scholarly journals Evaluation of Resistance to Rhabdocline Needlecast in Douglas Fir Variety Shuswap, with Quantitative Polymerase Chain Reaction

2010 ◽  
Vol 100 (4) ◽  
pp. 337-344 ◽  
Author(s):  
M. Catal ◽  
G. C. Adams ◽  
D. W. Fulbright
Keyword(s):  
Polymerase Chain Reaction ◽  
Quantitative Polymerase Chain Reaction ◽  
Douglas Fir ◽  
Chain Reaction ◽  
Disease Symptoms ◽  
Seed Sources ◽  
Release Times ◽  
Spore Release ◽  
Target Dna ◽  
Polymerase Chain

A quantitative polymerase chain reaction assay was developed that could detect DNA of Rhabdocline pseudotsugae and R. oblonga among DNA of Douglas fir needles to a limit as low as three copies of target DNA. Differential infection rates of two varieties (seed sources) of Douglas fir interplanted in a field were studied in relation to staggered bud breaks. Infection of Douglas fir var. San Isabel corresponded to ascospore release times for Rhabdocline spp., whereas infection of var. Shuswap Lake did not occur throughout the spore release period during 2 years of study, despite abundant inoculum and adequate moisture during bud break. Rhabdocline spp. DNA was never detected in Shuswap Lake and disease symptoms were not observed in any year. We provide evidence that Shuswap Lake is resistant and probably immune to Rhabdocline spp. infection and Rhabdocline needlecast under Michigan conditions.

Development of AFLP-derived, functionally specific markers for environmental persistence studies of fungal strains

2006 ◽  
Vol 52 (5) ◽  
pp. 451-461 ◽  
Author(s):  
S S Hynes ◽  
O Chaudhry ◽  
M A Providenti ◽  
M L Smith
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Genetically Modified Organisms ◽  
Quantitative Polymerase Chain Reaction ◽  
Pcr Primers ◽  
Chain Reaction ◽  
Environmental Persistence ◽  
Fungal Strains ◽  
Target Dna ◽  
Polymerase Chain

The ability to rapidly identify and quantify a microbial strain in a complex environmental sample has widespread applications in ecology, epidemiology, and industry. In this study, we describe a rapid method to obtain functionally specific genetic markers that can be used in conjunction with standard or real-time polymerase chain reaction (PCR) to determine the abundance of target fungal strains in selected environmental samples. The method involves sequencing of randomly cloned AFLP (amplified fragment length polymorphism) products from the target organism and the design of PCR primers internal to the AFLP fragments. The strain-specific markers were used to determine the fate of three industrially relevant fungi, Aspergillus niger, Aspergillus oryzae, and Chaetomium globosum, during a 4 month soil microcosm experiment. The persistence of each of the three fungal strains inoculated separately into intact soil microcosms was determined by PCR analyses of DNA directly extracted from soil. Presence and absence data based on standard PCR and quantification of the target DNA by real-time PCR showed that all three strains declined after inoculation (~14-, 32-, and 4-fold for A. niger, A. oryzae, and C. globosum, respectively) but remained detectable at the end of the experiment, suggesting that these strains would survive for extended periods if released into nature.Key words: Canada domestic substances list (DSL), Canadian Environmental Protection Act (CEPA), genetically modified organisms (GMO), quantitative polymerase chain reaction (qPCR).

scholarly journals Simultaneous One-Tube Quantification of Host and Pathogen DNA with Real-Time Polymerase Chain Reaction

2002 ◽  
Vol 92 (1) ◽  
pp. 112-116 ◽  
Author(s):  
L. M. Winton ◽  
J. K. Stone ◽  
L. S. Watrud ◽  
E. M. Hansen
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Fluorescent Dyes ◽  
Quantitative Polymerase Chain Reaction ◽  
Positive Control ◽  
Douglas Fir ◽  
Chain Reaction ◽  
Taqman Probes ◽  
Polymerase Chain ◽  
Pathogen Dna

Phaeocryptopus gaeumannii is a widespread foliar parasite of Douglas-fir. Although normally innocuous, the fungus also causes the defoliating disease Swiss needle cast in heavily infected needles. The extent of P. gaeumannii colonization in Douglas-fir foliage was estimated with real-time quantitative polymerase chain reaction (PCR) using TaqMan chemistry. In order to derive a normalized expression of colonization, both pathogen and host DNA were simultaneously amplified but individually detected by species-specific primers and TaqMan probes labeled with different fluorescent dyes. Detection of host DNA additionally provided an endogenous reference that served as both an internal positive control and adjusted for variation introduced by sample-to-sample differences in DNA extraction and PCR efficiencies. The genes employed for designing the TaqMan probes and primers were β-tubulin for the pathogen and a LEAFY/FLORICAULA-like gene involved in floral development for the tree host. Both probe/primer sets exhibited high precision and reproducibility over a linear range of 4 orders of magnitude. This eliminated the need to analyze samples in multiple dilutions when comparing lightly with heavily infected needles. Quantification of the fungus within needles was successful as early as 1 month after initial infection. Real-time PCR is the only method currently available to quantify P. gaeumannii colonization early in the first year of the colonization process.

scholarly journals Enumeration of viable and non-viable larvated Ascaris eggs with quantitative PCR

2012 ◽  
Vol 10 (4) ◽  
pp. 594-604 ◽  
Author(s):  
Maria Raynal ◽  
Eric N. Villegas ◽  
Kara L. Nelson
Keyword(s):  
Polymerase Chain Reaction ◽  
Detection Limit ◽  
Quantitative Polymerase Chain Reaction ◽  
High Heat ◽  
Chain Reaction ◽  
Direct Microscopy ◽  
Development Stages ◽  
Target Dna ◽  
Qpcr Method ◽  
Polymerase Chain

The goal of this study was to further develop an incubation-quantitative polymerase chain reaction (qPCR) method for quantifying viable Ascaris eggs by characterizing the detection limit and number of template copies per egg, determining the specificity of the method, and testing the method with viable and inactivated larvated eggs. The number of template copies per cell was determined by amplifying DNA from known numbers of eggs at different development stages; the value was estimated to be 32 copies. The specificity of the method was tested against a panel of bacteria, fungi, protozoa and helminths, and no amplification was found with non-target DNA. Finally, fully larvated eggs were inactivated by four different treatments: 254 nm ultraviolet light, 2,000 ppm NH3-N at pH 9, moderate heat (48 °C) and high heat (70 °C). Concentrations of treated eggs were measured by direct microscopy and incubation-qPCR. The qPCR signal decreased following all four treatments, and was in general agreement with the decrease in viable eggs determined by microscopy. The incubation-qPCR method for enumerating viable Ascaris eggs is a promising approach that can produce results faster than direct microscopy, and may have benefits for applications such as assessing biosolids.

AN IMPROVED METHOD FOR INHIBITOR FREE NUCLEIC ACIDS FROM POLYPHENOL RICH LEAVES OF MUSA SPP

2017 ◽  
Vol 23 (1) ◽  
Author(s):  
N.NANDHA KUMAR ◽  
K. SOURIANATHA SUNDARAM ◽  
D. SUDHAKAR ◽  
K.K. KUMAR
Keyword(s):  
Polymerase Chain Reaction ◽  
Quantitative Polymerase Chain Reaction ◽  
Proteinase K ◽  
Chain Reaction ◽  
Banana Plant ◽  
High Molecular Weight Dna ◽  
Musa Spp ◽  
Leaf Tissues ◽  
Polymerase Chain

Excessive presence of polysaccharides, polyphenol and secondary metabolites in banana plant affects the quality of DNA and it leads to difficult in isolating good quality of DNA. An optimized modified CTAB protocol for the isolation of high quality and quantity of DNA obtained from banana leaf tissues has been developed. In this protocol a slight increased salt (NaCl) concentration (2.0M) was used in the extraction buffer. Polyvinylpyrrolidone (PVP) and Octanol were used for the removal of polyphenols and polymerase chain reaction (PCR) inhibitors. Proteins like various enzymes were degraded by Proteinase K and removed by centrifugation from plant extract during the isolation process resulting in pure genomic DNA, ready to use in downstream applications including PCR, quantitative polymerase chain reaction (qPCR), ligation, restriction and sequencing. This protocol yielded a high molecular weight DNA isolated from polyphenols rich leaves of Musa spp which was free from contamination and colour. The average yields of total DNA from leaf ranged from 917.4 to 1860.9 ng/ìL. This modified CTAB protocol reported here is less time consuming 4-5h, reproducible and can be used for a broad spectrum of plant species which have polyphenol and polysaccharide compounds.

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.

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