Displaying publications 41 - 60 of 102 in total

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  1. Characterization of Polar and Non-Polar Compounds of House Edible Bird's Nest (EBN) from Johor, Malaysia
    Hun Lee T, Hau Lee C, Alia Azmi N, Kavita S, Wong S, Znati M, et al.
    Chem Biodivers, 2020 Jan;17(1):e1900419.
    PMID: 31721431 DOI: 10.1002/cbdv.201900419
    This work investigated the polar (PC: protein, amino acid and metabolite) and non-polar (NPC: fatty acid) compounds and bioactivity characteristics of the EBN harvested from the state of Johor in Malaysia. The electrophoretic gels exhibited 15 protein bands (16-173 kD) with unique protein profile. Amino acids analysis by AccQ⋅Tag method revealed 18 types of amino acids in EBN. Metabolite profiling was performed using High-Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Mass Spectrometer (HPLC-QTOF/MS) technique and a total of 54 compounds belonging to different groups were detected and identified. These findings help to uncover the relation of therapeutic activity of EBN. The EBN was further extracted with AcOEt and BuOH. The AcOEt extract was fractionated into three fractions (F1 -F3 ), and the high triglyceride content in F2 was verified by gC-FID. The three groups of fatty acids discovered in EBN are 48.43 % of poly-unsaturated (PUFA), 25.35 % of saturated fatty acids (SFA) and 24.74 % of mono-unsaturated fat (MUFA). This is the first time to report results ofEBN, BuOH, and AcOEt extracts and of fraction F2 (TEBN) on their analysis for their antioxidant activities by DPPH, ABTS and catalase assay and for their paraoxonase and anti-tyrosinase activities. The results showed that TEBN exhibited the significant bioactivity in all assays. These findings suggest that TEBN is a good source for natural bioactive compounds in promoting body vigor. Current work widened the content of EBN especially on the triglyceride and also marked the content of specific location (Johor, Malaysia) of EBN origin.
  2. Development of a validated instrument on socio-cultural and religious influences during menstruation in Malaysia
    Chew KS, Wong SSL, Hassan AK, Po KE, Zulkhairi N, Yusman NAL
    Med J Malaysia, 2021 Nov;76(6):814-819.
    PMID: 34806666
    INTRODUCTION: Although menstruation is a physiological process, it is shrouded with socio-cultural and religious beliefs. Healthcare providers should be aware that these influences may affect how women perceive their menstrual disorders. The primary objective of this study was to develop a validated questionnaire measuring the sociocultural and religious beliefs during menstruation.

    METHODS: In the first stage, a preliminary list of items measuring socio-cultural and religious beliefs during menstruation was generated. In the second stage, exploratory factor analysis was performed. Finally, confirmatory factor analysis using reflective measurement model and structural equation modelling was performed using partial least squares. The practices of these beliefs were included as mediating effect. Biological symptoms of menstruation were added in as another factor.

    RESULTS: A total of 400 female students from the Universiti Malaysia Sarawak, Malaysia were recruited. A preliminary list of 22 items was first generated. From the confirmatory factor analysis, two factors were iteratively removed due to poor factor loadings. Four factors were retained, i.e., i) "religious beliefs"; ii) "unpleasant (or dirty) nature of menstruation"; iii) "personal restrictions (dietary and behavior)"; and iv) "restrictions of interactions with male gender". In structural equation modelling, only 2 factors, i.e., the practices of "personal restrictions (dietary and behavioural)" and "restriction of interactions with males" had significant negative impact on quality of life.

    CONCLUSION: Menstruation should not be viewed purely from a biological lens as there are layers of sociocultural and religious beliefs surrounding it.

  3. Comparison of oxidative damage in Malaysian end-stage renal disease patients with or without non-insulin-dependent diabetes mellitus
    Kuppusamy UR, Indran M, Ahmad T, Wong SW, Tan SY, Mahmood AA
    Clin Chim Acta, 2005 Jan;351(1-2):197-201.
    PMID: 15563890 DOI: 10.1016/j.cccn.2004.09.014
    BACKGROUND: Comparisons of oxidative indices and total antioxidant status between end-stage renal disease (ESRD) patients with or without diabetes is scant, especially in the Asian population.
    METHOD: The assays were carried out according to known established protocols.
    RESULT: The present study showed that ESRD patients with or without non-insulin-dependent diabetes mellitus (NIDDM) did not have any significant differences in antioxidant enzyme activities, advanced glycated end products (AGE), advanced oxidized protein products (AOPP) and ferric reducing ability of plasma (FRAP), indicating that hyperglycemia does not exacerbate oxidative damage in ESRD. The regulation of catalase and glutathione peroxidase is also altered in ESRD. Elevated FRAP was observed in both ESRD groups (with and without NIDDM). The dialysis process did not alter the antioxidant enzyme activities but decreased AGEs and FRAP and increased AOPP levels.
    CONCLUSION: Oxidative stress is present in ESRD but this is not significantly exacerbated by hyperglycemia. The contribution of components in the pathology of renal failure towards oxidative stress exceeds that of hyperglycemia.
  4. Fluctuation of BCR-ABL1 qPCRIS level beyond 0.1%IS after stopping tyrosine kinase inhibitor in chronic myeloid leukaemia patients with deep molecular response for at least two years
    Kuan JW, Chang KM, Phan CL, Wong SP, Lim SM, Toh SG, et al.
    Med J Malaysia, 2021 May;76(3):414-416.
    PMID: 34031342
    Fluctuation of BCR-ABL1 real-time quantitative polymerase chain reaction in International Scale (qPCRIS) level below major molecular response (MMR) (0.1%IS) is a known phenomenon after stopping tyrosine kinase inhibitor (TKI) in chronic myeloid leukaemia (CML) patients who are attempting treatment free remission (TFR). We report here four cases of fluctuation beyond MMR during conduct of a Malaysia Stop TKI Trial (MSIT) to examine the validity of the commonly used relapse criterion - loss of MMR for one reading - aiming to provide evidence in setting relapse criteria for future CML patients who want to attempt TFR.
  5. Effect directed analysis of bioactive compounds in leaf extracts from two Salvia species by High-performance thin-layer chromatography
    Agatonovic-Kustrin S, Wong S, Dolzhenko AV, Gegechkori V, Ku H, Tan WK, et al.
    J Pharm Biomed Anal, 2023 Apr 01;227:115308.
    PMID: 36827737 DOI: 10.1016/j.jpba.2023.115308
    Extracts of two Salvia species, Salvia apiana (white sage) and Salvia officinalis (common sage) were screened for phytoconstituents with the ability to act as antidiabetic, cognitive enhancing, or antimicrobial agents, by hyphenation of high-performance thin-layer chromatography with enzymatic and microbial effect directed assays. Two bioactive zones with α-amylase inhibition (zone 1 and zone 2), 3 zones for acetylcholinesterase inhibition (zones 3, 4 and 5), and two zones for antimicrobial activity (zones 4 and 5) were detected. The compounds from the five bioactive zones were initially identified by coelution with standards and comparing the RF values of standards to the bioautograms. Identity was confirmed with ATR-FTIR spectra of the isolated compounds from the bioactive zones. A significantly higher α-amylase and acetylcholinesterase inhibition of S. apiana leaf extract was associated with a higher flavonoid and diterpenoid content. Fermented S. officinalis extract exhibited a significantly higher ability to inhibit α-amylase compared to other non-fermented extracts from this species, due to increased extraction of flavonoids. The ATR-FTIR spectra of 2 zones with α-amylase inhibition, indicated that flavonoids and phenolic acids were responsible for α-amylase inhibition. Multiple zones of acetylcholinesterase inhibition were related to the presence of phenolic abietane diterpenoids and triterpenoid acids. The presence of abietane diterpenoids and triterpenoid acids was also found responsible for the mild antimicrobial activity. Flash chromatography was used to isolate sufficient amounts of bioactive compounds for further characterisation via NMR and MS spectroscopy. Five compounds were assigned to the zones where bioactivity was observed: cirsimaritin (zone 1), a caffeic acid polymer (zone 2), 16-hydroxyrosmanol (zone 3), 16-hydroxycarnosic acid (zone 4), oleanolic and ursolic acids (zone 5).
  6. Fulltext Evaluation of bioactive compounds from Ficus carica L. leaf extracts via high-performance thin-layer chromatography combined with effect-directed analysis
    Agatonovic-Kustrin S, Wong S, Dolzhenko AV, Gegechkori V, Ku H, Tucci J, et al.
    J Chromatogr A, 2023 Sep 13;1706:464241.
    PMID: 37541060 DOI: 10.1016/j.chroma.2023.464241
    This study compares different solvent systems with the use of spontaneous fermentation on the phytochemical composition of leaf extracts from a locally grown white variety of common fig (Ficus carica Linn.). The aim was to detect and identify bioactive compounds that are responsible for acetylcholinesterase (AChE), α-amylase and cyclooxygenase-1 (COX-1) enzyme inhibition, and compounds that exhibit antimicrobial activity. Bioactive zones in chromatograms were detected by combining High-performance thin-layer chromatography (HPTLC) with enzymatic and biological assays. A new experimental protocol for measuring the relative half-maximum inhibitory concentration (IC50) was designed to evaluate the potency of the extracts compared to the potency of known inhibitors. Although the IC50 of the fig leaf extract for α-amylase and AChE inhibition were significantly higher when compared to IC50 for acarbose and donepezil, the COX-1 inhibition by the extract (IC50 = 627 µg) was comparable to that of salicylic acid (IC50 = 557 µg), and antimicrobial activity of the extract (IC50 = 375-511 µg) was similar to ampicillin (IC50 = 495 µg). Four chromatographic zones exhibited bioactivity. Compounds from detected bioactive bands were provisionally identified by comparing the band positions to coeluted standards, and by Fourier transform infrared (FTIR) spectra from eluted zones. Flash chromatography was used to separate selected extract into fractions and isolate fractions that are rich in bioactive compounds for further characterisation with nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS) analysis. The main constituents identified were umbelliferon (zone 1), furocoumarins psoralen and bergapten (zone 2), different fatty acids (zone 3 and 4), and pentacyclic triterpenoids (calotropenyl acetate or lupeol) and stigmasterol (zone 4).
  7. Analysis of Condition Index in Polymesoda expansa (Mousson 1849)
    Abdul Rahim A, Idris MH, Kamal AH, Wong SK, Arshad A
    Pak J Biol Sci, 2012 Jul 01;15(13):629-34.
    PMID: 24218932
    The Condition Index (CI) is a method to measure overall health of fish and that has been applied to estimate the effect that different environmental factors have on clam meat quality. The CI of local mangrove clam Polymesoda expansa in Kelulit, Miri Sarawak was determined from October 2010 to November 2011. Condition index that is generally used to characterize the physiological activity of organisms, varied from 1.8% in December 2010 to 3.4% in October 2011, with low values observed during the spawning period. The clam attained their best condition in quality of flesh weight during July-October. In present study, the CI showed a clear relationship with the reproductive cycle of P. expansa. However, no significant correlation (p > 0.05) was found between CI and the different physicochemical parameter of seawater. The data presented is necessary for developing sustainable management strategies and broodstock selection for the species which is crucial in aquaculture development.
  8. Bioassay-guided detection, identification and assessment of antibacterial and anti-inflammatory compounds from olive tree flower extracts by high-performance thin-layer chromatography linked to spectroscopy
    Agatonovic-Kustrin S, Wong S, Dolzhenko AV, Gegechkori V, Morton DW
    J Pharm Biomed Anal, 2024 Feb 15;239:115912.
    PMID: 38128161 DOI: 10.1016/j.jpba.2023.115912
    Olive trees are one of the most widely cultivated fruit trees in the world. The chemical compositions and biological activities of olive tree fruit and leaves have been extensively researched for their nutritional and health-promoting properties. In contrast, limited data have been reported on olive flowers. The present study aimed to analyse bioactive compounds in olive flower extracts and the effect of fermentation-assisted extraction on phenolic content and antioxidant activity. High-performance thin-layer chromatography (HPTLC) hyphenated with the bioassay-guided detection and spectroscopic identification of bioactive compounds was used for the analysis. Enzymatic and bacterial in situ bioassays were used to detect COX-1 enzyme inhibition and antibacterial activity. Multiple zones of antibacterial activity and one zone of COX-1 inhibition were detected in both, non-fermented and fermented, extracts. A newly developed HPTLC-based experimental protocol was used to measure the high-maximal inhibitory concentrations (IC50) for the assessment of the relative potency of the extracts in inhibiting COX-1 enzyme and antibacterial activity. Strong antibacterial activities detected in zones 4 and 7 were significantly higher in comparison to ampicillin, as confirmed by low IC50 values (IC50 = 57-58 µg in zone 4 and IC50 = 157-167 µg in zone 7) compared to the ampicillin IC50 value (IC50 = 495 µg). The COX-1 inhibition by the extract (IC50 = 76-98 µg) was also strong compared to that of salicylic acid (IC50 = 557 µg). By comparing the locations of the bands to coeluted standards, compounds from detected bioactive bands were tentatively identified. The eluates from bioactive HPTLC zones were further analysed by FTIR NMR, and LC-MS spectroscopy. Multiple zones of antibacterial activity were associated with the presence of triterpenoid acids, while COX-1 inhibition was related to the presence of long-chain fatty acids.
  9. Preparation and Optimization OF Palm-Based Lipid Nanoparticles Loaded with Griseofulvin
    Huei Lim W, Jean Tan Y, Sin Lee C, Meng Er H, Fung Wong S
    Iran J Pharm Res, 2017;16(2):451-461.
    PMID: 28979300
    Palm-based lipid nanoparticle formulation loaded with griseofulvin was prepared by solvent-free hot homogenization method. The griseofulvin loaded lipid nanoparticles were prepared via stages of optimisation, by altering the high pressure homogenisation (HPH) parameters, screening on palm-based lipids and Tween series surfactants and selection of lipid to surfactant ratios. A HPLC method has been validated for the drug loading capacity study. The optimum HPH parameter was determined to be 1500 bar with 5 cycles and among the palm-based lipid materials; Lipid C (triglycerides) was selected for the preparation of lipid nanoparticles. Tween 80 was chosen from the Tween series surfactants for its highest saturated solubility of griseofulvin at 53.1 ± 2.16 µg/mL. The optimum formulation of the griseofulvin loaded lipid nanoparticles demonstrated nano-range of particle size (179.8 nm) with intermediate distribution index (PDI) of 0.306, zeta potential of -27.9 mV and drug loading of 0.77%. The formulation was stable upon storage for 1 month at room temperature (25 (°)C) and 45 (°)C with consistent drug loading capacity.
  10. A comparative histopathological study of systemic candidiasis in association with experimentally induced breast cancer
    Choo ZW, Chakravarthi S, Wong SF, Nagaraja HS, Thanikachalam PM, Mak JW, et al.
    Oncol Lett, 2010 Jan;1(1):215-222.
    PMID: 22966285
    Systemic candidiasis is a fungal infection which coupled with solid malignancies places patients at high risk of succumbing to the disease. Few studies have shown evidence of the relationship between systemic candidiasis and malignancy-induced immunosuppression disease especially in breast cancer. At present, animal studies that exclusively demonstrate this relationship have yet to be conducted. The exact causative mechanism of systemic candidiasis is currently under much speculation. This study therefore aimed to demonstrate this relationship by observing the histopathological changes of organs harvested from female Balb/c mice which were experimentally induced with breast cancer and inoculated with systemic candidiasis. The mice were randomly assigned to five different groups (n=12). The first group (group 1) was injected with phosphate buffer solution, the second (group 2) with systemic candidiasis, the third (group 3) with breast cancer and the final two groups (groups 4 and 5) had both candidiasis and breast cancer at two different doses of candidiasis, respectively. Inoculation of mice with systemic candidiasis was performed by an intravenous injection of Candida albicans via the tail vein following successful culture methods. Induction of mice with breast cancer occurred via injection of 4T1 cancer cells at the right axillary mammary fatpad after effective culture methods. The prepared slides with organ tissues were stained with hematoxylin and eosin, periodic acidic schiff and gomori methenamine silver stains for a histopathological analysis. Grading of primary tumour and identification of metastatic deposits, as well as scoring of inflammation and congestion in all the respective organs was conducted. Statistical tests performed to compare groups 2 and 4 showed that group 4 exhibited a highly statistically significant increase in organ inflammation and congestion (p<0.01). The median severity of candidiasis in the kidneys and liver also increased in group 4 as compared to group 2. In conclusion, based on the above evidence, systemic candidiasis significantly increased in mice with breast cancer.
  11. Fulltext Effective removal of anionic textile dyes using adsorbent synthesized from coffee waste
    Wong S, Ghafar NA, Ngadi N, Razmi FA, Inuwa IM, Mat R, et al.
    Sci Rep, 2020 Feb 19;10(1):2928.
    PMID: 32076087 DOI: 10.1038/s41598-020-60021-6
    Adsorption of Reactive Black 5 and Congo Red from aqueous solution by coffee waste modified with polyethylenimine was investigated. The removal percentages of both dyes increased with amount of polyethyleneimine in the modified adsorbent. Characterization revealed that polyethyleneimine modification improved the adsorbent surface chemistry, while slight improvement of adsorbent textural properties was also observed. The adsorbent's excellent performance was demonstrated by high removal percentages towards the anionic dyes in most experimental runs. The modelling result showed that anionic dyes adsorption occurred via monolayer adsorption, and chemisorption was the rate-controlling step. The adsorbent possesses higher maximum adsorption capacity towards Reactive Black 5 (77.52 mg/g) than Congo Red (34.36 mg/g), due to the higher number of functional groups in Reactive Black 5 that interact with the adsorbent. This study reveals the potential of adsorbent derived from coffee waste in textile wastewater treatment. Furthermore, surface chemistry modification is proven as an effective strategy to enhance the performance of biowaste-derived adsorbents.
  12. Anhedonia among patients with Major Depressive Disorder: A comparison between patients on escitalopram and healthy controls
    Ng CG, Wong SK, Loh HS, Yee A
    Clin Ter, 2014;165(6):e384-90.
    PMID: 25524191 DOI: 10.7417/CT.2014.1778
    BACKGROUND AND AIMS: Escitalopram has widely been recognized as one of the most frequently used antidepressants, with superior tolerability and great efficacy in preventing major depressive disorder (MDD) relapse and recurrence. However, anhedonia, which is a core symptom of MDD, remains difficult to treat. This study investigates the hedonic levels of MDD patients treated with Escitalopram.

    MATERIALS AND METHODS: A total of 108 participants, 26 of whom with MDD on Escitalopram, were recruited in this cross sectional study. They were evaluated using the Snaith-Hamilton Pleasure Scale (SHAPS) and Beck Depression Inventory (BDI) questionnaires to assess their hedonic state, general mental health condition and level of depression.

    RESULTS: Our study shows that most items in the SHAPS scores are significantly different between MDD patients on Escitalopram and the controls.

    CONCLUSIONS: The hedonic capacity remains different between the two groups despite patients with MDD are put on Escitalopram treatment. Escitalopram fails to alleviate the hedonic state of MDD patients. Antidepressants that improve both depressive symptoms and hedonic states should be considered when treating MDD patients in clinical settings.
  13. Biological properties of sodium alkyl methyl ester sulfonate/alkyltrimethylammonium bromide surfactant mixtures
    Wong SP, Lim WH, Cheng SF, Chuah CH
    Colloids Surf B Biointerfaces, 2012 Jan 1;89:48-52.
    PMID: 21937202 DOI: 10.1016/j.colsurfb.2011.08.021
    Quaternary ammonium compounds (QACs) are commonly used as disinfectant in medical care, food industry, detergents and glue industries. This is due to a small concentration of QACs is sufficient to inhibit the growth of various bacteria strains. In this work, the inhibitive power of cationic surfactants, alkyltrimethylammonium bromide (C(n)TAB) in the presence of anionic surfactants, sodium alkyl methyl ester α-sulfonate (C(n)MES) was studied. The growth inhibition test with gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria were used to determine the toxicity of single and mixed surfactants. Results from this work showed that certain mixed surfactants have lower minimum inhibition concentration (MIC) as compared to the single C(n)TAB surfactants. Besides that, it was also found that alkyl chain length and the mixing ratios of the surfactants play a significant role in determining the mixture inhibitive power.
  14. Relationship between cervical spine injury and helmet use in motorcycle road crashes
    Ooi SS, Wong SV, Yeap JS, Umar R
    Asia Pac J Public Health, 2011 Jul;23(4):608-19.
    PMID: 21768134 DOI: 10.1177/1010539511413750
    Motorcycle helmets have been proven to prevent head injury and reduce fatality in road crashes. However, certain studies indicate that the helmet increases the mass to the head, and thus the potential of neck injury due to the flexion/extension of the head-neck segment in a road crash may increase. This study was conducted to evaluate the effects of motorcycle helmets and the ways in which the accidents that occurred affected the incidence of cervical spine injury. Nevertheless, it is not intended to and does not discredit the fact that helmet use prevents many motorcyclists from sustaining serious and fatal head injuries. A total of 76 cases were collected and analyzed based on the data collected from real-world crashes. The Abbreviated Injury Scale (AIS) was used to assess the severity of injury, whereas the statistical Pearson χ(2) correlation method was used for analysis. The results showed that motorcycle helmets did not affect the severity of cervical spine injury. However, when the samples were further subcategorized into different crash modes, it was found that helmets affect the incidence of a severe cervical spine injury. In frontal collisions, the use of helmets significantly reduces the severity of cervical spine injury, whereas in rear-end, side impact, and skidded accidents, the use of helmets increases the probability of a severe cervical spine injury. However, in the latter crash modes, a motorcyclist without a helmet will have to trade-off with head injury. A logistic regression model has been developed with respective crash modes and the probabilities of risk in having severe cervical spine injury have been calculated. Future designs in motorcycle helmets should therefore consider the significance of nonfrontal accidents and the interaction of helmet with other parts of the body by possibly considering the weight of the helmet.
  15. Effectiveness of a colour coded HbA1c graphical record in improving diabetes control in people with type 2 diabetes: a randomized control trial
    Wong SS, Ng CJ, Liew SM, Hussein N
    Diabetes Res Clin Pract, 2012 Feb;95(2):e41-4.
    PMID: 22119614 DOI: 10.1016/j.diabres.2011.11.001
    We conducted a six-month randomized-controlled-trial to evaluate the effectiveness of a colour-coded HbA1c-graphical record in improving HbA1c level among type 2 diabetes patients. There was an improvement in the mean HbA1c knowledge score but the usage of the colour-coded HbA1c-graphical record did not produce reduction in the HbA1c level.
    Study site: Primary care clinic, University Malaya Medical Centre, Kuala Lumpur, Malaysia
  16. Simulation of motorcycle crashes with w-beam guardrail: injury patterns and analysis
    Ibitoye AB, Hamouda AM, Wong SV, Umar RS
    Proc Inst Mech Eng H, 2009 Nov;223(8):1033-40.
    PMID: 20092099
    This study uses computer simulations to study the impact of a motorcycle with the conventional w-beam guardrail. A three-dimensional computer simulation of a scaled hybrid III 50th-percentile male dummy mounted on a motorcycle and colliding with a w-beam guardrail is carried out. A multi-body model of the motorcycle and finite element model of the guardrail are developed using commercially available software. The simulation model is validated with a physical crash test conducted with same initial impact configurations. Impacts at speeds of 32, 48, and 60 km/h at an impact angle at 45 degrees are considered. The predicted forces and accelerations are compared with the biomechanical limits for each body part and the risk of injury to the rider are evaluated. Speed was found to have a significant influence on the level of injury to the head, neck, chest, and femur. A significant reduction of the severity of injuries was found when the impact speed was reduced from 60 to 32km/h. The accelerations experienced by the head and chest are found to be higher than safe levels for impact speeds of 48 and 60 km/h. The biomechanical limit for the right femur is exceeded at all three considered impact speeds. Neck injuries are also a concern, with the predicted tension values and neck bending extent being higher than the biomechanical limit for the 60 km/h impact speed. In light of these results, it is suggested that the design of guardrails should be reviewed with a focus on the safety of motorcyclists.
  17. Immunogenic properties of recombinant ectodomain of Newcastle disease virus hemagglutinin-neuraminidase protein expressed in Escherichia coli
    Wong SK, Tan WS, Omar AR, Tan CS, Yusoff K
    Acta Virol., 2009;53(1):35-41.
    PMID: 19301949
    Hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus (NDV) plays a vital role in the viral infectivity, host immunity, and disease diagnosis. A portion of the HN gene encoding the ectodomain (nt 142-1739) was cloned and expressed in Escherichia coli yielding an insoluble HN protein and a soluble NusA-HN protein containing N-utilization substance A (NusA) fusion component. Both recombinant proteins were purified and used for immunization of chickens. The recombinant HN protein induced higher antibody titers as compared to the recombinant NusA-HN protein. These antibodies were able to react in immunoblot analysis with the corresponding recombinant proteins as well as with the HN protein of NDV.
  18. New mechanical disruption method for extraction of whole cell protein from Candida albicans
    Wong SF, Mak JW, Pook PC
    Southeast Asian J. Trop. Med. Public Health, 2007 May;38(3):512-8.
    PMID: 17877228
    Cell disruption or lysis is a crucial step to obtain cellular components for various biological studies. We subjected different concentrations of Candida albicans to 5, 10, 15 and 20 cycles of disruption. The degree of cell lysis was observed using light microscopy and the yields obtained were measured and analysed. The optimum extraction with 1 x 10(10) yeast cells/ml was achieved after 5 cycles of disruption with 1.0 mm diameter glass beads at 5,000 rpm. Approximately 80% of the cells were lysed and the protein yield was 6,000 microg/ml. SDS-PAGE analysis revealed approximately 25 distinct protein bands with molecular weights ranging from 8 kDa to 220 kDa. We conclude that this mechanical disruption of fungal cells is a rapid, efficient and inexpensive technique for extracting whole cell proteins from yeast cells.
  19. Optimization of coagulation-flocculation process for pulp and paper mill effluent by response surface methodological analysis
    Ahmad AL, Wong SS, Teng TT, Zuhairi A
    J Hazard Mater, 2007 Jun 25;145(1-2):162-8.
    PMID: 17161910
    Coagulation-flocculation is a proven technique for the treatment of high suspended solids wastewater. In this study, the central composite face-centered design (CCFD) and response surface methodology (RSM) have been applied to optimize two most important operating variables: coagulant dosage and pH, in the coagulation-flocculation process of pulp and paper mill wastewater treatment. The treated wastewater with high total suspended solids (TSS) removal, low SVI (sludge volume index) and high water recovery are the main objectives to be achieved through the coagulation-flocculation process. The effect of interactions between coagulant dosage and pH on the TSS removal and SVI are significant, whereas there is no interaction between coagulant dosage and water recovery. Quadratic models have been developed for the response variables, i.e. TSS removal, SVI and water recovery based on the high coefficient of determination (R(2)) value of >0.99 obtained from the analysis of variances (ANOVA). The optimum conditions for coagulant dosage and pH are 1045mgL(-1) and 6.75, respectively, where 99% of TSS removal, SVI of 37mLg(-1) and 82% of water recovery can be obtained.
  20. Treatment of pulp and paper mill wastewater by polyacrylamide (PAM) in polymer induced flocculation
    Wong SS, Teng TT, Ahmad AL, Zuhairi A, Najafpour G
    J Hazard Mater, 2006 Jul 31;135(1-3):378-88.
    PMID: 16431022
    The flocculation performances of nine cationic and anionic polyacrylamides with different molecular weights and different charge densities in the treatment of pulp and paper mill wastewater have been studied. The experiments were carried out in jar tests with the polyacrylamide dosages range of 0.5-15 mg l(-1), rapid mixing at 200 rpm for 2 min, followed by slow mixing at 40 rpm for 15 min and settling time of 30 min. The effectiveness of the polyacrylamides was measured based on the reduction of turbidity, the removal of total suspended solids (TSS) and the reduction of chemical oxygen demand (COD). Cationic polyacrlyamide Organopol 5415 with very high molecular weight and low charge density is found to give the highest flocculation efficiency in the treatment of the paper mill wastewater. It can achieve 95% of turbidity reduction, 98% of TSS removal, 93% of COD reduction and sludge volume index (SVI) of 14 ml g(-1) at the optimum dosage of 5 mg l(-1). SVI values of less than 70 m lg(-1) are found for all polyacrylamide at their respective optimum dosage. Based on the cost evaluation, the use of the polyacrylamides is economically feasible to treat the pulp and paper mill wastewaters. This result suggests that single-polymer system can be used alone in the coagulation-flocculation process due to the efficiency of the polyacrylamide. Sedimentation of the sludge by gravity thickening with settling time of 30 min is possible based on the settling characteristics of the sludge produced by Organopol 5415 that can achieve 91% water recovery and 99% TSS removal after 30 min settling.
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