scholarly journals Quantification of Cadophora luteo-olivacea From Grapevine Nursery Stock and Vineyard Soil Using Droplet Digital PCR

Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2269-2274 ◽  
Author(s):  
María Mercedes Maldonado-González ◽  
María del Pilar Martínez-Diz ◽  
Marcos Andrés-Sodupe ◽  
Rebeca Bujanda ◽  
Emilia Díaz-Losada ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Digital Pcr ◽  
Fungal Species ◽  
Droplet Digital Pcr ◽  
Taqman Probe ◽  
Planting Material ◽  
Low Concentrations ◽  
Nursery Stock ◽  
Species Specific ◽  
Detection And Quantification

Cadophora luteo-olivacea is the most prevalent Cadophora species associated with Petri disease and esca of grapevine. Accurate, early, and specific detection and quantification of C. luteo-olivacea are essential to alert growers and nurseries to the presence of the pathogens in soil and to prevent the spread of this pathogen through grapevine planting material. The aim of this study was to develop molecular tools to detect and quantify C. luteo-olivacea inoculum from environmental samples. Species specific primers based on the β-tubulin gene and a TaqMan probe for droplet digital PCR (ddPCR) and quantitative PCR (qPCR) were first developed to detect and quantify purified DNA of the target fungus. Specificity tests showed that the primers were able to amplify the C. luteo-olivacea DNA (20 isolates) while none of the 29 nontarget fungal species (58 isolates) tested were amplified. The ddPCR was shown to be more sensitive compared with qPCR in the detection and quantification of C. luteo-olivacea at very low concentrations and was further selected to accurately detect and quantify the fungus from environmental samples. Twenty-five of the 94 grafting plants (26.6%) analyzed by ddPCR tested positive to C. luteo-olivacea DNA (>3 copies/µl). C. luteo-olivacea was barely detected from vineyard soils. The procedure employed in this study revealed the presence of the pathogen in symptomless vines, which makes implementation of this technique suitable for certification schemes of C. luteo-olivacea-free grapevine planting material.

scholarly journals Droplet Digital PCR Technology for Detection of Ilyonectria liriodendri from Grapevine Environmental Samples

Plant Disease ◽  
2020 ◽  
Vol 104 (4) ◽  
pp. 1144-1150 ◽  
Author(s):  
María del Pilar Martínez-Diz ◽  
Marcos Andrés-Sodupe ◽  
Mónica Berbegal ◽  
Rebeca Bujanda ◽  
Emilia Díaz-Losada ◽  
...  
Keyword(s):  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Development Of Resistance ◽  
Planting Material ◽  
Fungal Abundance ◽  
Foot Disease ◽  
High Degree ◽  
Black Foot ◽  
Black Foot Disease ◽  
Detection And Quantification

Black-foot disease is one of the most important soilborne diseases affecting planting material in grapevine nurseries and young vineyards. Accurate, early, and specific detection and quantification of black-foot disease causing fungi are essential to alert growers and nurseries to the presence of the pathogens in soil, and to prevent the spread of these pathogens through grapevines using certified pathogen-free planting material and development of resistance. We comparatively assessed the accuracy, efficiency, and specificity of droplet digital PCR (ddPCR) and real-time PCR (qPCR) techniques for the detection and quantification of Ilyonectria liriodendri in bulk and rhizosphere soils, as well as grapevine endorhizosphere. Fungal abundance was not affected by soil-plant fractions. Both techniques showed a high degree of correlation across the samples assessed (R2 = 0.95) with ddPCR being more sensitive to lower target concentrations. Roots of asymptomatic vines were found to be a microbial niche that is inhabited by black-foot disease fungi.

scholarly journals Detection and quantification of chimerism by droplet digital PCR

Chimerism ◽  
2013 ◽  
Vol 4 (3) ◽  
pp. 102-108 ◽  
Author(s):  
David George ◽  
Juliann Czech ◽  
Bobby John ◽  
Min Yu ◽  
Lawrence J. Jennings
Keyword(s):  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Detection And Quantification

scholarly journals Comparative Use of Quantitative PCR (qPCR), Droplet Digital PCR (ddPCR), and Recombinase Polymerase Amplification (RPA) in the Detection of Shiga Toxin-Producing E. coli (STEC) in Environmental Samples

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3507
Author(s):  
Mark A. Ibekwe ◽  
Shelton E. Murinda ◽  
Stanley Park ◽  
Amarachukwu Obayiuwana ◽  
Marcia A. Murry ◽  
...  
Keyword(s):  
Quantitative Pcr ◽  
Environmental Samples ◽  
Point Of Care ◽  
Foodborne Pathogen ◽  
Digital Pcr ◽  
Absolute Quantification ◽  
Droplet Digital Pcr ◽  
Recombinase Polymerase Amplification ◽  
High Rate ◽  
E Coli

E. coli O157:H7 is a foodborne pathogen that constitutes a global threat to human health. However, the quantification of this pathogen in food and environmental samples may be problematic at the low cell numbers commonly encountered in environmental samples. In this study, we used recombinase polymerase amplification (RPA) for the detection of E. coli O157:H7, real-time quantitative PCR (qPCR) for quantification, and droplet digital PCR (ddPCR) for absolute and accurate quantification of E. coli O157:H7 from spiked and environmental samples. Primer and probe sets were used for the detection of stx1 and stx2 using RPA. Genes encoding for stx1, stx2, eae, and rfbE were used to quantify E. coli O157:H7 in the water samples. Furthermore, duplex ddPCR assays were used to quantify the pathogens in these samples. Duplex assay set 1 used stx1 and rfbE genes, while assay set 2 used stx2 and eae genes. Droplet digital PCR was used for the absolute quantification of E. coli O15:H7 in comparison with qPCR for the spiked and environmental samples. The RPA results were compared to those from qPCR and ddPCR in order to assess the efficiency of the RPA compared with the PCR methods. The assays were further applied to the dairy lagoon effluent (DLE) and the high rate algae pond (HRAP) effluent, which were fed with diluted DLE. The RPA detected was <10 CFU/mL, while ddPCR showed quantification from 1 to 104 CFU/mL with a high reproducibility. In addition, quantification by qPCR was from 103 to 107 CFU/mL of the wastewater samples. Therefore, the RPA assay has potential as a point of care tool for the detection of E. coli O157:H7 from different environmental sources, followed by quantification of the target concentrations.

scholarly journals Droplet Digital PCR Detection of the Erythropoietin Transgene from Horse Plasma and Urine for Gene-Doping Control

Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 243 ◽  
Author(s):  
Teruaki Tozaki ◽  
Aoi Ohnuma ◽  
Masaki Takasu ◽  
Mio Kikuchi ◽  
Hironaga Kakoi ◽  
...  
Keyword(s):  
Magnetic Beads ◽  
Genetic Manipulation ◽  
Digital Pcr ◽  
Absolute Quantification ◽  
Droplet Digital Pcr ◽  
Taqman Probe ◽  
Gene Doping ◽  
Athletic Ability ◽  
Horse Plasma ◽  
Primer Sets

Indiscriminate genetic manipulation to improve athletic ability is a major threat to human sports and the horseracing industry, in which methods involving gene-doping, such as transgenesis, should be prohibited to ensure fairness. Therefore, development of methods to detect indiscriminate genetic manipulation are urgently needed. Here, we developed a highly sensitive method to detect horse erythropoietin (EPO) transgenes using droplet digital PCR (ddPCR). We designed two TaqMan probe/primer sets, and the EPO transgene was cloned into a plasmid for use as a model. We extracted the spiked EPO transgene from horse plasma and urine via magnetic beads, followed by ddPCR amplification for absolute quantification and transgene detection. The results indicated high recovery rates (at least ~60% and ~40% in plasma and urine, respectively), suggesting successful detection of the spiked transgene at concentrations of >130 and 200 copies/mL of plasma and urine, respectively. Additionally, successful detection was achieved following intramuscular injection of 20 mg of the EPO transgene. This represents the first study demonstrating a method for detecting the EPO transgene in horse plasma and urine, with our results demonstrating its efficacy for promoting the control of gene-doping in the horseracing industry.

scholarly journals Development and Evaluation of a Single Dye Duplex Droplet Digital PCR Assay for the Rapid Detection and Quantification of Mycobacterium tuberculosis

2020 ◽  
Vol 8 (5) ◽  
pp. 701 ◽  
Author(s):  
Raphael Nyaruaba ◽  
Jin Xiong ◽  
Caroline Mwaliko ◽  
Nuo Wang ◽  
Belindah J. Kibii ◽  
...  
Keyword(s):  
Target Genes ◽  
Annealing Temperature ◽  
Single Channel ◽  
Digital Pcr ◽  
Absolute Quantification ◽  
Droplet Digital Pcr ◽  
Sample Concentration ◽  
Specificity And Sensitivity ◽  
Probe Concentration ◽  
Detection And Quantification

Droplet digital PCR (ddPCR) is a third generation of PCR that was recently developed to overcome the challenges of real-time fluorescence-based quantitative PCR (qPCR) in absolute quantification of pathogens. Few studies have been done on tuberculosis (TB) detection and quantification using ddPCR despite its many advantages over qPCR. From the few studies, none explores a single dye duplex assay for the detection and quantification of TB. In this study, steps toward developing and evaluating a duplex single dye (FAM) assay for detecting two targets (IS6110 and IS1081) are clearly described using simplex and duplex experiments. To achieve this, various parameters are investigated, including annealing temperature, primer and probe concentration, sensitivity and specificity, sample concentration, and inter/intra-assay variability. From the results, primer and probe concentration, annealing temperature, and sample concentration have an effect on the position and separation of droplets in both simplex and duplex assays. The copies of target genes in a duplex assay can be estimated accurately using the threshold tool with little inter-assay (CV <1%) and intra-assay (CV <6%) variability when compared to simplex assays. The ddPCR assay specificity and sensitivity are both 100% when compared to qPCR. This work shows steps toward the detection and quantification of two targets in a single channel, enabling higher multiplexing to include more targets in future works.

scholarly journals Droplet digital PCR for detection and quantification of circulating tumor DNA in plasma of head and neck cancer patients

BMC Cancer ◽  
2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Joost H. van Ginkel ◽  
Manon M. H. Huibers ◽  
Robert J. J. van Es ◽  
Remco de Bree ◽  
Stefan M. Willems
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Cancer Patients ◽  
Neck Cancer ◽  
Digital Pcr ◽  
Circulating Tumor Dna ◽  
Droplet Digital Pcr ◽  
Tumor Dna ◽  
Detection And Quantification

scholarly journals Effect of Amount of DNA on Digital PCR Assessment of Genetically Engineered Canola and Soybean Events

2020 ◽  
Author(s):  
Tigst Demeke ◽  
Monika Eng ◽  
Michelle Holigroski ◽  
Sung-Jong Lee
Keyword(s):  
Zero Tolerance ◽  
Digital Pcr ◽  
Absolute Quantification ◽  
Genetically Engineered ◽  
Droplet Digital Pcr ◽  
Chain Reaction ◽  
Low Level ◽  
Polymerase Chain ◽  
Reliable Quantification ◽  
Detection And Quantification

Abstract Low-level detection and quantification of genetically engineered (GE) traits with polymerase chain reaction (PCR) is challenging. For unapproved GE events, any level of detection is not acceptable in some countries because of zero tolerance. Droplet digital PCR (ddPCR) has been successfully used for absolute quantification of GE events. In this study, reliability of low level quantification of GE events with ddPCR was assessed using a total of 50, 100, 200, 400, and 600 ng DNA spiked at 0.01% and 0.1% concentration levels. Genetically engineered canola (GT73 and MON88302 events) and soybean (A2704-12 and DP305423 events) events were used for the study. For samples spiked at 0.1% level, reliable quantification was achieved for the four GE events using 50 or 100 ng DNA. Few target droplets were generated for 0.01% spiked GE samples using 50 and 100 ng DNA. Increasing the amount of DNA for ddPCR generated more number of target droplets. For GE canola events, the use of 400 and 600 ng DNA for ddPCR resulted in saturation. The use of multiple wells of 200 ng DNA (instead of 400 and 600 ng per well) helped to overcome the saturation problem. Overall, the use of high amount of DNA for ddPCR was helpful for the detection and quantification of 0.01% GE samples.

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