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Schwaiger G, Matt M, Streich P, Bromann S, Clauß M, Elsner M, Seidel M. Standard addition method for rapid, cultivation-independent quantification of Legionella pneumophila cells by qPCR in biotrickling filters. Analyst 2024; 149:2978-2987. [PMID: 38602145 DOI: 10.1039/d3an02207b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Cultivation-independent molecular biological methods are essential to rapidly quantify pathogens like Legionella pneumophila (L. pneumophila) which is important to control aerosol-generating engineered water systems. A standard addition method was established to quantify L. pneumophila in the very complex matrix of process water and air of exhaust air purification systems in animal husbandry. Therefore, cryopreserved standards of viable L. pneumophila were spiked in air and water samples to calibrate the total bioanalytical process which includes cell lysis, DNA extraction, and qPCR. A standard addition algorithm was employed for qPCR to determine the initial concentration of L. pneumophila. In mineral water, the recovery rate of this approach (73%-134% within the concentration range of 100-5000 Legionella per mL) was in good agreement with numbers obtained from conventional genomic unit (GU) calibration with DNA standards. In air samples of biotrickling filters, in contrast, the conventional DNA standard approach resulted in a significant overestimation of up to 729%, whereas our standard addition gave a more realistic recovery of 131%. With this proof-of-principle study, we were able to show that the molecular biology-based standard addition approach is a suitable method to determine realistic concentrations of L. pneumophila in air and process water samples of biotrickling filter systems. Moreover, this quantification strategy is generally a promising method to quantify pathogens in challenging samples containing a complex microbiota and the classical GU approach used for qPCR leads to unreliable results.
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Affiliation(s)
- Gerhard Schwaiger
- Institute of Water Chemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany.
| | - Marco Matt
- Institute of Water Chemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany.
| | - Philipp Streich
- Institute of Water Chemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany.
| | - Sarah Bromann
- Thuenen-Institute for Agricultural Technology, Bundesallee 47, D-38116 Braunschweig, Germany
| | - Marcus Clauß
- Thuenen-Institute for Agricultural Technology, Bundesallee 47, D-38116 Braunschweig, Germany
| | - Martin Elsner
- Institute of Water Chemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany.
| | - Michael Seidel
- Institute of Water Chemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany.
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Chen Y, Zhu Y, Peng C, Wang X, Wu J, Chen H, Xu J. A Point-of-Care Nucleic Acid Quantification Method by Counting Light Spots Formed by LAMP Amplicons on a Paper Membrane. BIOSENSORS 2024; 14:139. [PMID: 38534246 DOI: 10.3390/bios14030139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 03/28/2024]
Abstract
Nucleic acid quantification, allowing us to accurately know the copy number of target nucleic acids, is significant for diagnosis, food safety, agricultural production, and environmental protection. However, current digital quantification methods require expensive instruments or complicated microfluidic chips, making it difficult to popularize in the point-of-care detection. Paper is an inexpensive and readily available material. In this study, we propose a simple and cost-effective paper membrane-based digital loop-mediated isothermal amplification (LAMP) method for nucleic acid quantification. In the presence of DNA fluorescence dyes, the high background signals will cover up the amplicons-formed bright spots. To reduce the background fluorescence signals, a quencher-fluorophore duplex was introduced in LAMP primers to replace non-specific fluorescence dyes. After that, the amplicons-formed spots on the paper membrane can be observed; thus, the target DNA can be quantified by counting the spots. Take Vibrio parahaemolyticus DNA detection as an instance, a good linear relationship is obtained between the light spots and the copy numbers of DNA. The paper membrane-based digital LAMP detection can detect 100 copies target DNA per reaction within 30 min. Overall, the proposed nucleic acid quantification method has the advantages of a simple workflow, short sample-in and answer-out time, low cost, and high signal-to-noise, which is promising for application in resourced limited areas.
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Affiliation(s)
- Yanju Chen
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Yuanyuan Zhu
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Cheng Peng
- Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Xiaofu Wang
- Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Jian Wu
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Huan Chen
- Hangzhou Digital-Micro Biotech Co., Ltd., Hangzhou 311215, China
| | - Junfeng Xu
- Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
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Hyung JH, Hwang J, Moon SJ, Kim EJ, Kim DW, Park J. Development of a Method for Detecting Alexandrium pacificum Based on the Quantification of sxtA4 by Chip-Based Digital PCR. Toxins (Basel) 2022; 14:toxins14020111. [PMID: 35202138 PMCID: PMC8877084 DOI: 10.3390/toxins14020111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/28/2022] [Accepted: 01/29/2022] [Indexed: 11/18/2022] Open
Abstract
Alexandrium pacificum, which produces the paralytic shellfish toxin (PST) saxitoxin (STX), is one of the causative species of paralytic shellfish poisoning outbreaks in coastal areas of Korea. In this study, we developed a chip-based digital PCR (dPCR) method for A. pacificum detection and tested it for monitoring in Jinhae-Masan Bay. Using the sequence of an A. pacificum strain isolated in 2017, species-specific primers targeting sxtA4 (a STX biosynthesis-related gene) were designed and used in a dPCR, detecting 2.0 ± 0.24 gene copies per cell of A. pacificum. Cell abundance in field samples, estimated by a chip-based dPCR, was compared with the PST content, and measured using a mouse bioassay. A comparison with shellfish PST concentrations indicated that cell concentrations above 500 cells L−1, as measured using the dPCR assay, may cause shellfish PST concentrations to exceed the allowed limits for PSTs. Concordance rates between dPCR and PST results were 62.5% overall in 2018–2021, reaching a maximum of 91.7% in 2018–2019. The sensitivity of the dPCR assay was higher than that of microscopy and sxtA4-based qPCRs. Absolute quantification by chip-based dPCRs targeting sxtA4 in A. pacificum exhibits potential as a complementary approach to mouse bioassay PST monitoring for the prevention of toxic blooms.
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Affiliation(s)
- Jun-Ho Hyung
- Environment and Resource Convergence Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea; (J.-H.H.); (S.-J.M.); (E.-J.K.)
| | - Jinik Hwang
- West Sea Fisheries Research Institute, National Institute of Fisheries Science, Incheon 22383, Korea;
| | - Seung-Joo Moon
- Environment and Resource Convergence Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea; (J.-H.H.); (S.-J.M.); (E.-J.K.)
| | - Eun-Joo Kim
- Environment and Resource Convergence Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea; (J.-H.H.); (S.-J.M.); (E.-J.K.)
| | - Dong-Wook Kim
- Food Safety and Processing Research Division, National Institute of Fisheries Science, Busan 46083, Korea;
| | - Jaeyeon Park
- Environment and Resource Convergence Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea; (J.-H.H.); (S.-J.M.); (E.-J.K.)
- Correspondence: ; Tel.: +82-31-888-9042; Fax: +82-31-888-9040
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Yarimizu K, Sildever S, Hamamoto Y, Tazawa S, Oikawa H, Yamaguchi H, Basti L, Mardones JI, Paredes-Mella J, Nagai S. Development of an absolute quantification method for ribosomal RNA gene copy numbers per eukaryotic single cell by digital PCR. HARMFUL ALGAE 2021; 103:102008. [PMID: 33980448 DOI: 10.1016/j.hal.2021.102008] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
Recent increase of Harmful Algal Blooms (HAB) causes world-wide ecological, economical, and health issues, and more attention is paid to frequent coastal monitoring for the early detection of HAB species to prevent or reduce such impacts. Use of molecular tools in addition to traditional microscopy-based observation has become one of the promising methodologies for coastal monitoring. However, as ribosomal RNA (rRNA) genes are commonly targeted in molecular studies, variability in the rRNA gene copy number within and between species must be considered to provide quantitative information in quantitative PCR (qPCR), digital PCR (dPCR), and metabarcoding analyses. Currently, this information is only available for a limited number of species. The present study utilized a dPCR technology to quantify copy numbers of rRNA genes per single cell in 16 phytoplankton species, the majority of which are toxin-producers, using a newly developed universal primer set accompanied by a labeled probe with a fluorophore and a double-quencher. In silico PCR using the newly developed primers allowed the detection of taxa from 8 supergroups, demonstrating universality and broad coverage of the primer set. Chelex buffer was found to be suitable for DNA extraction to obtain DNA fragments with suitable size to avoid underestimation of the copy numbers. The study successfully demonstrated the first comparison of absolute quantification of 18S rRNA copy numbers per cell from 16 phytoplankton species by the dPCR technology.
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Affiliation(s)
- Kyoko Yarimizu
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan; Office of Industry-Academia-Government and Community Collaboration, Hiroshima University, 1-3-2 22 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-8511, Japan
| | - Sirje Sildever
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan; Department of Marine Systems, Tallinn University of Technology, Akadeemia tee 15A, 12618 Tallinn, Estonia
| | - Yoko Hamamoto
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - Satoshi Tazawa
- AXIOHELIX Co. Ltd, 12-17 Kandaizumicho, Chiyoda-ku, Tokyo 101-0024, Japan
| | - Hiroshi Oikawa
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - Haruo Yamaguchi
- Faculty of Agriculture and Marine Sciences, Kochi University, Nankoku, Kochi 783-8502, Japan
| | - Leila Basti
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan
| | - Jorge I Mardones
- Instituto de Fomento Pesquero, Centro de Estudios de Algas Nocivas (IFOP-CREAN), Padre Harter 574, Puerto Montt 5501679, Chile; Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
| | - Javier Paredes-Mella
- Instituto de Fomento Pesquero, Centro de Estudios de Algas Nocivas (IFOP-CREAN), Padre Harter 574, Puerto Montt 5501679, Chile
| | - Satoshi Nagai
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan.
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Lee HG, Kim HM, Min J, Park C, Jeong HJ, Lee K, Kim KY. Quantification of the paralytic shellfish poisoning dinoflagellate Alexandrium species using a digital PCR. HARMFUL ALGAE 2020; 92:101726. [PMID: 32113599 DOI: 10.1016/j.hal.2019.101726] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 12/01/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
A ubiquitous dinoflagellate, Alexandrium, produces paralytic shellfish toxin (PST), and its outbreaks have negative impacts on aquaculture, fisheries, human health, and the marine ecosystem. To minimize such damages, a routine monitoring program of toxic species must be implemented with a suitable analytical technique for their identification and quantification. However, the taxonomic identification and cell quantification of Alexandrium species based on their external morphology under a light microscope, or by using conventional molecular approaches have limited sensitivity and reproducibility. To address these challenges, we have developed an advanced protocol using droplet-digital PCR (ddPCR) for the discrimination and enumeration of three co-occurring Alexandrium species (A. affine, A. catenella, and A. pacificum) in environmental samples. Copies of species-specific internal transcribed spacer (ITS) per cell, which were calculated from environmental samples spiked with various numbers of culture cells, were used to estimate the abundance of species in the field samples. There were no significant differences in ITS copies estimated by the digital PCR assay between environmental samples from different localities, spiked artificially with a consistent number of cells from Alexandrium cultures. This sensitive assay was applied to determine the abundance and vertical distribution of those populations in the southern coastal waters of Korea. In spring, A. catenella was the dominant species, followed by the non-toxic A. affine in summers. A novel digital PCR assay can also be used to monitor other harmful marine protists that require high sample throughput and low detection limit with high accuracy and precision.
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Affiliation(s)
- Hyun-Gwan Lee
- Department of Oceanography, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea; Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea
| | - Hye Mi Kim
- Department of Oceanography, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea; Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea
| | - Juhee Min
- Department of Oceanography, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea; Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea
| | - Chungoo Park
- Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea; School of Biological Sciences and Technology, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Hae Jin Jeong
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Kitack Lee
- School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Kwang Young Kim
- Department of Oceanography, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea; Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea.
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A generic standard additions based method to determine endogenous analyte concentrations by immunoassays to overcome complex biological matrix interference. Sci Rep 2017; 7:17542. [PMID: 29235533 PMCID: PMC5727527 DOI: 10.1038/s41598-017-17823-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/30/2017] [Indexed: 11/16/2022] Open
Abstract
We describe a novel generic method to derive the unknown endogenous concentrations of analyte within complex biological matrices (e.g. serum or plasma) based upon the relationship between the immunoassay signal response of a biological test sample spiked with known analyte concentrations and the log transformed estimated total concentration. If the estimated total analyte concentration is correct, a portion of the sigmoid on a log-log plot is very close to linear, allowing the unknown endogenous concentration to be estimated using a numerical method. This approach obviates conventional relative quantification using an internal standard curve and need for calibrant diluent, and takes into account the individual matrix interference on the immunoassay by spiking the test sample itself. This technique is based on standard additions for chemical analytes. Unknown endogenous analyte concentrations within even 2-fold diluted human plasma may be determined reliably using as few as four reaction wells.
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Pang S, Cowen S. A generic standard additions based method to determine endogenous analyte concentrations by immunoassays to overcome complex biological matrix interference. Sci Rep 2017; 7:17542. [DOI: https:/doi.org/10.1038/s41598-017-17823-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/30/2017] [Indexed: 09/01/2023] Open
Abstract
AbstractWe describe a novel generic method to derive the unknown endogenous concentrations of analyte within complex biological matrices (e.g. serum or plasma) based upon the relationship between the immunoassay signal response of a biological test sample spiked with known analyte concentrations and the log transformed estimated total concentration. If the estimated total analyte concentration is correct, a portion of the sigmoid on a log-log plot is very close to linear, allowing the unknown endogenous concentration to be estimated using a numerical method. This approach obviates conventional relative quantification using an internal standard curve and need for calibrant diluent, and takes into account the individual matrix interference on the immunoassay by spiking the test sample itself. This technique is based on standard additions for chemical analytes. Unknown endogenous analyte concentrations within even 2-fold diluted human plasma may be determined reliably using as few as four reaction wells.
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Truong AS, Lochbaum CA, Boyce MW, Lockett MR. Tracking the Invasion of Small Numbers of Cells in Paper-Based Assays with Quantitative PCR. Anal Chem 2015; 87:11263-70. [PMID: 26507077 DOI: 10.1021/acs.analchem.5b02362] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Paper-based scaffolds are an attractive material for culturing mammalian cells in a three-dimensional environment. There are a number of previously published studies, which utilize these scaffolds to generate models of aortic valves, cardiac ischemia and reperfusion, and solid tumors. These models have largely relied on fluorescence imaging and microscopy to quantify cells in the scaffolds. We present here a polymerase chain reaction (PCR)-based method, capable of quantifying multiple cell types in a single culture with the aid of DNA barcodes: unique sequences of DNA introduced to the genome of individual cells or cell types through lentiviral transduction. PCR-based methods are highly specific and are amenable to high-throughput and multiplexed analyses. To validate this method, we engineered two different breast cancer lines to constitutively express either a green or red fluorescent protein. These cells lines allowed us to directly compare the ability of fluorescence imaging (of the fluorescent proteins) and qPCR (of the unique DNA sequences of the fluorescent proteins) to quantify known numbers of cells in the paper based-scaffolds. We also used both methods to quantify the distribution of these breast cell lines in homotypic and heterotypic invasion assays. In the paper-based invasion assays, a single sheet of paper containing cells suspended in a hydrogel was sandwiched between sheets of paper containing only hydrogel. The stack was incubated, and the cells invaded the adjacent layers. The individual sheets of the invasion assay were then destacked and the number of cells in each layer quantified. Our results show both methods can accurately detect cell populations of greater than 500 cells. The qPCR method can repeatedly and accurately detect as few as 50 cells, allowing small populations of highly invasive cells to be detected and differentiated from other cell types.
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Affiliation(s)
- Andrew S Truong
- Department of Chemistry, University of North Carolina at Chapel Hill , Kenan and Caudill Laboratories, 125 South Road, Chapel Hill, North Carolina 27599-3290, United States
| | - Christian A Lochbaum
- Department of Chemistry, University of North Carolina at Chapel Hill , Kenan and Caudill Laboratories, 125 South Road, Chapel Hill, North Carolina 27599-3290, United States
| | - Matthew W Boyce
- Department of Chemistry, University of North Carolina at Chapel Hill , Kenan and Caudill Laboratories, 125 South Road, Chapel Hill, North Carolina 27599-3290, United States
| | - Matthew R Lockett
- Department of Chemistry, University of North Carolina at Chapel Hill , Kenan and Caudill Laboratories, 125 South Road, Chapel Hill, North Carolina 27599-3290, United States.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill , 450 West Drive, Chapel Hill, North Carolina 27599-7295, United States
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Comparing real-time quantitative polymerase chain reaction analysis methods for precision, linearity, and accuracy of estimating amplification efficiency. Anal Biochem 2013; 449:76-82. [PMID: 24365068 DOI: 10.1016/j.ab.2013.12.020] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/06/2013] [Accepted: 12/15/2013] [Indexed: 11/21/2022]
Abstract
New methods are used to compare seven qPCR analysis methods for their performance in estimating the quantification cycle (Cq) and amplification efficiency (E) for a large test data set (94 samples for each of 4 dilutions) from a recent study. Precision and linearity are assessed using chi-square (χ(2)), which is the minimized quantity in least-squares (LS) fitting, equivalent to the variance in unweighted LS, and commonly used to define statistical efficiency. All methods yield Cqs that vary strongly in precision with the starting concentration N0, requiring weighted LS for proper calibration fitting of Cq vs log(N0). Then χ(2) for cubic calibration fits compares the inherent precision of the Cqs, while increases in χ(2) for quadratic and linear fits show the significance of nonlinearity. Nonlinearity is further manifested in unphysical estimates of E from the same Cq data, results which also challenge a tenet of all qPCR analysis methods - that E is constant throughout the baseline region. Constant-threshold (Ct) methods underperform the other methods when the data vary considerably in scale, as these data do.
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Burke DG, Dong L, Bhat S, Forbes-Smith M, Fu S, Pinheiro L, Jing W, Emslie KR. Digital Polymerase Chain Reaction Measured pUC19 Marker as Calibrant for HPLC Measurement of DNA Quantity. Anal Chem 2013; 85:1657-64. [DOI: 10.1021/ac302925f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
| | - Lianhua Dong
- National Institute of Metrology, Beijing, China, 100013
| | - Somanath Bhat
- National Measurement Institute, Lindfield, Australia 2070
| | | | - Shuang Fu
- National Measurement Institute, Lindfield, Australia 2070
| | | | - Wang Jing
- National Institute of Metrology, Beijing, China, 100013
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