Displaying publications 1 - 20 of 65 in total

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  1. Engku Nur Syafirah EAR, Nurul Najian AB, Foo PC, Mohd Ali MR, Mohamed M, Yean CY
    Acta Trop, 2018 Jun;182:223-231.
    PMID: 29545156 DOI: 10.1016/j.actatropica.2018.03.004
    Cholera, caused by Vibrio cholerae is a foodborne disease that frequently reported in food and water related outbreak. Rapid diagnosis of cholera infection is important to avoid potential spread of disease. Among available diagnostic platforms, loop-mediated isothermal amplification (LAMP) is regarded as a potential diagnostic tool due to its rapidity, high sensitivity and specificity and independent of sophisticated thermalcycler. However, the current LAMP often requires multiple pipetting steps, hence is susceptible to cross contamination. Besides, the strict requirement of cold-chain during transportation and storage make its application in low resource settings to be inconvenient. To overcome these problems, the present study is aimed to develop an ambient-temperature-stable and ready-to-use LAMP assay for the detection of toxigenic Vibrio cholerae in low resource settings. A set of specific LAMP primers were designed and tested against 155 V. cholerae and non-V. cholerae strains. Analytical specifity showed that the developed LAMP assay detected 100% of pathogenic V. cholerae and did not amplified other tested bacterial strains. Upon testing against stool samples spiked with toxigenic V. cholerae outbreak isolates, the LAMP assay detected all of the spiked samples (n = 76/76, 100%), in contrast to the conventional PCR which amplified 77.6% (n = 59/76) of the tested specimens. In term of sensitivity, the LAMP assay was 100-fold more sensitive as compared to the conventional PCR method, with LOD of 10 fg per μL and 10 CFU per mL. Following lyophilisation with addition of lyoprotectants, the dry-reagent LAMP mix has an estimated shelf-life of 90.75 days at room temperature.
    Matched MeSH terms: Nucleic Acid Amplification Techniques/methods*
  2. Nurul Najian AB, Engku Nur Syafirah EA, Ismail N, Mohamed M, Yean CY
    Anal Chim Acta, 2016 Jan 15;903:142-8.
    PMID: 26709307 DOI: 10.1016/j.aca.2015.11.015
    In recent years extensive numbers of molecular diagnostic methods have been developed to meet the need of point-of-care devices. Efforts have been made towards producing rapid, simple and inexpensive DNA tests, especially in the diagnostics field. We report on the development of a label-based lateral flow dipstick for the rapid and simple detection of multiplex loop-mediated isothermal amplification (m-LAMP) amplicons. A label-based m-LAMP lateral flow dipstick assay was developed for the simultaneous detection of target DNA template and a LAMP internal control. This biosensor operates through a label based system, in which probe-hybridization and the additional incubation step are eliminated. We demonstrated this m-LAMP assay by detecting pathogenic Leptospira, which causes the re-emerging disease Leptospirosis. The lateral flow dipstick was developed to detect of three targets, the LAMP target amplicon, the LAMP internal control amplicon and a chromatography control. Three lines appeared on the dipstick, indicating positive results for all representative pathogenic Leptospira species, whereas two lines appeared, indicating negative results, for other bacterial species. The specificity of this biosensor assay was 100% when it was tested with 13 representative pathogenic Leptospira species, 2 intermediate Leptospira species, 1 non-pathogenic Leptospira species and 28 other bacteria species. This study found that this DNA biosensor was able to detect DNA at concentrations as low as 3.95 × 10(-1) genomic equivalent ml(-1). An integrated m-LAMP and label-based lateral flow dipstick was successfully developed, promising simple and rapid visual detection in clinical diagnostics and serving as a point-of-care device.
    Matched MeSH terms: Nucleic Acid Amplification Techniques
  3. Foo PC, Chan YY, Mohamed M, Wong WK, Nurul Najian AB, Lim BH
    Anal Chim Acta, 2017 May 08;966:71-80.
    PMID: 28372729 DOI: 10.1016/j.aca.2017.02.019
    This study highlighted the development of a four target nitrocellulose-based nucleic acid lateral flow immunoassay biosensor in a dry-reagent strip format for interpretation of double-labelled double-stranded amplicons from thermostabilised triplex loop-mediated isothermal amplification assay. The DNA biosensor contained two test lines which captured biotin and texas red labelled amplicons; a LAMP internal amplification control line that captured digoxigenin labelled amplicon; and a chromatography control line that validated the functionality of the conjugated gold nanoparticles and membrane. The red lines on detection pad were generated when the gold nanoparticles conjugated antibody bound to the fluorescein labelled amplicons, and the capture agents bound to their specific hapten on the other 5' end of the double-stranded amplicon. The applicability of this DNA biosensor was demonstrated using amoebiasis-causing Entamoeba histolytica simultaneously with the non-pathogenic but morphologically identical Entamoeba dispar and Entamoeba moshkovskii. The biosensor detection limit was 10 E. histolytica trophozoites, and revealed 100% specificity when it was evaluated against 3 medically important Entamoeba species and 75 other pathogenic microorganisms. Heat stability test showed that the biosensor was stable for at least 181 days at ambient temperature. This ready-to-use and cold-chain-free biosensor facilitated the post-LAMP analysis based on visualisation of lines on strip instead of observation of amplicon patterns in agarose gel.
    Matched MeSH terms: Nucleic Acid Amplification Techniques*
  4. Loh Q, Omar N, Glökler J, Lim TS
    Anal Biochem, 2014 Oct 15;463:67-9.
    PMID: 24972268 DOI: 10.1016/j.ab.2014.06.012
    Immunoassays are often coupled to peroxidase activity for antigen detection. Sensitivity and speed of detection has been increased by the advent of hybrid methods such as immuno-PCR (polymerase chain reaction). However, a more simplified immunoassay that retains both colorimetric peroxidase detection and effective DNA amplification in a setting closer to field application conditions has been nonexistent. Here we describe a method that successfully combines a competitive immunoassay with the new isothermal quadruplex-primed amplification (QPA) to generate excess quadruplex reporter molecules with intrinsic peroxidase DNAzyme activity.
    Matched MeSH terms: Nucleic Acid Amplification Techniques*
  5. Choi JR, Liu Z, Hu J, Tang R, Gong Y, Feng S, et al.
    Anal Chem, 2016 06 21;88(12):6254-64.
    PMID: 27012657 DOI: 10.1021/acs.analchem.6b00195
    In nucleic acid testing (NAT), gold nanoparticle (AuNP)-based lateral flow assays (LFAs) have received significant attention due to their cost-effectiveness, rapidity, and the ability to produce a simple colorimetric readout. However, the poor sensitivity of AuNP-based LFAs limits its widespread applications. Even though various efforts have been made to improve the assay sensitivity, most methods are inappropriate for integration into LFA for sample-to-answer NAT at the point-of-care (POC), usually due to the complicated fabrication processes or incompatible chemicals used. To address this, we propose a novel strategy of integrating a simple fluidic control strategy into LFA. The strategy involves incorporating a piece of paper-based shunt and a polydimethylsiloxane (PDMS) barrier to the strip to achieve optimum fluidic delays for LFA signal enhancement, resulting in 10-fold signal enhancement over unmodified LFA. The phenomena of fluidic delay were also evaluated by mathematical simulation, through which we found the movement of fluid throughout the shunt and the tortuosity effects in the presence of PDMS barrier, which significantly affect the detection sensitivity. To demonstrate the potential of integrating this strategy into a LFA with sample-in-answer-out capability, we further applied this strategy into our prototype sample-to-answer LFA to sensitively detect the Hepatitis B virus (HBV) in clinical blood samples. The proposed strategy offers great potential for highly sensitive detection of various targets for wide application in the near future.
    Matched MeSH terms: Nucleic Acid Amplification Techniques
  6. Teoh BT, Sam SS, Tan KK, Johari J, Danlami MB, Hooi PS, et al.
    BMC Infect Dis, 2013;13:387.
    PMID: 23964963 DOI: 10.1186/1471-2334-13-387
    BACKGROUND: Early and rapid detection of dengue virus (DENV) infection during the febrile period is crucial for proper patient management and prevention of disease spread. An easy to perform and highly sensitive method is needed for routine implementation especially in the resource-limited rural healthcare settings where dengue is endemic.
    METHODS: A single-tube reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay with a set of nine primers was developed for the detection of all four DENV serotypes and their different genotypes. The sensitivity and specificity of the RT-LAMP were evaluated. The clinical applicability of RT-LAMP assay for detection of DENV RNA was assessed in a total of 305 sera of clinically-suspected dengue patients. The test results of RT-LAMP were statistically compared to those of quantitative reverse transcription-polymerase chain reaction (qRT-PCR), IgM- and IgG-capture enzyme-linked immunosorbent assays (ELISA).
    RESULTS: Acute DENV infection was confirmed in 171 samples (n = 305); 43.3% (74/171) and 46.8% (80/171) of the samples were positive for DENV using RT-LAMP and qRT-PCR, respectively. The combination of RT-LAMP with the dengue IgM and IgG ELISA increased detection of acute DENV infection to 97.7% (167/171), in comparison to only 70.8% (121/171) when dengue IgM and IgG ELISA alone were used. The RT-LAMP assays showed high concordance (κ = 0.939) with the qRT-PCR. The RT-LAMP assay detected up to 10 copies of virus RNA within an hour but 100% reproducibility (12/12) was achieved with 100 copies. There was no cross reactivity of RT-LAMP with other closely related arboviruses.
    CONCLUSION: The RT-LAMP assay developed in this study is sensitive, specific and simple to perform. The assay improved the detection of dengue when used in combination with serological methods.
    Matched MeSH terms: Nucleic Acid Amplification Techniques/methods*
  7. Tay BY, Ahmad N, Hashim R, Mohamed Zahidi J, Thong KL, Koh XP, et al.
    BMC Infect Dis, 2015;15:220.
    PMID: 26033227 DOI: 10.1186/s12879-015-0958-0
    Brucellosis is one of the most common zoonotic diseases worldwide. It can cause acute febrile illness in human and is a major health problem. Studies in human brucellosis in Malaysia is limited and so far no genotyping studies has been done on Brucella isolates. The aim of the study was to determine the genetic diversity among Brucella species isolated from human brucellosis, obtained over a 6-year period (2009-2014).
    Matched MeSH terms: Nucleic Acid Amplification Techniques
  8. Teoh BT, Chin KL, Samsudin NI, Loong SK, Sam SS, Tan KK, et al.
    BMC Infect Dis, 2020 Dec 11;20(1):947.
    PMID: 33308203 DOI: 10.1186/s12879-020-05585-4
    BACKGROUND: Early detection of Zika virus (ZIKV) infection during the viremia and viruria facilitates proper patient management and mosquito control measurement to prevent disease spread. Therefore, a cost-effective nucleic acid detection method for the diagnosis of ZIKV infection, especially in resource-deficient settings, is highly required.

    METHODS: In the present study, a single-tube reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for the detection of both the Asian and African-lineage ZIKV. The detection limit, strain coverage and cross-reactivity of the ZIKV RT-LAMP assay was evaluated. The sensitivity and specificity of the RT-LAMP were also evaluated using a total of 24 simulated clinical samples. The ZIKV quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay was used as the reference assay.

    RESULTS: The detection limit of the RT-LAMP assay was 3.73 ZIKV RNA copies (probit analysis, P ≤ 0.05). The RT-LAMP assay detected the ZIKV genomes of both the Asian and African lineages without cross-reacting with other arthropod-borne viruses. The sensitivity and specificity of the RT-LAMP assay were 90% (95% CI = 59.6-98.2) and 100% (95% CI = 78.5-100.0), respectively. The RT-LAMP assay detected ZIKV genome in 9 of 24 (37.5%) of the simulated clinical samples compared to 10 of 24 (41.7%) by qRT-PCR assay with a high level of concordance (κ = 0.913, P 

    Matched MeSH terms: Nucleic Acid Amplification Techniques/methods*
  9. Al-Marzooq F, Mohd Yusof MY, Tay ST
    Biomed Res Int, 2014;2014:601630.
    PMID: 24860827 DOI: 10.1155/2014/601630
    Ninety-three Malaysian extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolates were investigated for ciprofloxacin resistance. Two mismatch amplification mutation (MAMA) assays were developed and used to facilitate rapid detection of gyrA and parC mutations. The isolates were also screened for plasmid-mediated quinolone resistance (PMQR) genes including aac(6')-Ib-cr, qepA, and qnr. Ciprofloxacin resistance (MICs 4- ≥ 32  μ g/mL) was noted in 34 (37%) isolates, of which 33 isolates had multiple mutations either in gyrA alone (n = 1) or in both gyrA and parC regions (n = 32). aac(6')-Ib-cr was the most common PMQR gene detected in this study (n = 61), followed by qnrB and qnrS (n = 55 and 1, resp.). Low-level ciprofloxacin resistance (MICs 1-2  μ g/mL) was noted in 40 (43%) isolates carrying qnrB accompanied by either aac(6')-Ib-cr (n = 34) or a single gyrA 83 mutation (n = 6). Ciprofloxacin resistance was significantly associated with the presence of multiple mutations in gyrA and parC regions. While the isolates harbouring gyrA and/or parC alteration were distributed into 11 PFGE clusters, no specific clusters were associated with isolates carrying PMQR genes. The high prevalence of ciprofloxacin resistance amongst the Malaysian ESBL-producing K. pneumoniae isolates suggests the need for more effective infection control measures to limit the spread of these resistant organisms in the hospital.
    Matched MeSH terms: Nucleic Acid Amplification Techniques/methods
  10. Lim KT, Teh CS, Thong KL
    Biomed Res Int, 2013;2013:895816.
    PMID: 23509796 DOI: 10.1155/2013/895816
    Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), is an important human pathogen that produces a variety of toxins and causes a wide range of infections, including soft-tissue infections, bacteremia, and staphylococcal food poisoning. A loop-mediated isothermal amplification (LAMP) assay targeting the arcC gene of S. aureus was developed and evaluated with 119 S. aureus and 25 non-S. aureus strains. The usefulness of the assay was compared with the PCR method that targets spa and arcC genes. The optimal temperature for the LAMP assay was 58.5°C with a detection limit of 2.5 ng/μL and 10(2) CFU/mL when compared to 12.5 ng/μL and 10(3) CFU/mL for PCR (spa and arcC). Both LAMP and PCR assays were 100% specific, 100% sensitive, 100% positive predictive value (PPV), and 100% negative predictive value (NPV). When tested on 30 spiked blood specimens (21 MRSA, eight non-S. aureus and one negative control), the performance of LAMP and PCR was comparable: 100% specific, 100% sensitive, 100% PPV, and 100% NPV. In conclusion, the LAMP assay was equally specific with a shorter detection time when compared to PCR in the identification of S. aureus. The LAMP assay is a promising alternative method for the rapid identification of S. aureus and could be used in resource-limited laboratories and fields.
    Matched MeSH terms: Nucleic Acid Amplification Techniques/methods*
  11. Sayad A, Ibrahim F, Mukim Uddin S, Cho J, Madou M, Thong KL
    Biosens Bioelectron, 2018 Feb 15;100:96-104.
    PMID: 28869845 DOI: 10.1016/j.bios.2017.08.060
    Outbreaks of foodborne diseases have become a global health concern; hence, many improvements and developments have been made to reduce the risk of food contamination. We developed a centrifugal microfluidic automatic wireless endpoint detection system integrated with loop mediated isothermal amplification (LAMP) for monoplex pathogen detection. Six identical sets were designed on the microfluidic compact disc (CD) to perform 30 genetic analyses of three different species of foodborne pathogens. The consecutive loading, mixing, and aliquoting of the LAMP primers/reagents and DNA sample solutions were accomplished using an optimized square-wave microchannel, metering chambers and revulsion per minute (RPM) control. We tested 24 strains of pathogenic bacteria (Escherichia coli, Salmonella spp and Vibrio cholerae), with 8 strains of each bacterium, and performed DNA amplification on the microfluidic CD for 60min. Then, the amplicons of the LAMP reaction were detected using the calcein colorimetric method and further analysed via the developed electronic system interfaced with Bluetooth wireless technology to transmit the results to a smartphone. The system showed a limit of detection (LOD) of 3 × 10-5ngμL-1 DNA by analysing the colour change when tested with chicken meat spiked with the three pathogenic bacteria. Since the entire process was performed in a fully automated way and was easy to use, our microdevice is suitable for point-of-care (POC) testing with high simplicity, providing affordability and accessibility even to poor, resource-limited settings.
    Matched MeSH terms: Nucleic Acid Amplification Techniques/economics; Nucleic Acid Amplification Techniques/instrumentation*
  12. Abdullah J, Saffie N, Sjasri FA, Husin A, Abdul-Rahman Z, Ismail A, et al.
    Braz J Microbiol, 2014;45(4):1385-91.
    PMID: 25763045
    An in-house loop-mediated isothermal amplification (LAMP) reaction was established and evaluated for sensitivity and specificity in detecting the presence of Salmonella Typhi (S. Typhi) isolates from Kelantan, Malaysia. Three sets of primers consisting of two outer and 4 inner were designed based on locus STBHUCCB_38510 of chaperone PapD of S. Typhi genes. The reaction was optimised using genomic DNA of S. Typhi ATCC7251 as the template. The products were visualised directly by colour changes of the reaction. Positive results were indicated by green fluorescence and negative by orange colour. The test was further evaluated for specificity, sensitivity and application on field samples. The results were compared with those obtained by gold standard culture method and Polymerase Chain Reaction (PCR). This method was highly specific and -10 times more sensitive in detecting S. Typhi compared to the optimised conventional polymerase chain reaction (PCR) method.
    Matched MeSH terms: Nucleic Acid Amplification Techniques/methods*
  13. Abd Rahim MR, Kho SL, Kuppusamy UR, Tan JA
    Clin. Lab., 2015;61(9):1325-30.
    PMID: 26554253
    BACKGROUND: Beta-thalassemia is the most common genetic disorder in Malaysia. Confirmation of the β-globin gene mutations involved in thalassemia is usually carried out by molecular analysis of DNA extracted from leukocytes in whole blood. Molecular analysis is generally carried out when affected children are around 1 - 2 years as clinical symptoms are expressed during this period. Blood taking at this age can be distressing for the child. High yield and pure DNA extracted from non-invasive sampling methods can serve as alternative samples in molecular studies for genetic diseases especially in pediatric cases.

    METHODS: In this study, mouthwash, saliva, and buccal cytobrush samples were collected from β-thalassemia major patients who had previously been characterized using DNA extracted from peripheral blood. DNA was extracted from mouthwash, saliva, and buccal cytobrush samples using the conventional inexpensive phenol-chloroform method and was measured by spectrophotometry for yield and purity. Molecular characterization of β-globin gene mutations was carried out using the amplification refractory mutation system (ARMS).

    RESULTS: DNA extracted from mouthwash, saliva, and buccal cytobrush samples produced high concentration and pure DNA. The purified DNA was successfully amplified using ARMS. Results of the β-globin gene mutations using DNA from the three non-invasive samples were in 100% concordance with results from DNA extracted from peripheral blood.

    CONCLUSIONS: The conventional in-house developed methods for non-invasive sample collection and DNA extraction from these samples are effective and negate the use of more expensive commercial kits. In conclusion, DNA extracted from mouthwash, saliva, and buccal cytobrush samples provided sufficiently high amounts of pure DNA suitable for molecular analysis of β-thalassemia.

    Matched MeSH terms: Nucleic Acid Amplification Techniques
  14. Ng JB, Poh RY, Lee KR, Subrayan V, Deva JP, Lau AY, et al.
    Clin. Lab., 2016 Sep 01;62(9):1731-1737.
    PMID: 28164597 DOI: 10.7754/Clin.Lab.2016.160144
    BACKGROUND: Keratoconus is an ocular degeneration characterized by the thinning of corneal stroma that may lead to varying degrees of myopia and visual impairment. Genetic factors have been reported in the pathology of keratoconus where Asians have a higher incidence, earlier onset, and undergo earlier corneal grafts compared to Caucasians. The visual system homeobox 1 (VSX1) gene forms part of a paired-like homeodomain transcription factor which is responsible for ocular development. The gene was marked as a candidate in genetic studies of keratoconus in various populations. Single nucleotide polymorphisms (SNPs) in the VSX1 gene have been reported to be associated with keratoconus. The detection of the SNPs involves DNA amplification of the VSX1 gene followed by genomic sequencing. Thus, the objective of this study aims to establish sensitive and accurate screening protocols for the molecular characterization of VSX1 polymorphisms.

    METHODS: Keratoconic (n = 74) and control subjects (n = 96) were recruited based on clinical diagnostic tests and selection criteria. DNA extracted from the blood samples was used to genotype VSX1 polymorphisms. In-house designed primers and optimization of PCR conditions were carried out to amplify exons 1 and 3 of the VSX1 gene. PCR conditions including percentage GC content, melting temperatures, and differences in melting temperatures of primers were evaluated to produce sensitive and specific DNA amplifications.

    RESULTS: Genotyping was successfully carried out in 4 exons of the VSX1 gene. Primer annealing temperatures were observed to be crucial in enhancing PCR sensitivity and specificity. Annealing temperatures were carefully evaluated to produce increased specificity, yet not allowing sensitivity to be compromised. In addition, exon 1 of the VSX1 gene was amplified using 2 different sets of primers to produce 2 smaller amplified products with absence of non-specific bands. DNA amplification of exons 1 and 3 consistently showed single band products which were successfully sequenced to yield reproducible data.

    CONCLUSIONS: The use of in-house designed primers and optimized PCR conditions allowed sensitive and specific DNA amplifications that produced distinct single bands. The in-house designed primers and DNA amplification protocols established in this study provide an addition to the current repertoire of primers for accurate molecular characterization of VSX1 gene polymorphisms in keratoconus research.

    Matched MeSH terms: Nucleic Acid Amplification Techniques/methods*
  15. Wang LY, Wang YS, Cheng H, Zhang JP, Yeok FS
    Ecotoxicology, 2015 Oct;24(7-8):1705-13.
    PMID: 26044931 DOI: 10.1007/s10646-015-1502-0
    Chitinases in terrestrial plants have been reported these are involved in heavy metal tolerance/detoxification. This is the first attempt to reveal chitinase gene (AcCHI I) and its function on metal detoxification in mangroves Aegiceras corniculatum. RT-PCR and RACE techniques were used to clone AcCHI I, while real-time quantitative PCR was employed to assess AcCHI I mRNA expressions in response to Cadmium (Cd). The deduced AcCHI I protein consists of 316 amino acids, including a signal peptide region, a chitin-binding domain (CBD) and a catalytic domain. Protein homology modeling was performed to identify potential features in AcCHI I. The CBD structure of AcCHI I might be critical for metal tolerance/homeostasis of the plant. Clear tissue-specific differences in AcCHI I expression were detected, with higher transcript levels detected in leaves. Results demonstrated that a short duration of Cd exposure (e.g., 3 days) promoted AcCHI I expression in roots. Upregulated expression was also detected in leaves under 10 mg/kg Cd concentration stress. The present study demonstrates that AcCHI I may play an important role in Cd tolerance/homeostasis in the plant. Further studies of the AcCHI I protein, gene overexpression, the promoter and upstream regulation will be necessary for clarifying the functions of AcCHI I.
    Matched MeSH terms: Nucleic Acid Amplification Techniques
  16. Balachandra D, Ahmad H, Arifin N, Noordin R
    Eur J Clin Microbiol Infect Dis, 2021 Jan;40(1):27-37.
    PMID: 32729057 DOI: 10.1007/s10096-020-03949-x
    Laboratory diagnosis of Strongyloides infections can be grouped into direct and indirect detection methods, and a combination of the two methods is often needed to reach an accurate and timely diagnosis. This review focuses on non-conventional direct detection via molecular and antigen detection assays. Conventional PCR is the most commonly used molecular diagnostic for Strongyloides. Real-time PCR is accurate and highly sensitive for quantitative and qualitative analysis. Meanwhile, PCR-RFLP can efficiently distinguish human and dog isolates of S. stercoralis, S. fuelleborni (from monkey), and S. ratti (from rodent). Loop-mediated isothermal amplification (LAMP) amplifies DNA isothermally with high specificity, efficiency, and rapidity, and has potential for point-of-care (POC) translation. As for antigen detection assay, coproantigen detection ELISAs for strongyloidiasis traditionally relied on raising rabbit polyclonal antibodies against the parasite antigens for use as capture or detection reagents. Subsequently, hybridoma technology using animals has enabled the discovery of monoclonal antibodies specific to Strongyloides antigens and was utilised to develop antigen detection assays. In recent times, phage display technology has facilitated the discovery of scFv antibody against Strongyloides protein that can accelerate the development of such assays. Improvements in both direct detection methods are being made. Strongyloides molecular diagnostics is moving from the detection of a single infection to the simultaneous detection of soil-transmitted helminths. Meanwhile, antigen detection assays can also be multiplexed and aptamers can be used as antigen binders. In the near future, these two direct detection methods may be more widely used as diagnostic tools for strongyloidiasis.
    Matched MeSH terms: Nucleic Acid Amplification Techniques
  17. Lim KB, Jeevan NH, Jaya P, Othman MI, Lee YH
    Forensic Sci Int, 2001 Jun 01;119(1):109-12.
    PMID: 11348801
    Allele frequencies for the nine STRs genetic loci included in the AmpFlSTR Profiler kit were obtained from samples of unrelated individuals comprising 139-156 Malays, 149-153 Chinese and 132-135 Indians, residing in Malaysia.
    Matched MeSH terms: Nucleic Acid Amplification Techniques/instrumentation; Nucleic Acid Amplification Techniques/methods
  18. Chang YM, Swaran Y, Phoon YK, Sothirasan K, Sim HT, Lim KB, et al.
    Forensic Sci Int Genet, 2009 Jun;3(3):e77-80.
    PMID: 19414156 DOI: 10.1016/j.fsigen.2008.07.007
    17 Y-STRs (DYS456, DYS389I, DYS390, DYS389II, DYS458, DYS19, DYS385a/b, DYS393, DYS391, DYS439, DYS635 or Y-GATA C4, DYS392, Y-GATA H4, DYS437, DYS438 and DYS448) have been analyzed in 320 male individuals from Sarawak, an eastern state of Malaysia on the Borneo island using the AmpFlSTR Y-filer (Applied Biosystems, Foster City, CA). These individuals were from three indigenous ethnic groups in Sarawak comprising of 103 Ibans, 113 Bidayuhs and 104 Melanaus. The observed 17-loci haplotypes and the individual allele frequencies for each locus were estimated, whilst the locus diversity, haplotype diversity and discrimination capacity were calculated in the three groups. Analysis of molecular variance (AMOVA) indicated that 87.6% of the haplotypic variation was found within population and 12.4% between populations (fixation index F(ST)=0.124, p=0.000). This study has revealed that the indigenous populations in Sarawak are distinctly different to each other, and to the three major ethnic groups in Malaysia (Malays, Chinese and Indians), with the Melanaus having a strikingly high degree of shared haplotypes within. There are rare unusual variants and microvariants that were not present in Malaysian Malay, Chinese or Indian groups. In addition, occurrences of DYS385 duplications which were only noticeably present in Chinese group previously was also observed in the Iban group whilst null alleles were detected at several Y-loci (namely DYS19, DYS392, DYS389II and DYS448) in the Iban and Melanau groups.
    Matched MeSH terms: Nucleic Acid Amplification Techniques
  19. Lau HY, Botella JR
    PMID: 29375588 DOI: 10.3389/fpls.2017.02016
    Diagnostic technologies for the detection of plant pathogens with point-of-care capability and high multiplexing ability are an essential tool in the fight to reduce the large agricultural production losses caused by plant diseases. The main desirable characteristics for such diagnostic assays are high specificity, sensitivity, reproducibility, quickness, cost efficiency and high-throughput multiplex detection capability. This article describes and discusses various DNA-based point-of care diagnostic methods for applications in plant disease detection. Polymerase chain reaction (PCR) is the most common DNA amplification technology used for detecting various plant and animal pathogens. However, subsequent to PCR based assays, several types of nucleic acid amplification technologies have been developed to achieve higher sensitivity, rapid detection as well as suitable for field applications such as loop-mediated isothermal amplification, helicase-dependent amplification, rolling circle amplification, recombinase polymerase amplification, and molecular inversion probe. The principle behind these technologies has been thoroughly discussed in several review papers; herein we emphasize the application of these technologies to detect plant pathogens by outlining the advantages and disadvantages of each technology in detail.
    Matched MeSH terms: Nucleic Acid Amplification Techniques
  20. Wong CL, Yong CY, Ong HK, Ho KL, Tan WS
    Front Vet Sci, 2020;7:477.
    PMID: 32974392 DOI: 10.3389/fvets.2020.00477
    Foot-and-mouth disease (FMD) is a devastating livestock disease caused by foot-and-mouth disease virus (FMDV). Outbreaks of this disease in a country always result in conspicuous economic losses to livestock industry and subsequently lead to serious socioeconomic damages due to the immediate imposition of trade embargo. Rapid and accurate diagnoses are imperative to control this infectious virus. In the current review, enzyme-linked immunosorbent assay (ELISA)-based methods used in FMD diagnosis are extensively reviewed, particularly the sandwich, liquid-phase blocking, and solid-phase competition ELISA. The differentiation of infected animals from vaccinated animals using ELISA-based methods is also highlighted, in which the role of 3ABC polyprotein as a marker is reviewed intensively. Recently, more studies are focusing on the molecular diagnostic methods, which detect the viral nucleic acids based on reverse transcription-polymerase chain reaction (RT-PCR) and RT-loop-mediated isothermal amplification (RT-LAMP). These methods are generally more sensitive because of their ability to amplify a minute amount of the viral nucleic acids. In this digital era, the RT-PCR and RT-LAMP are progressing toward the mobile versions, aiming for on-site FMDV diagnosis. Apart from RT-PCR and RT-LAMP, another diagnostic assay specifically designed for on-site diagnosis is the lateral flow immunochromatographic test strips. These test strips have some distinct advantages over other diagnostic methods, whereby the assay often does not require the aid of an external device, which greatly lowers the cost per test. In addition, the on-site diagnostic test can be easily performed by untrained personnel including farmers, and the results can be obtained in a few minutes. Lastly, the use of FMDV diagnostic assays for progressive control of the disease is also discussed critically.
    Matched MeSH terms: Nucleic Acid Amplification Techniques
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