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Hu L, Ji YY, Zhu P, Lu RQ. Mutation-Selected Amplification droplet digital PCR: A new single nucleotide variant detection assay for TP53 R249S mutant in tumor and plasma samples. Anal Chim Acta 2024; 1318:342929. [PMID: 39067934 DOI: 10.1016/j.aca.2024.342929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 06/21/2024] [Accepted: 06/30/2024] [Indexed: 07/30/2024]
Abstract
The early detection of gene mutations in physiological and pathological processes is a powerful approach to guide decisions in precision medicine. However, detecting low-copy mutant DNA from clinical samples poses a challenge due to the enrichment of wild-type DNA backgrounds. In this study, we devised a novel strategy, named Mutation-Selected Amplification droplet digital PCR (MSA-ddPCR), to quantitatively analyze single nucleotide variants (SNVs) at low variant allele frequencies (VAFs). Using TP53R249S (a hotspot mutation associated with hepatocellular carcinoma) as a model, we optimized the concentration ratio of primers, the annealing temperature and nucleic acid amplification modifiers. Subsequently, we evaluated the linear range and precision of MSA-ddPCR by detecting TP53R249S and TP53wild-type (TP53WT) plasmid DNA, respectively. MSA-ddPCR demonstrated superior ability to discriminate between mutant DNA and wild-type DNA compared to traditional TaqMan-MGB PCR. We further applied MSA-ddPCR to analyze the TP53R249S mutation in 20 plasma samples and 15 formalin-fixed paraffin-embedded (FFPE) tissue samples, and assessed the agreement rates between MSA-ddPCR and amplicon high-throughput sequencing. The results showed that the limit of blanks of MSA-ddPCR are 0.449 copies μL-1 in the FAM channel and 0.452 copies μL-1 in the VIC channel. MSA-ddPCR could accurately quantify VAFs as low as 0.01 %, surpassing existing PCR and next-generation sequencing (NGS) methods. In the detection of clinical samples, a high correlation was found between MSA-ddPCR and amplicon high-throughput sequencing. Additionally, MSA-ddPCR outperformed sequencing methods in terms of detection time and simplicity of data analysis. MSA-ddPCR can be easily implemented into clinical practice and serve as a robust tool for detecting mutant genes due to its high sensitivity and accuracy.
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Affiliation(s)
- Ling Hu
- Department of Clinical Laboratory, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical School, Fudan University, Shanghai, 20032, China
| | - Yuan-Ye Ji
- Department of Medical Laboratory, Ningbo No.2 Hospital, Ningbo, 315010, China
| | - Peng Zhu
- Department of Medical Laboratory, Ningbo No.2 Hospital, Ningbo, 315010, China; Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, 315010, China.
| | - Ren-Quan Lu
- Department of Clinical Laboratory, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical School, Fudan University, Shanghai, 20032, China.
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Thompson WS, Saba L, Hasadsri L, Girard S, Schimmenti LA, Bendel-Stenzel EM, Wick MJ, Brumbaugh JE. Assessment of Aminoglycoside-Induced Hearing Loss Risk in the Perinatal Period. Am J Perinatol 2024. [PMID: 39008985 DOI: 10.1055/s-0044-1788335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
OBJECTIVE This study aimed to determine the prevalence and heteroplasmy level(s) of MT-RNR1 variants m.1555A > G and m.1494C > T, which are associated with aminoglycoside-induced hearing loss, in a general perinatal population. This study also aimed to characterize the association of these variants and their heteroplasmy levels with hearing loss outcomes with and without aminoglycoside exposure. STUDY DESIGN Droplet digital polymerase chain reaction was performed on 479 maternal DNA samples from a general perinatal biobank at our institution to detect the presence and heteroplasmy levels of MT-RNR1 variants m.1555A > G and m.1494C > T. Testing of paired neonatal specimen(s) was planned for positive maternal tests. A retrospective chart review was performed to characterize the population, identify aminoglycoside exposures, and determine hearing outcomes. RESULTS All maternal samples tested negative for MT-RNR1 variants m.1555A > G and m.1494C > T. Maternal and neonatal subjects had high rates of aminoglycoside exposure (15.9 and 13.9%, respectively). No subjects with sensorineural or mixed hearing loss had documented aminoglycoside exposure. CONCLUSION This study demonstrated that a larger sample size is needed to establish the prevalence of these variants as no subjects tested positive. Determination of variant prevalence in the neonatal population, association of variant heteroplasmy levels with hearing outcomes, and reliability of maternal testing as a surrogate for neonatal testing are important next steps toward universal prenatal or newborn screening. KEY POINTS · MT-RNR1 variants are associated with aminoglycoside-induced hearing loss.. · Prevalence of MT-RNR1 variants is uncertain.. · Universal screening for MT-RNR1 variants may be indicated..
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Affiliation(s)
- Whitney S Thompson
- Department of Clinical Genomics, Division of Neonatal Medicine, Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota
| | - Leslie Saba
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
| | - Linda Hasadsri
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Sylvie Girard
- Department of Obstetrics and Gynecology, Department of Immunology, Mayo Clinic, Rochester, Minnesota
| | - Lisa A Schimmenti
- Department of Clinical Genomics, Department of Otorhinolaryngology, Head and Neck Surgery, Department of Ophthalmology, Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | | | - Myra J Wick
- Department of Clinical Genomics, Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota
| | - Jane E Brumbaugh
- Division of Neonatal Medicine, Mayo Clinic, Rochester, Minnesota
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La Bella G, Basanisi MG, Nobili G, D’Antuono AM, Suffredini E, La Salandra G. Duplex Droplet Digital PCR Assay for Quantification of Hepatitis E Virus in Food. Viruses 2024; 16:413. [PMID: 38543778 PMCID: PMC10975721 DOI: 10.3390/v16030413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 05/23/2024] Open
Abstract
Hepatitis E virus (HEV) represents an emerging risk in industrialized countries where the consumption of contaminated food plays a pivotal role. Quantitative real-time RT-PCR (RT-qPCR) is one of the most suitable methods for the detection and quantification of viruses in food. Nevertheless, quantification using RT-qPCR has limitations. Droplet digital PCR (ddPCR) provides the precise quantification of nucleic acids without the need for a standard curve and a reduction in the effect on virus quantification due to the presence of inhibitors. The objectives of the present work were (i) to develop a method for the absolute quantification of HEV in swine tissues based on ddPCR technology and provide internal process control for recovery assessment and (ii) to evaluate the performance of the method by analyzing a selection of naturally contaminated wild boar muscle samples previously tested using RT-qPCR. The method was optimized using a set of in vitro synthesized HEV RNA and quantified dsDNA. The limit of detection of the developed ddPCR assay was 0.34 genome copies/µL. The analysis of the wild boar samples confirmed the validity of the ddPCR assay. The duplex ddPCR method showed no reduction in efficiency compared to individual assays. The method developed in the present study could represent a sensitive assay for the detection and absolute quantification of HEV RNA in food samples with the advantage of presenting the co-amplification of internal process control.
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Affiliation(s)
- Gianfranco La Bella
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Via Manfredonia 20, 71121 Foggia, Italy (G.N.); (A.M.D.); (G.L.S.)
| | - Maria Grazia Basanisi
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Via Manfredonia 20, 71121 Foggia, Italy (G.N.); (A.M.D.); (G.L.S.)
| | - Gaia Nobili
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Via Manfredonia 20, 71121 Foggia, Italy (G.N.); (A.M.D.); (G.L.S.)
| | - Anna Mattea D’Antuono
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Via Manfredonia 20, 71121 Foggia, Italy (G.N.); (A.M.D.); (G.L.S.)
| | - Elisabetta Suffredini
- Department of Food Safety Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, 00161 Rome, Italy;
| | - Giovanna La Salandra
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Via Manfredonia 20, 71121 Foggia, Italy (G.N.); (A.M.D.); (G.L.S.)
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Lopes J, Vidal-Folch N, Lundquist P, Schimmenti LA, Demirel N, Dean V, Olson J, Auth T, Butz M, Reed K, Wylam M, Balcom J, Boczek NJ, Hasadsri L. Aminoglycoside induced ototoxicity risk in the cystic fibrosis population: The utility of large-scale screening. Pediatr Pulmonol 2023; 58:819-824. [PMID: 36437230 DOI: 10.1002/ppul.26259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 10/24/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND MT-RNR1 variants are a well-known cause of aminoglycoside-induced hearing loss (AIHL). Individuals with cystic fibrosis (CF) routinely receive aminoglycosides and are at high risk of AIHL. However, genetic testing before treatment is not routinely performed due to perceived rarity of risk, and cost ineffectiveness with traditional technologies. AIM Assess the utility of large-scale screening for AIHL risk in the CF population, using digital droplet polymerase chain reaction (ddPCR), a novel and scalable low-cost molecular technique. METHODS Using a clinically validated ddPCR assay, we performed retrospective testing on 122 and prospective testing on 32 individuals with CF for the two most common pathogenic variants associated with AIHL, MT-RNR1 m.1555 A > G and m.1494 C > T. Our study screened the largest known cohort of pediatric cases of CF (94/154) for these specific alterations. RESULTS We identified two individuals positive for MT-RNR1 m.1555 A > G and no positives for m.1494 C > T. Of 32 prospective cases, 17 had aminoglycoside exposure. The positive case in our prospective group recently began inhaled tobramycin and denied hearing issues. The clinician adjusted to care for both the patient and sibling with CF (not included in cohort) who is presumed positive for m.1555 A > G due to the nature of mitochondrial inheritance. CONCLUSION Our findings demonstrate the utility of pretreatment screening in the cystic fibrosis population for AIHL risk using ddPCR, a scalable and robust testing methodology at a fraction of the cost as compared to other sequencing-based methods. Therefore, the use of large-scale screening for AIHL risk in the cystic fibrosis community should be re-visited.
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Affiliation(s)
- Jaime Lopes
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Noemi Vidal-Folch
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Patrick Lundquist
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Lisa A Schimmenti
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA
| | - Nadir Demirel
- Department of Pediatrics, Mayo Clinic, Rochester, Minnesota, USA
| | - Vicki Dean
- Department of Pediatrics, Mayo Clinic, Rochester, Minnesota, USA
| | - Janelle Olson
- Department of Pediatrics, Mayo Clinic, Rochester, Minnesota, USA
| | - Tom Auth
- Department of Research Services, Mayo Clinic, Rochester, Minnesota, USA
| | - Malinda Butz
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Katelyn Reed
- Department of Research Services, Mayo Clinic, Rochester, Minnesota, USA
| | - Mark Wylam
- Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Jessica Balcom
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Nicole J Boczek
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Linda Hasadsri
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
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Yang H, Ma Y, Xie X, Wang H, Li X, Fang D, Bai Y. Candida albicans enriched in orthodontic derived white spot lesions and shaped focal supragingival bacteriome. Front Microbiol 2023; 14:1084850. [PMID: 36760510 PMCID: PMC9902512 DOI: 10.3389/fmicb.2023.1084850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/09/2023] [Indexed: 01/25/2023] Open
Abstract
White spot lesions (WSLs) are common enamel infectious diseases in fixed orthodontic treatment, which might attribute to the dysbiosis of oral microbiome. However, the correlation of Candida albicans with oral bacteriome in WSLs still remains unrevealed. This study investigated the carriage of C. albicans and how it shaped the bacterial community in disease or healthy supragingival plaque, to explore the potential role of interkingdom interaction in orthodontic WSLs. In this study, 31 patients with WSLs (WSLs) and 23 healthy patients (Health) undergoing fixed orthodontic treatment were enrolled. The supragingival microbiota in both groups were determined using 16S rRNA gene sequencing. Colonization and abundance of C. albicans in the plaque were determined via culture-dependent and -independent methods. Among WSLs patients, the correlation of C. albicans and bacteriome was analyzed under QIIME2-based bioinformatics and Spearman's correlation coefficient. The raw reads were deposited into the NCBI Sequence Read Archive (SRA) database (Accession Number: SRP404186). Significant differences in microbial diversity as well as composition were observed between WSLs and Health groups. Leptotrichia remarkably enriched in the WSLs group, while Neisseria and Cardiobacterium significantly enriched in the Health group. In addition, 45% of WSLs patients were C. albicans carriers but none in patients without WSLs. Among all WSLs patients, beta diversity and microbial composition were distinguished between C. albicans carriers and non-carriers. In C. albicans carriers, Corynebacterium matruchotii and Streptococcus mutans significantly enriched whereas Saccharibacteria_TM7_G-1 significantly depleted. The abundance of C. albicans was positively associated with bacteria such as Streptococcus mutans, while the negative correlation was detected between C. albicans and several bacteria such as Cardiobacterium hominis and Streptococcus sanguinis. Our study elucidated the distinguished supragingival plaque microbiome between orthodontic patients with and without WSLs. C. albicans frequently existed and enriched in orthodontic derived WSLs. The carriage of C. albicans shape plaque bacterial community in demineralized lesions and might play roles in WSLs pathogenesis.
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Wang K, Liu L, Wang J, Sun X, Han Q, Zhou C, Xu X, Wang J. Quantification of hepatitis E virus in raw pork livers using droplet digital RT-PCR. Food Microbiol 2022; 109:104114. [DOI: 10.1016/j.fm.2022.104114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/01/2022] [Accepted: 08/08/2022] [Indexed: 10/14/2022]
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Solanky D, Fields JA, Iudicello JE, Ellis RJ, Franklin D, Clifford DB, Gelman BB, Marra CM, Morgello S, Rubin LH, Grant I, Heaton RK, Letendre SL, Mehta SR. Higher buccal mitochondrial DNA and mitochondrial common deletion number are associated with markers of neurodegeneration and inflammation in cerebrospinal fluid. J Neurovirol 2022; 28:281-290. [PMID: 35157246 PMCID: PMC9352370 DOI: 10.1007/s13365-022-01052-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 12/03/2021] [Accepted: 01/11/2022] [Indexed: 11/27/2022]
Abstract
Human immunodeficiency virus (HIV) infection is potentially associated with premature aging, but demonstrating this is difficult due to a lack of reliable biomarkers. The mitochondrial (mt) DNA "common deletion" mutation (mtCDM) is a 4977-bp deletion associated with aging and neurodegenerative diseases. We examined how mtDNA and mtCDM correlate with markers of neurodegeneration and inflammation in people with and without HIV (PWH and PWOH). Data from 149 adults were combined from two projects involving PWH (n = 124) and PWOH (n = 25). We measured buccal mtDNA and mtCDM by digital droplet PCR and compared them to disease and demographic characteristics and soluble biomarkers in cerebrospinal fluid (CSF) and blood measured by immunoassay. Participants had a median age of 52 years, with 53% white and 81% men. Median mtDNA level was 1,332 copies/cell (IQR 1,201-1,493) and median mtCDM level was 0.36 copies × 102/cell (IQR 0.31-0.42); both were higher in PWH. In the best model adjusting for HIV status and demographics, higher mtDNA levels were associated with higher CSF amyloid-β 1-42 and 8-hydroxy-2'-deoxyguanosine and higher mtCDM levels were associated with higher plasma soluble tumor necrosis factor receptor II. The differences in mtDNA markers between PWH and PWOH support potential premature aging in PWH. Our findings suggest mtDNA changes in oral tissues may reflect CNS processes, allowing the use of inexpensive and easily accessible buccal biospecimens as a screening tool for CSF inflammation and neurodegeneration. Confirmatory and mechanistic studies on mt genome alterations by HIV and ART may identify interventions to prevent or treat neurodegenerative complications.
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Affiliation(s)
- Dipesh Solanky
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
| | - Jerel A Fields
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Jennifer E Iudicello
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ronald J Ellis
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Donald Franklin
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
| | - David B Clifford
- Division of Infectious Diseases, Washington University at St. Louis, St. Louis, MO, 63110, USA
| | - Benjamin B Gelman
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Christina M Marra
- Deparment of Neurology, University of Washington, Seattle, WA, 98104, USA
| | - Susan Morgello
- Department of Neurology, Icahn School of Medicine at Mt, Sinai, New York, NY, 10029, USA
| | - Leah H Rubin
- Department of Neurology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Igor Grant
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Robert K Heaton
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Scott L Letendre
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Sanjay R Mehta
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
- Department of Medicine, VA San Diego Healthcare System, La Jolla, CA, 92161, USA.
- Infectious Diseases Division, VA San Diego Healthcare System, La Jolla, 92161, USA.
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Deng H, Zhang Y, Ding J, Wang F. Detection of Very Low-Level Somatic Mosaic COL4A5 Splicing Variant in Asymptomatic Female Using Droplet Digital PCR. Front Med (Lausanne) 2022; 9:847056. [PMID: 35360741 PMCID: PMC8963732 DOI: 10.3389/fmed.2022.847056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 02/09/2022] [Indexed: 12/02/2022] Open
Abstract
Background Alport syndrome is a hereditary glomerulopathy featured by haematuria, proteinuria, and progressive renal failure. X-linked Alport syndrome (XLAS) due to COL4A5 disease-causing variants is the most common form. In the case of XLAS resulting from 10–18% presumed de novo COL4A5 disease-causing variants, there are only a few studies for mosaicism in the probands or parents. Very low-level (<1.0%) somatic mosaicism for COL4A5 disease-causing variants has not been published. Materials and Methods Chinese XLAS families with suspected parental mosaicism were enrolled in the present study to evaluate the forms of mosaicism, to offer more appropriate genetic counseling. PCR and direct sequencing were used to detect COL4A5 disease-causing variants harbored by the affected probands in parental multi-tissue DNAs (peripheral blood, urine sediments, saliva, hair), and droplet digital PCR (ddPCR) was used to quantify the mutant COL4A5 allelic fractions in parental different samples such as peripheral blood, saliva, and urine sediments. Results A Chinese asymptomatic female with suspected somatic and germline mosaicism was enrolled in the present study. She gave birth to two boys with XLAS caused by a hemizygous disease-causing variant c. 2245-1G>A in COL4A5 (NM_033380) intron 28, whereas this disease-causing variant was not detected in genomic DNA extracted from peripheral blood leukocytes in the woman using Sanger sequencing. She had multiple normal urine test results, and continuous linear immunofluorescence staining of α2 (IV) and α5 (IV) chains of skin tissue. Sanger sequencing demonstrated that COL4A5 disease-causing variant c. 2245-1G>A was not detected in her genomic DNAs isolated from urine sediments, saliva, and hair roots. Using ddPCR, the wild-type and mutant-type (c.2245-1G>A) COL4A5 was identified in the female's genomic DNAs isolated from peripheral blood, saliva, and urine sediments. The mutant allelic fractions in these tissues were 0.26% (peripheral blood), 0.73% (saliva), and 1.39% (urine), respectively. Conclusions Germline and very low-level somatic mosaicism for a COL4A5 splicing variant was detected in an asymptomatic female, which highlights that parental mosaicism should be excluded when a COL4A5 presumed de novo disease-causing variant is detected.
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Wu H, Ma X, Chu Y, Qi X, Zou B, Liu Y, Zhou G. Digital Nucleic Acid Signal Amplification Platform for Highly Sensitive DNA Mutation Analysis. Anal Chem 2022; 94:3858-3864. [PMID: 35212518 DOI: 10.1021/acs.analchem.1c04765] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Digital nucleic acid analysis technology has shown great application potential due to its excellent performance. However, most current digital nucleic acid detection methods are based on PCR or other template amplification strategies. Here, we present an alternative analysis platform based on digital nucleic acid signal amplification in droplets termed dNASA. Using a bead-based controllable extension bridged cascade signal amplification reaction, we achieved an ultralow background, high efficiency, and highly specific nucleic acid signal amplification analysis. As a "proof of concept", we demonstrated the feasibility of the proposed dNASA platform in single-base DNA mutation analysis using artificially synthesized samples. This platform provides innovative ideas for the field of digital nucleic acid analysis.
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Affiliation(s)
- Haiping Wu
- Department of Clinical Pharmacy, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science & Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing 210002, China.,School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Xueping Ma
- Department of Clinical Pharmacy, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science & Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing 210002, China
| | - Yanan Chu
- Department of Clinical Pharmacy, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science & Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing 210002, China
| | - Xiemin Qi
- Department of Clinical Pharmacy, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science & Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing 210002, China
| | - Bingjie Zou
- Department of Clinical Pharmacy, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science & Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing 210002, China.,Key Laboratory of Drug Quality Control and Pharmacovigilance of Ministry of Education, China Pharmaceutical University, Nanjing 210009, China.,School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Yunlong Liu
- State Key Laboratory of Natural Medicines, Department of Biomedical Engineering, School of Engineering, China Pharmaceutical University, Nanjing 210009, China
| | - Guohua Zhou
- Department of Clinical Pharmacy, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science & Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing 210002, China.,School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
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Li N, Zhang Y, Shen M, Xu Y. A fully integrated SNP genotyping system for hereditary hearing-loss detection. LAB ON A CHIP 2022; 22:697-708. [PMID: 34923580 DOI: 10.1039/d1lc00805f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hereditary hearing loss is one of the most common human neurosensory disorders, and there is a great need for early intervention methods such as genetically screening newborns. Single nucleotide polymorphisms (SNPs) are the major genetic targets for hearing-loss screening. In this study, a fully integrated SNP genotyping system was constructed to identify hereditary hearing loss-related genetic markers from human whole blood. The entire detection process, including blood cell lysis, nucleic acid extraction, the reaction mixture distribution, the chambers sealing and the two-colour multiplex competitive allele-specific polymerase chain reaction (KASP), can be automatically conducted in a self-contained cassette within 3 hours. To critically evaluate the performance of the system, its specificity, sensitivity and stability were assessed. Then, 13 clinical samples were genotyped with this fluidic cassette system to detect seven hotspot deafness-associated mutations in three genes (MT-RNR1, GJB2 and SLC26A4). The detection results of the cassette system were 100% concordant with those obtained by Sanger sequencing, proving its accuracy in the genetic screening of inherited hearing loss.
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Affiliation(s)
- Nan Li
- State Key Laboratory of Membrane Biology, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, China.
| | - Yuanyue Zhang
- State Key Laboratory of Membrane Biology, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, China.
| | - Minjie Shen
- State Key Laboratory of Membrane Biology, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, China.
| | - Youchun Xu
- State Key Laboratory of Membrane Biology, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, China.
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Tan YL, Huang AQ, Tang LJ, Jiang JH. Multiplexed droplet loop-mediated isothermal amplification with scorpion-shaped probes and fluorescence microscopic counting for digital quantification of virus RNAs. Chem Sci 2021; 12:8445-8451. [PMID: 34221326 PMCID: PMC8221175 DOI: 10.1039/d1sc00616a] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Highly sensitive digital nucleic acid techniques are of great significance for the prevention and control of epidemic diseases. Here we report the development of multiplexed droplet loop-mediated isothermal amplification (multiplexed dLAMP) with scorpion-shaped probes (SPs) and fluorescence microscopic counting for simultaneous quantification of multiple targets. A set of target-specific fluorescence-activable SPs are designed, which allows establishment of a novel multiplexed LAMP strategy for simultaneous detection of multiple cDNA targets. The digital multiplexed LAMP assay is thus developed by implementing the LAMP reaction using a droplet microfluidic chip coupled to a droplet counting microwell chip. The droplet counting system allows rapid and accurate counting of the numbers of total droplets and the positive droplets by collecting multi-color fluorescence images of the droplets in a microwell. The multiplexed dLAMP assay was successfully demonstrated for the quantification of HCV and HIV cDNA with high precision and detection limits as low as 4 copies per reaction. We also verified its potential for simultaneous digital assay of HCV and HIV RNA in clinical plasma samples. This multiplexed dLAMP technique can afford a useful platform for highly sensitive and specific detection of nucleic acids of viruses and other pathogens, enabling rapid diagnosis and prevention of infectious diseases. The development of multiplexed dLAMP with scorpion-shaped probes and fluorescence microscopic counting affords simultaneous digital quantification of multiple virus RNAs.![]()
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Affiliation(s)
- Ya-Ling Tan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University Changsha 410082 P. R. China +86-731-88822577 +86-731-88822872
| | - A-Qian Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University Changsha 410082 P. R. China +86-731-88822577 +86-731-88822872
| | - Li-Juan Tang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University Changsha 410082 P. R. China +86-731-88822577 +86-731-88822872
| | - Jian-Hui Jiang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University Changsha 410082 P. R. China +86-731-88822577 +86-731-88822872
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Tang Z, Tang X, Xue L, Guan M. [A non-invasive method for detecting mitochondrial tRNA Thr15927G>A mutation]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2021; 41:151-156. [PMID: 33509769 DOI: 10.12122/j.issn.1673-4254.2021.01.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To explore the feasibility of detecting maternal hereditary mitochondrial tRNAThr15927G>A (m.15927G>A) mutation using buccal swabs. METHODS We performed sequence analysis of mitochondrial DNA in blood samples from 2070 cases of maternal hereditary mitochondrial disease in the First Affiliated Hospital of Wenzhou Medical University, and identified 3 patients with m.15927G>A mutation.Buccal swabs and blood samples were obtained from the 3 patients (mutation group) and 3 normal volunteers (control group).After extracting whole genomic DNA from all the samples, the DNA concentration and purity were analyzed.The PCR products were subjected to dot blot hybridization, Southern blot hybridization, and DNA sequencing analysis to verify the feasibility of detecting m.15927G>A mutation using buccal swabs. RESULTS There was no significant difference in DNA concentration extracted from buccal swabs and blood samples in either the mutation group or the control group (P > 0.05), but the purity of manually extracted oral mucosa DNA was significantly lower than that of whole blood and oral mucosa DNA extracted using commercial kits (P < 0.05).Dot blot hybridization and Southern blot hybridization both yielded positive results in the control group but negative results in the mutation group.DNA sequencing identified m.15927G>A mutation in all the samples from the mutation group. CONCLUSIONS Buccal swabs collection accurate is an accurate and sensitive method for the detection of m.15927G>A mutation.
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Affiliation(s)
- Zhining Tang
- School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou 325035, China
| | - Xiaowen Tang
- School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou 325035, China
| | - Ling Xue
- School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou 325035, China
| | - Minxin Guan
- School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou 325035, China
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13
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Zhao Y, Zuo X, Li Q, Chen F, Chen YR, Deng J, Han D, Hao C, Huang F, Huang Y, Ke G, Kuang H, Li F, Li J, Li M, Li N, Lin Z, Liu D, Liu J, Liu L, Liu X, Lu C, Luo F, Mao X, Sun J, Tang B, Wang F, Wang J, Wang L, Wang S, Wu L, Wu ZS, Xia F, Xu C, Yang Y, Yuan BF, Yuan Q, Zhang C, Zhu Z, Yang C, Zhang XB, Yang H, Tan W, Fan C. Nucleic Acids Analysis. Sci China Chem 2020; 64:171-203. [PMID: 33293939 PMCID: PMC7716629 DOI: 10.1007/s11426-020-9864-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/04/2020] [Indexed: 12/11/2022]
Abstract
Nucleic acids are natural biopolymers of nucleotides that store, encode, transmit and express genetic information, which play central roles in diverse cellular events and diseases in living things. The analysis of nucleic acids and nucleic acids-based analysis have been widely applied in biological studies, clinical diagnosis, environmental analysis, food safety and forensic analysis. During the past decades, the field of nucleic acids analysis has been rapidly advancing with many technological breakthroughs. In this review, we focus on the methods developed for analyzing nucleic acids, nucleic acids-based analysis, device for nucleic acids analysis, and applications of nucleic acids analysis. The representative strategies for the development of new nucleic acids analysis in this field are summarized, and key advantages and possible limitations are discussed. Finally, a brief perspective on existing challenges and further research development is provided.
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Affiliation(s)
- Yongxi Zhao
- Institute of Analytical Chemistry and Instrument for Life Science, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, 710049 China
| | - Xiaolei Zuo
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
| | - Qian Li
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Feng Chen
- Institute of Analytical Chemistry and Instrument for Life Science, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, 710049 China
| | - Yan-Ru Chen
- Cancer Metastasis Alert and Prevention Center, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350108 China
| | - Jinqi Deng
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
| | - Da Han
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
| | - Changlong Hao
- State Key Lab of Food Science and Technology, International Joint Research Laboratory for Biointerface and Biodetection, School of Food Science and Technology, Jiangnan University, Wuxi, 214122 China
| | - Fujian Huang
- Faculty of Materials Science and Chemistry, Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan, 430074 China
| | - Yanyi Huang
- College of Chemistry and Molecular Engineering, Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
| | - Guoliang Ke
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 China
| | - Hua Kuang
- State Key Lab of Food Science and Technology, International Joint Research Laboratory for Biointerface and Biodetection, School of Food Science and Technology, Jiangnan University, Wuxi, 214122 China
| | - Fan Li
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
| | - Jiang Li
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800 China
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210 China
| | - Min Li
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
| | - Na Li
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014 China
| | - Zhenyu Lin
- Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, 350116 China
| | - Dingbin Liu
- College of Chemistry, Research Center for Analytical Sciences, State Key Laboratory of Medicinal Chemical Biology, and Tianjin Key Laboratory of Molecular Recognition and Biosensing, Nankai University, Tianjin, 300071 China
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1 Canada
| | - Libing Liu
- Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190 China
- College of Chemistry, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Xiaoguo Liu
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Chunhua Lu
- Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, 350116 China
| | - Fang Luo
- Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, 350116 China
| | - Xiuhai Mao
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
| | - Jiashu Sun
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
| | - Bo Tang
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014 China
| | - Fei Wang
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Jianbin Wang
- School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology (ICSB), Chinese Institute for Brain Research (CIBR), Tsinghua University, Beijing, 100084 China
| | - Lihua Wang
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800 China
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210 China
| | - Shu Wang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1 Canada
| | - Lingling Wu
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
| | - Zai-Sheng Wu
- Cancer Metastasis Alert and Prevention Center, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350108 China
| | - Fan Xia
- Faculty of Materials Science and Chemistry, Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan, 430074 China
| | - Chuanlai Xu
- State Key Lab of Food Science and Technology, International Joint Research Laboratory for Biointerface and Biodetection, School of Food Science and Technology, Jiangnan University, Wuxi, 214122 China
| | - Yang Yang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
| | - Bi-Feng Yuan
- Department of Chemistry, Wuhan University, Wuhan, 430072 China
| | - Quan Yuan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 China
| | - Chao Zhang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
| | - Zhi Zhu
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Key Laboratory for Chemical Biology of Fujian Province, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 China
| | - Chaoyong Yang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Key Laboratory for Chemical Biology of Fujian Province, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 China
| | - Xiao-Bing Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 China
| | - Huanghao Yang
- Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, 350116 China
| | - Weihong Tan
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 China
| | - Chunhai Fan
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127 China
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240 China
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Hai X, Li Y, Zhu C, Song W, Cao J, Bi S. DNA-based label-free electrochemical biosensors: From principles to applications. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.116098] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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15
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Decreased mitochondrial DNA copy number in children with cerebral palsy quantified by droplet digital PCR. Clin Chim Acta 2020; 503:122-127. [DOI: 10.1016/j.cca.2020.01.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/20/2020] [Accepted: 01/20/2020] [Indexed: 01/10/2023]
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Zhu X, Su S, Fu M, Peng Z, Wang D, Rui X, Wang F, Liu X, Liu B, Zhu L, Yang W, Gao N, Huang G, Jing G, Guo Y. A density-watershed algorithm (DWA) method for robust, accurate and automatic classification of dual-fluorescence and four-cluster droplet digital PCR data. Analyst 2019; 144:4757-4771. [PMID: 31290860 DOI: 10.1039/c9an00637k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Droplet digital PCR (ddPCR) is a single-molecule amplification technology with broad applications in precision medicine and clinical diagnosis. Dual-fluorescence and four-cluster ddPCR (two/four-ddPCR) assay is an effective way to quantify copy numbers. Currently, two/four-ddPCR data are usually classified with manual thresholds. For clinical applications, automatic and accurate methods are required to avoid subjectivity in diagnosis. Although there are some automatic classification algorithms, their accuracy and robustness still need to be improved to meet the needs of clinical diagnosis. Therefore, a new method is in high demand to automatically classify two/four-ddPCR data in an accurate and robust way. Here, a novel density-watershed algorithm (DWA) method was developed for the accurate, automatic and unsupervised classification of two/four-ddPCR data. First, data gridding was applied to a scatter plot of the fluorescence signal intensity to calculate data densities. Based on the data densities, the watershed algorithm was used to divide the gridded scatter plot into isolated regions automatically. Next, an optimal cluster pattern was determined based on these isolated regions, and excess regions were merged. Finally, the two/four-ddPCR data were classified based on the merged regions, and DNA template copy numbers were calculated accordingly. Using the DWA method for the quantification of both wild types and mutants of epidermal growth factor receptor (EGFR) L858R and T790M, the classification results were highly consistent with expectations, and significantly better than commonly-used automatic algorithms for now. The computed template copy numbers scaled proportionally to the relative concentration of input templates (r2 > 0.998) in four orders of magnitude with a good reproducibility, and achieved a limit of detection over 40 times lower than the commonly-used automatic algorithms. Furthermore, the DWA method was validated on 254 clinical DNA samples derived from frozen tissues, formalin-fixed paraffin-embedded tissues and peripheral blood. In most cases, the DWA method derived accurate and valid classification results. This highly effective DWA method may be widely used for automatically classifying two/four-ddPCR data, and it will greatly promote the application of ddPCR in clinical diagnosis.
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Affiliation(s)
- Xiurui Zhu
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
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