Optimization of 6-carboxy-X-rhodamine concentration for real-time polymerase chain reaction using molecular beacon chemistry

2007 ◽  
Vol 53 (3) ◽  
pp. 391-397 ◽  
Author(s):  
Gehua Wang ◽  
Erin Becker ◽  
Christine Mesa
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Real Time Pcr ◽  
Molecular Beacon ◽  
Quantitative Polymerase Chain Reaction ◽  
Luxs Gene ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Shiga Toxin 2 ◽  
Polymerase Chain

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.

scholarly journals Analysis and validation of a highly sensitive one-step nested quantitative real-time polymerase chain reaction assay for specific detection of severe acute respiratory syndrome coronavirus 2

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Qrt Pcr ◽  
Highly Sensitive ◽  
One Step ◽  
Polymerase Chain

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30 to 60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. Method In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. Result The limit of detection (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI: 363.23–1145.69) for ORF1ab and 528.1 (95% CI: 347.7–1248.7) for N, 401.8 (95% CI: 284.8–938.3) for ORF1ab and 336.8 (95% CI: 244.6–792.5) for N, and 194.74 (95% CI: 139.7–430.9) for ORF1ab and 189.1 (95% CI: 130.9–433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. Conclusion In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.

Quantitative Real-Time Polymerase Chain Reaction Detection of BK Virus Using Labeled Primers

2010 ◽  
Vol 134 (3) ◽  
pp. 444-448 ◽  
Author(s):  
Zhengming Gu ◽  
Jianmin Pan ◽  
Matthew J. Bankowski ◽  
Randall T. Hayden
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Real Time Pcr ◽  
Quantitative Polymerase Chain Reaction ◽  
Bk Virus ◽  
Clinical Samples ◽  
Quantitative Detection ◽  
Chain Reaction ◽  
Pcr Method ◽  
Polymerase Chain

Abstract Context.—BK virus infections among immunocompromised patients are associated with disease of the kidney or urinary bladder. High viral loads, determined by quantitative polymerase chain reaction (PCR), have been correlated with clinical disease. Objective.—To develop and evaluate a novel method for real-time PCR detection and quantification of BK virus using labeled primers. Design.—Patient specimens (n = 54) included 17 plasma, 12 whole blood, and 25 urine samples. DNA was extracted using the MagNA Pure LC Total Nucleic Acid Isolation Kit (Roche Applied Science, Indianapolis, Indiana); sample eluate was PCR-amplified using the labeled primer PCR method. Results were compared with those of a user-developed quantitative real-time PCR method (fluorescence resonance energy transfer probe hybridization). Results.—Labeled primer PCR detected less than 10 copies per reaction and showed quantitative linearity from 101 to 107 copies per reaction. Analytical specificity of labeled primer PCR was 100%. With clinical samples, labeled primer PCR demonstrated a trend toward improved sensitivity compared with the reference method. Quantitative assay comparison showed an R2 value of 0.96 between the 2 assays. Conclusions.—Real-time PCR using labeled primers is highly sensitive and specific for the quantitative detection of BK virus from a variety of clinical specimens. These data demonstrate the applicability of labeled primer PCR for quantitative viral detection and offer a simplified method that removes the need for separate oligonucleotide probes.

Quantitative assessment of hematopoietic chimerism after bone marrow transplantation by real-time quantitative polymerase chain reaction

Blood ◽  
2002 ◽  
Vol 99 (12) ◽  
pp. 4618-4625 ◽  
Author(s):  
Mehdi Alizadeh ◽  
Marc Bernard ◽  
Bruno Danic ◽  
Charly Dauriac ◽  
Brigitte Birebent ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Stem Cell ◽  
Real Time ◽  
Real Time Pcr ◽  
Quantitative Assessment ◽  
Quantitative Polymerase Chain Reaction ◽  
Chain Reaction ◽  
Hematopoietic Stem ◽  
Pcr Method ◽  
Polymerase Chain

We have developed a real-time quantitative polymerase chain reaction (PCR) assay using TaqMan technology (Applied Biosystems, Foster City, CA) for monitoring donor cell engraftment in allogenic hematopoietic stem cell transplant recipients. For this purpose, we selected 19 specific sequence polymorphisms belonging to 11 human biallelic loci located on 9 different chromosomes. Using a set of specially designed primers and fluorogenic probes, we evaluated the 19 markers' informativity on a panel of 126 DNA samples from 63 recipient/donor pairs. In more than 90% of these pairs, discrimination between recipient and donor genetic profile was possible. By using serial dilutions of mixed DNAs, we evaluated the linearity and sensitivity of the method. A linear correlation with rhigher than 0.98 and a sensitivity of 0.1% proved reproducible. Fluorescent-based PCR of short tandem repeats (STR-PCR) and real-time PCR chimerism assay were compared with a panel of artificial cell mixtures. The main advantage of the real-time PCR method over STR-PCR chimerism assays is the absence of PCR competition and plateau biases, and results evidenced greater sensitivity and linearity with the real-time PCR method. Furthermore, different samples can be tested in the same PCR run with a final result in fewer than 48 hours. Finally, we prospectively analyzed patients who received allografts and present 4 different clinical situations that illustrate the informativity level of our method. In conclusion, this new assay provides an accurate quantitative assessment of mixed chimerism that can be useful in guiding early implementation of additional treatments in hematopoietic stem cell transplantation.

scholarly journals Analysis and validation of a highly sensitive one-step nested quantitative real-time polymerase chain reaction assay for specific detection of severe acute respiratory syndrome coronavirus 2

2020 ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Qrt Pcr ◽  
Highly Sensitive ◽  
One Step ◽  
Polymerase Chain

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30–60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. Method: In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. Result The LoD (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI): 363.23–1145.69) for ORF1ab and 528.1 (95% CI: 347.7–1248.7) for N, 401.8 (95% CI: 284.8–938.3) for ORF1ab and 336.8 (95% CI: 244.6–792.5) for N, and 194.74 (95% CI: 139.7–430.9) for ORF1ab and 189.1 (95% CI: 130.9–433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. Conclusion In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.

scholarly journals Analysis and validation of a highly sensitive one-step nested quantitative real-time polymerase chain reaction assay for specific detection of severe acute respiratory syndrome coronavirus 2

2020 ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Qrt Pcr ◽  
Highly Sensitive ◽  
One Step ◽  
Polymerase Chain

Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30%-60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. The LoD (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI): 363.23-1145.69) for ORF1ab and 528.1 (95% CI: 347.7-1248.7) for N, 401.8 (95% CI: 284.8-938.3) for ORF1ab and 336.8 (95% CI: 244.6-792.5) for N, and 194.74 (95% CI: 139.7-430.9) for ORF1ab and 189.1 (95% CI: 130.9-433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.

scholarly journals Evaluation method for asymmetric uncertainty of quantitative polymerase chain reaction measurements of deoxyribonucleic acids with low copy number

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Unoh Ki ◽  
Takeru Suzuki ◽  
Satoshi Nakazawa ◽  
Yuuki Yonekawa ◽  
Kazuki Watanabe ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Confidence Interval ◽  
Real Time ◽  
Real Time Pcr ◽  
Copy Number ◽  
Limit Of Detection ◽  
Quantitative Polymerase Chain Reaction ◽  
Chain Reaction ◽  
Low Copy Number ◽  
Polymerase Chain

AbstractRecently, in food safety and various other fields, qualitative and quantitative gene analysis using real-time polymerase chain reaction (PCR) method has become increasingly popular. The limit of detection (LOD) and quantifiable range for these measurements depends on the range and precision of DNA calibrators’ concentrations. Low-copy-number nucleic acid reference materials with low uncertainty produced by an inkjet system have been developed to allow for precise measurements in a low-copy-number region. However, when using a calibrator with a low copy number near one, the copy number distribution is asymmetric. Consequently, the confidence intervals of estimated copy numbers can include negative values when conventional methods of uncertainty estimation are used. A negative confidence interval is irrelevant in the context of copy number, which is always positive value or zero. Here, we propose a method to evaluate the uncertainty of real-time PCR measurements with representative values and an asymmetric 95% confidence interval. Moreover, we use the proposed method for the actual calculation of uncertainty of real-time PCR measurement results for low-copy-number DNA samples and demonstrate that the proposed method can evaluate the precision of real-time PCR measurements more appropriately in a low-copy-number region.

scholarly journals Simple and rapid detection of common fetal aneuploidies using peptide nucleic acid probe-based real-time polymerase chain reaction

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Subeen Hong ◽  
Seung Mi Lee ◽  
Sohee Oh ◽  
So Yeon Kim ◽  
Young Mi Jung ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Nucleic Acid ◽  
Real Time ◽  
Real Time Pcr ◽  
Peptide Nucleic Acid ◽  
Melting Curve ◽  
Peak Height ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Polymerase Chain

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.

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 ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Early Detection ◽  
Bombyx Mori ◽  
Real Time ◽  
Real Time Pcr ◽  
Simultaneous Detection ◽  
Post Inoculation ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Polymerase Chain

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.

scholarly journals Early Detection of Leifsonia xyli subsp. xyli in Sugarcane Leaves by Real-Time Polymerase Chain Reaction

Plant Disease ◽  
2007 ◽  
Vol 91 (4) ◽  
pp. 430-434 ◽  
Author(s):  
M. P. Grisham ◽  
Y.-B. Pan ◽  
E. P. Richard
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Real Time Pcr ◽  
Close Agreement ◽  
Leaf Tissue ◽  
Conventional Pcr ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Polymerase Chain ◽  
Pcr Assays

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.

scholarly journals Validation of a Real-Time Polymerase Chain Reaction Assay for the Identification of Meloidogyne arenaria

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 835-838 ◽  
Author(s):  
Paula Agudelo ◽  
Stephen A. Lewis ◽  
Bruce A. Fortnum
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Real Time Pcr ◽  
Soil Samples ◽  
Meloidogyne Arenaria ◽  
Chain Reaction ◽  
Pcr Assay ◽  
The Real ◽  
Polymerase Chain ◽  
Species Specific

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.

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