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Aijuka M, Buys EM. Detection of extended-spectrum beta-lactamase cefotaxime resistance and virulence genes in Escherichia coli by duplex quantitative real-time PCR and melt curve analysis. Lett Appl Microbiol 2020; 71:54-60. [PMID: 31930506 DOI: 10.1111/lam.13274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/19/2019] [Accepted: 01/06/2020] [Indexed: 11/29/2022]
Abstract
Emerging virulent and antibiotic-resistant pathogens present a global public health risk. Routine monitoring of prevalence within the clinical, environmental and food production setting is vital. Quantitative real-time PCR (qPCR) coupled with melting curve analysis can rapidly and accurately characterize pathogens. We evaluated commercial qPCR mixes based on SYBR Green l and EvaGreen for developing an assay for simultaneously detecting antibiotic resistance (extended-spectrum beta-lactamase, ESBL and blaCTX-M ) and virulence (stx1, stx2 and eae) genes in Escherichia coli (n = 12) isolated from irrigation water and irrigated vegetables. SYBR Green and EvaGreen detected two amplicons (stx1 and blaCTX-M ) and (stx2 and eae) in a single reaction. A higher mean melting temperature (Tm ) separation between targeted amplicons and smoother melting curves were observed with the EvaGreen suggesting better performance when targeting multiple amplicons. Through simple stepwise optimization of DNA, cycling, primers, reaction volume and melting curve scanning rate, we adopted a conventional PCR assay for detection of large amplicons (375-1580 bp) for qPCR. This may facilitate development of cost-effective tailor-made assays for rapid and accurate monitoring of emerging foodborne and environmental pathogens in resource constrained regions.
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Affiliation(s)
- M Aijuka
- Department of Consumer and Food Sciences, University of Pretoria, Hatfield, Pretoria, South Africa
| | - E M Buys
- Department of Consumer and Food Sciences, University of Pretoria, Hatfield, Pretoria, South Africa
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Shevelev GY, Kabilov MR, Lomzov AA, Dovydenko IS, Pyshnyi DV. Features of Determining Thermodynamic Parameters of Formation of Nucleic Acid Complexes Using Thermal Denaturation with Fluorimetric Signal Detection. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162019060359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kim JH, Park Y, Kim WJ, Kim AY, Nguyen P, Lyu DP, Lee HS, Koh YH. Developing molecular diagnostics for detection of red imported fire ants using two genes, Sinv11108 and Sinv11977. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2019; 102:e21610. [PMID: 31452246 DOI: 10.1002/arch.21610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/16/2019] [Accepted: 07/19/2019] [Indexed: 06/10/2023]
Abstract
Aggressive red imported fire ants (RIFAs) are expanding their habitat due to active international trade and global warming. To prevent infestation and settlement, RIFAs must be removed during the quarantine process. Because RIFAs are social insects and have different morphological characteristics depending on their castes, non-ant taxonomists have difficulty confirming RIFAs based on their morphological characteristics alone. The disadvantages of previously reported RIFA molecular diagnostics are that they require additional steps, such as restriction enzyme digestion followed by agarose gel electrophoresis separation or DNA sequence verification for polymerase chain reaction (PCR)-amplified products. To overcome these drawbacks, two RIFA-specific genes were selected and used to develop diverse PCR-based RIFA molecular diagnostic techniques. We found that RIFAs could be confirmed by conventional PCR targeting of two RIFA-specific genes followed by agarose electrophoresis separation. In addition, TaqMan probe real-time PCR methods had the advantage of confirming RIFAs immediately after the reactions were completed by observing fluorescence indexes. Finally, multiplex PCRs enhanced RIFA specificity and sensitivity. The new molecular diagnostic methods developed in this study had the advantages of reducing false positive and negative results together with high specificity and sensitivity for RIFAs.
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Affiliation(s)
- Ji-Hye Kim
- Department of Biomedical Gerontology, Hallym University, Chuncheon, Gangwon-do, Korea
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Youngjin Park
- Plant Quarantine Technology Center, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbuk-do, Korea
| | | | - A-Young Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Phuong Nguyen
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Dong Pyo Lyu
- Department of Forest Science, SangJi University, Wonju, Gangwon-do, Korea
| | - Heung Sik Lee
- Plant Quarantine Technology Center, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbuk-do, Korea
| | - Young Ho Koh
- Department of Biomedical Gerontology, Hallym University, Chuncheon, Gangwon-do, Korea
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
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Employing DNA binding dye to improve detection of Enterocytozoon hepatopenaei in real-time LAMP. Sci Rep 2019; 9:15860. [PMID: 31676806 PMCID: PMC6825238 DOI: 10.1038/s41598-019-52459-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 10/16/2019] [Indexed: 01/25/2023] Open
Abstract
Enterocytozoon hepatopenaei (EHP) is a pathogen in the pancreatic tissue of prawn, as reported in recent years. Enterosporidiosis caused by EHP in Penaeus genus is spreading widely, which seriously threatens the sustainable development of shrimp aquaculture in the world. Empolying the DNA binding dye of SYTO-16, a real-time quantitative loop-mediated isothermal amplification (LAMP) method has been established herein to detect EHP. The primer sequences used in the LAMP reaction were according to the SSU rRNA gene. The LAMP assay has reached a sensitivity of 101 copies/µL and no cross-reaction with other aquatic pathogens. Compared with normal PCR, the efficiency of the LAMP technique is more sensitive, which has a shorter detection time. The use of fluorescent nucleic acid dye (SYTO-16) reveals a more satisfactory performance relative to calcein. The quantitative LAMP assay can be considered as a valid tool for rapid detection of microsporidian in prawns. Our study provides a scientific basis to follow the effect of the pathogen infection on growth of cultured penaeid shrimp.
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Selection of suitable reference genes for gene expression studies in myxosporean (Myxozoa, Cnidaria) parasites. Sci Rep 2019; 9:15073. [PMID: 31636316 PMCID: PMC6803631 DOI: 10.1038/s41598-019-51479-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 10/02/2019] [Indexed: 12/25/2022] Open
Abstract
Myxozoans (Cnidaria: Myxozoa) are an extremely diversified group of endoparasites some of which are causative agents of serious diseases in fish. New methods involving gene expression studies have emerged over the last years to better understand and control myxozoan diseases. Quantitative RT-PCR is the most extensively used approach for gene expression studies. However, the accuracy of the results depends on the normalization of the data to reference genes. We studied the expression of eight commonly used reference genes, adenosylhomocysteinase (AHC1), beta actin (ACTB), eukaryotic translation elongation factor 2 (EF2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), hypoxanthine-guanine phosphoribosyltransferase 1 (HPRT1), DNA-directed RNA polymerase II (RPB2), 18S ribosomal RNA (18S), 28S ribosomal RNA (28S) across different developmental stages of three myxozoan species, Sphaerospora molnari, Myxobolus cerebralis and Ceratonova shasta, representing the three major myxozoan linages from the largest class Myxosporea. The stable reference genes were identified using four algorithms: geNorm, NormFinder, Bestkeeper and ΔCq method. Additionally, we analyzed transcriptomic data from S. molnari proliferative and spore-forming stages to compare the relative amount of expressed transcripts with the most stable reference genes suggested by RT-qPCR. Our results revealed that GAPDH and EF2 are the most uniformly expressed genes across the different developmental stages of the studied myxozoan species.
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Quyen TL, Ngo TA, Bang DD, Madsen M, Wolff A. Classification of Multiple DNA Dyes Based on Inhibition Effects on Real-Time Loop-Mediated Isothermal Amplification (LAMP): Prospect for Point of Care Setting. Front Microbiol 2019; 10:2234. [PMID: 31681184 PMCID: PMC6803449 DOI: 10.3389/fmicb.2019.02234] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/11/2019] [Indexed: 12/16/2022] Open
Abstract
LAMP has received great interest and is widely utilized in life sciences for nucleic acid analysis. To monitor a real-time LAMP assay, a fluorescence DNA dye is an indispensable component and therefore the selection of a suitable dye for real-time LAMP is a need. To aid this selection, we investigated the inhibition effects of twenty-three DNA dyes on real-time LAMP. Threshold time (Tt) values of each real-time LAMP were determined and used as an indicator of the inhibition effect. Based on the inhibition effects, the dyes were classified into four groups: (1) non-inhibition effect, (2) medium inhibition effect, (3) high inhibition effect, and (4) very high inhibition effect. The signal to noise ratio (SNR) and the limit of detection (LOD) of the dyes in groups 1, 2, and 3 were further investigated, and possible inhibition mechanisms of the DNA dyes on the real-time LAMP are suggested and discussed. Furthermore, a comparison of SYTO 9 in different LAMP reactions and different systems is presented. Of the 23 dyes tested, SYTO 9, SYTO 82, SYTO 16, SYTO 13, and Miami Yellow were the best dyes with no inhibitory effect, low LOD and high SNR in the real-time LAMP reactions. The present classification of the dyes will simplify the selection of fluorescence dye for real-time LAMP assays in point of care setting.
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Affiliation(s)
- Than Linh Quyen
- Department of Biotechnology and Biomedicine, Technical University of Denmark (DTU-Bioengineering), Lyngby, Denmark
| | - Tien Anh Ngo
- Laboratory of Applied Micro and Nanotechnology (LAMINATE), National Food Institute, Technical University of Denmark (DTU-Food), Lyngby, Denmark
| | - Dang Duong Bang
- Laboratory of Applied Micro and Nanotechnology (LAMINATE), National Food Institute, Technical University of Denmark (DTU-Food), Lyngby, Denmark
| | - Mogens Madsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark (DTU-Bioengineering), Lyngby, Denmark
| | - Anders Wolff
- Department of Biotechnology and Biomedicine, Technical University of Denmark (DTU-Bioengineering), Lyngby, Denmark
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Koppert J, Jean-Ruel H, O'Neill D, Harder C, Willmore W, Ianoul A, Albert J. Self-heating tilted fiber Bragg grating device for melt curve analysis of solid-phase DNA hybridization and thermal cycling. Anal Bioanal Chem 2019; 411:6813-6823. [PMID: 31432237 DOI: 10.1007/s00216-019-02072-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/11/2019] [Accepted: 08/05/2019] [Indexed: 01/05/2023]
Abstract
We demonstrate a DNA-based optical fiber device that uses an in-fiber grating, a light absorbing coating with surface anchored DNA, and a built-in optical thermometer. This device is used for precisely thermal cycling surface DNA spots bound by a simple UV cross-linking technique. Near-infrared light of wavelengths near 1550 nm and guided power near 300 mW is coupled out of the fiber core by a tilted fiber Bragg grating inscribed in the fiber and absorbed by the coating to increase its temperature to more than 95 °C. A co-propagating broadband light signal (also in the near-infrared region) is used to measure the reflection spectrum of the grating and thus the temperature from the wavelength shifts of the reflection peaks. The device is capable of sensitive DNA melt analysis and can be used for DNA amplification. Graphical abstract.
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Affiliation(s)
- Jason Koppert
- Department of Electronics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Hubert Jean-Ruel
- Department of Electronics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.,Spartan Biosciences Inc., 2934 Baseline Road #500, Nepean, ON, K2H B2, Canada
| | - Devin O'Neill
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Chris Harder
- Spartan Biosciences Inc., 2934 Baseline Road #500, Nepean, ON, K2H B2, Canada
| | - William Willmore
- Department of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Anatoli Ianoul
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Jacques Albert
- Department of Electronics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
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Xu Q, Dong J, Ma X, Zhao Y, Li CC, Zhang CY. Structurally Defined Ru(II) Metallointercalators for Real-Time Monitoring of DNA Amplification Reactions. Anal Chem 2019; 91:8777-8782. [DOI: 10.1021/acs.analchem.9b02244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Qinfeng Xu
- School of Food and Biological Engineering, National R&D Center for Goat Dairy Products Processing Technology, Shaanxi University of Science and Technology, Xi’an 710021, P. R. China
| | - Jing Dong
- School of Food and Biological Engineering, National R&D Center for Goat Dairy Products Processing Technology, Shaanxi University of Science and Technology, Xi’an 710021, P. R. China
| | - Xiya Ma
- School of Food and Biological Engineering, National R&D Center for Goat Dairy Products Processing Technology, Shaanxi University of Science and Technology, Xi’an 710021, P. R. China
| | - Yanni Zhao
- School of Food and Biological Engineering, National R&D Center for Goat Dairy Products Processing Technology, Shaanxi University of Science and Technology, Xi’an 710021, P. R. China
| | - Chen-chen Li
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P. R. China
| | - Chun-yang Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P. R. China
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Zimmers ZA, Adams NM, Gabella WE, Haselton FR. Fluorophore-Quencher Interactions Effect on Hybridization Characteristics of Complementary Oligonucleotides. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2019; 11:2862-2867. [PMID: 32661463 PMCID: PMC7357715 DOI: 10.1039/c9ay00584f] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nucleic acids are often covalently modified with fluorescent reporter molecules to create a hybridization state-dependent optical signal. Designing such a nucleic acid reporter involves selecting a fluorophore, quencher, and fluorescence quenching design. This report outlines the effect that these choices have on the DNA hybridization characteristics by examining six fluorophores in four quenching schemes: a quencher molecule offset from the fluorophore by 0, 5, or 10 bases, and nucleotide quenching. The similar binding characteristics of left-handed L-DNA were evaluated in comparison with right-handed DNA to quantify the effect of each quenching scheme. These results were applied to the Adaptive PCR method, which monitors fluorescently-labeled L-DNA as a sentinel for analogous unlabeled D-DNA in the reaction. All of the tested fluorophores and quenching schemes increased the annealing temperature of the oligonucleotide pairs by values ranging from 0.5 to 8.5 °C relative to unlabeled oligonucleotides. The design with the smallest increase (0.5 °C) was a sense strand with a FAM fluorophore and an anti-sense strand with Black Hole Quencher 2 offset by 10 bases from the FAM. An identical design that did not offset the quencher molecules resulted in a shift in annealing temperature of 5 °C. PCR was performed using temperature switching based on each of these L-DNA designs, and efficiency was significantly increased for the 10-base offset design, which had the smallest shift in annealing temperature. These results highlight the importance of selecting an appropriate fluorescence quenching scheme for nucleic acid optical signals.
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Affiliation(s)
- Zackary A Zimmers
- 5932 Stevenson Center Science and Engineering, Vanderbilt University
| | - Nicholas M Adams
- 5932 Stevenson Center Science and Engineering, Vanderbilt University
| | - William E Gabella
- 5932 Stevenson Center Science and Engineering, Vanderbilt University
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Ye J, Xu M, Tian X, Cai S, Zeng S. Research advances in the detection of miRNA. J Pharm Anal 2019; 9:217-226. [PMID: 31452959 PMCID: PMC6702429 DOI: 10.1016/j.jpha.2019.05.004] [Citation(s) in RCA: 195] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/10/2019] [Accepted: 05/22/2019] [Indexed: 12/13/2022] Open
Abstract
MicroRNAs (miRNAs) are a family of endogenous, small (approximately 22 nucleotides in length), noncoding, functional RNAs. With the development of molecular biology, the research of miRNA biological function has attracted significant interest, as abnormal miRNA expression is identified to contribute to serious human diseases such as cancers. Traditional methods for miRNA detection do not meet current demands. In particular, nanomaterial-based methods, nucleic acid amplification-based methods such as rolling circle amplification (RCA), loop-mediated isothermal amplification (LAMP), strand-displacement amplification (SDA) and some enzyme-free amplifications have been employed widely for the highly sensitive detection of miRNA. MiRNA functional research and clinical diagnostics have been accelerated by these new techniques. Herein, we summarize and discuss the recent progress in the development of miRNA detection methods and new applications. This review will provide guidelines for the development of follow-up miRNA detection methods with high sensitivity and specificity, and applicability to disease diagnosis and therapy.
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Affiliation(s)
- Jiawei Ye
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Mingcheng Xu
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xueke Tian
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Sheng Cai
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Su Zeng
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, Zhejiang University, Hangzhou, Zhejiang 310058, China
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61
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Morozov VN, Kuzmin VA. fluorescence self-quenching of Hoechst 33258 and SYBR Green I Dyes in a DNA Cholesteric liquid-Crystalline matrix. HIGH ENERGY CHEMISTRY 2019. [DOI: 10.1134/s0018143919020103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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62
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Development of a fluorescence-based method for the rapid determination of Zika virus polymerase activity and the screening of antiviral drugs. Sci Rep 2019; 9:5397. [PMID: 30932009 PMCID: PMC6444013 DOI: 10.1038/s41598-019-41998-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 03/20/2019] [Indexed: 12/14/2022] Open
Abstract
Zika virus (ZIKV) is an emerging pathogen that has been associated with large numbers of cases of severe neurologic disease, including Guillain-Barré syndrome and microcephaly. Despite its recent establishment as a serious global public health concern there are no licensed therapeutics to control this virus. Accordingly, there is an urgent need to develop methods for the high-throughput screening of antiviral agents. We describe here a fluorescence-based method to monitor the real-time polymerization activity of Zika virus RNA-dependent RNA polymerase (RdRp). By using homopolymeric RNA template molecules, de novo RNA synthesis can be detected with a fluorescent dye, which permits the specific quantification and kinetics of double-strand RNA formation. ZIKV RdRp activity detected using this fluorescence-based assay positively correlated with traditional assays measuring the incorporation of radiolabeled nucleotides. We also validated this method as a suitable assay for the identification of ZIKV inhibitors targeting the viral polymerase using known broad-spectrum inhibitors. The assay was also successfully adapted to detect RNA polymerization activity by different RdRps, illustrated here using purified RdRps from hepatitis C virus and foot-and-mouth disease virus. The potential of fluorescence-based approaches for the enzymatic characterization of viral polymerases, as well as for high-throughput screening of antiviral drugs, are discussed.
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Ferreira BH, Ramírez-Prado JH, Neves GWP, Torrado E, Sampaio P, Felipe MSS, Vasconcelos AT, Goldman GH, Carvalho A, Cunha C, Lopes-Bezerra LM, Rodrigues F. Ploidy Determination in the Pathogenic Fungus Sporothrix spp. Front Microbiol 2019; 10:284. [PMID: 30858833 PMCID: PMC6397882 DOI: 10.3389/fmicb.2019.00284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/04/2019] [Indexed: 11/16/2022] Open
Abstract
The pathogenic clade of the Sporothrix genus comprises the etiological agents of sporotrichosis, a worldwide emergent disease. Despite the growing understanding of their successful pathogen traits, there is little information on genome sizes and ploidy within the genus. Therefore, in this work, we evaluated the ploidy of four species of the Sporothrix genus, specifically Sporothrix brasiliensis, Sporothrix schenckii, Sporothrix globosa, and Sporothrix pallida. Through cell cycle analysis of the yeast-phase cells, we showed that the DNA content of G0/G1 cells was similar to the genome size determined by whole genome sequencing. Moreover, ploidy of S. schenckii, S. brasiliensis, and S. pallida that was determined by allele composition using next-generation sequencing (NGS) data is consistent with monomorphic positions at each allele. These data show that the analyzed strains of Sporothrix are haploid, or at least aneuploid, thereby laying the foundation for the development of a molecular toolbox for Sporothrix spp.
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Affiliation(s)
- Beatriz H. Ferreira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Braga, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, University of Minho, Braga, Portugal
| | | | - Gabriela W. P. Neves
- Laboratory of Cellular Mycology and Proteomics, Biology Institute, University of Rio de Janeiro State, Rio de Janeiro, Brazil
| | - Egídio Torrado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Braga, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, University of Minho, Braga, Portugal
| | - Paula Sampaio
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal
| | - Maria Sueli S. Felipe
- Genomic Science and Biotechnology, Catholic University of Brasília, Brasília, Brazil
- Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Ana Tereza Vasconcelos
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis, Brazil
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Agostinho Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Braga, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, University of Minho, Braga, Portugal
| | - Cristina Cunha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Braga, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, University of Minho, Braga, Portugal
| | - Leila M. Lopes-Bezerra
- Laboratory of Cellular Mycology and Proteomics, Biology Institute, University of Rio de Janeiro State, Rio de Janeiro, Brazil
- Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, Brazil
| | - Fernando Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Braga, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, University of Minho, Braga, Portugal
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Cristofalo M, Kovari D, Corti R, Salerno D, Cassina V, Dunlap D, Mantegazza F. Nanomechanics of Diaminopurine-Substituted DNA. Biophys J 2019; 116:760-771. [PMID: 30795872 DOI: 10.1016/j.bpj.2019.01.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 10/27/2022] Open
Abstract
2,6-diaminopurine (DAP) is a nucleobase analog of adenine. When incorporated into double-stranded DNA (dsDNA), it forms three hydrogen bonds with thymine. Rare in nature, DAP substitution alters the physical characteristics of a DNA molecule without sacrificing sequence specificity. Here, we show that in addition to stabilizing double-strand hybridization, DAP substitution also changes the mechanical and conformational properties of dsDNA. Thermal melting experiments reveal that DAP substitution raises melting temperatures without diminishing sequence-dependent effects. Using a combination of atomic force microscopy (AFM), magnetic tweezer (MT) nanomechanical assays, and circular dichroism spectroscopy, we demonstrate that DAP substitution increases the flexural rigidity of dsDNA yet also facilitates conformational shifts, which manifest as changes in molecule length. DAP substitution increases both the static and dynamic persistence length of DNA (measured by AFM and MT, respectively). In the static case (AFM), in which tension is not applied to the molecule, the contour length of DAP-DNA appears shorter than wild-type (WT)-DNA; under tension (MT), they have similar dynamic contour lengths. At tensions above 60 pN, WT-DNA undergoes characteristic overstretching because of strand separation (tension-induced melting) and spontaneous adoption of a conformation termed S-DNA. Cyclic overstretching and relaxation of WT-DNA at near-zero loading rates typically yields hysteresis, indicative of tension-induced melting; conversely, cyclic stretching of DAP-DNA showed little or no hysteresis, consistent with the adoption of the S-form, similar to what has been reported for GC-rich sequences. However, DAP-DNA overstretching is distinct from GC-rich overstretching in that it happens at a significantly lower tension. In physiological salt conditions, evenly mixed AT/GC DNA typically overstretches around 60 pN. GC-rich sequences overstretch at similar if not slightly higher tensions. Here, we show that DAP-DNA overstretches at 52 pN. In summary, DAP substitution decreases the overall stability of the B-form double helix, biasing toward non-B-form DNA helix conformations at zero tension and facilitating the B-to-S transition at high tension.
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Affiliation(s)
- Matteo Cristofalo
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - Daniel Kovari
- Department of Physics, Emory University, Atlanta, Georgia
| | - Roberta Corti
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - Domenico Salerno
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy.
| | - Valeria Cassina
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - David Dunlap
- Department of Physics, Emory University, Atlanta, Georgia.
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Mahmoud M, Laufer S, Deigner HP. An aptamer based thermofluorimetric assay for ethanolamine. Biochimie 2019; 158:233-237. [PMID: 30685448 DOI: 10.1016/j.biochi.2019.01.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/21/2019] [Indexed: 12/26/2022]
Abstract
There is a great need for fast, simple and precise diagnostic assays capable of direct quantification of biomarkers in complex biological matrices. Yet, the commonly used techniques such as ELISA/Immunoassays are tedious and involve various steps e.g. blocking, washing and signal development. Moreover, most of these assays have very limited ability of detecting small molecules and have hardly any multiplexing capabilities. The gold standard and alternative, mass-spectrometry, however, depends upon expensive hardware and is incompatible with point of care (POC) diagnostics. As opposed to POC assays for proteins or larger targets where variable formats are readily available. Here, we present a simple, versatile and fast one-step assay for detecting a small molecule, ethanolamine as example. The assay makes use of commonly available qPCR machines to detect target-concentration dependent shifts in the melting temperatures of aptamer beacons. The method allows detection of ethanolamine in the low nM range without requiring tedious elaboration of assay conditions as required for molecular beacons at room temperature. If generalizable, it may change the situation of small molecule assays significantly.
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Affiliation(s)
- Mostafa Mahmoud
- Furtwangen University, Institute of Precision Medicine, Jakob-Kienzle-Straße 17, 78054, Villingen-Schwenningen, Germany; Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Stefan Laufer
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Hans-Peter Deigner
- Furtwangen University, Institute of Precision Medicine, Jakob-Kienzle-Straße 17, 78054, Villingen-Schwenningen, Germany; Fraunhofer Institute IZI, Leipzig, EXIM Department, Schillingallee 68, D-18057, Rostock, Germany.
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66
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Zhang Y, Xin CX, Zhang LT, Deng YL, Wang X, Chen XY, Wang ZQ. Detection of Fungi from Low-Biomass Spacecraft Assembly Clean Room Aerosols. ASTROBIOLOGY 2018; 18:1585-1593. [PMID: 30383981 DOI: 10.1089/ast.2017.1803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Highly sensitive and rapid detection of airborne fungi in space stations is essential to ensure disease prevention and equipment safety. In this study, quantitative loop-mediated isothermal amplification (qLAMP) was used to detect fungi in the aerosol of the low-biomass environment of China's space station assembly clean room (CSSAC). A qLAMP primer set for detecting a wide range of aerosol fungi was developed by aligning 34 sequences of isolated fungal species and 17 space station aerosol-related fungal species. Optimization of sample pretreatment conditions of the LAMP reaction increased the quantitative results by 1.29-1.96 times. The results showed that our qLAMP system had high amplification specificity for fungi, with a quantifiable detection limit as low as 102. The detected fungal biomass in the aerosol of CSSAC was 9.59 × 102-2.20 × 105 28S rRNA gene copy numbers/m3. This qLAMP assay may therefore replace traditional colony-forming unit and quantitative PCR methods as an effective strategy for detecting fungi in space stations.
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Affiliation(s)
- Ying Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Cong-Xin Xin
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Lan-Tao Zhang
- Institute of Manned Space System Engineering, China Academy of Space Technology, Beijing, China
| | - Yu-Lin Deng
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Xiang Wang
- Institute of Manned Space System Engineering, China Academy of Space Technology, Beijing, China
| | - Xiang-Yu Chen
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhao-Qian Wang
- School of Life Science, Beijing Institute of Technology, Beijing, China
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67
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Spangler MA, Huettmann F, Herriott IC, López JA. Development, validation, and evaluation of an assay for the detection of wood frogs (Rana sylvatica) in environmental DNA. CONSERV GENET RESOUR 2018. [DOI: 10.1007/s12686-017-0881-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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68
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Yuan H, Chao Y, Li S, Tang MYH, Huang Y, Che Y, Wong AST, Zhang T, Shum HC. Picoinjection-Enabled Multitarget Loop-Mediated Isothermal Amplification for Detection of Foodborne Pathogens. Anal Chem 2018; 90:13173-13177. [PMID: 30354065 DOI: 10.1021/acs.analchem.8b03673] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In this study, we develop a method to detect multiple DNAs of foodborne pathogens by encapsulating emulsion droplets for loop-mediated isothermal amplification (LAMP). In contrast to the traditional bulk-phase LAMP, which involves a labor-intensive mixing process, with our method, different primers are automatically mixed with DNA samples and LAMP buffers after picoinjection. By directly observing and analyzing the fluorescence intensity of the resultant droplets, one can detect DNA from different pathogens, with a detection limit 500 times lower than that obtained by bulk-phase LAMP. We further demonstrate the ability to quantify bacteria concentration by detecting bacterial DNA in practical samples, showing great potential in monitoring water resources and their contamination by pathogenic bacteria.
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Affiliation(s)
- Hao Yuan
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518057 , China.,Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
| | - Youchuang Chao
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518057 , China.,Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
| | - ShanShan Li
- School of Biological Sciences , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
| | - Matthew Y H Tang
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518057 , China.,Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
| | - Yue Huang
- Centre for Environmental Engineering Research, Department of Civil Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
| | - You Che
- Centre for Environmental Engineering Research, Department of Civil Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
| | - Alice S T Wong
- School of Biological Sciences , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
| | - Tong Zhang
- Centre for Environmental Engineering Research, Department of Civil Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
| | - Ho Cheung Shum
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518057 , China.,Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China
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69
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Ghoniem SM, El Deeb AH, Aggour MG, Hussein HA. Development and evaluation of a multiplex reverse-transcription real-time PCR assay for detection of equine respiratory disease viruses. J Vet Diagn Invest 2018; 30:924-928. [PMID: 30239276 DOI: 10.1177/1040638718799388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We developed a multiplex reverse-transcription real-time PCR (RT-rtPCR) assay for the simultaneous detection of the main equine respiratory viruses: equid alphaherpesviruses 1 and 4 (EHV-1, -4) and equine influenza virus (EIV; species Influenza A virus). The primers and probes amplified only the targeted viruses, and there were no inter-assay cross-amplifications or nonspecific interactions. The multiplex assay efficiencies were 92.5%, 97%, and 90% for EHV-1, EHV-4, and EIV, respectively. The R2 values of the monoplex and multiplex assays were ⩾0.990, and the slopes were -3.37 to -3.59. The performance of the assay was evaluated by analyzing 152 samples from clinically infected horses. EHV-1 DNA was detected in 12 samples, EHV-4 DNA in 9 samples, and both EHV-1 and EHV-4 in 4 samples. The accuracy of the assay was confirmed by comparing these results using commercial rtPCR and RT-rtPCR kits. Our multiplex RT-rtPCR was a sensitive, specific, accurate, and cost-effective method for the detection of the target viruses whether they occur alone or as part of coinfections.
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Affiliation(s)
- Shimaa M Ghoniem
- Departments of Virology (Ghoniem), Animal Health Research Institute, Dokki, Egypt.,Biotechnology (Aggour), Animal Health Research Institute, Dokki, Egypt.,Department of Virology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt (El Deeb, Hussein)
| | - Ayman H El Deeb
- Departments of Virology (Ghoniem), Animal Health Research Institute, Dokki, Egypt.,Biotechnology (Aggour), Animal Health Research Institute, Dokki, Egypt.,Department of Virology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt (El Deeb, Hussein)
| | - Mohammed G Aggour
- Departments of Virology (Ghoniem), Animal Health Research Institute, Dokki, Egypt.,Biotechnology (Aggour), Animal Health Research Institute, Dokki, Egypt.,Department of Virology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt (El Deeb, Hussein)
| | - Hussein A Hussein
- Departments of Virology (Ghoniem), Animal Health Research Institute, Dokki, Egypt.,Biotechnology (Aggour), Animal Health Research Institute, Dokki, Egypt.,Department of Virology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt (El Deeb, Hussein)
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70
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Zhao L, Wang J, Li GX, Qiu FZ, Chen C, Zhao MC, Wang L, Duan SX, Feng ZS, Ma XJ. A highly sensitive 1-tube nested real-time RT-PCR assay using LNA-modified primers for detection of respiratory syncytial virus. Diagn Microbiol Infect Dis 2018; 93:101-106. [PMID: 30266400 PMCID: PMC7126397 DOI: 10.1016/j.diagmicrobio.2018.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/23/2018] [Accepted: 09/03/2018] [Indexed: 12/31/2022]
Abstract
Respiratory syncytial virus (RSV) causes serious respiratory tract infection worldwide. The relatively low RSV load makes it difficult to detect in frail, elderly, and severely immune-compromised patients. In the present study, we developed a locked nucleic acid–-based 1-tube nested real-time RT-PCR (OTNRT-PCR) assay with the advantages of extremely high sensitivity, facile operability, and less likelihood of cross-contamination. The sensitivity, specificity, and clinical performance of the OTNRT-PCR assay were compared in parallel with a conventional TaqMan probe-based real-time PCR (qRT-PCR) assay and a traditional 2-step nested RT-PCR assay. The limit of detection of the OTNRT-PCR assay was 1.02 × 10−1 TCID50/mL, equivalent to the traditional 2-step nested RT-PCR assay and 25-fold lower than the qRT-PCR assay. Of 616 nasopharyngeal aspirates tested, 143 RSV-negative samples by qRT-PCR were confirmed as positive by sequencing the OTNRT-PCR products. We therefore conclude that OTNRT-PCR is more sensitive than qRT-PCR for detection of RSV in clinical samples.
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Affiliation(s)
- Li Zhao
- Hebei Medical University, Shijiazhuang, 050031, Hebei, China; Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
| | - Ji Wang
- Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
| | - Gui-Xia Li
- Children's Hospital of Hebei Province, Shijiazhuang, 050031, Hebei, China.
| | - Fang-Zhou Qiu
- Hebei Medical University, Shijiazhuang, 050031, Hebei, China; Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
| | - Chen Chen
- Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
| | - Meng-Chuan Zhao
- Children's Hospital of Hebei Province, Shijiazhuang, 050031, Hebei, China.
| | - Le Wang
- Children's Hospital of Hebei Province, Shijiazhuang, 050031, Hebei, China.
| | - Su-Xia Duan
- Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China; Children's Hospital of Hebei Province, Shijiazhuang, 050031, Hebei, China.
| | - Zhi-Shan Feng
- Children's Hospital of Hebei Province, Shijiazhuang, 050031, Hebei, China.
| | - Xue-Jun Ma
- Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
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71
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Fernández Asensio A, Iglesias T, Cotarelo A, Espina M, Blanco-González E, Sierra L, Montes-Bayón M. Multiplex polymerase chain reaction in combination with gel electrophoresis-inductively coupled plasma mass spectrometry: A powerful tool for the determination of gene copy number variations and gene expression changes. Anal Chim Acta 2018; 1023:64-73. [DOI: 10.1016/j.aca.2018.03.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 03/09/2018] [Accepted: 03/10/2018] [Indexed: 12/14/2022]
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72
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Sundarrajan S, Parambath S, Suresh S, Rao S, Padmanabhan S. Novel properties of recombinant Sso7d-Taq DNA polymerase purified using aqueous two-phase extraction: Utilities of the enzyme in viral diagnosis. BIOTECHNOLOGY REPORTS 2018; 19:e00270. [PMID: 30197870 PMCID: PMC6127375 DOI: 10.1016/j.btre.2018.e00270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 06/18/2018] [Accepted: 06/19/2018] [Indexed: 11/03/2022]
Abstract
Sso7d-Taq fusion protein purified using a single step of aqueous Two-Phase Extraction (ATPE) is >95% pure and is active. The S-Taq protein has higher thermostability and detergent tolerance over regular Taq polymerase and can be used for PCR's from direct whole blood. The PCR efficiency rate of S-Taq is higher than Taq polymerase and can be used to detect DNA viruses in a clinical setting efficiently. S-Taq can tolerate higher concentrations of magnesium ions and can be used for in-situ PCR’s. S-Taq can be used to carry out PCR’s of bacterial recombinants directly from the overnight culture since it is resistant to inhibition to Luria Bertani broth. This unique property of S-Taq will enable researchers to screen recombinants without the need to isolate the plasmid DNA of recombinants. This would be a huge cost savings for companies engaged in molecular biology research involving PCR’s.
Using Sso7d from Sulfolobus solfataricus as the DNA binding protein fused to Taq DNA polymerase at its amino terminus, we report the hyper-expression and a novel purification methodology of Sso7d-Taq polymerase (S-Taq) using aqueous two-phase extraction system followed by Ni-affinity chromatography. The utility of such a fusion enzyme in carrying out PCR of human genes from whole blood directly and in detecting hepatitis B virus from clinical samples is demonstrated in this article. We present data on the enhanced thermo-stability of S-Taq DNA polymerase over Taq DNA polymerase and also provide evidence of its higher stability with detergents in comparison to Taq polymerase. The purified S-Taq protein showed acceptable limits of host genomic DNA levels without the use of DNases and other DNA precipitating agents and shows promising potential for use in PCR based diagnostics, in-situ PCR’s and forensic science.
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73
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Singpanomchai N, Akeda Y, Tomono K, Tamaru A, Santanirand P, Ratthawongjirakul P. Naked eye detection of the Mycobacterium tuberculosis complex by recombinase polymerase amplification-SYBR green I assays. J Clin Lab Anal 2018; 33:e22655. [PMID: 30129085 DOI: 10.1002/jcla.22655] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/19/2018] [Accepted: 07/28/2018] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Rapid diagnosis of Mycobacterium tuberculosis (Mtb) is key to controlling the spread of tuberculosis, which is a global health concern. In this study, isothermal recombinase polymerase amplification (RPA) was developed to detect specific targets of Mtb, IS6110 and IS1081. Additionally, SYBR Green I was used for endpoint detection of the RPA products by the naked eye. METHOD A total of 146 genomic Mtb DNA samples and 24 genomic nontuberculous mycobacteria (NTM) DNA samples were amplified at IS6110 and IS1081 by RPA. After a complete amplification, the RPA amplicons were examined by agarose gel electrophoresis (RPA-AGE) and SYBR Green I (RPA-S) assays. The performance of the RPA assays was evaluated by comparing them to a conventional PCR. RESULTS The RPA assay demonstrated to have a good capability to differentiate Mtb from NTM with a very short turnaround time at a constant temperature. Compared to conventional PCR, the sensitivities and specificities of RPA-AGE for IS6110 and IS1081 were 100%. The specificity of RPA-S was 100% for both targets; however, its sensitivities for IS6110 and IS1081 were 97.95% and 99.32%, respectively. The limits of detection of IS6110 RPA-AGE and RPA-S were 0.05 and 0.5 ng, respectively, while the LODs of IS1081 RPA-AGE and RPA-S were 0.00005 and 0.05 ng, respectively. Both RPA assays showed a satisfying diagnostic specificity, with no cross-reaction with other bacteria. CONCLUSION A rapid, sensitive, naked eye RPA assay can be integrated into point-of-care diagnosis for Mtb detection, especially in remote areas where laboratory instrument resources are limited.
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Affiliation(s)
- Nuntita Singpanomchai
- Program of Molecular sciences in Medical Microbiology and Immunology, Department of Transfusion Medicine and Clinical Microbiology, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Yukihiro Akeda
- Division of Infection Control and Prevention, Osaka University Hospital, Osaka University, Osaka, Japan
| | - Kazunori Tomono
- Division of Infection Control and Prevention, Osaka University Hospital, Osaka University, Osaka, Japan
| | - Aki Tamaru
- Department of Bacteriology, Osaka Prefectural Institute of Public Health, Osaka, Japan
| | - Pitak Santanirand
- Microbiology Unit, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Panan Ratthawongjirakul
- Research Group of Innovative Diagnosis of Antimicrobial Resistance, Department of Transfusion Medicine and Clinical Microbiology, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand
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74
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Ahmed FE, Gouda MM, Hussein LA, Ahmed NC, Vos PW, Mohammad MA. Role of Melt Curve Analysis in Interpretation of Nutrigenomics' MicroRNA Expression Data. Cancer Genomics Proteomics 2018; 14:469-481. [PMID: 29109097 DOI: 10.21873/cgp.20057] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 10/05/2017] [Accepted: 10/26/2017] [Indexed: 12/23/2022] Open
Abstract
This article illustrates the importance of melt curve analysis (MCA) in interpretation of mild nutrogenomic micro(mi)RNA expression data, by measuring the magnitude of the expression of key miRNA molecules in stool of healthy human adults as molecular markers, following the intake of Pomegranate juice (PGJ), functional fermented sobya (FS), rich in potential probiotic lactobacilli, or their combination. Total small RNA was isolated from stool of 25 volunteers before and following a three-week dietary intervention trial. Expression of 88 miRNA genes was evaluated using Qiagen's 96 well plate RT2 miRNA qPCR arrays. Employing parallel coordinates plots, there was no observed significant separation for the gene expression (Cq) values, using Roche 480® PCR LightCycler instrument used in this study, and none of the miRNAs showed significant statistical expression after controlling for the false discovery rate. On the other hand, melting temperature profiles produced during PCR amplification run, found seven significant genes (miR-184, miR-203, miR-373, miR-124, miR-96, miR-373 and miR-301a), which separated candidate miRNAs that could function as novel molecular markers of relevance to oxidative stress and immunoglobulin function, for the intake of polyphenol (PP)-rich, functional fermented foods rich in lactobacilli (FS), or their combination. We elaborate on these data, and present a detailed review on use of melt curves for analyzing nutigenomic miRNA expression data, which initially appear to show no significant expressions, but are actually more subtle than this simplistic view, necessitating the understanding of the role of MCA for a comprehensive understanding of what the collective expression and MCA data collectively imply.
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Affiliation(s)
- Farid E Ahmed
- GEM Tox Labs, Institute for Research in Biotechnology, Greenville, NC, U.S.A.
| | - Mostafa M Gouda
- Department of Nutrition & Food Science, National Research Centre, Dokki, Cairo, Egypt
| | - Laila A Hussein
- Department of Nutrition & Food Science, National Research Centre, Dokki, Cairo, Egypt
| | - Nancy C Ahmed
- GEM Tox Labs, Institute for Research in Biotechnology, Greenville, NC, U.S.A
| | - Paul W Vos
- Department of Biostatistics, College of Allied Health Sciences, East Carolina University, Greenville, NC, U.S.A
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75
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Aloisio M, Morelli M, Elicio V, Saldarelli P, Ura B, Bortot B, Severini G, Minafra A. Detection of four regulated grapevine viruses in a qualitative, single tube real-time PCR with melting curve analysis. J Virol Methods 2018; 257:42-47. [DOI: 10.1016/j.jviromet.2018.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 04/06/2018] [Accepted: 04/08/2018] [Indexed: 10/17/2022]
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76
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Ma Q, Gao Z. A simple and ultrasensitive fluorescence assay for single-nucleotide polymorphism. Anal Bioanal Chem 2018; 410:3093-3100. [PMID: 29644378 DOI: 10.1007/s00216-018-0874-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/11/2017] [Accepted: 01/12/2018] [Indexed: 11/30/2022]
Abstract
In this report, a simple, label-free and highly efficient nucleic acid amplification technique is developed for ultrasensitive detection of single-nucleotide polymorphism (SNP). Briefly, a designed padlock probe is first circularized by a DNA ligase when it perfectly complements to a mutant gene. Then, the mutant gene functions as a primer to initiate branched rolling circle amplification reaction (BRCA), generating a large number of branched DNA strands and a lot of pyrophosphate molecules which is equivalent to the number of nucleotides consumed. With the addition of a terpyridine-Zn(II) complex, pyrophosphate molecules can be sensitively detected owing to the formation of a fluorescent terpyridine-Zn(II)-pyrophosphate complex. The fluorescence intensity is directly associated with the content of the mutant gene in a sample solution. On the other hand, the circulation of the padlock probe is prohibited when it hybridizes with the wild-type gene. In this assay, the accumulative nature of the BRCA process produces a detection limit of 0.1 pM and an excellent selectivity factor of 1000 toward SNP. As little as 0.1% mutant in the wild-type gene can be successfully detected. The simple procedure, high sensitivity, and high selectivity of this assay offer a potentially viable alternative for routine SNP analysis. Graphical abstract A simple and label-free fluorescence assay for SNP detection by coupling BRCA with selective fluorescence detection of pyrophosphate using the terpyridine-Zn(II) complex.
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Affiliation(s)
- Qian Ma
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, Singapore, 117543, Singapore
| | - Zhiqiang Gao
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, Singapore, 117543, Singapore.
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77
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Park CK, Hong SK, Kim YH, Cho H. Nucleic Acid-Binding Fluorochromes and Nanoparticles: Structural Aspects of Binding Affinity and Fluorescence Intensity. Macromol Res 2018. [DOI: 10.1007/s13233-018-6053-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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78
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Dalsecco LS, Palhares RM, Oliveira PC, Teixeira LV, Drummond MG, de Oliveira DAA. A Fast and Reliable Real-Time PCR Method for Detection of Ten Animal Species in Meat Products. J Food Sci 2018; 83:258-265. [PMID: 29377112 DOI: 10.1111/1750-3841.14001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 10/19/2017] [Accepted: 11/02/2017] [Indexed: 11/29/2022]
Abstract
Species substitution in meat products is a common problem reported worldwide. This type of food fraud is, typically, an intentional act for economic gain, using sources of low-priced meats in high-value meat products. Consequences include economic, health, and religious concerns. Highly sensitive and efficient techniques are thus required to detect meat species. This paper describes a method based on real-time PCR to detect 10 animal species (Bos taurus, Sus scrofa, Ovis aries, Capra hircus, Gallus gallus, Meleagris gallopavo, Bubalus bubalis, Equus caballus, Felis catus, and Canis familiaris) in meat product. The method combines species-specific and universal (used here as internal positive control) primers, and applies melt curve analysis for amplicon checking. Method accuracy was evaluated on 46 experimental meat mixtures and all species were correctly identified in all cases, at 1% test sensitivity. Analysis of 14 commercial meat products revealed that 6 of 14 samples had nondeclared bovine and/or chicken material. We performed an interlaboratory comparison using the reference meat mixtures and commercial samples, achieving 100% of reproducibility. The developed test proved to be effective and reliable for routine analysis of meat products. PRACTICAL APPLICATION This paper describes a fast and reliable method for species detection in meat products based on real-time PCR. It can be applied for analysis of in natura or processed meat. The method proposed here can play an important role in controlling the origin of meat products, ensuring their quality and safety for the entire food industry-producers to consumers.
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Affiliation(s)
- Lissandra Sousa Dalsecco
- Laboratório de Genética Animal (LGEV), Escola de Veterinária, Univ. Federal de Minas Gerais, Avenida Antônio Carlos 6627, Belo Horizonte, Minas Gerais, Brazil
| | - Rafael Melo Palhares
- Myleus Biotechnology, Avenida José Cândido da Silveira 2100, Belo Horizonte, Minas Gerais, Brazil
| | | | - Lilian Viana Teixeira
- Laboratório de Genética Animal (LGEV), Escola de Veterinária, Univ. Federal de Minas Gerais, Avenida Antônio Carlos 6627, Belo Horizonte, Minas Gerais, Brazil
| | | | - Denise Aparecida Andrade de Oliveira
- Laboratório de Genética Animal (LGEV), Escola de Veterinária, Univ. Federal de Minas Gerais, Avenida Antônio Carlos 6627, Belo Horizonte, Minas Gerais, Brazil
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Sensitive and specific detection of microRNAs based on two-stage amplification reaction using molecular beacons as turn-on probes. Talanta 2017; 179:685-692. [PMID: 29310294 DOI: 10.1016/j.talanta.2017.11.068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/16/2017] [Accepted: 11/28/2017] [Indexed: 12/13/2022]
Abstract
In this study, a rapid, sensitive, and specific assay for detecting miRNAs was developed based on a two-stage amplification reaction (TSAR) using molecular beacons (MBs) as turn-on probes. In the TSAR, different miRNAs can be converted to the same reporter oligonucleotides (Y), which can hybridize with the same MB. Therefore, in combination with specific templates, this method can be applied to multiplex miRNA detection by simply using the same MB. The loop region of the MB was screened by computer simulation methods. In particular, to improve the specificity of the MB in real sample analysis, the maximum similarity of the MB loop region to the human genome and human transcriptome is less than 70%. Two MBs were designed in this study. MB I, with nine flanking base pairs in its stem region, was used for real-time monitoring of the production of Y during the TSAR. MB II, with five flanking base pairs in its stem region, was used to detect the production of Y at the end of the TSAR. This assay exhibited high sensitivity with a limit of detection of 2.0 × 10-16M and 6.7 × 10-16M using MB I and MB II as turn-on probes, respectively. In addition, this assay can clearly discriminate single base differences in miRNA sequences, and the TSAR can be completed under isothermal conditions. Accordingly, the isothermal reaction conditions and simple fluorescence measurement can greatly contribute to the development of a fast point-of-care detection system.
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80
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Redhead M, Satchell R, McCarthy C, Pollack S, Unitt J. Thermal Shift as an Entropy-Driven Effect. Biochemistry 2017; 56:6187-6199. [DOI: 10.1021/acs.biochem.7b00860] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Martin Redhead
- Bioscience
Department, Sygnature Discovery, Nottingham NG1 1GF, U.K
| | - Rupert Satchell
- Bioscience
Department, Sygnature Discovery, Nottingham NG1 1GF, U.K
| | - Ciara McCarthy
- Bioscience
Department, Sygnature Discovery, Nottingham NG1 1GF, U.K
| | - Scott Pollack
- Bioscience
Department, Sygnature Discovery, Nottingham NG1 1GF, U.K
| | - John Unitt
- Bioscience
Department, Sygnature Discovery, Nottingham NG1 1GF, U.K
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81
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Shah K, Bentley E, Tyler A, Richards KSR, Wright E, Easterbrook L, Lee D, Cleaver C, Usher L, Burton JE, Pitman JK, Bruce CB, Edge D, Lee M, Nazareth N, Norwood DA, Moschos SA. Field-deployable, quantitative, rapid identification of active Ebola virus infection in unprocessed blood. Chem Sci 2017; 8:7780-7797. [PMID: 29163915 PMCID: PMC5694917 DOI: 10.1039/c7sc03281a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/20/2017] [Indexed: 01/01/2023] Open
Abstract
The West African Ebola virus outbreak underlined the importance of delivering mass diagnostic capability outside the clinical or primary care setting in effectively containing public health emergencies caused by infectious disease. Yet, to date, there is no solution for reliably deploying at the point of need the gold standard diagnostic method, real time quantitative reverse transcription polymerase chain reaction (RT-qPCR), in a laboratory infrastructure-free manner. In this proof of principle work, we demonstrate direct performance of RT-qPCR on fresh blood using far-red fluorophores to resolve fluorogenic signal inhibition and controlled, rapid freeze/thawing to achieve viral genome extraction in a single reaction chamber assay. The resulting process is entirely free of manual or automated sample pre-processing, requires no microfluidics or magnetic/mechanical sample handling and thus utilizes low cost consumables. This enables a fast, laboratory infrastructure-free, minimal risk and simple standard operating procedure suited to frontline, field use. Developing this novel approach on recombinant bacteriophage and recombinant human immunodeficiency virus (HIV; Lentivirus), we demonstrate clinical utility in symptomatic EBOV patient screening using live, infectious Filoviruses and surrogate patient samples. Moreover, we evidence assay co-linearity independent of viral particle structure that may enable viral load quantification through pre-calibration, with no loss of specificity across an 8 log-linear maximum dynamic range. The resulting quantitative rapid identification (QuRapID) molecular diagnostic platform, openly accessible for assay development, meets the requirements of resource-limited countries and provides a fast response solution for mass public health screening against emerging biosecurity threats.
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Affiliation(s)
- Kavit Shah
- Westminster Genomic Services , Department of Biomedical Sciences , Faculty of Science and Technology , University of Westminster , 115 New Cavendish Str , London W1W 6UW , UK
- BGResearch Ltd. , 6 The Business Centre, Harvard Way, Harvard Industrial Estate , Kimbolton , Huntingdon PE28 0NJ , UK
| | - Emma Bentley
- Department of Biomedical Sciences , Faculty of Science and Technology , University of Westminster , 115 New Cavendish Str , London W1W 6UW , UK
| | - Adam Tyler
- BioGene Ltd. , 8 The Business Centre, Harvard Way, Harvard Industrial Estate , Kimbolton , Huntingdon PE28 0NJ , UK
| | - Kevin S R Richards
- Public Health England , National Infection Service , High Containment Microbiology Department , Porton Down , Salisbury , Wiltshire SP4 0JG , UK
| | - Edward Wright
- Department of Biomedical Sciences , Faculty of Science and Technology , University of Westminster , 115 New Cavendish Str , London W1W 6UW , UK
| | - Linda Easterbrook
- Public Health England , National Infection Service , High Containment Microbiology Department , Porton Down , Salisbury , Wiltshire SP4 0JG , UK
| | - Diane Lee
- Fluorogenics LIMITED , Building 227, Tetricus Science Park, Dstl Porton Down , Salisbury , Wiltshire SP4 0JQ , UK
| | - Claire Cleaver
- Fluorogenics LIMITED , Building 227, Tetricus Science Park, Dstl Porton Down , Salisbury , Wiltshire SP4 0JQ , UK
| | - Louise Usher
- Westminster Genomic Services , Department of Biomedical Sciences , Faculty of Science and Technology , University of Westminster , 115 New Cavendish Str , London W1W 6UW , UK
| | - Jane E Burton
- Public Health England , National Infection Service , High Containment Microbiology Department , Porton Down , Salisbury , Wiltshire SP4 0JG , UK
| | - James K Pitman
- Public Health England , National Infection Service , High Containment Microbiology Department , Porton Down , Salisbury , Wiltshire SP4 0JG , UK
| | - Christine B Bruce
- Public Health England , National Infection Service , High Containment Microbiology Department , Porton Down , Salisbury , Wiltshire SP4 0JG , UK
| | - David Edge
- BioGene Ltd. , 8 The Business Centre, Harvard Way, Harvard Industrial Estate , Kimbolton , Huntingdon PE28 0NJ , UK
| | - Martin Lee
- Fluorogenics LIMITED , Building 227, Tetricus Science Park, Dstl Porton Down , Salisbury , Wiltshire SP4 0JQ , UK
| | - Nelson Nazareth
- BioGene Ltd. , 8 The Business Centre, Harvard Way, Harvard Industrial Estate , Kimbolton , Huntingdon PE28 0NJ , UK
| | - David A Norwood
- Diagnostic Systems Division and Virology Division , United States Army Medical Research Institute of Infectious Diseases , Fort Detrick , MD 21701-5011 , USA
| | - Sterghios A Moschos
- Westminster Genomic Services , Department of Biomedical Sciences , Faculty of Science and Technology , University of Westminster , 115 New Cavendish Str , London W1W 6UW , UK
- Department of Biomedical Sciences , Faculty of Science and Technology , University of Westminster , 115 New Cavendish Str , London W1W 6UW , UK
- Department of Applied Sciences , Faculty of Health and Life Sciences , Northumbria University , C4.03 Ellison Building, Ellison Place , Newcastle Upon Tyne , Tyne and Wear NE1 8ST , UK . ; Tel: +44(0) 191 215 6623
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82
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High-resolution melting analysis for prenatal diagnosis of beta-thalassemia in northern Thailand. Int J Hematol 2017; 106:757-764. [PMID: 28791595 DOI: 10.1007/s12185-017-2306-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 10/19/2022]
Abstract
High-resolution melting (HRM) analysis is a rapid mutation analysis which assesses the pattern of reduction of fluorescence signal after subjecting the amplified PCR product with saturated fluorescence dye to an increasing temperature. We used HRM analysis for prenatal diagnosis of beta-thalassemia disease in northern Thailand. Five PCR-HRM protocols were used to detect point mutations in five different segments of the beta-globin gene, and one protocol to detect the 3.4 kb beta-globin deletion. We sought to characterize the mutations in carriers and to enable prenatal diagnosis in 126 couples at risk of having a fetus with beta-thalassemia disease. The protocols identified 18 common mutations causing beta-thalassemia, including the rare codon 132 (A-T) mutation. Each mutation showed a specific HRM pattern and all results were in concordance with those from direct DNA sequencing or gap-PCR methods. In cases of beta-thalassemia disease resulting from homozygosity for a mutation or compound heterozygosity for two mutations on the same amplified segment, the HRM patterns were different to those of a single mutation and were specific for each combination. HRM analysis is a simple and useful method for mutation identification in beta-thalassemia carriers and prenatal diagnosis of beta-thalassemia in northern Thailand.
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83
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Wang W, Zijlstra RT, Gänzle MG. Identification and quantification of virulence factors of enterotoxigenic Escherichia coli by high-resolution melting curve quantitative PCR. BMC Microbiol 2017; 17:114. [PMID: 28506262 PMCID: PMC5433089 DOI: 10.1186/s12866-017-1023-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 05/05/2017] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Diagnosis of enterotoxigenic E. coli (ETEC) associated diarrhea is complicated by the diversity of E.coli virulence factors. This study developed a multiplex quantitative PCR assay based on high-resolution melting curves analysis (HRM-qPCR) to identify and quantify genes encoding five ETEC fimbriae related to diarrhea in swine, i.e. K99, F41, F18, F6 and K88. METHODS Five fimbriae expressed by ETEC were amplified in multiple HRM-qPCR reactions to allow simultaneous identification and quantification of five target genes. The assay was calibrated to allow quantification of the most abundant target gene, and validated by analysis of 30 samples obtained from piglets with diarrhea and healthy controls, and comparison to standard qPCR detection. RESULTS The five amplicons with melting temperatures (Tm) ranging from 74.7 ± 0.06 to 80.5 ± 0.15 °C were well-separated by HRM-qPCR. The area of amplicons under the melting peak correlated linearly to the proportion of the template in the calibration mixture if the proportion exceeded 4.8% (K88) or <1% (all other amplicons). The suitability of the method was evaluated using 30 samples from weaned pigs aged 6-7 weeks; 14 of these animals suffered from diarrhea in consequence of poor sanitary conditions. Genes encoding fimbriae and enterotoxins were quantified by HRM-qPCR and/or qPCR. The multiplex HRM-qPCR allowed accurate analysis when the total gene copy number of targets was more than 1 × 105 / g wet feces and the HRM curves were able to simultaneously distinguish fimbriae genes in the fecal samples. The relative quantification of the most abundant F18 based on melting peak area was highly correlated (P < 0.001; r2 = 0.956) with that of individual qPCR result but the correlation for less abundant fimbriae was much lower. CONCLUSIONS The multiplex HRM assay identifies ETEC virulence factors specifically and efficiently. It correctly indicated the predominant fimbriae type and additionally provides information of presence/ absence of other fimbriae types and it could find broad applications for pathogen diagnosis.
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Affiliation(s)
- Weilan Wang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For Centre, Edmonton, AB, T6G 2P5, Canada
| | - Ruurd T Zijlstra
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For Centre, Edmonton, AB, T6G 2P5, Canada
| | - Michael G Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For Centre, Edmonton, AB, T6G 2P5, Canada.
- College of Bioengineering and Food Science, Hubei University of Technology, Wuhan, Hubei, People's Republic of China.
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84
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Lee JH, Cheglakov Z, Yi J, Cronin TM, Gibson KJ, Tian B, Weizmann Y. Plasmonic Photothermal Gold Bipyramid Nanoreactors for Ultrafast Real-Time Bioassays. J Am Chem Soc 2017; 139:8054-8057. [DOI: 10.1021/jacs.7b01779] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Jung-Hoon Lee
- Department
of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Zoya Cheglakov
- Department
of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Jaeseok Yi
- The
James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Timothy M. Cronin
- Department
of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Kyle J. Gibson
- Department
of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Bozhi Tian
- Department
of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
- The
James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- The
Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Yossi Weizmann
- Department
of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
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85
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Yaren O, Alto BW, Gangodkar PV, Ranade SR, Patil KN, Bradley KM, Yang Z, Phadke N, Benner SA. Point of sampling detection of Zika virus within a multiplexed kit capable of detecting dengue and chikungunya. BMC Infect Dis 2017; 17:293. [PMID: 28427352 PMCID: PMC5399334 DOI: 10.1186/s12879-017-2382-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 04/04/2017] [Indexed: 04/25/2024] Open
Abstract
Background Zika, dengue, and chikungunya are three mosquito-borne viruses having overlapping transmission vectors. They cause diseases having similar symptoms in human patients, but requiring different immediate management steps. Therefore, rapid (< one hour) discrimination of these three viruses in patient samples and trapped mosquitoes is needed. The need for speed precludes any assay that requires complex up-front sample preparation, such as extraction of nucleic acids from the sample. Also precluded in robust point-of-sampling assays is downstream release of the amplicon mixture, as this risks contamination of future samples that will give false positives. Methods Procedures are reported that directly test urine and plasma (for patient diagnostics) or crushed mosquito carcasses (for environmental surveillance). Carcasses are captured on paper samples carrying quaternary ammonium groups (Q-paper), which may be directly introduced into the assay. To avoid the time and instrumentation requirements of PCR, the procedure uses loop-mediated isothermal amplification (LAMP). Downstream detection is done in sealed tubes, with dTTP-dUTP mixtures in the LAMP with a thermolabile uracil DNA glycosylase (UDG); this offers a second mechanism to prevent forward contamination. Reverse transcription LAMP (RT-LAMP) reagents are distributed dry without requiring a continuous chain of refrigeration. Results The tests detect viral RNA in unprocessed urine and other biological samples, distinguishing Zika, chikungunya, and dengue in urine and in mosquitoes infected with live Zika and chikungunya viruses. The limits of detection (LODs) are ~0.71 pfu equivalent viral RNAs for Zika, ~1.22 pfu equivalent viral RNAs for dengue, and ~38 copies of chikungunya viral RNA. A handheld, battery-powered device with an orange filter was constructed to visualize the output. Preliminary data showed that this architecture, working with pre-prepared tubes holding lyophilized reagent/enzyme mixtures and shipped without a chain of refrigeration, also worked with human plasma samples to detect chikungunya and dengue in Pune, India. Conclusions A kit, complete with a visualization device, is now available for point-of-sampling detection of Zika, chikungunya, and dengue. The assay output is read in ca. 30 min by visualizing (human eye) three-color coded fluorescence signals. Assay in dried format allows it to be run in low-resource environments. Electronic supplementary material The online version of this article (doi:10.1186/s12879-017-2382-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ozlem Yaren
- Foundation for Applied Molecular Evolution (FfAME), Gainesville, FL, USA
| | - Barry W Alto
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, FL, USA
| | | | | | - Kunal N Patil
- GenePath Dx (Causeway Healthcare), Pune, Maharashtra, India
| | - Kevin M Bradley
- Foundation for Applied Molecular Evolution (FfAME), Gainesville, FL, USA
| | - Zunyi Yang
- Foundation for Applied Molecular Evolution (FfAME), Gainesville, FL, USA
| | - Nikhil Phadke
- GenePath Dx (Causeway Healthcare), Pune, Maharashtra, India
| | - Steven A Benner
- Foundation for Applied Molecular Evolution (FfAME), Gainesville, FL, USA. .,Firebird Biomolecular Sciences LLC, Alachua, FL, USA.
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86
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Jansson L, Koliana M, Sidstedt M, Hedman J. Blending DNA binding dyes to improve detection in real-time PCR. ACTA ACUST UNITED AC 2017; 14:34-37. [PMID: 28459006 PMCID: PMC5397098 DOI: 10.1016/j.btre.2017.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/10/2017] [Accepted: 02/12/2017] [Indexed: 11/19/2022]
Abstract
The success of real-time PCR (qPCR) analysis is partly limited by the presence of inhibitory compounds in the nucleic acid samples. For example, humic acid (HA) from soil and aqueous sediment interferes with amplification and also quenches the fluorescence of double-stranded (ds) DNA binding dyes, thus hindering amplicon detection. We aimed to counteract the HA fluorescence quenching effect by blending complementary dsDNA binding dyes, thereby elevating the dye saturation levels and increasing the fluorescence signals. A blend of the four dyes EvaGreen, ResoLight, SYBR Green and SYTO9 gave significantly higher fluorescence intensities in the presence and absence of HA, compared with the dyes applied separately and two-dye blends. We propose blending of dyes as a generally applicable means for elevating qPCR fluorescence signals and thus enabling detection in the presence of quenching substances.
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Affiliation(s)
- Linda Jansson
- Applied Microbiology, Department of Chemistry, Lund University, Lund, SE-221 00, Sweden
| | - Marianne Koliana
- Applied Microbiology, Department of Chemistry, Lund University, Lund, SE-221 00, Sweden
| | - Maja Sidstedt
- Applied Microbiology, Department of Chemistry, Lund University, Lund, SE-221 00, Sweden
- Swedish National Forensic Centre, Linköping, SE-591 94, Sweden
| | - Johannes Hedman
- Applied Microbiology, Department of Chemistry, Lund University, Lund, SE-221 00, Sweden
- Swedish National Forensic Centre, Linköping, SE-591 94, Sweden
- Corresponding author at: Applied Microbiology, Department of Chemistry, Lund University, Lund, SE-221 00, Sweden.Applied MicrobiologyDepartment of ChemistryLund UniversityLundSE-221 00Sweden
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87
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Kong JE, Wei Q, Tseng D, Zhang J, Pan E, Lewinski M, Garner OB, Ozcan A, Di Carlo D. Highly Stable and Sensitive Nucleic Acid Amplification and Cell-Phone-Based Readout. ACS NANO 2017; 11:2934-2943. [PMID: 28234452 DOI: 10.1021/acsnano.6b08274] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Key challenges with point-of-care (POC) nucleic acid tests include achieving a low-cost, portable form factor, and stable readout, while also retaining the same robust standards of benchtop lab-based tests. We addressed two crucial aspects of this problem, identifying a chemical additive, hydroxynaphthol blue, that both stabilizes and significantly enhances intercalator-based fluorescence readout of nucleic acid concentration, and developing a cost-effective fiber-optic bundle-based fluorescence microplate reader integrated onto a mobile phone. Using loop-mediated isothermal amplification on lambda DNA we achieve a 69-fold increase in signal above background, 20-fold higher than the gold standard, yielding an overall limit of detection of 25 copies/μL within an hour using our mobile-phone-based platform. Critical for a point-of-care system, we achieve a >60% increase in fluorescence stability as a function of temperature and time, obviating the need for manual baseline correction or secondary calibration dyes. This field-portable and cost-effective mobile-phone-based nucleic acid amplification and readout platform is broadly applicable to other real-time nucleic acid amplification tests by similarly modulating intercalating dye performance and is compatible with any fluorescence-based assay that can be run in a 96-well microplate format, making it especially valuable for POC and resource-limited settings.
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Affiliation(s)
- Janay E Kong
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
| | - Qingshan Wei
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
| | - Derek Tseng
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
| | - Jingzi Zhang
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
| | - Eric Pan
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
| | - Michael Lewinski
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
| | - Omai B Garner
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
| | - Aydogan Ozcan
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
| | - Dino Di Carlo
- Department of Bioengineering, ‡Department of Electrical Engineering, ∥Department of Pathology & Laboratory Medicine, ^Department of Mechanical and Aerospace Engineering, ⊥California NanoSystems Institute, and ¶Jonsson Comprehensive Cancer Center, University of California Los Angeles , Los Angeles, California 90095, United States
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de Kruijf M, Coffey A, O'Mahony J. The investigation of the truncated mbtA gene within the mycobactin cluster of Mycobacterium avium subspecies paratuberculosis as a novel diagnostic marker for real-time PCR. J Microbiol Methods 2017; 136:40-48. [PMID: 28285167 DOI: 10.1016/j.mimet.2017.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 03/07/2017] [Accepted: 03/07/2017] [Indexed: 12/20/2022]
Abstract
The inability of Mycobacterium avium subspecies paratuberculosis (MAP) to produce endogenous mycobactin in-vitro is most likely due to the presence of a truncated mbtA gene within the mycobactin cluster of MAP. The main goal of this study was to investigate this unique mbtA truncation as a potential novel PCR diagnostic marker for MAP. Novel primers were designed that were located within the truncated region and the contiguous MAP2179 gene. Primers were evaluated against non-MAP isolates and no amplicons were generated. The detection limit of this mbtA-MAP2179 target was evaluated using a range of MAP DNA concentrations, MAP inoculated faecal material and 20 MAP isolates. The performance of mbtA-MAP2179 was compared to the established f57 target. The detection limits recorded for MAP K-10 DNA and from MAP K-10 inoculated faecal samples were 0.34pg and 104CFU/g respectively for both f57 and mbtA-MAP2179. A detection limit of 103CFU/g was recorded for both targets, but not achieved consistently. The detection limit of MAP from inoculated faecal material was successful at 103CFU/g for mbtA-MAP2179 when FAM probe real-time PCR was used. A MAP cell concentration of 102CFU/g was detected successfully, but again not consistently achieved. All 20 mycobacterial isolates were successfully identified as MAP by f57 and mbtA-MAP2179. Interestingly, the mbtA-MAP2179 real-time PCR assay resulted in the formation of a unique melting curve profile that contained two melting curve peaks rather than one single peak. This melting curve phenomenon was attributed towards the asymmetrical GC% distribution within the mbtA-MAP2179 amplicon. This study investigated the implementation of the mbtA-MAP2179 target as a novel diagnostic marker and the detection limits obtained with mbtA-MAP2179 were comparable to the established f57 target, making the mbtA-MAP2179 an adequate confirmatory target. Moreover, the mbtA-MAP2179 target could be implemented in multiplex real-time PCR assays and with its unique melting curve profile adds increased specificity to MAP diagnostic tests.
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Affiliation(s)
- Marcel de Kruijf
- Cork Institute of Technology, Department of Biological Sciences, Rossa Avenue, Bishopstown, Cork, Ireland
| | - Aidan Coffey
- Cork Institute of Technology, Department of Biological Sciences, Rossa Avenue, Bishopstown, Cork, Ireland
| | - Jim O'Mahony
- Cork Institute of Technology, Department of Biological Sciences, Rossa Avenue, Bishopstown, Cork, Ireland.
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Fattahi S, Amirbozorgi G, Lotfi M, Amini Navaei B, Kavoosian S, Asouri M, Akhavan-Niaki H. Development of a Universal Taqman Probe for mRNA Gene Expression Analysis. IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY TRANSACTION A-SCIENCE 2017. [DOI: 10.1007/s40995-017-0173-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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90
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Schoenbrunner NJ, Gupta AP, Young KKY, Will SG. Covalent modification of primers improves PCR amplification specificity and yield. Biol Methods Protoc 2017; 2:bpx011. [PMID: 32161793 PMCID: PMC6994073 DOI: 10.1093/biomethods/bpx011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/31/2017] [Accepted: 11/09/2017] [Indexed: 01/01/2023] Open
Abstract
We report a method for covalent modification of primers that enhances the specificity of PCR and increases the yield of specific amplification products at the end of PCR. The introduction of thermally stable covalent modifications, such as alkyl groups to the exocyclic amines of deoxyadenosine or cytosine residues at the 3'-ends of primers results in enhanced specificity of reactions. This higher specificity can result in greater sensitivity of detection by reducing competition with non-productive reactions. The reduction in the amplification of unintended byproducts is most apparent when both primers are modified at their respective 3'-ends. The T Ms of such modified primers are only slightly affected by the inclusion of these modifiers. The principal mode of action is believed to be driven by the poor enzyme extension of substrates with closely juxtaposed bulky alkyl groups, such as would result from the replication of primer dimer artifact.
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Affiliation(s)
| | | | | | - Stephen G Will
- Research Department, Roche Molecular Systems, Inc., 4300 Hacienda Drive, Pleasanton, CA 94588, USA
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91
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Dhas DBB, Ashmi AH, Bhat BV, Parija SC, Banupriya N. Modified low cost SNP genotyping technique using cycle threshold (Ct) & melting temperature (Tm) values in allele specific real-time PCR. Indian J Med Res 2016; 142:555-62. [PMID: 26658590 PMCID: PMC4743342 DOI: 10.4103/0971-5916.171282] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background & objectives: Genotyping has now become one of the major diagnostic means for almost all diseases. Among the advanced techniques that are used to study single nucleotide polymorphisms (SNPs), only a few are applicable for routine disease diagnosis. Their applicability mainly depends on three factors: cost, time, and accuracy. The primary objective of this study was to propose allele-specific real-time PCR as a rapid, low cost and simple genotyping method for routine diagnostics. Methods: Two SNPs, rs3014866 and rs2149356 were analysed using allele-specific real-time PCR. The polymerase chain reaction was carried out using RealQ PCR master mix containing SYBR Green DNA I dye followed by melt curve analysis. The results were validated by agarose gel electrophoresis and DNA sequencing. Results: The allelic discrimination and zygosity of the two SNPs were assessed by combined cycle threshold (Ct) and melting temperature (Tm) values. Variations in Ct and Tm values among the two alleles were observed in both rs3014866 (Ct: C allele - 24±1, T allele - 27±1; Tm: C allele - 82.5±0.3, T allele - 86.3±0.2) and rs2149356 (Ct: C allele - 24±1, A allele - 26±1; Tm: C allele - 79.4±0.2, A allele - 80.4±0.3). Based on the variations, homozygous and heterozygous alleles were detected. Agarose gel electrophoresis and DNA sequencing also confirmed the allelic variation and zygosity observed in real-time PCR. Interpretation & conclusions: In diagnostic settings where a large number of samples are analysed daily, allele-specific real-time PCR assay may serve as a simple, low cost and efficient method of genotyping.
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Affiliation(s)
| | | | - B Vishnu Bhat
- Department of Paediatrics, Jawaharlal Institute of Postgraduate Medical Education & Research, Puducherry, India
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92
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Poisonous or non-poisonous plants? DNA-based tools and applications for accurate identification. Int J Legal Med 2016; 131:1-19. [PMID: 27796590 DOI: 10.1007/s00414-016-1460-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/05/2016] [Indexed: 11/25/2022]
Abstract
Plant exposures are among the most frequently reported cases to poison control centres worldwide. This is a growing condition due to recent societal trends oriented towards the consumption of wild plants as food, cosmetics, or medicine. At least three general causes of plant poisoning can be identified: plant misidentification, introduction of new plant-based supplements and medicines with no controls about their safety, and the lack of regulation for the trading of herbal and phytochemical products. Moreover, an efficient screening for the occurrence of plants poisonous to humans is also desirable at the different stages of the food supply chain: from the raw material to the final transformed product. A rapid diagnosis of intoxication cases is necessary in order to provide the most reliable treatment. However, a precise taxonomic characterization of the ingested species is often challenging. In this review, we provide an overview of the emerging DNA-based tools and technologies to address the issue of poisonous plant identification. Specifically, classic DNA barcoding and its applications using High Resolution Melting (Bar-HRM) ensure high universality and rapid response respectively, whereas High Throughput Sequencing techniques (HTS) provide a complete characterization of plant residues in complex matrices. The pros and cons of each approach have been evaluated with the final aim of proposing a general user's guide to molecular identification directed to different stakeholder categories interested in the diagnostics of poisonous plants.
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93
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Park KW, Batule BS, Kang KS, Park KS, Park HG. Rapid and ultrasensitive detection of microRNA by target-assisted isothermal exponential amplification coupled with poly (thymine)-templated fluorescent copper nanoparticles. NANOTECHNOLOGY 2016; 27:425502. [PMID: 27622680 DOI: 10.1088/0957-4484/27/42/425502] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We devised a novel method for rapid and ultrasensitive detection of target microRNA (miRNA) by employing target-assisted isothermal exponential amplification (TAIEA) combined with poly (thymine)-templated fluorescent copper nanoparticles (CuNPs) as signaling probes. The target miRNA hybridizes to the unimolecular template DNA and works as a primer for the extension reaction to form double-stranded product, which consequently generates two nicking endonuclease recognition sites. By simultaneous nicking and displacement reactions, exponential amplification generates many poly (thymine) strands as final products, which are employed for the synthesis of fluorescent CuNPs. Based on the fluorescent signal from CuNPs, target miRNA is detected as low as 0.27 fM around 1 h of total analysis time. The diagnostic capability of this system has been successfully demonstrated by reliably detecting target miRNA from different cell lysates, showing its great potential towards real clinical applications.
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Affiliation(s)
- Kwan Woo Park
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
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94
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Wang J, Pan X, Liang X. Assessment for Melting Temperature Measurement of Nucleic Acid by HRM. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2016; 2016:5318935. [PMID: 27833775 PMCID: PMC5090098 DOI: 10.1155/2016/5318935] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 08/04/2016] [Accepted: 09/06/2016] [Indexed: 06/06/2023]
Abstract
High resolution melting (HRM), with a high sensitivity to distinguish the nucleic acid species with small variations, has been widely applied in the mutation scanning, methylation analysis, and genotyping. For the aim of extending HRM for the evaluation of thermal stability of nucleic acid secondary structures on sequence dependence, we investigated effects of the dye of EvaGreen, metal ions, and impurities (such as dNTPs) on melting temperature (Tm ) measurement by HRM. The accuracy of HRM was assessed as compared with UV melting method, and little difference between the two methods was found when the DNA Tm was higher than 40°C. Both insufficiency and excessiveness of EvaGreen were found to give rise to a little bit higher Tm , showing that the proportion of dye should be considered for precise Tm measurement of nucleic acids. Finally, HRM method was also successfully used to measure Tm s of DNA triplex, hairpin, and RNA duplex. In conclusion, HRM can be applied in the evaluation of thermal stability of nucleic acid (DNA or RNA) or secondary structural elements (even when dNTPs are present).
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Affiliation(s)
- Jing Wang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Xiaoming Pan
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Xingguo Liang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
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95
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Liberio MS, Sadowski MC, Davis RA, Rockstroh A, Vasireddy R, Lehman ML, Nelson CC. The ascidian natural product eusynstyelamide B is a novel topoisomerase II poison that induces DNA damage and growth arrest in prostate and breast cancer cells. Oncotarget 2016; 6:43944-63. [PMID: 26733491 PMCID: PMC4791278 DOI: 10.18632/oncotarget.6267] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 10/08/2015] [Indexed: 12/25/2022] Open
Abstract
As part of an anti-cancer natural product drug discovery program, we recently identified eusynstyelamide B (EB), which displayed cytotoxicity against MDA-MB-231 breast cancer cells (IC50 = 5 μM) and induced apoptosis. Here, we investigated the mechanism of action of EB in cancer cell lines of the prostate (LNCaP) and breast (MDA-MB-231). EB inhibited cell growth (IC50 = 5 μM) and induced a G2 cell cycle arrest, as shown by a significant increase in the G2/M cell population in the absence of elevated levels of the mitotic marker phospho-histone H3. In contrast to MDA-MB-231 cells, EB did not induce cell death in LNCaP cells when treated for up to 10 days. Transcript profiling and Ingenuity Pathway Analysis suggested that EB activated DNA damage pathways in LNCaP cells. Consistent with this, CHK2 phosphorylation was increased, p21CIP1/WAF1 was up-regulated and CDC2 expression strongly reduced by EB. Importantly, EB caused DNA double-strand breaks, yet did not directly interact with DNA. Analysis of topoisomerase II-mediated decatenation discovered that EB is a novel topoisomerase II poison.
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Affiliation(s)
- Michelle S Liberio
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, Australia.,Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Martin C Sadowski
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, Australia
| | - Rohan A Davis
- Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Anja Rockstroh
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, Australia
| | - Raj Vasireddy
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, Australia
| | - Melanie L Lehman
- Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colleen C Nelson
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, Australia
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96
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Villinger J, Mbaya MK, Ouso D, Kipanga PN, Lutomiah J, Masiga DK. Arbovirus and insect-specific virus discovery in Kenya by novel six genera multiplex high-resolution melting analysis. Mol Ecol Resour 2016; 17:466-480. [PMID: 27482633 DOI: 10.1111/1755-0998.12584] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 07/02/2016] [Accepted: 07/05/2016] [Indexed: 02/03/2023]
Abstract
A broad diversity of arthropod-borne viruses (arboviruses) of global health concern are endemic to East Africa, yet most surveillance efforts are limited to just a few key viral pathogens. Additionally, estimates of arbovirus diversity in the tropics are likely to be underestimated as their discovery has lagged significantly over past decades due to limitations in fast and sensitive arbovirus identification methods. Here, we developed a nearly pan-arbovirus detection assay that uses high-resolution melting (HRM) analysis of RT-PCR products from highly multiplexed assays to differentiate broad diversities of arboviruses. We differentiated 15 viral culture controls and seven additional synthetic viral DNA sequence controls, within Flavivirus, Alphavirus, Nairovirus, Phlebovirus, Orthobunyavirus and Thogotovirus genera. Among Bunyamwera, sindbis, dengue and Thogoto virus serial dilutions, detection by multiplex RT-PCR-HRM was comparable to the gold standard Vero cell plaque assays. We applied our low-cost method for enhanced broad-range pathogen surveillance from mosquito samples collected in Kenya and identified diverse insect-specific viruses, including a new clade in anopheline mosquitoes, and Wesselsbron virus, an arbovirus that can cause viral haemorrhagic fever in humans and has not previously been isolated in Kenya, in Culex spp. and Anopheles coustani mosquitoes. Our findings demonstrate how multiplex RT-PCR-HRM can identify novel viral diversities and potential disease threats that may not be included in pathogen detection panels of routine surveillance efforts. This approach can be adapted to other pathogens to enhance disease surveillance and pathogen discovery efforts, as well as the study of pathogen diversity and viral evolutionary ecology.
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Affiliation(s)
- Jandouwe Villinger
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772, Nairobi, 00100, Kenya
| | - Martin K Mbaya
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772, Nairobi, 00100, Kenya.,Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi, Kenya
| | - Daniel Ouso
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772, Nairobi, 00100, Kenya.,Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi, Kenya
| | - Purity N Kipanga
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772, Nairobi, 00100, Kenya.,Zoological Institute, Katholieke Universiteit, Naamsestraat 59, P.O. Box 3000, Leuven, Belgium
| | - Joel Lutomiah
- Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Daniel K Masiga
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772, Nairobi, 00100, Kenya
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97
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Niu P, Qi S, Yu B, Zhang C, Wang J, Li Q, Ma X. Development of a highly sensitive real-time nested RT-PCR assay in a single closed tube for detection of enterovirus 71 in hand, foot, and mouth disease. Arch Virol 2016; 161:3003-10. [PMID: 27475103 PMCID: PMC7086773 DOI: 10.1007/s00705-016-2985-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 07/11/2016] [Indexed: 12/29/2022]
Abstract
Enterovirus 71 (EV71) is one of the major causative agents of outbreaks of hand, foot, and mouth disease (HFMD). A commercial TaqMan probe-based real-time PCR assay has been widely used for the differential detection of EV71 despite its relatively high cost and failure to detect samples with a low viral load (Ct value > 35). In this study, a highly sensitive real-time nested RT-PCR (RTN RT-PCR) assay in a single closed tube for detection of EV71 in HFMD was developed. The sensitivity and specificity of this assay were evaluated using a reference EV71 stock and a panel of controls consisting of coxsackievirus A16 (CVA16) and common respiratory viruses, respectively. The clinical performance of this assay was evaluated and compared with those of a commercial TaqMan probe-based real-time PCR (qRT-PCR) assay and a traditional two-step nested RT-PCR assay. The limit of detection for the RTN RT-PCR assay was 0.01 TCID50/ml, with a Ct value of 38.3, which was the same as that of the traditional two-step nested RT-PCR assay and approximately tenfold lower than that of the qRT-PCR assay. When testing the reference strain EV71, this assay showed favorable detection reproducibility and no obvious cross-reactivity. The testing results of 100 clinical throat swabs from HFMD-suspected patients revealed that 41 samples were positive for EV71 by both RTN RT-PCR and traditional two-step nested RT-PCR assays, whereas only 29 were EV71 positive by qRT-PCR assay.
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Affiliation(s)
- Peihua Niu
- Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Shunxiang Qi
- Institute for Viral Disease Control and Prevention, Center for Disease Control and Prevention of Hebei, Shijiazhuang, Hebei, People's Republic of China
| | - Benzhang Yu
- Department of Laboratory Medicine, Shengli Oil Field Central Hospital, Jinan Road, Dongying, Shandong, People's Republic of China
| | - Chen Zhang
- Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Ji Wang
- Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Qi Li
- Institute for Viral Disease Control and Prevention, Center for Disease Control and Prevention of Hebei, Shijiazhuang, Hebei, People's Republic of China.
| | - Xuejun Ma
- Key Laboratory for Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
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98
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Yasmeen A, Du F, Zhao Y, Dong J, Chen H, Huang X, Cui X, Tang Z. Sequence-Specific Biosensing of DNA Target through Relay PCR with Small-Molecule Fluorophore. ACS Chem Biol 2016; 11:1945-51. [PMID: 27158915 DOI: 10.1021/acschembio.5b01081] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Polymerase chain reaction coupled with signal generation offers sensitive recognition of target DNA sequence; however, these procedures require fluorophore-labeled oligonucleotide probes and high-tech equipment to achieve high specificity. Therefore, intensive research has been conducted to develop reliable, convenient, and economical DNA detection methods. The relay PCR described here is the first sequence-specific detection method using a small-molecule fluorophore as a sensor and combines the classic 5'-3' exonuclease activity of Taq polymerase with an RNA mimic of GFP to build a label-free DNA detection platform. Primarily, Taq polymerase cleaves the 5' noncomplementary overhang of the target specific probe during extension of the leading primer to release a relay oligo to initiate tandem PCR of the reporting template, which encodes the sequence of RNA aptamer. Afterward, the PCR product is transcribed to mRNA, which could generate a fluorescent signal in the presence of corresponding fluorophore. In addition to high sensitivity and specificity, the flexibility of choosing different fluorescent reporting signals makes this method versatile in either single or multiple target detection.
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Affiliation(s)
- Afshan Yasmeen
- Natural
Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Feng Du
- Natural
Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Yongyun Zhao
- Natural
Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Juan Dong
- Natural
Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Haodong Chen
- Natural
Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Xin Huang
- Natural
Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Xin Cui
- Natural
Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Zhuo Tang
- Natural
Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
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99
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Oscorbin IP, Belousova EA, Zakabunin AI, Boyarskikh UA, Filipenko ML. Comparison of fluorescent intercalating dyes for quantitative loop-mediated isothermal amplification (qLAMP). Biotechniques 2016; 61:20-5. [PMID: 27401670 DOI: 10.2144/000114432] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 03/15/2016] [Indexed: 11/23/2022] Open
Abstract
Real-time or quantitative loop-mediated isothermal amplification (qLAMP) is a promising technique for the accurate detection of pathogens in organisms and the environment. Here we present a comparative study of the performance of six fluorescent intercalating dyes-SYTO-9, SYTO-13, SYTO-82, SYBR Green I, SYBR Gold, EvaGreen-in three different qLAMP model systems. SYTO-9 and SYTO-82, which had the best results, were used for additional enzyme and template titration studies. SYTO-82 demonstrated the best combination of time-to-threshold (Tt) and signal-to-noise ratio (SNR).
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Affiliation(s)
- Igor P Oscorbin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russian Federation
| | - Ekaterina A Belousova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Aleksandr I Zakabunin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Ulyana A Boyarskikh
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Maksim L Filipenko
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russian Federation
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100
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Irshad M, Gupta P, Mankotia DS, Ansari MA. Multiplex qPCR for serodetection and serotyping of hepatitis viruses: A brief review. World J Gastroenterol 2016; 22:4824-4834. [PMID: 27239109 PMCID: PMC4873875 DOI: 10.3748/wjg.v22.i20.4824] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/09/2016] [Accepted: 03/30/2016] [Indexed: 02/06/2023] Open
Abstract
The present review describes the current status of multiplex quantitative real time polymerase chain reaction (qPCR) assays developed and used globally for detection and subtyping of hepatitis viruses in body fluids. Several studies have reported the use of multiplex qPCR for the detection of hepatitis viruses, including hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). In addition, multiplex qPCR has also been developed for genotyping HBV, HCV, and HEV subtypes. Although a single step multiplex qPCR assay for all six hepatitis viruses, i.e., A to G viruses, is not yet reported, it may be available in the near future as the technologies continue to advance. All studies use a conserved region of the viral genome as the basis of amplification and hydrolysis probes as the preferred chemistries for improved detection. Based on a standard plot prepared using varying concentrations of template and the observed threshold cycle value, it is possible to determine the linear dynamic range and to calculate an exact copy number of virus in the specimen. Advantages of multiplex qPCR assay over singleplex or other molecular techniques in samples from patients with co-infection include fast results, low cost, and a single step investigation process.
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MESH Headings
- DNA, Viral/blood
- DNA, Viral/genetics
- Hepatitis Viruses/classification
- Hepatitis Viruses/genetics
- Hepatitis Viruses/immunology
- Hepatitis, Viral, Human/blood
- Hepatitis, Viral, Human/diagnosis
- Hepatitis, Viral, Human/genetics
- Hepatitis, Viral, Human/immunology
- Humans
- Multiplex Polymerase Chain Reaction
- Predictive Value of Tests
- Reproducibility of Results
- Serogroup
- Serologic Tests/methods
- Serotyping
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