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Law J.W.-F.,Monash University | Ab Mutalib N.-S.,UKM Medical Molecular Biology Institute | Chan K.-G.,University of Malaya | Lee L.-H.,Monash University
Frontiers in Microbiology | Year: 2015

Listeria monocytogenes, a foodborne pathogen that can cause listeriosis through the consumption of food contaminated with this pathogen. The ability of L. monocytogenes to survive in extreme conditions and cause food contaminations have become a major concern. Hence, routine microbiological food testing is necessary to prevent food contamination and outbreaks of foodborne illness. This review provides insight into the methods for cultural detection, enumeration, and molecular identification of L. monocytogenes in various food samples. There are a number of enrichment and plating media that can be used for the isolation of L. monocytogenes from food samples. Enrichment media such as buffered Listeria enrichment broth, Fraser broth, and University of Vermont Medium (UVM) Listeria enrichment broth are recommended by regulatory agencies such as Food and Drug Administration-bacteriological and analytical method (FDA-BAM), US Department of Agriculture-Food and Safety (USDA-FSIS), and International Organization for Standardization (ISO). Many plating media are available for the isolation of L. monocytogenes, for instance, polymyxin acriflavin lithium-chloride ceftazidime aesculin mannitol, Oxford, and other chromogenic media. Besides, reference methods like FDA-BAM, ISO 11290 method, and USDA-FSIS method are usually applied for the cultural detection or enumeration of L. monocytogenes. most probable number technique is applied for the enumeration of L. monocytogenes in the case of low level contamination. Molecular methods including polymerase chain reaction, multiplex polymerase chain reaction, real-time/quantitative polymerase chain reaction, nucleic acid sequence-based amplification, loop-mediated isothermal amplification, DNA microarray, and next generation sequencing technology for the detection and identification of L. monocytogenes are discussed in this review. Overall, molecular methods are rapid, sensitive, specific, time- and labor-saving. In future, there are chances for the development of new techniques for the detection and identification of foodborne with improved features. © 2015 Law, Ab Mutalib, Chan and Lee. Source


Murad N.A.A.,Queensland Institute of Medical Research | Murad N.A.A.,UKM Medical Molecular Biology Institute | Cullen J.K.,Queensland Institute of Medical Research | McKenzie M.,Monash Institute of Medical Research | And 13 more authors.
Mitochondrion | Year: 2013

Defects in the recognition and/or repair of damage to DNA are responsible for a sub-group of autosomal recessive ataxias. Included in this group is a novel form of ataxia with oculomotor apraxia characterised by sensitivity to DNA damaging agents, a defect in p53 stabilisation, oxidative stress and resistance to apoptosis. We provide evidence here that the defect in this patient's cells is at the level of the mitochondrion. Mitochondrial membrane potential was markedly reduced in cells from the patient and ROS levels were elevated. This was accompanied by lipid peroxidation of mitochondrial proteins involved in electron transport and RNA synthesis. However, no gross changes or alteration in composition or activity of mitochondrial electron transport complexes was evident. Sequencing of mitochondrial DNA revealed a mutation, I349T, in the mitochondrial cytochrome b gene. These results describe a patient with an apparently novel form of AOA characterised by a defect at the level of the mitochondrion. © 2012 Elsevier B.V. and Mitochondria Research Society. Source


Vui-Kee K.,National University of Malaysia | Mohamed Rose I.,National University of Malaysia | Ghazali R.,Histopathology Unit | Jamal R.,UKM Medical Molecular Biology Institute | And 2 more authors.
Kaohsiung Journal of Medical Sciences | Year: 2012

Nonepithelial ovarian cancer (NEOC) is a rare cancer that is often misdiagnosed as other malignant tumors. Research on this cancer using fresh tissues is nearly impossible because of its limited number of samples within a limited time provided. The study is to identify potential genes and their molecular pathways related to NEOC using formalin-fixed paraffin embedded samples. Total RNA was extracted from eight archived NEOCs and seven normal ovaries. The RNA samples with RNA integrity number >2.0, purity >1.7 and cycle count value <28 cycles were hybridized to the Illumina Whole-Genome DASL assay (cDNA-mediated annealing, selection, extension, and ligation). We analyzed the results using the GeneSpring GX11.0 and FlexArray software to determine the differentially expressed genes. Microarray results were validated using an immunohistochemistry method. Statistical analysis identified 804 differentially expressed genes with 443 and 361 genes as overexpressed and underexpressed in cancer, respectively. Consistent findings were documented for the overexpression of eukaryotic translation elongation factor 1 alpha 1, E2F transcription factor 2, and fibroblast growth factor receptor 3, except for the down-regulated gene, early growth response 1 (EGR1). The immunopositivity staining for EGR1 was found in the majority of cancer tissues. This finding suggested that the mRNA level of a transcript did not always match with the protein expression in tissues. The current gene profile can be the platform for further exploration of the molecular mechanism of NEOC. Copyright © 2012, Elsevier Taiwan LLC. All rights reserved. Source


Teh L.K.,University Technology of MARA | Langmia I.M.,University Technology of MARA | Fazleen Haslinda M.H.,University Technology of MARA | Ngow H.A.,IIUM Kuantan | And 5 more authors.
Journal of Clinical Pharmacy and Therapeutics | Year: 2012

What is known and Objectives: Testing for cytochrome P450-2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) variant alleles is recommended by the FDA for dosing of warfarin. However, dose prediction models derived from data obtained in one population may not be applicable to another. We therefore studied the impact of genetic polymorphisms of CYP2C9 and VKORC1 on warfarin dose requirement in Malaysia. Methods: Patients who were attending clinics at our hospital and prescribed warfarin with stabilized INR levels of 2-4 were selected. DNA was extracted from blood samples and subsequently genotyped for CYP2C9*1,*2,*3, VKORC1 (G-1639A) and VKORC1 C1173T. Linear regression modelling using age, CYP2C9 and VKORC1 genotypes, sex, weight and height was undertaken to define a warfarin dosing algorithm. An initial model was developed using data from one cohort of patients and validated using data from a second cohort. Results and Discussion: A model which included age and variants of CYP2C9 and VKORC1 account for about 37% of the variability in warfarin dose required to achieve INR of 2-4. Among the parameters evaluated, only VKORC1 (G-1639A) and (C1173T) alleles, and age correlated with warfarin dose at 6 month. The mean dose predicted using the algorithm derived from cohort 1 was lower than the actual dose for cohort 2 (3·30 mg, SD 0·84 vs. 3·45 mg, SD 1·42). There was no relationship between INR values and the dose taken by the patients. Race, sex, weight and height did not correlate with dose. What is new and Conclusion: This study identifies factors which affect warfarin dosing in the Malaysia population. However, our best model does not account sufficiently for the variability in dose requirements for it to be used in dose prediction for the individual patient. Other important influential factors affecting warfarin dose requirement remain to be identified. © 2011 Blackwell Publishing Ltd. Source


Looi M.-L.,UKM Medical Molecular Biology Institute | Zakaria H.,University Technology of MARA | Osman J.,UKM Medical Molecular Biology Institute | Jamal R.,UKM Medical Molecular Biology Institute
Clinical Laboratory | Year: 2012

Background: Saliva has been suggested as an attractive resource for evaluating physiological and pathological conditions in humans. This study aims to evaluate saliva sampling as an alternative to blood sampling for molecular testing. Methods: We compared the yield, purity, and performance of DNA isolated from blood to that isolated from saliva using the non-invasive collection kit (Oragene® DNA OG500 and OG575 kit). Saliva DNA was extracted by manual purification and QIAamp DNA mini kit. Blood DNA was isolated by salt-precipitation and DNAzol reagent. We also evaluated the quality of saliva DNA by PCR-based analysis. Results: We found that the DNA yield from saliva (7.8 μg/0.5 mL saliva sample) from the manual purification method was comparable to the DNA yield from blood by the salt precipitation method (7.4 ug/0.5 mL blood sample). DNA extracted from saliva and blood were both of high purity (A 260/280 >1.70). Genotype results (PCR-RFLP and direct sequencing) for all sets of blood-saliva DNA samples were in 100% concordance. Conclusions: Saliva samples, when extracted by the manual purification method, provide a similar amount of human DNA as compared to the amount obtained from blood. Saliva is a viable alternative DNA source for genotyping studies. Source

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