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  1. Surface plasmon resonance biosensor for real-time detection of genetically modified organisms
    Yoke-Kqueen, C., Son, R.
    International Food Research Journal, 2010;17(2):477-483.
    MyJurnal
    Application of surface plasmon resonance (SPR) biosensor in detection of genetically modified organism (GMO) is demonstrated. A total of four biotinylated probes namely Tnosb, P35Sb, LECb and TSQb were successfully immobilized onto the SA chip. Results analysis indicated that the SPR system with the sensor chip immobilized with the Tnosb, P35Sb, LECb and TSQb biotinylated probes potentially detect complementary standard fragments as low as 1 nM. Biospecific interaction analysis (BIA), employing surface plasmon resonance (SPR) and biosensor technologies provide easy, rapid and automatable approach in detection of GMOs. Short assay times, label free DNA hybridization reaction and no toxic compounds are required, i.e. ethidium bromide, and the reusability of the sensor surface are some of the factors that contribute to the general advantages of the surface plasmon resonance (SPR) biosensor system in detection of GMOs.
  2. Fulltext Molecular quantitation and characterization of Vibrio cholerae from different seafood obtained from wetmarket and supermarket
    Vengadesh, L., Son, R., Yoke-Kqueen, C.
    International Food Research Journal, 2012;19(1):45-50.
    MyJurnal
    Vibrio cholerae still represents a significant threat to human health worldwide despite the advances in hygiene, consumer knowledge, food treatment and food processing. In Malaysia, statistics in year 2009 have shown that among the food and water borne diseases, food poisoning has the highest incidence rate of 36.17 per 100,000 populations and with a mortality rate of 0.01 per 100,000 populations. In this study, 22 seafood samples comprising of fish, squid, crustacean and mollusks purchased from wet market and supermarket were analyzed. The Most Probable Number (MPN) and real time PCR was used to enumerate the Vibrio cholerae in seafood sample. The results showed that MPN-real time PCR of the samples from wet market had a maximum of >1100 MPN/g compare to 93 MPN/g enumerated from the MPN plate. The MPN-real time PCR in the samples from supermarket indicated 290 MPN/g as compared to 240 MPN/g enumerated from the MPN plate. The standard curves showed that there was a good linear correlation between the Ct values. The minimum level of detection of Vibrio cholerae standard DNA at targeted gene was 3 x 10-5 ng/μl.
  3. Fulltext Molecular characterisation of Vibrio parahaemolyticus carrying tdh and trh genes using ERIC-, RAPD- and BOX-PCR on local Malaysia bloody clam and Lala
    Yoke-Kqueen, C., Teck-Ee, K., Son, R, Yoshitsugu, N., Mitsuaki, N.
    International Food Research Journal, 2013;20(6):3299-3305.
    MyJurnal
    Molecular typing methods have been widely applied for many purposes. In this study, such methods were adopted as DNA fingerprinting tools to determine the origin and divergence of virulent Vibrio parahaemolyticus strains found in local seafood. Although not all strain carry virulent tdh and trh gene, increasing prevalence demands an effective fingerprinting scheme which can constantly monitor and trace the sources of such emerging food pathogens. By using ERIC-, RAPD-, and BOX-PCR methods, 33 Vibrio parahaemolyticus isolates from local Malaysia bloody clam (Anadara granosa) and Lala (Orbicularia orbiculata) with confirmed presence of tdh and trh gene were characterised, followed by determination of clonal relatedness among virulent strains using cluster analysis and discriminatory index. This study also involved application of Immunomagnetic Separation (IMS) Method which significantly improved the specificity of strain isolation. Cluster analysis using Unweighted Pair Group Mathematical Averaging (UPGMA) and Dice Coefficient shown clustering according to isolation food source, IMS level and haemolysin gene possessed. Nevertheless, different DNA fingerprinting methods generated different clustering at different similarity cut-off percentage, regardless as individual or as composite dendrograms. ERIC- and RAPD-PCR composite fingerprinting relatively shown the highest discriminatory index at following similarity cutoff percentage: 0.68 at 50%; 0.83 at 65%; and 0.93 at 75%. Discriminatory power increased with similarity cut-off percentage. However, result also suggested that BOX-PCR might be an effective fingerprinting tool, as it generated three clusters with no single-colony isolate at 70% similarity cut-off. This study not only achieved its objective to determine clonal relatedness among virulent strains from local seafood via characterisation, but also speculated the best possible combination of molecular typing methods to effectively do so.
  4. Fulltext Bioprotective properties of three Malaysia Phyllanthus species: An investigation of the antioxidant and antimicrobial activities
    Poh-Hwa, T., Yoke-Kqueen, C., Indu Bala, J., Son, R.
    International Food Research Journal, 2011;18(3):-.
    MyJurnal
    The aim of this work was to investigate the antioxidant and antimicrobial of Phyllanthus amarus, Phyllanthus niruri and Phyllanthus urinaria. P. niruri was found to possess the highest antioxidant activity, the activity decreased in the order P. niruri > P. amarus > P. urinaria for water extract. However, the activity decreased in the order P. niruri > P. urinaria > P. amarus for methanol extract. The result correlation between the antioxidant activity and total phenolic content revealed a positive correlation of 0.954 < r 2 < 1.000 for both water and methanol extract. Methanol extract showed higher total phenolic content and antioxidant activity as compared with water extract. Lowest Minimum Inhibitory Concentration (MIC) value for water extract against the selected microorganism was >2.5 mg/mL meanwhile, for methanol extract was 2.5 mg/mL and >0.625 mg/mL were the value for water and methanol extract. Methanol extract showed better inhibition potential than water extract
  5. Random amplified polymorphic DNA analysis of genetically modified organisms
    Yoke-Kqueen C, Radu S
    J Biotechnol, 2006 Dec 15;127(1):161-6.
    PMID: 16860900
    Randomly amplified polymorphic DNA (RAPD) was used to analyzed 78 samples comprises of certified reference materials (soya and maize powder), raw seeds (soybean and maize), processed food and animal feed. Combination assay of two arbitrary primers in the RAPD analysis enable to distinguish genetically modified organism (GMO) reference materials from the samples tested. Dendrogram analysis revealed 13 clusters at 45% similarity from the RAPD. RAPD analysis showed that the maize and soybean samples were clustered differently besides the GMO and non-GMO products.
  6. Fulltext Molecular characterization and antimicrobial resistance profiling of Salmonella enterica subsp. enterica isolated from ‘Selom’ (Oenanthe stolonifera)
    Learn-Han, L., Yoke-Kqueen, C., Shiran, M.S., Sabrina, S., Noor Zaleha, A.S., Sim, J.H., et al.
    International Food Research Journal, 2009;16(2):191-202.
    MyJurnal
    Fifty-nine isolates of Salmonella enterica subsp. enterica (S. enterica) isolated from indigenous vegetables, ‘selom’ (Oenanthe stolonifera) associated with 13 different serovars were obtained from Chemistry Department of Malaysia. The isolates encompass the common serovar, Salmonella enterica subsp. enterica serovar Weltevreden (S. Weltevreden) (39%) and Salmonella enterica subsp. enterica serovar Agona (S. Agona) (8.5%). Frequencies of the other 11 Salmonella serovars were ranged from 1.7% to 5.1%. All isolates were characterized by Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR), random amplified polymorphic DNA (RAPD), plasmid profiling and antimicrobial susceptibility testing. The results demonstrated ERIC-PCR, RAPD and composite analysis of both are suitable typing methods for S. enterica by demonstrating good discriminative ability and can be utilize as a rapid approach of comparing S. enterica isolates for epidemiological investigation. From this study, ERIC-PCR is exhibited lower discriminatory power when compare with RAPD. On the other hand, plasmid profiles yielded 32 profiles with molecular size ranging from 1129 bp to 17911 bp. Thirteen antimicrobial agents were included in this study and all isolates showed 100% (59/59) resistant to erythromycin and showed Multiple Antimicrobial Resistance (MAR) indexes ranging from 0.08 to 0.68. Dendrogram generated from antimicrobial resistance profiling exhibited poor discriminatory capability at serovar level. Although poultry still remain as the common reservoir for multidrug resistant (MDR) Salmonella. The isolation of 13 Salmonella serovars from selom that showed high MDR in this study is alarming. These results supported the notion that indigenous vegetable (selom) are gaining more antimicrobial resistance and could be potential health hazards.
  7. Caenorhabditis elegans-based analysis of Salmonella enterica
    Chai-Hoon, K., Jiun-Horng, S., Shiran, M.S., Son, R., Sabrina, S., Noor Zaleha, A.S., et al.
    International Food Research Journal, 2010;17(4):845-852.
    MyJurnal
    Caenorhabditis elegans (C. elegans) have been widely used as an infection model for mammalian related pathogens with promising results. The bacterial factors required for virulence in non-mammalian host C. elegans play a role in mammalian systems. Previous reported that Salmonella found in vegetable and poultry meat could be potential health hazards to human. This study evaluated the pathogenicity of various serovars of Salmonella enterica (S. enterica) that recovered from local indigenous vegetables and poultry meat using C. elegans as a simple host model. Almost all S. enterica isolates were capable of colonizing the intestine of C. elegans, causing a significant reduction in the survival of nematodes. The colonization of Salmonella in C. elegans revealed that the ability of S. enterica in killing C. elegans correlates with its accumulation in the intestine to achieve full pathogenicity. Using this model, the virulence mechanisms of opportunistic pathogenic S. enterica were found to be not only relevant for the interactions of the bacteria with C. elegans but also with mammalian hosts including humans. Hence, C. elegans model could provide valuable insight into preliminary factors from the host that contributes to the environmental bacterial pathogenesis scenario.
  8. miR-205 in situ expression and localization in head and neck tumors - a tissue array study
    Nurul-Syakima AM, Learn-Han L, Yoke-Kqueen C
    Asian Pac J Cancer Prev, 2014;15(21):9071-5.
    PMID: 25422181
    BACKGROUND: microRNAs are small non-coding RNA that control gene expression by mRNA degradation or translational inhibition. These molecules are known to play essential roles in many biological and physiological processes. miR-205 may be differentially expressed in head and neck cancers; however, there are conflicting data and localization of expression has yet to be determined.

    MATERIALS AND METHODS: miR-205 expression was investigated in 48 cases of inflammatory, benign and malignant tumor tissue array of the neck, oronasopharynx, larynx and salivary glands by Locked Nucleic Acid in situ hybridization (LNA-ISH) technology.

    RESULTS: miR-205 expression was significantly differentially expressed across all of the inflammatory, benign and malignant tumor tissues of the neck. A significant increase in miR-205 staining intensity (p<0.05) was observed from inflammation to benign and malignant tumors in head and neck tissue array, suggesting that miR-205 could be a biomarker to differentiate between cancer and non-cancer tissues.

    CONCLUSIONS: LNA-ISH revealed that miR-205 exhibited significant differential cytoplasmic and nuclear staining among inflammation, benign and malignant tumors of head and neck. miR-205 was not only exclusively expressed in squamous epithelial malignancy. This study offers information and a basis for a comprehensive study of the role of miR-205 that may be useful as a biomarker and/or therapeutic target in head and neck tumors.

  9. Fulltext Characterization of multiple-antimicrobial-resistant Salmonella enterica Subsp. enterica isolated from indigenous vegetables and poultry in Malaysia
    Yoke-Kqueen C, Learn-Han L, Noorzaleha AS, Son R, Sabrina S, Jiun-Horng S, et al.
    Lett Appl Microbiol, 2008 Mar;46(3):318-24.
    PMID: 18179445 DOI: 10.1111/j.1472-765X.2007.02311.x
    The aims of this communication were to study characterization of serogroups among Salmonella isolates and the relationship of antimicrobial resistance to serogroups. Multiple antimicrobial resistance (MAR) was performed on 189 Salmonella enterica isolates associated with 38 different serovars that were recovered from poultry and four types of indigenous vegetables.
  10. Fulltext Identification of actinomycete communities in Antarctic soil from Barrientos Island using PCR-denaturing gradient gel electrophoresis
    Learn-Han L, Yoke-Kqueen C, Shiran MS, Vui-Ling CM, Nurul-Syakima AM, Son R, et al.
    Genet. Mol. Res., 2012;11(1):277-91.
    PMID: 22370930 DOI: 10.4238/2012.February.8.3
    The diversity of specific bacteria taxa, such as the actinomycetes, has not been reported from the Antarctic island of Barrientos. The diversity of actinomycetes was estimated with two different strategies that use PCR-denaturing gradient gel electrophoresis. First, a PCR was applied, using a group-specific primer that allows selective amplification of actinomycete sequences. Second, a nested-PCR approach was used that allows the estimation of the relative abundance of actinomycetes within the bacterial community. Molecular identification, which was based on 16S rDNA sequence analysis, revealed eight genera of actinomycetes, Actinobacterium, Actinomyces, an uncultured Actinomycete, Streptomyces, Leifsonia, Frankineae, Rhodococcus, and Mycobacterium. The uncultured Actinomyces sp and Rhodococcus sp appear to be the prominent genera of actinomycetes in Barrientos Island soil. PCR-denaturing gradient gel electrophoresis patterns were used to look for correlations between actinomycete abundance and environmental characteristics, such as type of rookery and vegetation. There was a significant positive correlation between type of rookery and abundance of actinomycetes; soil samples collected from active chinstrap penguin rookeries had the highest actinomycete abundance. Vegetation type, such as moss, which could provide a microhabitat for bacteria, did not correlate significantly with actinomycete abundance.
  11. Analysis of Salmonella Agona and Salmonella Weltevreden in Malaysia by PCR fingerprinting and antibiotic resistance profiling
    Learn-Han L, Yoke-Kqueen C, Salleh NA, Sukardi S, Jiun-Horng S, Chai-Hoon K, et al.
    Antonie Van Leeuwenhoek, 2008 Oct;94(3):377-87.
    PMID: 18548329 DOI: 10.1007/s10482-008-9254-y
    Forty-eight strains of Salmonella enterica subsp. enterica serovar Agona and 33 strains of Salmonella enterica subsp. enterica serovar Weltevreden were characterized by random amplified polymorphic DNA (RAPD) fingerprinting using 3 different arbitrary primer, Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR) and antimicrobial susceptibility testing. By using RAPD, 81 strains (44 strains of S. Agona and 33 strains of S. Weltevreden) can be clustered into 14 groups and 6 single isolates whereas ERIC-PCR produced 7 clusters and 3 single isolates. Thirteen antimicrobial agents were used and all the isolates were resistant to erythromycin and showed Multiple Antimicrobial Resistance indexes, ranging from 0.08 to 0.62. Poultry still remain as the common reservoir for multi-drug-resistant Salmonella. On the other hand, vegetables contaminated with S. Weltevreden showed a gain in antimicrobial resistance. Besides that, consistent antibiograms were observed from S. Weltevreden isolated at Kajang wet market on 2000/08/02.
  12. p53 codon 72 polymorphisms and random amplified polymorphic DNA analysis of non-melanoma skin cancer through archival formalin-fixed paraffin-embedded tissue
    Yoke-Kqueen C, Ab Mutalib NS, Sidik SM, Learn-Han L, Geok-Chin T
    Oncol Rep, 2012 Mar;27(3):753-63.
    PMID: 22159872 DOI: 10.3892/or.2011.1581
    Non-melanoma skin cancer (NMSC) is classified among the ten most frequent cancers in Malaysia. A common polymorphism at codon 72 of the p53 tumor suppressor gene and its influence on cancer risk has been studied for different types of cancer with mixed and inconsistent results with limited published data on the Malaysian population so far. In the present study, the frequency of p53 codon 72 polymorphism in 60 patients with NMSC was investigated from archival formalin-fixed paraffin-embedded (FFPE) tissue obtained from Hospital Universiti Kebangsaan Malaysia (HUKM). Additionally, random amplified polymorhic DNA -polymorphic chain reaction (RAPD-PCR) was employed for preliminary biomarker development. NMSC FFPE samples (70%) possess Arg/Arg, 20% with Pro/Pro and 10% with Arg/Pro. In total, there was no significant difference in the p53 codon 72 genotypes between histological types of NMSC, gender, race, tumor location and age group. However, there was an apparent age-associated increase in the Arg/Arg genotype but did not reach statistical significance (P=0.235). NMSC types and demographic characteristics did not influence genotype distribution. On the other hand, BCC and SCC distributions are influenced by age group, race and tumor location.
  13. Differential microRNA expression and identification of putative miRNA targets and pathways in head and neck cancers
    Nurul-Syakima AM, Yoke-Kqueen C, Sabariah AR, Shiran MS, Singh A, Learn-Han L
    Int J Mol Med, 2011 Sep;28(3):327-36.
    PMID: 21637912 DOI: 10.3892/ijmm.2011.714
    MicroRNAs (miRNAs) are small noncoding RNAs that involved in various cancer-related cellular processes. Diverse studies on expression profiling of miRNAs have been performed and the data showed that some miRNAs are up-regulated or down-regulated in cancer. Until now, there are no data published on the miRNA expression in head and neck cancers from Malaysia. Hence, this study aimed to investigate potentially crucial miRNAs in head and neck cancer patients from Malaysian populations. A global miRNA profiling was performed on 12 samples of head and neck cancer tissue using microarray analysis followed by validation using real-time RT-PCR. Microarray analysis identified 10 miRNAs that could distinguish malignant head and neck cancer lesions from normal tissues; 7 miRNAs (hsa-miR-181a-2*, hsa-miR-29b-1*, hsa-miR-181a, hsa-miR-181b, hsa-miR-744, hsa-miR-1271 and hsa-miR-221*) were up-regulated while 3 miRNAs (hsa-miR-141, hsa-miR-95 and hsa-miR-101) were down-regulated. These miRNAs may contribute in a simple profiling strategy to identify individuals at higher risk of developing head and neck cancers, thus helping in the elucidation of the molecular mechanisms involved in head and neck cancer pathogenesis.
  14. Analysis of chemical constituents, antimicrobial and anticancer activities of dichloromethane extracts of Sordariomycetes sp. endophytic fungi isolated from Strobilanthes crispus
    Jinfeng EC, Mohamad Rafi MI, Chai Hoon K, Kok Lian H, Yoke Kqueen C
    World J Microbiol Biotechnol, 2017 Jan;33(1):5.
    PMID: 27844243
    Plants are primary source of natural product drugs. However, with every new bioactive molecule reported from a plant source, there follows reports of endangered status or even extinction of a medicinally important plant due to over-harvesting. Hence, the attention turned towards fungi namely the endophytes, which reside within medicinally important plants and thus may have acquired their medicinal properties. Strobilanthes crispus is a traditional medicinal plant which has been used traditionally to treat kidney stones, diabetes, hypertension and cancer as well as having antimicrobial activities. In our efforts to bioprospect for anticancer and antimicrobial metabolites, two fungal endophytes most closely related to the Sordariomycetes sp. showed promising results. Sample (PDA)BL3 showed highest significant antimicrobial activity against 6 bacteria at 200 µg/disc whereas sample (PDA)BL5 has highest significant anticancer activity against all 5 cancer cell lines at concentrations ranging from 30 to 300 μg/ml. As for the gas chromatography coupled with mass spectrometry (GC-MS) results, a total of 20 volatile metabolites identified from sample (PDA)BL3 and 21 volatile metabolites identified from sample (PDA)BL5 having more than 1% abundance. Both GC-MS analysis showed that compound Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl) has the highest abundance at 15.10% abundance for sample (PDA)BL3 and 19.00% abundance for sample (PDA)BL5 respectively. In conclusion, these results have shown bio-prospecting potential of endophytic fungi having antimicrobial and anticancer activities as well as its potential secondary metabolites of interest. Therefore, this work has further indicated the medicinal and industrial potential of endophytic fungi.
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