Displaying publications 1 - 20 of 433 in total

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  1. Rosnina AG, Tan YS, Abdullah N, Vikineswary S
    World J Microbiol Biotechnol, 2016 Feb;32(2):18.
    PMID: 26745978 DOI: 10.1007/s11274-015-1959-2
    Pleurotus citrinopileatus (yellow oyster mushroom) has an attractive shape and yellow colour but the fragile texture complicates packaging, and its strong aroma is unappealing to consumers. This study aimed to improve the characteristics and yield of P. citrinopileatus by interspecies mating between monokaryotic cultures of P. citrinopileatus and P. pulmonarius. Ten monokaryon cultures of the parental lines were crossed in all combinations to obtain hybrids. Eleven compatible mating pairs were obtained and cultivated to observe their sporophore morphology and yield. The selected hybrid, i.e. P1xC9, was beige in colour while hybrid P3xC8 was yellow in colour. Their sporophores had less offensive aroma, improved texture and higher yield. The DNA sequences of these hybrids were found to be in the same clade as the P. citrinopileatus parent with a bootstrap value of 99%. High bootstrap values indicate high genetic homology between hybrids and the P. citrinopileatus parent. The biological efficiencies of these hybrids P1xC9 (70.97%) and P3xC8 (52.14%) were also higher than the P. citrinopileatus parent (35.63%). Interspecies hybrids obtained by this mating technique can lead to better strains of mushrooms for genetic improvement of the Pleurotus species.
  2. Amjad N, Osman HA, Razak NA, Kassian J, Din J, bin Abdullah N
    World J Gastroenterol, 2010 Sep 21;16(35):4443-7.
    PMID: 20845512
    AIM: To study the presence of Helicobacter pylori (H. pylori) virulence factors and clinical outcome in H. pylori infected patients.

    METHODS: A prospective analysis of ninety nine H. pylori-positive patients who underwent endoscopy in our Endoscopy suite were included in this study. DNA was isolated from antral biopsy samples and the presence of cagA, iceA, and iceA2 genotypes were determined by polymerase chain reaction and a reverse hybridization technique. Screening for H. pylori infection was performed in all patients using the rapid urease test (CLO-Test).

    RESULTS: From a total of 326 patients who underwent endoscopy for upper gastrointestinal symptoms, 99 patients were determined to be H. pylori-positive. Peptic ulceration was seen in 33 patients (33%). The main virulence strain observed in this cohort was the cagA gene isolated in 43 patients. cagA was associated with peptic ulcer pathology in 39.5% (17/43) and in 28% (16/56) of non-ulcer patients. IceA1 was present in 29 patients (29%) and iceA2 in 15 patients (15%). Ulcer pathology was seen in 39% (11/29) of patients with iceA1, while 31% (22/70) had normal findings. The corresponding values for iceA2 were 33% (5/15) and 33% (28/84), respectively.

    CONCLUSION: Virulence factors were not common in our cohort. The incidence of factors cagA, iceA1 and iceA2 were very low although variations were noted in different ethnic groups.

  3. Tijani H, Yuzir A, Abdullah N
    Waste Manag, 2018 Aug;78:770-780.
    PMID: 32559969 DOI: 10.1016/j.wasman.2018.06.045
    In this study, a two-stage domesticated shear-loop anaerobic contact stabilization (SLACS) system is introduced as a new reactor design to enhance methane productivity with significant reduction in hydrogen sulphide (H2S) synthesis. Due to the rich sulfate content in industrial wastewaters, the initial fermentation phase of anaerobic digestion is highly acidifying and often leads to severe performance losses, digester's instability, and even culture crash. The SLACS system functions as a dissimilatory sulfate reduction - methanogenic reactor consisting of two compartments, a shear-loop anaerobic bed (SLAB) unit and an anaerobic plug flow (APF) unit. The functional role of the SLAB unit is not limited to acidogenesis but also sulfidogenic processes, which curtails H2S generation in the APF unit (methanogenic stage). Experimental observations indicated that pH serves a critical role in the cohabitation of acidogenic and sulfidogenic microbes in the SLAB unit. Although acidogenesis was not influenced by pH within the range of 4.5-6.0, it is vital to stabilize the pH of this unit at 5.4 to establish a steady sulfate reduction of above 75%. The highest desulfurization achieved in this compartment was 88% under a hydraulic retention time (HRT) of 4 h. With an average methane productivity of 256 mL g-1 VS, the methanogenic performance of the two-stage domesticated SLACS system shows a 32% methanogenic proficiency higher than that of the one-stage digestion system. Microbial community structure within the system carried out via Next Generation Sequencing (NGS) provided qualitative data on the sludge's sulfidogenic and methanogenic performance.
  4. Zulkipli AF, Zakaria NM, Abdikarim MH, Azlan M, Abdullah N, Nor NM, et al.
    Trop Life Sci Res, 2018 Jul;29(2):53-76.
    PMID: 30112141 MyJurnal DOI: 10.21315/tlsr2018.29.2.5
    Macrophage apoptosis exerts an efficient mechanism in controlling intracellular infection during innate immune response against various pathogens including malaria parasites. This study was carried out to determine the apoptosis activity in mouse macrophage cell line J774A.1 infected with a Mycobacterium bovis bacille Calmette-Guerin (BCG) clone and a recombinant BCG clone expressing the C-terminus of merozoite surface protein-1 (BCG-MSP1C) of Plasmodium falciparum for 48 h. In this study, a parent BCG cells was used as a control. The nuclear staining with Hoechst 33342 showed that the BCG-MSP1C cells was capable of increasing the nuclear condensation and morphological stages of apoptosis in the infected cells compared to the BCG-infected cells and the lipopolysaccharide (LPS)-stimulated cells. The flow cytometric analysis using Annexin-V and Propidium iodide (PI) staining confirmed that the BCG-MSP1C cells significantly increased the percentage of early apoptotic activity in the infected macrophage higher than the one stimulated by the parent BCG cells and LPS. This apoptotic response corresponded with the reduction of the anti-apoptotic Bcl-2 protein expression and higher p53 expression. The colorimetric assay demonstrated that the BCG cells capable of stimulating higher production of caspase-1, -3, -8 and -9 while the BCG-MSP1C cells stimulated the expression of caspase-1 and -9 in the infected macrophages, suggesting the involvement of mitochondrial-mediated (intrinsic) pathway of apoptosis. In conclusion, both the BCG and BCG-MSP1C cells are capable of inducing macrophage apoptosis activity in the mouse macrophage cell line J774A.1. This mechanism is important for the elimination of pathogens such as malaria parasite during the phagocytosis activity of macrophage. However, the BCG-MSP1C cells showed higher apoptosis activity than those produced by the parent BCG cells.
  5. Haslinda MS, Aiyub Z, Bakar NK, Tohar N, Musa Y, Abdullah NR, et al.
    Trop Biomed, 2015 Mar;32(1):129-39.
    PMID: 25801263
    An antiplasmodial screening of Phyllanthus debilis and Phyllanthus urinaria was carried out. The medicinal plants were extracted and evaluated for in vitro antiplasmodial activity against D10 (chloroquine-sensitive, CQS) and Gombak A (chloroquine-resistant, CQR) strains of Plasmodium falciparum. The methanolic crudes from the soxhlet extraction were active against both strains however, P. urinaria (IC50 8.9 μg/ml with CQR strain) exhibited better anti-malarial activity compared to P. debilis (IC50 12.2 μg/ml with CQR strain). Furthermore, the methanolic crude of P. urinaria obtained by the cold extraction has good anti-malarial activity towards CQS (IC50 4.1 μg/ml). The concentration of macronutrients (calcium and magnesium) and trace metals (copper, manganese, iron and zinc) from three Phyllanthus species i.e. P. debilis Klein ex Wild., Phyllanthus niruri L., P. urinaria L. and Alpinia conchigera Griff. were determined using microwave digestion method and analyzed by Flame Atomic Absorption Spectroscopy. Standard Reference Material 1547 (peach leaves) was used to validate the method throughout this study. The recovery values were in the range of 80% to 120% which were in very good agreement with the certified values. The three Phyllanthus species and leaves of A. conchigera showed the highest concentration of calcium compared to other metals and macronutrients studied. The significant presence of all the important macronutrients and trace metals which are essential for human health and well-being substantiate their use medicinally in traditional practices.
  6. Chen CD, Nazni WA, Lee HL, Hashim R, Abdullah NA, Ramli R, et al.
    Trop Biomed, 2014 Jun;31(2):381-6.
    PMID: 25134909 MyJurnal
    This study reported the ant species that were recovered from monkey carcasses in three different ecological habitats in Malaysia. The study was conducted from 9 May - 10 October 2007, 6 May - 6 August 2008 and 26 May - 14 July 2009 in forested area (Gombak, Selangor), coastal area (Tanjong Sepat, Selangor) and highland area (Bukit Cincin, Pahang), respectively. Monkey carcass was used as a model for human decomposition in this study. A total of 4 replicates were used in each of the study sites. Ants were observed to prey on eggs, larvae, pupae and newly emerged flies. This study found that ant species could be found at all stages of decomposition, indicating that ants were not a significant indicator for faunal succession. However, different species of ants were obtained from monkey carcasses placed in different ecological habitats. Cardiocondyla sp. was only found on carcasses placed in the coastal area; while Pheidole longipes, Hypoponera sp. and Pachycondyla sp. were solely found on carcasses placed in the highland area. On the other hand, Pheidologeton diversus and Paratrechina longicornis were found in several ecological habitats. These data suggests that specific ant species can act as geographic indicators for different ecological habitats in forensic entomology cases in Malaysia.
  7. Bamaiyi PH, Hassan L, Khairani-Bejo S, Zainal Abidin M, Ramlan M, Krishnan N, et al.
    Trop Biomed, 2012 Dec;29(4):513-8.
    PMID: 23202595
    A study was carried out to isolate Brucella melitensis using established bacteriological and PCR techniques in Brucella seropositive goats in farms in Selangor, Negeri Sembilan, Melaka and Pulau Pinang. Brucella melitensis was isolated from 7 of 134 reactors with the highest isolation from the vaginal swabs (57.14%) followed by the spleen (28.57%), uterine fluid (14.29%). No Brucella was isolated from the lymph nodes. PCR confirmed all the seven isolates as B. melitensis and isolates were phylogenetically related to other isolates from India, Iran, and Israel but most closely related to isolates from Singapore.
  8. Gopal Katherason S, Naing L, Jaalam K, Kamarul Iman Musa K, Nik Abdullah NM, Aiyar S, et al.
    Trop Biomed, 2010 Aug;27(2):308-16.
    PMID: 20962730 MyJurnal
    Nosocomial blood stream infection (or nosocomial bacteremia) is a common problem in hospitals worldwide, including Malaysia. A three-year prospective cohort study (October 2003-March 2007) of the incidences, risk factors, and patterns of the microorganisms causing bacteremia was conducted using a validated surveillance form in three intensive care units (ICUs) in Malaysia. Center for Disease Control criteria were used to diagnose bacteremia. Patients were monitored from admission until the end point of study, which was the first detection of bacteremia in the blood in each patient. The frequency of occurrence of bacteremia with clinical symptoms was 10.7% (n=23). Bacteremia was observed to occur within a mean length of stay of 10 days in ICU. The rate of device-related infection was 10.4% per device utilization days with a device utilization rate of 95.9%/1000 patient days. The total number of patient days was 2309 and the period of device utilization was 2211 days. The common bacteria detected were extended-spectrum beta-lactamases (ESBLs) Klebsiella pneumoniae (n=6); Pseudomonas aeruginosa (n=6); Acinetobacter species (n=5); Methicillin-resistant Staphylococcus aureus (MRSA)(n=3); and (non- ESBL) Klebsiella pneumoniae (n=2). Multivariable analysis using Cox Proportional Hazard Model showed that the predictors for developing bacteremia were cancer, MRSA carriage, duration of central venous catheter (CVC) infusion, frequency change of CVC, and the administration of hydrocortisone drugs. These results indicate that a combination of nursing and medical interventions as well as patients' severity of illness could lead to bacteremia in ICU. Strategic implementation of quality assurance measures in ICUs could help to control this problem.
  9. Abdelhaleem AA, Elamin EM, Elhassan AM, Nail AM, Abdullah NE, Mukhtar MM
    Trop Biomed, 2020 Dec 01;37(4):877-883.
    PMID: 33612741 DOI: 10.47665/tb.37.4.877
    Sudanese mucosal leishmaniasis (ML) is a rare clinical form of leishmaniasis and characterized by persistent ulcer of the oral and/or the nasal mucous membranes caused by Leishmania donovani. No data is available about the systemic and local immune responses in mucosal leishmaniasis. This study aimed to measure the systemic and the local cytokines responses of Sudanese ML patients compared to cured cutaneous leishmaniasis patients (Leishmanin skin test positive, LST+ve) and unexposed healthy controls (Leishmanin skin test negative, LST-ve). Six parasitological confirmed ML patients, 7 LST+ve, and 6 LST-ve were enrolled. Systemic Th-1 (IFN-γ and TNF-α), Th-2 (IL-10 and IL-13), Treg (TGF-β1), and inflammatory cytokines IL-6 and IL-8 concentration were measured in the supernatant of whole blood samples following stimulation with live L. donovani promastigotes using ELISA. Local intralesion IL-10, IFN-γ, and IL-13 expression was measured using Real Time PCR. A significant high concentrations of IFN-γ, TNFα, IL-10, TGFβ, IL-6, and IL-8 were detected in the supernatant of stimulated whole blood samples of ML patients compared with the LST+ve and LST-ve controls. Using Real Time-PCR and primers for various cytokines, a significant high expression of TH2 cytokines IL-10 and IL-13 mRNA was detected in contrast to a low TH1 cytokine IFN-γ mRNA in the mucosal lesion. There is a clear dichotomy in the cytokine response during Mucosal leishmaniasis. A significantly high TH1, inflammatory and Treg cytokines response is produced systemically, in contrast to a significant high TH2 cytokines response in the mucosal lesion.
  10. Kathirvalu G, Chandramathi S, S A A, Atiya N, Begum S, Christophe W, et al.
    Trop Biomed, 2023 Jun 01;40(2):152-159.
    PMID: 37650400 DOI: 10.47665/tb.40.2.004
    Antibiotics which once a boon in medicine and saved millions of lives are now facing an ever-growing menace of antibacterial resistance, which desperately needs new antibacterial drugs which are innovative in chemistry and mode of action. For many years, the world has turned to natural plants with antibacterial properties to combat antibiotic resistance. On that basis, we aimed to identify plants with antibacterial and antibiotic potentiating properties. Seventeen different extracts of 3 plants namely Burkillanthus malaccensis, Diospyros hasseltii and Cleisthanthus bracteosus were tested against multi-drug resistant Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Methicillinresistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA). Antibacterial activity of hexane, methanol and chloroform extracts of bark, seed, fruit, flesh and leaves from these plants were tested using, disk diffusion assay, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Antibiotic potentiating capabilities were tested using time-kill assay. B. malaccensis fruit chloroform extract showed the biggest zone of inhibition against MRSA (13.00±0.0 mm) but C. bracteosus bark methanol extract showed the biggest inhibition zone against MSSA (15.33±0.6 mm). Interestingly, bark methanol extract of C. bracteosus was active against MRSA (8.7±0.6 mm), MSSA (7.7±0.6 mm) (Gram-positive) and A. baumannii (7.7±0.6 mm) (Gram-negative). Overall, the leaf methanol and bark methanol extract of C. bracteosus warrants further investigation such as compound isolation and mechanism of action for validating its therapeutic use as antibiotic potentiator importantly against MRSA and A. baumannii.
  11. Bamaiyi PH, Hassan L, Khairani-Bejo S, ZainalAbidin M, Ramlan M, Krishnan N, et al.
    Trop Anim Health Prod, 2014 Jun;46(5):739-45.
    PMID: 24633657 DOI: 10.1007/s11250-014-0557-x
    Caprine brucellosis is a bacterial zoonotic infection affecting goats especially in developing countries all over the world. In Malaysia, the risk factors associated with this infection in farms have not been studied. A case-control study was carried out in goat farms in four states of Malaysia to elucidate the risk factors associated with the infection on the farms using structured questionnaires and face-to-face interviews. Results indicate that the introduction of new animals (OR = 5.25; 90 % CI = 1.46, 18.88), younger age category of farms (OR = 5.53; 90 % CI = 1.09, 21.66), and farms with single breed of goats (OR = 8.50; 90 % CI = 1.27, 41.97) were significant risk factors for brucellosis. In order to control brucellosis or possibly eradicate it in goat farms, these factors need to be dealt with. Enforcing stringent importation protocols or complete ban of goat importation from brucellosis endemic countries will help reduce risk of introducing new infection into the country.
  12. Teng ST, Abdullah N, Hanifah AH, Tan SN, Gao C, Law IK, et al.
    Toxicon, 2021 Sep 30;202:132-141.
    PMID: 34600910 DOI: 10.1016/j.toxicon.2021.09.018
    In March 2018, an algal bloom of Pseudo-nitzschia was detected, for the first time, in a semi-enclosed lagoon in Miri, Sarawak, Malaysia Borneo. The plankton samples were collected for cell enumeration and species identification by electron microscopy and molecular characterization. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was performed to detect and quantify the neurotoxin domoic acid (DA) in both the plankton and shellfish samples. The abundance of Pseudo-nitzschia cells ranged from 5.6 × 105 to 3.5 × 106 cell L-1 during the bloom event. Morphological observation of the cells by transmission electron microscopy showed that the plankton samples comprised a single Pseudo-nitzschia morphotype resembling P. cuspidata. The ITS2 sequence-structure phylogenetic inference further supported the species identity as Pseudo-nitzschia cuspidata. Low levels of DA were detected in the plankton samples, with cellular DA, particulate DA, and dissolved DA of 257-504 fg DA cell-1, 676 ng L-1, and 15 ng L-1, respectively. The amount of DA, 8 μg g-1 tissue, was found present in the shellfish sample (Magallana sp.) which is below the regulatory limit of 20 μg DA g-1 tissue. The study documented, for the first time, DA contamination in shellfish that associated with bloom of P. cuspidata in the Western Pacific region.
  13. Ahmad NS, Abdullah N, Yasin FM
    Toxicol Rep, 2020;7:693-699.
    PMID: 32528857 DOI: 10.1016/j.toxrep.2020.04.015
    Toxicity effect of reduced graphene oxide (rGO) and titanium dioxide (TiO2) nanomaterials (NMs) on Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria was assessed. For both strains, study demonstrated that the toxicity was time and concentration dependent which led to reduction in growth rate and cell death. Upon NMs exposure, an instantaneous cell death in E. coli culture was observed. This is in contrast with B. subtilis, in which the culture growth remained in the log phase; however their growth rate constant,

    μ
    g

    was reduced by ∼70%. The discrepancy between E. coli and B. subtilis was due to strain-specific response upon contact with NMs. TEM, SEM and EDX analysis revealed direct physical surface-surface interaction, as evidence from the adherence of NMs on the cell surface.
  14. Oladosu Y, Rafii MY, Abdullah N, Abdul Malek M, Rahim HA, Hussin G, et al.
    ScientificWorldJournal, 2014;2014:190531.
    PMID: 25431777 DOI: 10.1155/2014/190531
    Genetic based knowledge of different vegetative and yield traits play a major role in varietal improvement of rice. Genetic variation gives room for recombinants which are essential for the development of a new variety in any crop. Based on this background, this work was carried out to evaluate genetic diversity of derived mutant lines and establish relationships between their yield and yield components using multivariate analysis. To achieve this objective, two field trials were carried out on 45 mutant rice genotypes to evaluate their growth and yield traits. Data were taken on vegetative traits and yield and its components, while genotypic and phenotypic coefficients, variance components, expected genetic advance, and heritability were calculated. All the genotypes showed variations for vegetative traits and yield and its components. Also, there was positive relationship between the quantitative traits and the final yield with the exception of number of tillers. Finally, the evaluated genotypes were grouped into five major clusters based on the assessed traits with the aid of UPGMA dendrogram. So hybridization of group I with group V or group VI could be used to attain higher heterosis or vigour among the genotypes. Also, this evaluation could be useful in developing reliable selection indices for important agronomic traits in rice.
  15. Abdullah N, Mohd Said S, Marlina A, Roslan MF, Azil A, Nordin AR
    ScientificWorldJournal, 2015;2015:860537.
    PMID: 25879076 DOI: 10.1155/2015/860537
    A dimeric iron(II) complex, trans-[Fe2(CH3COO)4(L1)2] (1), and a trinuclear iron(II) complex, [Fe3(CH3COO)4(H2O)4(L2)] (2), were studied as potential dye-sensitised solar cell materials. The structures of both complexes were deduced by a combination of instrumental analyses and molecular modelling. Variable-temperature magnetic susceptibility data suggested that 1 was made up of 56.8% high-spin (HS) and 43.2% low-spin (LS) Fe(II) atoms at 294 K and has a moderate antiferromagnetic interaction (J=-81.2 cm(-1)) between the two Fe(II) centres, while 2 was made up of 27.7% HS and 72.3% LS Fe(II) atoms at 300 K. The optical band gaps (Eo) for 1 were 1.9 eV (from absorption spectrum) and 2.2 eV (from fluorescence spectrum), electrochemical bandgap (Ee) was 0.83 eV, excited state lifetime (τ) was 0.67 ns, and formal redox potential (E'(FeIII/FeII)) was +0.63 V. The corresponding values for 2 were 3.5 eV (from absorption spectrum), 1.8 eV (from fluorescence spectrum), 0.69 eV, 2.8 ns, and +0.41 V.
  16. Borhanuddin B, Mohd Nawi A, Shah SA, Abdullah N, Syed Zakaria SZ, Kamaruddin MA, et al.
    ScientificWorldJournal, 2018;2018:2979206.
    PMID: 30111990 DOI: 10.1155/2018/2979206
    Cardiovascular disease (CVD) leads to high morbidity and mortality rate worldwide. Therefore, it is important to determine the risk of CVD across the sociodemographic factors to strategize preventive measures. The current study consisted of 53,122 adults between the ages of 35 and 65 years from The Malaysian Cohort project during recruitment phase from year 2006 to year 2012. Sociodemographic profile and physical activity level were assessed via self-reported questionnaire, whereas relevant CVD-related biomarkers and biophysical variables were measured to determine the Framingham Risk Score (FRS). The main outcome was the 10-year risk of CVD via FRS calculated based on lipid profile and body mass index (BMI) associated formulae. The BMI-based formula yielded a higher estimation of 10-year CVD risk than the lipid profile-based formula in the study for both males (median = 13.2% and 12.7%, respectively) and females (median = 4.3% and 4.2%, respectively). The subgroup with the highest risk for 10-year CVD events (based on both FRS formulae) was the Malay males who have lower education level and low physical activity level. Future strategies for the reduction of CVD risk should focus on screening via BMI-based FRS in this at-risk subpopulation to increase the cost-effectiveness of the prevention initiatives.
    Study name: The Malaysian Cohort (TMC) project
  17. Sidi H, Abdullah N, Puteh SE, Midin M
    J Sex Med, 2007 Nov;4(6):1642-54.
    PMID: 17608666
    Female sexual dysfunction (FSD) is a prevalent sexual health problem that has been inadequately investigated in Malaysia, a nation with a conservative multiethnic society.
  18. Sidi H, Puteh SE, Abdullah N, Midin M
    J Sex Med, 2007 Mar;4(2):311-21.
    PMID: 17040486
    Female sexual dysfunction (FSD) is a prevalent sexual health problem that does not spare the women in Malaysia, a nation with a conservative multiethnic society.
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