scholarly journals Development of SARS-CoV-2 packaged RNA reference material for nucleic acid testing

2021 ◽  
Author(s):  
Sang-Soo Lee ◽  
Seil Kim ◽  
Hee Min Yoo ◽  
Da-Hye Lee ◽  
Young-Kyung Bae
Keyword(s):  
Nucleic Acid ◽  
Copy Number ◽  
Target Gene ◽  
Target Genes ◽  
Digital Pcr ◽  
Number Concentration ◽  
Droplet Digital Pcr ◽  
Molecular Testing ◽  
Testing Laboratories ◽  
Viral Target

AbstractNucleic acid tests to detect the SARS-CoV-2 virus have been performed worldwide since the beginning of the COVID-19 pandemic. For the quality assessment of testing laboratories and the performance evaluation of molecular diagnosis products, reference materials (RMs) are required. In this work, we report the production of a lentiviral SARS-CoV-2 RM containing approximately 12 kilobases of its genome including common diagnostics targets such as RdRp, N, E, and S genes. The RM was measured with multiple assays using two different digital PCR platforms. To measure the homogeneity and stability of the lentiviral SARS-CoV-2 RM, reverse transcription droplet digital PCR (RT-ddPCR) was used with in-house duplex assays. The copy number concentration of each target gene in the extracted RNA solution was then converted to that of the RM solution. Their copy number values are measured to be from 1.5 × 105 to 2.0 × 105 copies/mL. The RM has a between-bottle homogeneity of 4.80–8.23% and is stable at 4 °C for 1 week and at −70 °C for 6 months. The lentiviral SARS-CoV-2 RM closely mimics real samples that undergo identical pre-analytical processes for SARS-CoV-2 molecular testing. By offering accurate reference values for the absolute copy number of viral target genes, the developed RM can be used to improve the reliability of SARS-CoV-2 molecular testing.

scholarly journals Accurate measurement of transgene copy number in crop plants using droplet digital PCR

2017 ◽  
Vol 90 (5) ◽  
pp. 1014-1025 ◽  
Author(s):  
Ray Collier ◽  
Kasturi Dasgupta ◽  
Yan-Ping Xing ◽  
Bryan Tarape Hernandez ◽  
Min Shao ◽  
...  
Keyword(s):  
Copy Number ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Crop Plants ◽  
Transgene Copy Number

scholarly journals DNA isolation protocol effects on nuclear DNA analysis by microarrays, droplet digital PCR, and whole genome sequencing, and on mitochondrial DNA copy number estimation

2017 ◽  
Author(s):  
Elizabeth Nacheva ◽  
Katya Mokretar ◽  
Aynur Soenmez ◽  
Alan M Pittman ◽  
Colin Grace ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Human Brain ◽  
Frontal Cortex ◽  
Genome Sequencing ◽  
Copy Number ◽  
Dna Isolation ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Whole Genome ◽  
Salting Out

AbstractPotential bias introduced during DNA isolation is inadequately explored, although it could have significant impact on downstream analysis. To investigate this in human brain, we isolated DNA from cerebellum and frontal cortex using spin columns under different conditions, and salting-out. We first analysed DNA using array CGH, which revealed a striking wave pattern suggesting primarily GC-rich cerebellar losses, even against matched frontal cortex DNA, with a similar pattern on a SNP array. The aCGH changes varied with the isolation protocol. Droplet digital PCR of two genes also showed protocol-dependent losses. Whole genome sequencing showed GC-dependent variation in coverage with spin column isolation from cerebellum. We also extracted and sequenced DNA from substantia nigra using salting-out and phenol / chloroform. The mtDNA copy number, assessed by reads mapping to the mitochondrial genome, was higher in substantia nigra when using phenol / chloroform. We thus provide evidence for significant method-dependent bias in DNA isolation from human brain, as reported in rat tissues. This may contribute to array “waves”, and could affect copy number determination, particularly if mosaicism is being sought, and sequencing coverage. Variations in isolation protocol may also affect apparent mtDNA abundance.

Abstract P613: Absolute Gene Quantification Of Intrarenal Renin-angiotensin System Components Using Droplet Digital PCR Analysis

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Ryousuke Satou ◽  
Akemi Katsurada ◽  
Kayoko Miyata ◽  
Andrei Derbenev ◽  
Andrea Zsombok
Keyword(s):  
Copy Number ◽  
System Analysis ◽  
Renin Angiotensin System ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Gene Copy ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Copy Numbers ◽  
Intrarenal Ras

The intrarenal renin-angiotensin system (RAS) has been shown to play crucial roles in the development of hypertension and RAS associated kidney injury including diabetic nephropathy. Although some circulating RAS components are filtered into kidneys and contribute to the regulation of intrarenal RAS activity, evaluating expression levels of RAS components in the kidney is important to elucidate the mechanisms underlying intrarenal RAS activation. Digital PCR is a new technique that has been established to quantify absolute target gene levels, which allows for comparisons of different gene levels. Thus, this study was performed to establish profiles of absolute gene copy numbers for intrarenal RAS components in wild-type (WT) rats, WT and streptozotocin (STZ)-induced diabetic mice. Male Sprague-Dawley rats (N=5) and male C57BL/6J mice were used in this study. The mice were subjected to either control (N=5) or STZ (200 mg/kg, N=4) injection. Seven days after STZ injection, copy numbers of renal cortical angiotensinogen (AGT), angiotensin-converting enzyme (ACE), ACE2, angiotensin type 1 receptor a (AT1a), and AT2 mRNA were determined by a droplet digital PCR. Since (pro)renin proteins produced by juxtaglomerular cells are secreted to circulating system, analysis of renin mRNA was excluded from this evaluation. In the renal cortex of WT rats, the copy number of AGT was higher than other measured RAS components (AGT: 719.2±46.6, ACE: 116.0±14.9, ACE2: 183.6±21.5, AT1a: 196.0±25.2 copies in 1 ng total RNA). AT2 levels were lower than other components (0.068±0.01 copies). In WT mice, ACE exhibited the highest copy number in the components (AGT: 447.2±29.0, ACE: 1662.4±61.2, ACE2: 676.8±41.5, AT1a: 867.0±16.8, AT2: 0.049±0.01 copies). Although STZ-induced diabetes did not change ACE2 and AT1a, ACE levels were reduced (765.5±98.1 copies) and AT2 levels were augmented (0.10±0.01 copies) as previously demonstrated. Accordingly, the absolute quantification by digital PCR established precise gene profiles of intrarenal RAS components, which will provide rationales for targeting the each component in future studies. Furthermore, the results indicate that the high sensitive assay accurately quantifies rare target genes including intrarenal AT2.

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 Comparative analysis of HER2 copy number between plasma and tissue samples in gastric cancer using droplet digital PCR

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Boram Kim ◽  
Soo Kyung Nam ◽  
Soo Hyun Seo ◽  
Kyoung Un Park ◽  
Sang-Hoon Ahn ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Comparative Analysis ◽  
Copy Number ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Tissue Samples

scholarly journals Application of droplet digital PCR for the detection of vector copy number in clinical CAR/TCR T cell products

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Alex Lu ◽  
Hui Liu ◽  
Rongye Shi ◽  
Yihua Cai ◽  
Jinxia Ma ◽  
...  
Keyword(s):  
T Cell ◽  
Copy Number ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Vector Copy Number
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