MyMedR

Displaying publications 121 - 140 of 272 in total

Abstract:

Sort:

Diploid and triploid African catfish (Clarias gariepinus) differ in biomarker responses to the pesticide chlorpyrifos

Karami A, Goh YM, Jahromi MF, Lazorchak JM, Abdullah M, Courtenay SC

Sci Total Environ, 2016 07 01;557-558:204-11.
PMID: 26994807 DOI: 10.1016/j.scitotenv.2016.03.030

The impacts of environmental stressors on polyploid organisms are largely unknown. This study investigated changes in morphometric, molecular, and biochemical parameters in full-sibling diploid and triploid African catfish (Clarias gariepinus) in response to chlorpyrifos (CPF) exposures. Juvenile fish were exposed to three concentrations of CPF (mean measured μg/L (SD): 9.71 (2.27), 15.7 (3.69), 31.21 (5.04)) under a static-renewal condition for 21days. Diploid control groups had higher hepatosomatic index (HSI), plasma testosterone (T), and brain GnRH and cyp19a2 expression levels than triploids. In CPF-exposed groups, changes in HSI, total weight and length were different between the diploid and triploid fish. In contrast, condition factor did not alter in any of the treatments, while visceral-somatic index (VSI) changed only in diploids. In diploid fish, exposure to CPF did not change brain 11β-hsd2, ftz-f1, foxl2, GnRH or cyp19a2 mRNA levels, while reduced tph2 transcript levels compared to the control group. In contrast, 11β-hsd2 and foxl2 expression levels were changed in triploids following CPF exposures. In diploids, plasma T levels showed a linear dose-response reduction across CPF treatments correlating with liver weight and plasma total cholesterol concentrations. In contrast, no changes in plasma cholesterol and T concentrations were observed in triploids. Plasma cortisol and 17-β estradiol (E2) showed no response to CPF exposure in either ploidy. Results of this first comparison of biomarker responses to pesticide exposure in diploid and polyploid animals showed substantial differences between diploid and triploid C. gariepinus.
Differential proteomic analysis of embryogenic lines in oil palm (Elaeis guineensis Jacq)

Tan HS, Liddell S, Ong Abdullah M, Wong WC, Chin CF

J Proteomics, 2016 06 30;143:334-345.
PMID: 27130535 DOI: 10.1016/j.jprot.2016.04.039

Oil palm tissue culture is one way to produce superior oil palm planting materials. However, the low rate of embryogenesis is a major hindrance for the adoption of this technology in oil palm tissue culture laboratories. In this study, we use proteomic technologies to compare differential protein profiles in leaves from palms of high and low proliferation rates in tissue culture in order to understand the underlying biological mechanism for the low level of embryogenesis. Two protein extraction methods, namely trichloroacetic acid/acetone precipitation and polyethylene glycol fractionation were used to produce total proteins and fractionated protein extracts respectively, with the aim of improving the resolution of protein species using two-dimensional gel electrophoresis. A total of 40 distinct differential abundant protein spots were selected from leaf samples collected from palms with proven high and low proliferation rates. The variant proteins were subsequently identified using mass spectrometric analysis. Twelve prominent protein spots were then characterised using real-time polymerase chain reaction to compare the mRNA expression and protein abundant profiles. Three proteins, namely triosephosphate isomerase, l-ascorbate peroxidase, and superoxide dismutase were identified to be potential biomarker candidates at both the protein abundant and mRNA expression levels.
BIOLOGICAL SIGNIFICANCE: In this study, proteomic analysis was used to identify abundant proteins from total protein extracts. PEG fractionation was used to reveal lower abundant proteins from both high and low proliferation embryogenic lines of oil palm samples in tissue culture. A total of 40 protein spots were found to be significant in abundance and the mRNA levels of 12 of these were assessed using real time PCR. Three proteins namely, triosephosphate isomerase, l-ascorbate peroxidase and superoxide dismutase were found to be concordant in their mRNA expression and protein abundance. Triosephosphate isomerase is a key enzyme in glycolysis. Both l-ascorbate peroxidase and superoxide dismutase play a role in anti-oxidative scavenging defense systems. These proteins have potential for use as biomarkers to screen for high and low embryogenic oil palm samples.
Aspirin Enhances Osteogenic Potential of Periodontal Ligament Stem Cells (PDLSCs) and Modulates the Expression Profile of Growth Factor-Associated Genes in PDLSCs

Abd Rahman F, Mohd Ali J, Abdullah M, Abu Kasim NH, Musa S

J. Periodontol., 2016 07;87(7):837-47.
PMID: 26846966 DOI: 10.1902/jop.2016.150610

BACKGROUND: This study investigates the effects of aspirin (ASA) on the proliferative capacity, osteogenic potential, and expression of growth factor-associated genes in periodontal ligament stem cells (PDLSCs).
METHODS: Mesenchymal stem cells (MSCs) from PDL tissue were isolated from human premolars (n = 3). The MSCs' identity was confirmed by immunophenotyping and trilineage differentiation assays. Cell proliferation activity was assessed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Polymerase chain reaction array was used to profile the expression of 84 growth factor-associated genes. Pathway analysis was used to identify the biologic functions and canonic pathways activated by ASA treatment. The osteogenic potential was evaluated through mineralization assay.
RESULTS: ASA at 1,000 μM enhances osteogenic potential of PDLSCs. Using a fold change (FC) of 2.0 as a threshold value, the gene expression analyses indicated that 19 genes were differentially expressed, which includes 12 upregulated and seven downregulated genes. Fibroblast growth factor 9 (FGF9), vascular endothelial growth factor A (VEGFA), interleukin-2, bone morphogenetic protein-10, VEGFC, and 2 (FGF2) were markedly upregulated (FC range, 6 to 15), whereas pleotropin, FGF5, brain-derived neurotrophic factor, and Dickkopf WNT signaling pathway inhibitor 1 were markedly downregulated (FC 32). Of the 84 growth factor-associated genes screened, 35 showed high cycle threshold values (≥35).
CONCLUSIONS: ASA modulates the expression of growth factor-associated genes and enhances osteogenic potential in PDLSCs. ASA upregulated the expression of genes that could activate biologic functions and canonic pathways related to cell proliferation, human embryonic stem cell pluripotency, tissue regeneration, and differentiation. These findings suggest that ASA enhances PDLSC function and may be useful in regenerative dentistry applications, particularly in the areas of periodontal health and regeneration.
Fulltext Increased soluble HLA-DRB1in B-cell acute lymphoblastic leukaemia

Hassan N, Dhaliwal JS, Mohd Ibrahim H, Osman R, HIdris SZ, Lee le J, et al.

Malays J Pathol, 2015 Aug;37(2):83-90.
PMID: 26277663 MyJurnal

Soluble HLA (sHLA) are potential tumour markers released in order to counter immune surveillance. sHLA-class II is less known especially in acute lymphoblastic leukaemia (ALL). This study aimed to investigate soluble, surface and allelic expression of HLA Class II (sHLA-DR) in B-cell ALL patients and compare with soluble expression in normal individuals. A sandwich enzyme-linked immunosorbent assay (ELISA) was developed to measure soluble HLA-DRB1 in plasma. Flow cytometric analysis was performed to determine median fluorescence intensity in HLA-DR surface expression. HLA-DNA typing by polymerase chain reaction, sequence specific oligonucleotides, PCRSSO was performed to determine HLA-DRB1 type in ALL samples. Results showed sHLA-DRB1 (mean±SEM) was significantly increased (p=0.001) in plasma of ALL patients (0.260 ±0.057 μg/mL; n=30) compared to healthy controls (0.051 ± 0.007µg/mL; n=31) of Malay ethnicity. However, these levels did not correlate with percentage or median fluorescence intensity of HLA-DR expressed on leukemia blasts (CD19+CD34 ± CD45(lo)HLA-DR+) or in the normal B cell population (CD19+CD34- CD45(hi)HLA-DR+) of patients. No significant difference was observed in gender (male/female) or age (paediatric/adult). Only a trend in reduced sHLA was observed in patients carrying HLA-DR04. These results have to be validated with a larger number of samples.
Ingestion of food pellets containing Escherichia coli overexpressing the heat-shock protein DnaK protects Penaeus vannamei (Boone) against Vibrio harveyi (Baumann) infection

Sinnasamy S, Noordin NM, MacRae TH, Bin Abdullah MI, Bossier P, Wahid ME, et al.

J Fish Dis, 2016 May;39(5):577-84.
PMID: 26132358 DOI: 10.1111/jfd.12390

Feeding aquatic animals with bacterial encapsulated heat-shock proteins (Hsps) is potentially a new method to combat vibriosis, an important disease affecting aquatic animals used in aquaculture. Food pellets comprised of shrimp and containing Escherichia coli overexpressing either DnaK-DnaJ-GrpE, the prokaryotic equivalents of Hsp70-Hsp40-Hsp20, or only DnaK were fed to juveniles of the white leg shrimp Penaeus vannamei, and protection against pathogenic Vibrio harveyi was determined. Maintaining pellets at different temperatures for varying lengths of time reduced the number of live adhering E. coli, as did contact with sea water, demonstrating that storage and immersion adversely affected bacterial survival and attachment to pellets. Feeding P. vannamei with E. coli did not compromise their survival, indicating that the bacteria were not pathogenic to shrimp. Feeding P. vannamei with pellets containing bacteria overproducing DnaK (approximately 60 cells g(-1) pellets) boosted P. vannamei survival twofold against V. harveyi, suggesting that DnaK plays a role in Vibrio tolerance. Pellets containing DnaK were effective in providing protection to P. vannamei for up to 2 weeks before loss of viability and that DnaK encapsulated by these bacteria enhanced shrimp resistance against Vibrio infection.
Detection of malaria in Malaysia by nested polymerase chain reaction amplification of dried blood spots on filter papers

Singh B, Cox-Singh J, Miller AO, Abdullah MS, Snounou G, Rahman HA

Trans R Soc Trop Med Hyg, 1996 9 1;90(5):519-21.
PMID: 8944260

A modified nested polymerase chain reaction (PCR) method for detection of Plasmodium falciparum, P. vivax and P. malariae was combined with a simple blood collection and deoxyribonucleic acid (DNA) extraction method and evaluated in Malaysia. Finger-prick blood samples from 46 hospital patients and 120 individuals living in malaria endemic areas were spotted on filter papers and dried. The simple Chelex method was used to prepare DNA templates for the nested PCR assay. Higher malaria prevalence rates for both clinical (78.2%) and field samples (30.8%) were obtained with the nested PCR method than by microscopy (76.1% and 27.5%, respectively). Nested PCR was more sensitive than microscopy in detecting mixed P. falciparum and P. vivax infections, detected 5 more malaria samples than microscopy on the first round of microscopical examination, and detected malaria in 3 microscopically negative samples. Nested PCR failed to detect parasite DNA in 2 microscopically positive samples, an overall sensitivity of 97.4% compared to microscopy. The nested PCR method, when coupled with simple dried blood spot sampling, is a useful tool for collecting accurate malaria epidemiological data, particularly in remote regions of the world.
Association of p53 tumor suppressor gene with paraclinical and clinical modalities of gliomas patients in Malaysia

Yusoff AA, Abdullah J, Abdullah MR, Mohd Ariff AR, Isa MN

Acta Neurochir (Wien), 2004 Jun;146(6):595-601.
PMID: 15168228

Alteration of the tumor suppressor gene p53 is considered to be a critical step in the development of human cancer. Changes in this gene have been detected in a wide range of human tumours, including gliomas. In glioma, the presence of p53 gene alterations has been associated with worse prognosis.
Fulltext Induction of apoptosis and role of paclitaxel-loaded hyaluronic acid-crosslinked nanoparticles in the regulation of AKT and RhoA

Chaudhry GE, Akim A, Zafar MN, Abdullah MA, Sung YY, Muhammad TST

J Adv Pharm Technol Res, 2020 07 14;11(3):101-106.
PMID: 33102192 DOI: 10.4103/japtr.JAPTR_26_20

Cancer is a complex multifactorial disease and leading causes of death worldwide. Despite the development of many anticancer drugs, there is a reduced survival rate due to severe side effects. The nontargeted approach of convention drugs is one of the leading players in context to toxicity. Hyaluronan is a versatile bio-polymer and ligand of the receptor (CD44) on cancer cells. The MCF-7 and HT-29 cancer cell lines treated with hyaluronic acid-paclitaxel (HA-PTX) showed the distinguishing morphological features of apoptosis. Flow cytometric analysis showed that HA-PTX induces apoptosis as a significant mode of cell death. The activation level of tumor suppressor protein (p53) increased after PTX treatment in MCF-7, but no changes observed in HT-29 might be due to hereditary mutations. The lack of suppression in AKT and Rho A protein suggest the use of possible inhibitors in future studies which might could play a role in increasing the sensitivity of drug towards mutated cells line and reducing the possibilities for cancer cell survival, migration, and metastasis.
Fulltext Simultaneous Adsorption of Cationic Dyes from Binary Solutions by Thiourea-Modified Poly(acrylonitrile-co-acrylic acid): Detailed Isotherm and Kinetic Studies

Adeyi AA, Jamil SNAM, Abdullah LC, Choong TSY, Lau KL, Abdullah M

Materials (Basel), 2019 Sep 08;12(18).
PMID: 31500398 DOI: 10.3390/ma12182903

In this study, simultaneous adsorption of cationic dyes was investigated by using binary component solutions. Thiourea-modified poly(acrylonitrile-co-acrylic acid) (TMPAA) polymer was used as an adsorbent for uptake of cationic dyes (malachite green, MG and methylene blue, MB) from aqueous solution in a binary system. Adsorption tests revealed that TMPAA presented high adsorption of MG and MB at higher pH and higher dye concentrations. It suggested that there are strong electrostatic attractions between the surface functional groups of the adsorbent and cationic dyes. The equilibrium analyses explain that both extended Langmuir and extended models are suitable for the description of adsorption data in the binary system. An antagonistic effect was found, probably due to triangular (MG) and linear (MB) molecular structures that mutually hinder the adsorption of both dyes on TMPAA. Besides, the kinetic studies for sorption of MG and MB dyes onto adsorbent were better represented by a pseudo-second-order model, which demonstrates chemisorption between the polymeric TMPAA adsorbent and dye molecules. According to experimental findings, TMPAA is an attractive adsorbent for treatment of wastewater containing multiple cationic dyes.
Phytoaccumulation of Zn, Pb, and Cd in Conocarpus lancifolius irrigated with wastewater: does physiological response influence heavy metal uptake?

Rasheed F, Zafar Z, Waseem ZA, Rafay M, Abdullah M, Salam MMA, et al.

Int J Phytoremediation, 2020;22(3):287-294.
PMID: 31468990 DOI: 10.1080/15226514.2019.1658711

Conocarpus lancifolius is a fast-growing and drought tolerant tree species with phytoremediation potential in arid environments. The present study was conducted to evaluate the phytoaccumulation potential under wastewater treatment. The experiment was performed in a greenhouse where 3-month-old seedlings were irrigated with industrial wastewater and growth, biomass and physiological parameters were measured. Concentrations of zinc (Zn), lead (Pb), and cadmium (Cd) in leaves, shoots, and roots along with translocation and tolerance index were also determined. The results showed that under wastewater treatment total biomass increased from 24.2 to 31.5 g, net CO2 assimilation rate increased from 9.93 to 13.3 μmol m-2 s-1, and water use efficiency increased from 1.7 to 2.42. Similarly, heavy metals (Zn, Pb, and Cd) accumulation in stem, leaves, and roots increased significantly under wastewater treatment where the highest concentration of Zn, Pb and Cd was found in roots followed by leaves and stem, respectively. Tolerance index was found >1, and translocation factor of all heavy metals was found >1. The study revealed that phytoaccumulation potential of C. lancifolius was mainly driven by improved net CO2 assimilation rate and water use efficiency.
Anthraquinones production, hydrogen peroxide level and antioxidant vitamins in Morinda elliptica cell suspension cultures from intermediary and production medium strategies

Chong TM, Abdullah MA, Fadzillah NM, Lai OM, Lajis NH

Plant Cell Rep, 2004 Jul;22(12):951-8.
PMID: 15067428

The effects of medium strategies [maintenance (M), intermediary (G), and production (P) medium] on cell growth, anthraquinone (AQ) production, hydrogen peroxide (H2O2) level, lipid peroxidation, and antioxidant vitamins in Morinda elliptica cell suspension cultures were investigated. These were compared with third-stage leaf and 1-month-old callus culture. With P medium strategy, cell growth at 49 g l(-1), intracellular AQ content at 42 mg g(-1) DW, and H2O2 level at 9 micromol g(-1) FW medium were the highest as compared to the others. However, the extent of lipid peroxidation at 40.4 nmol g(-1) FW and total carotenoids at 13.3 mg g(-1) FW for cultures in P medium were comparable to that in the leaf, which had registered sevenfold lower AQ and 2.2-fold lower H2O2 levels. Vitamin C content at 30-120 microg g(-1) FW in all culture systems was almost half the leaf content. On the other hand, vitamin E content was around 400-500 microg g(-1) FW in 7-day-old cultures from all medium strategies and reduced to 50-150 microg g(-1) FW on day 14 and 21; as compared to 60 microg g(-1) FW in callus and 200 microg g(-1) FW in the leaf. This study suggests that medium strategies and cell growth phase in cell culture could influence the competition between primary and secondary metabolism, oxidative stresses and antioxidative measures. When compared with the leaf metabolism, these activities are dynamic depending on the types and availability of antioxidants.
DNA methylation changes in clonally propagated oil palm

Sarpan N, Taranenko E, Ooi SE, Low EL, Espinoza A, Tatarinova TV, et al.

Plant Cell Rep, 2020 Sep;39(9):1219-1233.
PMID: 32591850 DOI: 10.1007/s00299-020-02561-9

KEY MESSAGE: Several hypomethylated sites within the Karma region of EgDEF1 and hotspot regions in chromosomes 1, 2, 3, and 5 may be associated with mantling. One of the main challenges faced by the oil palm industry is fruit abnormalities, such as the "mantled" phenotype that can lead to reduced yields. This clonal abnormality is an epigenetic phenomenon and has been linked to the hypomethylation of a transposable element within the EgDEF1 gene. To understand the epigenome changes in clones, methylomes of clonal oil palms were compared to methylomes of seedling-derived oil palms. Whole-genome bisulfite sequencing data from seedlings, normal, and mantled clones were analyzed to determine and compare the context-specific DNA methylomes. In seedlings, coding and regulatory regions are generally hypomethylated while introns and repeats are extensively methylated. Genes with a low number of guanines and cytosines in the third position of codons (GC3-poor genes) were increasingly methylated towards their 3' region, while GC3-rich genes remain demethylated, similar to patterns in other eukaryotic species. Predicted promoter regions were generally hypomethylated in seedlings. In clones, CG, CHG, and CHH methylation levels generally decreased in functionally important regions, such as promoters, 5' UTRs, and coding regions. Although random regions were found to be hypomethylated in clonal genomes, hypomethylation of certain hotspot regions may be associated with the clonal mantling phenotype. Our findings, therefore, suggest other hypomethylated CHG sites within the Karma of EgDEF1 and hypomethylated hotspot regions in chromosomes 1, 2, 3 and 5, are associated with mantling.
Potential CD34 signaling through phosphorylated-BAD in chemotherapy-resistant acute myeloid leukemia

Yiau SK, Lee C, Mohd Tohit ER, Chang KM, Abdullah M

J Recept Signal Transduct Res, 2019 Jun;39(3):276-282.
PMID: 31509041 DOI: 10.1080/10799893.2019.1660899

Acute myeloid leukemia (AML) constitutively express growth factors and cytokines for survival. Chemotherapy alters these signals to induce cell death. However, drug resistance in AML remains a major hindrance to successful treatment and early warning is unavailable. Modulation of signaling pathways during chemotherapy may provide a window to detect response and predict treatment outcome. Blood samples collected from AML patients before and at day-3 of induction therapy were compared for changes in expression of CD117, CD34, pro-inflammatory cytokines and mediators of Akt and MAPK pathways, using multi-color flow cytometry. Nine patients were diagnosed as drug-resistant and seven sensitive to chemotherapy. Twelve were paired. Average percentages of CD34 (66.8 ± 11.7% vs. 26.2 ± 5.8%, p = 0.033) and pBAD (66.9 ± 8.2% vs. 28.9 ± 8.2%, p = 0.016) were significantly increased in chemo-resistant (N = 9) compared to chemo-sensitive (N = 5) samples. Percentages of CD34 were strongly correlated with pBAD (R = 0.785; p = 0.001; N = 14) and pFKHR (R = 0.755; p = 0.002; N = 14) at day-3 induction. Chemo-sensitive cases expressed significantly higher percentages of IL-18Rα (71.9 ± 9.6% vs. 29.8 ± 5.8%, p = 0.016). Though not significantly different in the outcome, IL-1β was strongly associated with activated Akt-S473, IL-6 with phosphorylated JNK and FKHR while TNF-α appeared to trigger Bim, in treated samples. These preliminary results suggested AML cells resistant to chemotherapy increased expression of CD34 and may signal through pBAD while cells sensitive to chemotherapy-induced IL18Rα expression. These were observed early during induction therapy. Identifying CD34 is interesting as it is a convenient marker to monitor drug-resistance in AML patients. Inhibition of CD34 and pBAD signaling may be important in treating drug-resistant AML.
Fulltext Data for the industrial and municipal environmental wastes hazard contaminants assessment with integration of RES2D techniques and Oasis Montaj software

Arifin MH, Kayode JS, Ismail KI, Abdullah M, Embrandiri A, Nazer SM, et al.

Data Brief, 2020 Dec;33:106595.
PMID: 33318980 DOI: 10.1016/j.dib.2020.106595

Industrial, and municipal wastes are part of the main sources of environmental hazards as well as groundwater and surface water pollutions. If not well composed, treated, and safely disposed, it could permeate through the subsurface lithologies by reaching down to the underground water aquifers, particularly in zones of unprotected aquifer units. Pollutants, most especially the landfills leachates that encompassed organic contaminants, ammonia, nitrates, total nitrogen, suspended solids, heavy metals and soluble inorganic salts, i.e., soluble nitrogen, sulphur compound, sulphate and chlorides, could posed undesirable environmental impacts due to inappropriate disposals that may give rise to gaseous fumes and leachate formations. An electrical resistivity geophysical technique utilizing the RES2D no-invasive, cost-effective and rapid method of data collection was integrated with the 3D Oasis Montaj software to approximate the volume of the generated rectangular prism model of the contaminants delineated from mixtures of the industrial, and municipal wastes plumes to be 312,000 m 3.
Efficacy of live attenuated vaccine derived from the Streptococcus agalactiae on the immune responses of Oreochromis niloticus

Laith AA, Abdullah MA, Nurhafizah WWI, Hussein HA, Aya J, Effendy AWM, et al.

Fish Shellfish Immunol, 2019 Jul;90:235-243.
PMID: 31009810 DOI: 10.1016/j.fsi.2019.04.052

Streptococcus agalactiae species have been recognized as the main pathogen causing high mortality in fish leading to significant worldwide economical losses to the aquaculture industries. Vaccine development has become a priority in combating multidrug resistance in bacteria; however, there is a lack of commercial live attenuated vaccine (LAV) against S. agalactiae in Malaysia. The aim of this study is to compare two methods using attenuated bacteria as live vaccine and to evaluate the efficacy of selected LAV on the immune responses and resistance of Oreochromis niloticus (tilapia) against S. agalactiae. The LAV derived from S. agalactiae had been weakened using the chemical agent Acriflavine dye (LAV1), whereas the second vaccine was weakened using serial passages of bacteria on broth media (LAV2). Initial immunization was carried out only on day one, given twice-in the morning and evening, for the 42 day period. Serum samples were collected to determine the systemic antibody (IgM) responses and lysozymal (LSZ) activity using ELISA. On day 43 after immunization, the fish were injected intraperitoneally (i.p) with 0.1 mL of S. agalactiae at LD50 = 1.5 × 105 (CFU)/fish. Fish were monitored daily for 10 days. Clinical signs, mortality and the relative percent of survival (RPS) were recorded. Trial 1 results showed a significant increased (P 
Mucosal responses of brown-marbled grouper Epinephelus fuscoguttatus (Forsskål, 1775) following intraperitoneal infection with Vibrio harveyi

Chieng CCY, Daud HM, Yusoff FM, Thompson KD, Abdullah M

J Fish Dis, 2020 Oct;43(10):1249-1258.
PMID: 32830331 DOI: 10.1111/jfd.13222

Groupers are popular aquaculture species in South-East Asia, but their cultivation is affected by infectious disease outbreaks. Mucosa-associated lymphoid tissues provide a first-line defence against pathogens; however, few studies are available relating to cellular or proteomic responses of mucosal immunity in grouper. Skin, gill and intestine were sampled from brown-marbled grouper Epinephelus fuscoguttatus (Forsskål, 1775) at 4 and 96 hr post-infection (hpi) and 7 days post-infection (dpi) following intraperitoneal infection with Vibrio harveyi, and stained with haematoxylin/eosin and Alcian Blue/periodic acid-Schiff. Skin mucus was analysed by 2D-gel electrophoresis, and proteins modulated by the bacterial infection identified. In the infected fish, significant increases in sacciform cells in skin and increased levels of nucleoside diphosphate kinase in mucus were detected at 4 hpi. At 96 hpi, goblet cells containing acidic mucins significantly increased in the intestine, while those containing mixed mucins increased in skin and gills of infected fish. Proteasome subunit alpha type-I and extracellular Cu/Zn superoxide dismutase levels also increased in mucus. Rodlet and mast cells did not appear to respond to the infection. Mucosal tissues of grouper appeared actively involved in response to Vibrio infection. This information may help future research on improving grouper health, production and vaccine development.
Fulltext Linear-Nonlinear Stiffness Responses of Carbon Fiber-Reinforced Polymer Composite Materials and Structures: A Numerical Study

R Koloor SS, Karimzadeh A, Abdullah MR, Petrů M, Yidris N, Sapuan SM, et al.

Polymers (Basel), 2021 Jan 22;13(3).
PMID: 33498984 DOI: 10.3390/polym13030344

The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures.
Fulltext Mycobiome in the Gut: A Multiperspective Review

Chin VK, Yong VC, Chong PP, Amin Nordin S, Basir R, Abdullah M

Mediators Inflamm, 2020;2020:9560684.
PMID: 32322167 DOI: 10.1155/2020/9560684

Human gut is home to a diverse and complex microbial ecosystem encompassing bacteria, viruses, parasites, fungi, and other microorganisms that have an undisputable role in maintaining good health for the host. Studies on the interplay between microbiota in the gut and various human diseases remain the key focus among many researchers. Nevertheless, advances in sequencing technologies and computational biology have helped us to identify a diversity of fungal community that reside in the gut known as the mycobiome. Although studies on gut mycobiome are still in its infancy, numerous sources have reported its potential role in host homeostasis and disease development. Nonetheless, the actual mechanism of its involvement remains largely unknown and underexplored. Thus, in this review, we attempt to discuss the recent advances in gut mycobiome research from multiple perspectives. This includes understanding the composition of fungal communities in the gut and the involvement of gut mycobiome in host immunity and gut-brain axis. Further, we also discuss on multibiome interactions in the gut with emphasis on fungi-bacteria interaction and the influence of diet in shaping gut mycobiome composition. This review also highlights the relation between fungal metabolites and gut mycobiota in human homeostasis and the role of gut mycobiome in various human diseases. This multiperspective review on gut mycobiome could perhaps shed new light for future studies in the mycobiome research area.
Bone marrow-derived mesenchymal stem cells modulate BV2 microglia responses to lipopolysaccharide

Ooi YY, Ramasamy R, Rahmat Z, Subramaiam H, Tan SW, Abdullah M, et al.

Int Immunopharmacol, 2010 Dec;10(12):1532-40.
PMID: 20850581 DOI: 10.1016/j.intimp.2010.09.001

The immunoregulatory properties of mesenchymal stem cells (MSC) have been demonstrated on a wide range of cells. Here, we describe the modulatory effects of mouse bone marrow-derived MSC on BV2 microglia proliferation rate, nitric oxide (NO) production and CD40 expression. Mouse bone marrow MSC were co-cultured with BV2 cells at various seeding density ratios and activated with lipopolysaccharide (LPS). We show that MSC exert an anti-proliferative effect on microglia and are potent producers of NO when stimulated by soluble factors released by LPS-activated BV2. MSC suppressed proliferation of both untreated and LPS-treated microglia in a dose-dependent manner, significantly reducing BV2 proliferation at seeding density ratios of 1:0.2 and 1:0.1 (p
Selection of reference genes for quantitative studies in acute myeloid leukaemia

Lee C, Yiau KXS, Lee LJ, Chong PP, Chang KM, Abdullah M

Malays J Pathol, 2019 Dec;41(3):313-326.
PMID: 31901916

INTRODUCTION: Quantitative polymerase chain reaction (qPCR) is commonly used in the investigation of acute myeloid leukaemias (AML). Stable reference genes (RG) are essential for accurate and reliable reporting but no standard method for selection has been endorsed.
MATERIALS AND METHODS: We evaluated simple statistics and published model-based approaches. Multiplex-qPCR was conducted to determine the expression of 24 candidate RG in AMLs (N=9). Singleplex-qPCR was carried out on selected RG (SRP14, B2M and ATP5B) and genes of interest in AML (N=15) and healthy controls, HC (N=12).
RESULTS: RG expression levels in AML samples were highly variable and coefficient of variance (CV) ranged from 0.37% to 10.17%. Analysis using GeNorm and Normfinder listed different orders of most stable genes but the top seven (ACTB, UBE2D2, B2M, NF45, RPL37A, GK, QARS) were the same. In singleplex-qPCR, SRP14 maintained the lowest CV in AML samples. B2M, one of most stable reference genes in AML, was expressed near significantly different in AML and HC. GeNorm selected ATP5B+SRP14 while Normfinder chose SRP14+B2M as the best two RG in combination. The median expressions of combined RG genes in AML compared to HC were less significantly different than individually implying smaller expression variation after combination. Genes of interest normalised with RG in combination or individually, displayed significantly different expression patterns.
CONCLUSIONS: The selection of best reference gene in qPCR must consider all sample sets. Model-based approaches are important in large candidate gene analysis. This study showed combination of RG SRP14+B2M was the most suitable normalisation factor for qPCR analysis of AML and healthy individuals.

Filters

Please provide feedback to Administrator ([email protected])

External Links