scholarly journals Characterization and Event Specific-Detection by Quantitative Real-Time PCR of T25 Maize Insert

2005 ◽  
Vol 88 (2) ◽  
pp. 536-546 ◽  
Author(s):  
Cécile Collonnier ◽  
Alexandra Schattner ◽  
Georges Berthier ◽  
Francine Boyer ◽  
Géraldine Coué-Philippe ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Detection System ◽  
Integration Site ◽  
Ribosomal Gene ◽  
Cauliflower Mosaic Virus ◽  
Plant Genome ◽  
35S Promoter ◽  
Specific Detection ◽  
A Genome

Abstract T25 is one of the 4 maize transformation events from which commercial lines have so far been authorized in Europe. It was created by polyethylene glycol-mediated transformation using a construct bearing one copy of the synthetic pat gene associated with both promoter and terminator of the 35S ribosomal gene from cauliflower mosaic virus. In this article, we report the sequencing of the whole T25 insert and the characterization of its integration site by using a genome walking strategy. Our results confirmed that one intact copy of the initial construct had been integrated in the plant genome. They also revealed, at the 5′ junction of the insert, the presence of a second truncated 35S promoter, probably resulting from rearrangements which may have occurred before or during integration of the plasmid DNA. The analysis of the junction fragments showed that the integration site of the insert presented high homologies with the Huck retrotransposon family. By using one primer annealing in the maize genome and the other in the 5′ end of the integrat ed DNA, we developed a reliable event-specific detection system for T25 maize. To provide means to comply with the European regulation, a real-time PCR test was designed for specific quantitation of T25 event by using Taqman® chemistry.

scholarly journals Validation of a Novel Diagnostic Approach Combining the VersaTREK™ System for Recovery and Real-Time PCR for the Identification of Mycobacterium chimaera in Water Samples

2021 ◽  
Vol 9 (5) ◽  
pp. 1031
Author(s):  
Roberto Zoccola ◽  
Alessia Di Blasio ◽  
Tiziana Bossotto ◽  
Angela Pontei ◽  
Maria Angelillo ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Detection System ◽  
Bacterial Load ◽  
Microbial Control ◽  
Hospital Setting ◽  
Sample Volume ◽  
Analytical Sensitivity ◽  
Initial Water

Mycobacterium chimaera is an emerging pathogen associated with endocarditis and vasculitis following cardiac surgery. Although it can take up to 6–8 weeks to culture on selective solid media, culture-based detection remains the gold standard for diagnosis, so more rapid methods are urgently needed. For the present study, we processed environmental M. chimaera infected simulates at volumes defined in international guidelines. Each preparation underwent real-time PCR; inoculates were placed in a VersaTREK™ automated microbial detection system and onto selective Middlebrook 7H11 agar plates. The validation tests showed that real-time PCR detected DNA up to a concentration of 10 ng/µL. A comparison of the isolation tests showed that the PCR method detected DNA in a dilution of ×102 CFU/mL in the bacterial suspensions, whereas the limit of detection in the VersaTREK™ was <10 CFU/mL. Within less than 3 days, the VersaTREK™ detected an initial bacterial load of 100 CFU. The detection limit did not seem to be influenced by NaOH decontamination or the initial water sample volume; analytical sensitivity was 1.5 × 102 CFU/mL; positivity was determined in under 15 days. VersaTREK™ can expedite mycobacterial growth in a culture. When combined with PCR, it can increase the overall recovery of mycobacteria in environmental samples, making it potentially applicable for microbial control in the hospital setting and also in environments with low levels of contamination by viable mycobacteria.

Rapid detection and quantitation of hepatitis B virus DNA by real-time PCR using a new fluorescent (FRET) detection system

2004 ◽  
Vol 30 (2) ◽  
pp. 191-195 ◽  
Author(s):  
Sani Hussein Aliyu ◽  
Muktar Hassan Aliyu ◽  
Hamisu M Salihu ◽  
Surendra Parmar ◽  
Hamid Jalal ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Real Time ◽  
Real Time Pcr ◽  
Rapid Detection ◽  
Detection System ◽  
Hepatitis B Virus Dna ◽  
B Virus

scholarly journals Specific detection of Lysobacter antibioticus strains in agricultural soil using PCR and real-time PCR

2018 ◽  
Vol 365 (20) ◽  
Author(s):  
Fu Lina ◽  
Wang Ting ◽  
Wei Lanfang ◽  
Yang Jun ◽  
Liu Qi ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Agricultural Soil ◽  
Specific Detection

scholarly journals A TaqMan-based real-time PCR assay for specific detection of novel duck reovirus in China

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Shuai Zhang ◽  
Weihua Li ◽  
Xiaodong Liu ◽  
Xudong Li ◽  
Bin Gao ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Specific Detection ◽  
Pcr Assay

scholarly journals Quantification of the 35S Promoter in DNA Extracts from Genetically Modified Organisms Using Real-Time Polymerase Chain Reaction and Specificity Assessment on Various Genetically Modified Organisms, Part I: Operating Procedure

2005 ◽  
Vol 88 (2) ◽  
pp. 547-557 ◽  
Author(s):  
Sophie Fernandez ◽  
Chrystèle Charles-Delobel ◽  
Angèle Geldreich ◽  
Georges Berthier ◽  
Francine Boyer ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Real Time ◽  
Genetically Modified Organisms ◽  
Limit Of Detection ◽  
Genetically Modified ◽  
Collaborative Study ◽  
Cauliflower Mosaic Virus ◽  
Performance Criteria ◽  
35S Promoter ◽  
Conserved Sequence

Abstract A highly sensitive quantitative real-time assay targeted on the 35S promoter of a commercial genetically modified organism (GMO) was characterized (sF/sR primers) and developed for an ABI Prism® 7700 Sequence Detection System and TaqMan® chemistry. The specificity assessment and performance criteria of sF/sR assay were compared to other P35S-targeted published assays. sF/sR primers amplified a 79 base pair DNA sequence located in a part of P35S that is highly conserved among many caulimovirus strains, i.e., this consensus part of CaMV P35S is likely to be present in many GM events. According to the experimental conditions, the absolute limit of detection for Bt176 corn was estimated between 0.2 and 2 copies of equivalent genome (CEG). The limit of quantification was reached below 0.1% Bt176 content. A Cauliflower Mosaic Virus control (CaMV) qualitative assay targeted on the ORF III of the viral genome was also used as a control (primers 3F/3R) to assess the presence of CaMV in plant-derived products. The specificity of this test was assessed on various CaMV strains, including the Figwort Mosaic Virus (FMV) and solanaceous CaMV strains. Considering the performance of sF/sR quantification test, the highly conserved sequence, and the small size of the amplicon, this assay was tested in a collaborative study in order to be proposed as an international standard.

Multiplex, Construct-Specific, and Real-Time PCR-Based Analytical Methods for Bt Rice with cry1Ac Gene

2012 ◽  
Vol 95 (1) ◽  
pp. 186-194 ◽  
Author(s):  
Gurinder Jit Randhawa ◽  
Monika Singh
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Analytical Methods ◽  
Camv 35S Promoter ◽  
35S Promoter ◽  
Pcr Assay ◽  
Cry1ac Gene ◽  
Camv 35S ◽  
Bt Rice ◽  
Pcr Assays

Abstract Qualitative and quantitative analytical methods based on PCR for Bacillus thuringiensis (Bt) rice hybrid, namely, MRP 5401 Bt expressing a modified version of the Bt cry1Ac gene, are reported here. Multiplex PCR assays were developed to target the cry1Ac transgene, Cauliflower mosaic virus (CaMV) 35S promoter, Agrobacterium tumefaciens nopaline synthase (nos) terminator, the neomycin phosphotransferase II (nptII) marker gene, and an endogenous α-tubulin (TubA) gene in Bt rice. The 3.178 kb region of inserted gene construct comprising the region of the CaMV 35S promoter and cry1Ac gene was amplified, and the construct integrity was confirmed by the nested PCR. The LOD for cry1Ac gene-specific simplex PCR was 0.01%, as established using Bt rice DNA dilutions with 100, 10, 1.0, 0.1, 0.05, 0.01, and 0.001% genetically modified trait. A real-time PCR assay was also developed to quantify the cry1Ac gene. The method performance of the reported real-time PCR assay was in line with the acceptance criteria of Codex Alimentarius Commission ALINORM 10/33/23, with LOD and LOQ values of 0.05%. The reliable PCR assays prior to commercial release of Bt rice would facilitate efficient regulatory compliance for identification of genetic trait, labeling requirements, and effective risk assessment and management. They could also address consumers' concerns and legal disputes that may arise.

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