Browse publications by year: 2016

  1. Mohd. Yunus Shukor
    MyJurnal
    The growth of microorganism on substrates, whether toxic or not usually exhibits sigmoidal
    pattern. This sigmoidal growth pattern can be modelled using primary models such as Logistic,
    modified Gompertz, Richards, Schnute, Baranyi-Roberts, Von Bertalanffy, Buchanan threephase
    and Huang. Previously, the modified Gompertz model was chosen to model the growth of
    Burkholderia sp. strain Neni-11 on acrylamide, which shows a sigmoidal curve. The modified
    Gompertz model relies on the ordinary least squares method, which in turn relies heavily on
    several important assumptions, which include that the data does not show autocorrelation. In this
    work we perform statistical diagnosis test to test for the presence of autocorrelation using the
    Durbin-Watson test and found that the model was adequate and robust as no autocorrelation of
    the data was found.
    MeSH terms: Biological Phenomena; Biometry; Cell Cycle; Least-Squares Analysis; Burkholderia; Acrylamide; Cell Proliferation
  2. Yadzir, Z.H.M., Gafar, A.A., Rahman, M.F., Yakasai, M.H., Abdullah, M.A., Shamaan, N.A., et al.
    MyJurnal
    Contamination of organic xenobiotic pollutants and heavy metals in a contaminated site allows
    the use of multiple bacterial degraders or bacteria with the ability to detoxify numerous toxicants
    at the same time. A previously isolated SDS- degrading bacterium, Acinetobacter baumannii
    strain Serdang 1 was shown to reduce molybdenum to molybdenum-blue. The bacterium works
    optimally at pH 6.5, the temperature range between 25 and 34°C with glucose serves as the best
    electron donor for molybdate reduction. This bacterium required additional concentration of
    phosphate at 5.0 mM and molybdate between 15 and 25 mM. The absorption spectrum of the
    molybdenum blue obtained is similar to the molybdenum blue from other earlier reported
    molybdate reducing bacteria, as it resembles a reduced phosphomolybdate closely. Ag(i), As(v),
    Pb(ii) and Cu(ii) inhibited molybdenum reduction by 57.3, 36.8, 27.7 and 10.9%, respectively, at
    1 p.p.m. Acrylamide was efficiently shown to support molybdenum reduction at a lower
    efficiency than glucose. Phenol, acrylamide and propionamide could support the growth of this
    bacterium independently of molybdenum reduction. This bacterium capability to detoxify several
    toxicants is an important tool for bioremediation in the tropical region.
  3. Abubakar M. Umar, Tham, Lik Gin, Natarajan Perumal, Nur A. Yasid, Hassan Mohd Daud, Mohd Y. Shukor
    MyJurnal
    In this work we assess the potential of acetylcholinesterase (AChE) from Oreochromis
    mossambicus (Toman) as a sensitive test for the presence of insecticides. The partial purification
    and characterization of a soluble AChE from Oreochromis mossambicus brain tissues using
    affinity chromatography gel (procainamide–Sephacryl S-1000) showed that the partially purified
    AChE was most active on acetylthiocholine (ATC) but had low activities on
    propionylthiocholine (PTC) and butyrylthiocholine (BTC), indicating that the partially purified
    fraction was predominantly AChE. Soluble AChE was partially purified 9.27-fold with a 91.12%
    yield. The partially purified AChE displayed the highest activity on ATC at pH 7 and at 30oC
    using 0.1 M Tris buffer. The enzyme exhibited Michaelis-Menten kinetic constants, Km, for
    ATC, BTC and PTC at 36, 77 and 250 μM, respectively, and the maximum velocities, Vmax, were
    18.75, 0.12 and 0.05 μmol/min/mg protein, respectively. Moreover, the AChE from
    Oreochromis mossambicus presented comparable sensitivity to carbamates and
    organophosphates insecticides than that from Electrophorus electricus and many other fish
    AChE by comparing half maximal inhibitory concentration values. Therefore, the enzyme is a
    valuable source for insecticides detection in Malaysian waters at lower cost.
  4. Abubakar M. Umar, Tham, Lik Gin, Natarajan Perumal, Nur Adeela Yasid, Hassan Mohd Daud, Mohd Yunus Shukor
    MyJurnal
    Acetylcholinesterase (AChE) is usually used as an inhibitive assay for insecticides. A lesserknown
    property of AChE is its inhibition by heavy metals. In this work, we evaluate an AChE
    from brains of Clarias batrachus (catfish) exposed to wastes from aquaculture industry as an
    inhibitive assay for heavy metals. We discovered that the AChE was inhibited completely by
    Hg2+, Ag2+, Pb2+, Cu2+, Cd2+, Cr6+ and Zn2+ during initial screening. When tested at various
    concentrations, the heavy metals exhibited exponential decay type inhibition curves. The
    calculated IC50 (mg/L) for the heavy metals Ag2+, Cu2+, Hg2+, Cr6+ and Cd2+ were 0.088, 0.078,
    0.071, 0.87 and 0.913, respectively. The IC50 for these heavy metals are comparable, and some
    are lower than the IC50 values from the cholinesterases from previously studied fish. The assay
    can be carried out in less than 30 minutes at ambient temperature.
    MeSH terms: Acetylcholinesterase; Animals; Biological Assay; Brain; Catfishes; Cholinesterases; Insecticides; Temperature; Aquaculture; Metals, Heavy; Inhibitory Concentration 50
  5. Yakasai, H.M., Karamba, K.I., Yasid, N.A., Abd. Rahman, F., Shukor, M.Y., Halmi, M.I.E.
    MyJurnal
    Molybdenum, an emerging pollutant, has being demonstrated recently to be toxic to
    spermatogenesis in several animal model systems. Metal mines especially gold mine often use
    cyanide and hence isolation of metal-reducing and cyanide-degrading bacteria can be useful for
    the bioremediation of these pollutants. Preliminary screening shows that three cyanide-degrading
    bacteria were able to reduce molybdenum to molybdenum blue (Mo-blue) when grown on a
    molybdate low phosphate minimal salts media. Phylogenetic analyses of the 16S rRNA gene of
    the best reducer indicates that it belongs to the Serratia genus. A variety of mathematical models
    such as logistic, Gompertz, Richards, Schnute, Baranyi-Roberts, von Bertalanffy, Buchanan
    three-phase and Huang were used to model molybdenum reduction, and the best model based on
    statistical analysis was modified Gompertz with lowest values for RMSE and AICc, highest
    adjusted R2 values, with Bias Factor and Accuracy Factor nearest to unity (1.0). The reduction
    constants obtained from the model will be used to carry out secondary modelling to study the
    effect of various parameters such as substrate, pH and temperature to molybdenum reduction.
    MeSH terms: Animals; Biodegradation, Environmental; Cyanides; Gold; Models, Theoretical; Molybdenum; Phosphates; Phylogeny; RNA, Ribosomal, 16S; Salts; Serratia; Spermatogenesis; Temperature; Models, Animal
  6. Pan B, Pei FQ, Ruan CW, Lin RX, Cen YZ, Liu MR, et al.
    PMID: 30141606
    Objective: To diagnose and treat the first imported active case of Plasmodium knowlesi infection in China.

    Methods: The clinical information of the patient was collected. Microscopy of blood smear was conducted after Giemsa staining. Genomic DNA was extracted from blood, and PCR was conducted to amplify rDNA. The PCR products were sequenced and analyzed with BLAST

    Results: The patient returned from a one-week tour in a tropical rain forest in Malaysia. The first disease attack occurred in Guangzhou on Oct. 16, 2014, with fever, shivering and sweating. The patient was initially diagnosed as malaria and hospitalized on Oct. 26, 2014. Microscopic observation revealed typical forms of P. knowlesi in blood smear. The red blood cells became enlarged, with big trophozoites appearing as a ring with dual cores and dark brown malaria pigment. The trophozoites were slightly bigger and thicker than P. falciparum. The schizont had 6-8 merozoites, with obvious brown malaria pigment. PCR resulted in a specific band of 1 099 bp. BLAST analysis showed that the sequence of the PCR product was 99% homologous to P. knowlesi (acession No. AM910985.1, L07560.1 and AY580317.1). The patient was diagnosed as P. knowlesi infection, and was then given an 8-day treatment with chloroquine and primaquine, together with dihydroartemisinin piperaquine phosphate tablet. The patient was discharged after recovery on Oct. 28, 2014.

    Conclusion: According to the clinical symptoms, epidemiological history and laboratory test, the patient has been confirmed as P. knowlesi infection. It may also be the first active case of knowlesi malaria reported in China.

    MeSH terms: Animals; Antimalarials; China; Chloroquine; Erythrocytes; Hemeproteins; Humans; Malaria*; Microscopy; Primaquine; Quinolines; Polymerase Chain Reaction; Plasmodium knowlesi*; Artemisinins; Trophozoites
  7. Goh YK, Marzuki NF, Tan SY, Tan SS, Tung HJ, Goh YK, et al.
    Mycology, 2016;7(1):36-44.
    PMID: 30123614 DOI: 10.1080/21501203.2015.1137985
    The influence of different medium components (glucose, sucrose, and fructose) on the growth of different Ganoderma isolates and species was investigated using mixture design. Ten sugar combinations based on three simple sugars were generated with two different concentrations, namely 3.3% and 16.7%, which represented low and high sugar levels, respectively. The media were adjusted to either pH 5 or 8. Ganoderma isolates (two G. boninense from oil palm, one Ganoderma species from coconut palm, G. lingzhi, and G. australe from tower tree) grew faster at pH 8. Ganoderma lingzhi proliferated at the slowest rate compared to all other tested Ganoderma species in all the media studied. However, G. boninense isolates grew the fastest. Different Ganoderma species were found to have different sugar preferences. This study illustrated that the mixture design can be used to determine the optimal combinations of sugar or other nutrient/chemical components of media for fungal growth.
    MeSH terms: Biological Phenomena; Cocos; Food; Fructose; Fungi; Glucose; Monosaccharides; Sucrose; Trees; Reishi; Arecaceae; Ganoderma
  8. Aftab RA, Khan AH, SYed Sulaiman SA, Ali I, Hassali A, Saleem F
    Turk J Med Sci, 2016 Nov 17;46(5):1300-1305.
    PMID: 27966326 DOI: 10.3906/sag-1405-45
    BACKGROUND/AIM: Multiple asthma guidelines have been developed to reduce asthma mortality, morbidity, and cost associated with asthma worldwide. In Malaysia, within this context, it is relatively unknown to what extent doctors adhere to the asthma guidelines. This study aimed to assess guideline adherence and calculate the cost of adhered and nonadhered prescriptions by medical doctors in a public tertiary health care facility.
    MATERIALS AND METHODS: A cross-sectional study was carried out at Hospital Pulau Pinang, Malaysia. One hundred and eighty patients, a total of 30 patients per doctor, were enrolled to assess guideline adherence. The patients were followed for a second visit to assess their lung function. The costs of adhered and nonadhered prescriptions were calculated.
    RESULTS: One hundred and forty-three patients (79%) received guideline (Global Initiative for Asthma 2011)-adhering pharmacotherapy. In the majority of patients (n = 133, 73.9%) asthma control was classified as partially controlled. There was no significant association observed between patient asthma control and patient demographics; however, there was a significant difference (P < 0.001) between lung function values from the first and second visits. The cost of adhered prescription was higher (70.1 Malaysian ringgit) than that of nonadhered prescription (13.74 Malaysian ringgit).
    CONCLUSION: Fair levels of guideline adherence were observed. Emphasis should be placed on identifying appropriate cost-effective medication regimens based on patient asthma control and constant feedback from patients.
    Study site: Respiratory clinic, Hospital Pulau Pinang, Pulau Pinang, Malaysia
    MeSH terms: Asthma*; Cross-Sectional Studies; Hospitals, General; Humans; Malaysia; Outpatient Clinics, Hospital; Guideline Adherence; Tertiary Care Centers
  9. Zahari Z, Inrahim MA, Tan SC, Mohamad N, Ismail R
    Turk J Med Sci, 2016 Dec 20;46(6):1743-1748.
    PMID: 28081321 DOI: 10.3906/sag-1507-132
    BACKGROUND/AIM: Sleep disturbances may contribute to poor treatment outcomes in opioid-dependent patients. The extent to which the sleep profiles of opioid-dependent patients differ from those of the general Malaysian population is not documented. This study compared opioid-naive subjects and opioid-dependent patients on methadone maintenance therapy (MMT) in terms of their sleep quality.

    MATERIALS AND METHODS: Participants comprised Malay male opioid-naive subjects (n = 159) and opioid-dependent patients (n = 160) from MMT clinics in Kelantan, Malaysia, between March and October 2013. Sleep quality was evaluated using the translated and validated Malay version of the Pittsburgh Sleep Quality Index (PSQI).

    RESULTS: The opioid-dependent patients exhibited higher global PSQI scores [adjusted mean (95% CI) = 5.46 (5.02, 5.90)] than the opioid-naive group [4.71 (4.26, 5.15)] [F (1, 313) = 4.77, P = 0.030].

    CONCLUSION: This study confirmed the poorer sleep quality among opioid-dependent patients on MMT, as manifested by their higher global PSQI scores. The sleep complaints in this patient population are a factor to consider and, when necessary, sleep evaluation and treatment should be undertaken to improve MMT patients' quality of sleep and overall treatment outcome.

    MeSH terms: Analgesics, Opioid; Humans; Malaysia; Male; Methadone; Opioid-Related Disorders; Sleep*; Sleep Wake Disorders
  10. Mustafa S, Hassan NB, Tan SC, Ab Rahman AK, Low LL, Wan Yusuf WN
    Turk J Med Sci, 2016 Dec 20;46(6):1875-1881.
    PMID: 28081342 DOI: 10.3906/sag-1503-116
    BACKGROUND/AIM: Nevirapine is a reverse-transcriptase inhibitor widely used in combination therapy to treat HIV infection. Nevirapine is extensively metabolized in the liver and CYP2B6 is mainly responsible for oxidation of 3-hydroxynevirapine (3-OH NVP). This study aims to explore CYP2B6 activity by measuring 2-hydroxynevirapine (2-OH NVP) and 3-OH NVP in plasma and to identify factors associated with nevirapine pharmacokinetic parameters.

    MATERIALS AND METHODS: A total of 112 patients were recruited and treated with nevirapine-based antiretroviral therapy. Plasma nevirapine and metabolite concentrations were assayed using high-performance liquid chromatography via liquid-liquid extraction.

    RESULTS: Thirty-nine (34.8%) of the patients had no 3-OH NVP detected in their plasma while 2-OH NVP was detected in all patients. Metabolite concentrations were low compared to nevirapine. Positive correlations were observed between nevirapine and its metabolites, 2-OH NVP (P < 0.01) and 3-OH NVP (P = 0.012). Nevirapine concentration was decreased when concomitantly administered with methadone. Univariate analysis showed that ALT level, AST level, and detection of 3-OH NVP were associated with nevirapine pharmacokinetic parameters.

    CONCLUSION: The variability of nevirapine pharmacokinetic parameters was caused by liver enzymes and the presence of 3-OH NVP metabolites. The presence of 3-OH NVP can probably be used to distinguished CYP2B6 activity and efficacy of nevirapine in patients with HIV infection.

    MeSH terms: Humans; HIV Infections; Reverse Transcriptase Inhibitors; Anti-HIV Agents; Nevirapine; Cytochrome P-450 CYP2B6/blood*
  11. Mohd. Yunus Shukor
    MyJurnal
    Most often than not, microorganism’s growth curve is sigmoidal in characteristics.
    The modified Gompertz model via nonlinear regression using the least square method
    is one of the most popular methods to describe the growth curve. One of the
    assumptions of a good model is that the variance of the data must be homogenous
    (homoscedasticity). In this work, two statistical diagnostics; the Bartlett and the
    Levene’s tests was performed to a modified Gompertz model utilized to model the
    growth of the bacterium Burkholderia sp. strain Neni-11 on acrylamide in order to
    satisfy the requirement above and found that data conformed to the requirement
    indicating the modified Gompertz model is a robust model for modelling the bacterial
    growth process.
  12. Abo-Shakeer, L.K.A., Yakasai, M.H., Rahman, M.F., Syed, M.A., Bakar, N.A., Othman, A.R.
    MyJurnal
    Molybdenum is an emerging pollutant. Bioremediation of this heavy metal is possible by the
    mediation of Mo-reducing bacteria. These bacteria contain the Mo-reducing enzymes that can
    conver toxic soluble molybdenum into molybdenum blue; a less soluble and less toxic form of the
    metal. To date only the enzyme has been purified from only one bacterium. The aim of this study is
    to purify the Mo-reducing enzyme from a previously isolated Mo-reducing bacterium Bacillus
    pumilus strain Lbna using ammonium sulphate fractionation followed by ion exchange and then
    gel filtration. Two clear bands were obtained after the gel filtration step with molecular weights
    of 70 and 100 kDa. This indicates that further additional purification methods need to be used
    to get a purified fraction. Hence, additional steps of chromatography such as hydroxyapatite or
    chromatofocusing techniques can be applied in the future.
    MeSH terms: Ammonium Sulfate; Bacillus; Biodegradation, Environmental; Chromatography, Gel; Ion Exchange; Molecular Weight; Molybdenum; Durapatite; Metals, Heavy
  13. Halmi, M.I.E., Khayat, M.E., Rahman, M.F.A., Gunasekaran, B., Masdor, N.A.
    MyJurnal
    In this work, a temporal monitoring work for heavy metals from an effluent discharge point in
    the Juru Industrial Estate was carried out using the protease extracted from garlic (Allium
    sativum) as the principal bioassay system. casein-Coomassie-dye binding assay method has
    utilized this purpose. The periodic sampling results for one day of a location in the Juru
    Industrial Estate showed temporal variation of copper concentration coinciding with garlic
    protease inhibition with the highest concentrations of copper occurring between 12.00 and 16.00
    hours of between 3 and 3.5 mg/L copper. The crude proteases extracted from Allium sativum
    successfully detect temporal variation of copper form this location. In conclusion, this assay
    method has the potential to be a rapid, sensitive, and economic inhibitive assay for the largescale
    biomonitoring works for the heavy metal copper from this area.
    MeSH terms: Biological Assay; Caseins; Copper; Environmental Monitoring; Garlic; Peptide Hydrolases; Endopeptidases; Protease Inhibitors; Metals, Heavy
  14. Jamulidin, S.N.K., Manogaran. M., Yakasai, M.H., Rahman, M.F.A., Shukor, M.Y.
    MyJurnal
    In this study, a novel glyphosate-degrading shows the ability to reduce molybdenum to
    molybdenum blue. The enzyme from this bacterium was partially purified and partially
    characterized to ascertain whether the Mo-reducing enzyme from this bacterium shows better or
    lower efficiency in reducing molybdenum compared to other Mo-reducing bacterium that only
    exhibits a single biotransformation activity. The enzyme was partially purified using ammonium
    sulphate fractionation. The Vmax for the electron donating substrate or NADH was at 1.905 nmole
    Mo blue/min while the Km was 6.146 mM. The regression coefficient was 0.98. Comparative
    assessment with the previously characterized Mo-reducing enzyme from various bacteria showed
    that the Mo-reducing enzyme from Burkholderia vietnamiensis strain AQ5-12 showed a lower
    enzyme activity.
    MeSH terms: Biotransformation; Electrons; Glycine; Molybdenum; NAD; Sulfates; Sulfur Oxides; Burkholderia; Ammonium Compounds
  15. Abubakar Aisami, Allamin Ibrahim Alkali, Nur Adeela Yasid
    MyJurnal
    Phenolic compounds or phenols are a group of aromatic compounds that comprises a hydroxyl
    group (OH) that is directly bonded to an aromatic ring. Phenols are injurious to organisms even
    at even low concentrations with many of them are categorized as dangerous pollutants because of
    their likely harm to human well-being. This review attempts to discuss the various merits and
    demerits of immobilization matrices employed for phenol-degrading microorganisms’
    immobilization. One of several key points of cellular immobilization is the capacity to protect
    bioremediation agents towards toxic levels of specific toxicants and safeguarding from predatory
    microorganisms. However, this shielding course of action should never impede the diffusion of
    substrates into the pores of the immobilization structure. In the end the choice of a particular
    immobilization method will strongly hinge on aspects of economy, safety and efficacy.
  16. Ali H, Kabir N, Shah MR, Muhammad A, Ali S, Mehmood S, et al.
    Toxicol Res (Camb), 2016 Nov 01;5(6):1688-1698.
    PMID: 30090468 DOI: 10.1039/c6tx00165c
    This study investigated the molecular mechanism(s) of the protective effects of a C-alkylated flavonoid, viscosine on an animal model of CCl4-induced hepatotoxicity. Viscosine at 20, 50 and 100 mg kg-1 was orally administered in a dose dependent manner per day for 3 days before the CCl4 (1 : 1 v/v in olive oil, 1 ml kg-1) treatment and 2 days after the treatment. Hepatoprotection was assessed in terms of reduction in serum enzyme activities (ALT, AST, and ALP) that occur after CCl4 injury, and by histopathology and immunohistochemistry. The rise in serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) in CCl4-intoxicated rats was markedly suppressed by viscosine in a concentration dependent manner. The decrease in the activity of hepatic antioxidant enzyme, SOD, was significantly prevented by viscosine, likewise gradually the levels of MDA and GSH were also normalized compared to silymarin. Viscosine also reduced the CCl4-induced damaged area from 2% to 0% as assessed by histopathology and prevented the mixed inflammatory infiltrate. Viscosine attenuated the inflammation in the liver around the injured central vein region by downregulating the CCl4 induced activation of hepatic CD68+ macrophages, thereby reducing their number as well. The expression of inducible nitric oxide synthase (iNOS) was more potentially suppressed by viscosine compared to the FDA approved positive control silymarin. The results of this study indicate that viscosine could be effective in protecting the liver from acute CCl4-induced injury. The hepatoprotective mechanisms of viscosine may be related to the free radical scavenging and attenuation of oxidative stress, as well as to the inhibition of inflammatory response in the liver. Here, we are proposing a novel mechanism of action of viscosine and suggesting that it may be a safe and better in vivo antioxidant.
  17. Binns C, Low WY
    Asia Pac J Public Health, 2016 Oct;28(7):560-561.
    PMID: 28071955 DOI: 10.1177/1010539516671035
  18. Ahmad Razi Othman, Intan Safinar Ismail, Norhani Abdullah, Syahida Ahmad
    MyJurnal
    Jatropha curcas is a multipurpose plant that has been suggested as a possible cure to
    inflammation. It can be used as a source of animal feed, live fence, biodiesel and in traditional
    medicine. Practitioners have used various extraction techniques to extract the active components
    of the plant. This article compares the efficiency of three methods of drying technique for the
    extraction of the total phenolic content from the plant. The freeze-drying method was the best
    method compared to oven dry and air dry. The freeze-drying method dries J. curcas root sample
    faster and preserve the total phenolic content better than the other methods.
    MeSH terms: Animals; Animal Feed; Desiccation; Freeze Drying; Inflammation; Preservation, Biological; Jatropha; Biofuels
  19. Che Engku Noramalina Che-Engku-Chik, Siti Sarah Othman, Helmi Wasoh, Nor Azah Yusof, Jaafar Abdullah, Mohd Hazani Mat Zaid
    MyJurnal
    Despite the continued effort globally made to control the growing case of Tuberculosis (TB), it
    continues to be regarded as the second deadliest disease after the HIV. There are various
    methods developed to diagnose TB, most of which having the criteria of sensitive, selective,
    cheap and portable to be used in robust applications. Even with the advancement in medication,
    the important keys including early stage diagnosis is yet to be considered. In diagnosing TB, the
    only technique remained as the gold standard method is the culturing method, which is the Acid
    Fast Bacilli (AFB) staining. On the other hand, molecular technique utilising Polymerase Chain
    Reaction (PCR) assay is preferred as a non-culturing method. Additionally, as molecular
    techniques become advanced, real-time PCR or quantitative PCR (qPCR) using multiple probes
    in one shot has raised interest among researchers, because it can skip the process of gel
    electrophoresis. Recently, researchers have been working on electrochemical DNA sensors
    which are sensitive, selective, rapid, cheap and can meet with point of care (POC) testing
    requirements to diagnose TB.
    MeSH terms: DNA; Electrophoresis; Staining and Labeling; Tuberculosis; HIV Infections; Point-of-Care Systems; Real-Time Polymerase Chain Reaction
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