular beacon chemistry for PCR assay of luxS and stx2 genes.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Subeen Hong ◽  
Seung Mi Lee ◽  
Sohee Oh ◽  
So Yeon Kim ◽  
Young Mi Jung ◽  
...  

AbstractTo examine the detection performance of a peptide nucleic acid (PNA) probe-based real-time time polymerase chain reaction (PCR) assay to detect common aneuploidies. Using amniotic fluid samples, PNA probe based real-time PCR (Patio DEP Detection Kit; SeaSun Biomaterials, Korea) assay was performed. PNA probe was designed to hybridize to similar sequences located on different segments of target chromosomes (21, 18, and 13) and a reference chromosome. Amplification of target sequences and melting curve analysis was performed. When analyzing the melting curve, the ratio of the peak height of the target and reference chromosome was calculated and determined as aneuploidy if the ratio of peak height was abnormal. All the results from the PNA probe-based real-time PCR and melting curve analyses were compared to those from conventional karyotyping. Forty-two cases with common aneuploidies (24 of trisomy 21, 12 of trisomy 18, and 6 of trisomy 13) and 131 cases with normal karyotype were analyzed. When comparing the karyotyping results, the sensitivity and specificity of the PNA probe-based real-time PCR assay were both 100%. The level of agreement was almost perfect (k = 1.00). PNA real-time PCR assay is a rapid and easy method for detecting common aneuploidies.


Plant Disease ◽  
2007 ◽  
Vol 91 (4) ◽  
pp. 430-434 ◽  
Author(s):  
M. P. Grisham ◽  
Y.-B. Pan ◽  
E. P. Richard

A real-time, polymerase chain reaction (PCR) assay was developed for detecting Leifsonia xyli subsp. xyli in sugarcane leaf tissue. Real-time PCR assays were conducted on the youngest, fully expanded leaf of three cultivars collected bi-weekly from field nurseries between 11 April and 19 July 2005. L. xyli subsp. xyli infection was detected in leaves collected at all sampling dates, including those from 1-month-old plants on 11 April. Assays conducted on older, more rapidly growing plants (28 July and 21 October 2005) indicated that leaf position affects assay efficiency. Conventional PCR was less efficient than real-time PCR for detecting L. xyli subsp. xyli in leaf tissue. Real-time PCR was used to rank cultivars for susceptibility to L. xyli subsp. xyli infection based on the relative titer of L. xyli subsp. xyli in leaves of inoculated, 3- and 4-month-old greenhouse-grown plants. The ranking of cultivars by real-time PCR was in close agreement with the ranking determined by tissue-blot enzyme immunoassay performed on tissue from 7- to 9-month-old stalks.


Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 835-838 ◽  
Author(s):  
Paula Agudelo ◽  
Stephen A. Lewis ◽  
Bruce A. Fortnum

Meloidogyne arenaria is an economically important parasite of many crops worldwide. Identification and detection of this species in soil samples is necessary for the design of crop rotation systems, selection of resistant cultivars, and potential use of biological control options. The objective of this study was to develop and validate a real-time polymerase chain reaction (PCR) assay, using species-specific primers and SYBR Green I Dye, for identification of M. arenaria. The specificity of the assay was confirmed by testing for amplification of DNA from other Meloidogyne spp. and from M. arenaria populations of different geographic origins. Field soil samples containing a mixture of M. arenaria and M. incognita were used to compare identification by the real-time PCR assay with identification by esterase phenotype analysis of mature females and by morphometrics of juveniles. The real-time PCR assay provided an accurate and sensitive means for the identification of single juveniles from soil samples.


Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1523-1530 ◽  
Author(s):  
G. Licciardello ◽  
F. M. Grasso ◽  
P. Bella ◽  
G. Cirvilleri ◽  
V. Grimaldi ◽  
...  

Phoma tracheiphila is the causal agent of a tracheomycotic disease of citrus called mal secco causing the dieback of twigs and branches. This pathogen is of quarantine concern; therefore, fast and reliable protocols are required to detect it promptly. A specific primer pair and a dual-labeled fluorogenic probe were used in a real-time polymerase chain reaction (PCR) with the Cepheid Smart Cycler II System (Transportable Device TD configuration) to detect this fungus in citrus samples. Real-time PCR assay was compared to modified conventional PCR assay. The sensitivity of the former was evaluated by testing P. tracheiphila DNA dilutions, and the minimum amount detectable was about 500 fg, whereas the linear quantification range was within 100 ng to 1 pg. Conventional PCR sensitivity was 10 pg. Conventional and real-time PCR successfully detected the fungus in woody samples of naturally infected lemon and artificially inoculated sour orange seedlings. Nevertheless, real-time PCR was about 10- to 20-fold more sensitive than conventional PCR, and preliminary results indicate that the former technique achieves quantitative monitoring of the fungus in tissues. Simple and rapid procedures to obtain suitable DNA samples from fungal cultures and citrus woody samples for PCR assays enable diagnosis to be completed in a short time.


Author(s):  
Dinh Thi Thu Hang ◽  
Vu Thi Nga ◽  
Hoang Van Tong ◽  
Hoang Xuan Su ◽  
Le Quoc Tuan ◽  
...  

This article aims to establish a novel cytochrome b real-time PCR assay using Taqman probe for identification of P. malariae and its discrimination from other Plasmodium human infecting species. The optimization of real-time PCR assay with 1X QuantiTect Probe PCR Master Mix, primers and probe used at concentrations of 0.4 μM and 0.1 μM, respectively; and 2.5 mM MgCl2, 5 μl DNA template and deionized H2O of 20 μl, was performed using a real-time PCR instrument. The developed real-time PCR assay was evaluated for the limit of detection, stability on standard panels (109-100 copies/ µl), as well as the sensitivity, specificity on control groups. The probit analysis demonstrates that the 95% detection limit was <0.5 parasite/μl, both the sensitivity and specificity of the assay were 100% when evaluated on the control groups.  Additionally, the assay initially evaluated on 41 clinical samples including 21 malaria samples and 20 samples of volunteer blood donors, identified 1 positive sample with P. malariae from the disease group, which shows a concordant result with nested PCR. This novel Cyt b real-time PCR assay for identifying P. malariae may also facilitate earlier discrimination of P. malariae from other Plasmodium parasites with high sensitivity. Keywords Cytochrome b, malaria parasite, plasmodium malariae, mitochondria, real-time PCR. References [1] B. Singh, C. Daneshvar, Human infections and detection of Plasmodium knowlesi, Clinical microbiology reviews 26(2) (2013) 165-84. https://doi.org/10.1128/cmr.00079-12.[2] World Health Organization, Regional and global trends in burden of malaria cases and deaths, World malaria report 2019, Geneva, pp. 4-12.[3] World Health Organization, Progress towards elimination during the RBM decade 2000-2010, Eliminating malaria: learning from the past, looking ahead, Geneva (2011), pp. 39-70.[4] J.M. Vinetz, J. Li, T.F. McCutchan, et al., Plasmodium malariae infection in an asymptomatic 74-year-old Greek woman with splenomegaly, N Engl J Med 338(6) (1998) 367-71. https://doi.org/10.1056/NEJM199802053380605.[5] E. Lo, K. Nguyen, J. Nguyen, et al., Plasmodium malariae Prevalence and csp Gene Diversity, Kenya, 2014 and 2015, Emerg Infect Dis 23(4) (2017) 601-610. https://doi.org/10.3201/eid2304.161245.[6] W.E. Collins, G.M. Jeffery, Plasmodium malariae: parasite and disease, Clinical microbiology reviews 20(4) (2007) 579-92. https://doi.org/10.1128/CMR.00027-07.[7] M. Adams, S.N. Joshi, G. Mbambo, et al., An ultrasensitive reverse transcription polymerase chain reaction assay to detect asymptomatic low-density Plasmodium falciparum and Plasmodium vivax infections in small volume blood samples, Malar J 14 (2015) 520. https://doi.org/10.1186/s12936-015-1038-z.[8] W. Xu, U. Morris, B. Aydin-Schmidt, et al., SYBR Green real-time PCR-RFLP assay targeting the plasmodium cytochrome B gene-a highly sensitive molecular tool for malaria parasite detection and species determination, PloS one 10(3) (2015) e0120210. https://doi.org/10.1371/journal.pone.0120210.[9] E.M. Burd, Validation of laboratory-developed molecular assays for infectious diseases, Clinical microbiology reviews 23(3) (2010) 550-76. https://doi.org/10.1128/CMR.00074-09.[10] G. Snounou, S. Viriyakosol, X.P. Zhu, et al., High sensitivity of detection of human malaria parasites by the use of nested polymerase chain reaction, Molecular and biochemical parasitology 61(2) (1993) 315-20. https://doi.org/10.1016/0166-6851(93)90077-b.[11] C.G. Haanshuus, K. Morch, B. Blomberg, et al., Assessment of malaria real-time PCR methods and application with focus on low-level parasitaemia, PloS one 14(7) (2019) e0218982. https://doi.org/10.1371/journal.pone.0218982.[12] F. Perandin, N. Manca, A. Calderaro, et al., Development of a real-time PCR assay for detection of Plasmodium falciparum, Plasmodium vivax, and Plasmodium ovale for routine clinical diagnosis, Journal of clinical microbiology 42(3) (2004) 1214-9. https://doi.org/10.1128/jcm.42.3.1214-1219.2004.[13] C.E. Oriero, J.P. van Geertruyden, J. Jacobs, et al., Validation of an apicoplast genome target for the detection of Plasmodium species using polymerase chain reaction and loop mediated isothermal amplification, Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases 21(7) (2015) 686 e1-7. https://doi.org/10.1016/j.cmi.2015.02.025.[14] D.F. Echeverry, N.A. Deason, J. Davidson, et al., Human malaria diagnosis using a single-step direct-PCR based on the Plasmodium cytochrome oxidase III gene, Malaria journal 15 (2016) 128. https://doi.org/10.1186/s12936-016-1185-x.[15] P. Li, Z. Zhao, H. Xing, et al., Plasmodium malariae and Plasmodium ovale infections in the China-Myanmar border area, Malaria journal 15(1) (2016) 557. https://doi.org/10.1186/s12936-016-1605-y.[16] E.T.J. Chong, J.W.F. Neoh, T.Y. Lau, et al., Genetic and haplotype analyses targeting cytochrome b gene of Plasmodium knowlesi isolates of Malaysian Borneo and Peninsular Malaysia, Acta tropica 181 (2018) 35-39. https://doi.org/10.1016/j.actatropica.2018.01.018.[17] C. Farrugia, O. Cabaret, F. Botterel, et al., Cytochrome b gene quantitative PCR for diagnosing Plasmodium falciparum infection in travelers, Journal of clinical microbiology 49(6) (2011) 2191-5. https://doi.org/10.1128/JCM.02156-10.[18] C. Wongsrichanalai, M.J. Barcus, S. Muth, et al., A review of malaria diagnostic tools: microscopy and rapid diagnostic test (RDT), The American journal of tropical medicine and hygiene 77(6 Suppl) (2007) 119-27.[19] H.V. Nguyen, P.V.D. Eede, C. van Overmeir, et al., Marked age-dependent prevalence of symptomatic and patent infections and complexity of distribution of human Plasmodium species in central Vietnam, The American journal of tropical medicine and hygiene 87(6) (2012) 989-995. https://doi.org/10.4269/ajtmh.2012.12-0047.  


2009 ◽  
Vol 99 (5) ◽  
pp. 582-590 ◽  
Author(s):  
Renaud Ioos ◽  
Céline Fourrier ◽  
Gabriela Iancu ◽  
Thomas R. Gordon

Fusarium circinatum is the causal agent of pitch canker disease on numerous Pinus spp. This aggressive fungus may infect pine seed cryptically and, therefore, can easily be spread long distances by the seed trade. F. circinatum has recently been listed as a quarantine organism in numerous countries throughout the world, which prompted the development of a specific and sensitive tool for the detection of this pathogen in conifer seed. A new detection protocol for F. circinatum based on a biological enrichment step followed by a real-time polymerase chain reaction (PCR) assay was developed. Several enrichment protocols were compared and a 72-h incubation of the seed with potato dextrose broth was the most efficient technique to increase F. circinatum biomass before DNA extraction. The relative accuracy, specificity, and sensitivity of the real-time PCR assay was evaluated in comparison with a previously published conventional PCR test on 420 seed DNA extracts. The real-time PCR described here proved to be highly specific and significantly more sensitive than the conventional PCR, and enabled the detection of F. circinatum in samples artificially contaminated with less than 1/1,000 infected seed, as well as in naturally infected samples. Last, in order to routinely check the quality of the seed DNA extracts, a primer–probe combination that targets a highly conserved region within the 18S ribosomal DNA in plants or fungi was successfully developed. This assay allows for quick and reliable detection of F. circinatum in seed, which can help to prevent long-distance spread of the pathogen via contaminated seed lots.


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