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Query: "author" (Bogožalec Košir Alexandra) .

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1.
Evaluation of DNA extraction methods for reliable quantification of Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa
Alexandra Bogožalec Košir, Dane Lužnik, Viktorija Tomič, Mojca Milavec, 2023, original scientific article

Abstract: Detection and quantification of DNA biomarkers relies heavily on the yield and quality of DNA obtained by extraction from different matrices. Although a large number of studies have compared the yields of different extraction methods, the repeatability and intermediate precision of these methods have been largely overlooked. In the present study, five extraction methods were evaluated, using digital PCR, to determine their efficiency in extracting DNA from three different Gram-negative bacteria in sputum samples. The performance of two automated methods (GXT NA and QuickPick genomic DNA extraction kit, using Arrow and KingFisher Duo automated systems, respectively), two manual kit-based methods (QIAamp DNA mini kit; DNeasy UltraClean microbial kit), and one manual non-kit method (CTAB), was assessed. While GXT NA extraction kit and the CTAB method have the highest DNA yield, they did not meet the strict criteria for repeatability, intermediate precision, and measurement uncertainty for all three studied bacteria. However, due to limited clinical samples, a compromise is necessary, and the GXT NA extraction kit was found to be the method of choice. The study also showed that dPCR allowed for accurate determination of extraction method repeatability, which can help standardize molecular diagnostic approaches. Additionally, the determination of absolute copy numbers facilitated the calculation of measurement uncertainty, which was found to be influenced by the DNA extraction method used.
Keywords: nucleic acid, dPCR, DNA extraction methods, Gram-negative bacteria
Published in DiRROS: 12.07.2024; Views: 19; Downloads: 5
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2.
Fast and accurate multiplex identification and quantification of seven genetically modified soybean lines using six-color digital PCR
Alexandra Bogožalec Košir, Sabine Muller, Jana Žel, Mojca Milavec, Allison C. Mallory, David Dobnik, 2023, original scientific article

Abstract: The proliferation of genetically modified organisms (GMOs) presents challenges to GMO testing laboratories and policymakers. Traditional methods, like quantitative real-time PCR (qPCR), face limitations in quantifying the increasing number of GMOs in a single sample. Digital PCR (dPCR), specifically multiplexing, offers a solution by enabling simultaneous quantification of multiple GMO targets. This study explores the use of the Naica six-color Crystal dPCR platform for quantifying five GM soybean lines within a single six-plex assay. Two four-color assays were also developed for added flexibility. These assays demonstrated high specificity, sensitivity (limit of detection or LOD < 25 copies per reaction) and precision (bias to an estimated copy number concentration <15%). Additionally, two approaches for the optimization of data analysis were implemented. By applying a limit-of-blank (LOB) correction, the limit of quantification (LOQ) and LOD could be more precisely determined. Pooling of reactions additionally lowered the LOD, with a two- to eight-fold increase in sensitivity. Real-life samples from routine testing were used to confirm the assays’ applicability for quantifying GM soybean lines in complex samples. This study showcases the potential of the six-color Crystal dPCR platform to revolutionize GMO testing, facilitating comprehensive analysis of GMOs in complex samples.
Keywords: digital PCR, dPCR, quantification, multiplexing, genetically modified organisms, 6-color system, virus diagnostics, virology
Published in DiRROS: 29.03.2024; Views: 300; Downloads: 134
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