Displaying publications 61 - 80 of 1161 in total

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  1. Surendran A, Siddiqui Y, Saud HM, Ali NS, Manickam S
    J Appl Microbiol, 2018 Sep;125(3):876-887.
    PMID: 29786938 DOI: 10.1111/jam.13922
    AIM: Lignolytic (lignin degrading) enzyme, from oil palm pathogen Ganoderma boninense Pat. (Syn G. orbiforme (Ryvarden)), is involved in the detoxification and the degradation of lignin in the oil palm and is the rate-limiting step in the infection process of this fungus. Active inhibition of lignin-degrading enzymes secreted by G. boninense by various naturally occurring phenolic compounds and estimation of efficiency on pathogen suppression was aimed at.

    METHODS AND RESULTS: In our work, 10 naturally occurring phenolic compounds were evaluated for their inhibitory potential towards the lignolytic enzymes of G. boninense. Additionally, the lignin-degrading enzymes were characterized. Most of the peholic compounds exhibited an uncompetitive inhibition towards the lignin-degrading enzymes. Benzoic acid was the superior inhibitor to the production of lignin-degrading enzymes, when compared between the 10 phenolic compounds. The inhibitory potential of the phenolic compounds towards the lignin-degrading enzymes are higher than that of the conventional metal ion inhibitor. The lignin-degrading enzymes were stable in a wide range of pH but were sensitive to higher temperature.

    CONCLUSION: The study demonstrated the inhibitor potential of 10 naturally occurring phenolic compounds towards the lignin-degrading enzymes of G. boninense with different efficacies.

    SIGNIFICANCE AND IMPACT OF THE STUDY: The study has shed a light towards a new management strategy to control basal stem rot disease in oil palm. It serves as a replacement for the existing chemical control.

    Matched MeSH terms: Ganoderma/enzymology*
  2. Mazlan SNHS, Ali MSM, Rahman RNZRA, Sabri S, Jonet MA, Leow TC
    Int J Biol Macromol, 2018 Nov;119:1188-1194.
    PMID: 30102982 DOI: 10.1016/j.ijbiomac.2018.08.022
    GDSL esterase J15 (EstJ15) is a member of Family II of lipolytic enzyme. The enzyme was further classified in subgroup SGNH hydrolase due to the presence of highly conserve motif, Ser-Gly-Asn-His in four conserved blocks I, II, III, and V, respectively. X-ray quality crystal of EstJ15 was obtained from optimized formulation containing 0.10 M ammonium sulphate, 0.15 M sodium cacodylate trihydrate pH 6.5, and 20% PEG 8000. The crystal structure of EstJ15 was solved at 1.38 Å with one molecule per asymmetric unit. The structure exhibits α/β hydrolase fold and shared low amino acid sequence identity of 23% with the passenger domain of the autotransporter EstA of Pseudomonas aeruginosa. The active site is located at the centre of the structure, formed a narrow tunnel that hinder long substrates to be catalysed which was proven by the protein-ligand docking analysis. This study facilitates the understanding of high substrate specificity of EstJ15 and provide insights on its catalytic mechanism.
    Matched MeSH terms: Photobacterium/enzymology*
  3. Chong JL, Wickneswari R, Ismail BS, Salmijah S
    Pak J Biol Sci, 2008 Feb 01;11(3):476-9.
    PMID: 18817177
    This study reports the results of the partial DNA sequence analysis of the 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) gene in glyphosate-resistant (R) and glyphosate-susceptible (S) biotypes of Eleusine indica (L.) Gaertn from Peninsular Malaysia. Sequencing results revealed point mutation at nucleotide position 875 in the R biotypes of Bidor, Chaah and Temerloh. In the Chaah R population, substitution of cytosine (C) to adenine (A) resulted in the change of threonine (Thr106) to proline (Pro106) and from C to thymidine (T) in the Bidor R population, leading to serine (Ser106) from Pro106. As for the Temerloh R, C was substituted by T resulting in the change of Pro106 to Ser106. A new mutation previously undetected in the Temerloh R was revealed with C being substituted with A, resulting in the change of Pro106 to Thr106 indicating multiple founding events rather than to the spread of a single resistant allele. There was no point mutation recorded at nucleotide position 875 previously demonstrated to play a pivotal role in conferring glyphosate resistance to E. indica for the Lenggeng, Kuala Selangor, Melaka R populations. Thus, there may be another resistance mechanism yet undiscovered in the resistant Lenggeng, Kuala Selangor and Melaka populations.
    Matched MeSH terms: Eleusine/enzymology*
  4. Choi SH, Vera Cruz CM, Leach JE
    Appl Environ Microbiol, 1998 May;64(5):1663-8.
    PMID: 9572933
    The presence or absence of two DNA modification systems, XorI and XorII, in 195 strains of Xanthomonas oryzae pv. oryzae collected from different major rice-growing countries of Asia was assessed. All four possible phenotypes (XorI+ XorII+, XorI+ XorII-, XorI- XorII+ and XorI- XorII-) were detected in the population at a ratio of approximately 1:2:2:2. The XorI+ XorII+ and XorI- XorII+ phenotypes were observed predominantly in strains from southeast Asia (Philippines, Malaysia, and Indonesia), whereas strains with the phenotypes XorI- XorII- and XorI+ XorII- were distributed in south Asia (India and Nepal) and northeast Asia (China, Korea, and Japan), respectively. Based on the prevalence and geographic distribution of the XorI and XorII systems, we suggest that the XorI modification system originated in northeast Asia and was later introduced to southeast Asia, while the XorII system originated in southeast Asia and moved to northeast Asia and south Asia. Genomic DNA from all tested strains of X. oryzae pv. oryzae that were resistant to digestion by endonuclease XorII or its isoschizomer PvuI also hybridized with a 7.0-kb clone that contained the XorII modification system, whereas strains that were digested by XorII or PvuI lacked DNA that hybridized with the clone. Size polymorphisms were observed in fragments that hybridized with the 7.0-kb clone. However, a single hybridization pattern generally was found in XorII+ strains within a country, indicating clonal maintenance of the XorII methyl-transferase gene locus. The locus was monomorphic for X. oryzae pv. oryzae strains from the Philippines and all strains from Indonesia and Korea.
    Matched MeSH terms: Xanthomonas/enzymology*
  5. Imam MU, Ismail M
    Int J Mol Sci, 2012;13(7):8597-608.
    PMID: 22942722 DOI: 10.3390/ijms13078597
    Xenobiotics constantly influence biological systems through several means of interaction. These interactions are disturbed in type 2 diabetes, with implications for disease outcome. We aimed to study the implications of such disturbances on type 2 diabetes and rice consumption, the results of which could affect management of the disease in developing countries. In a type 2 diabetic rat model induced through a combination of high fat diet and low dose streptozotocin injection, up-regulation of xenobiotic metabolism genes in the diabetic untreated group was observed. Xenobiotic metabolism genes were upregulated more in the white rice (WR) group than the diabetic untreated group while the brown rice (BR) group showed significantly lower expression values, though not as effective as metformin, which gave values closer to the normal non-diabetic group. The fold changes in expression in the WR group compared to the BR group for Cyp2D4, Cyp3A1, Cyp4A1, Cyp2B1, Cyp2E1, Cyp2C11, UGT2B1, ALDH1A1 and Cyp2C6 were 2.6, 2, 1.5, 4, 2.8, 1.5, 1.8, 3 and 5, respectively. Our results suggest that WR may upregulate these genes in type 2 diabetes more than BR, potentially causing faster drug metabolism, less drug efficacy and more toxicity. These results may have profound implications for rice eating populations, constituting half the world's population.
    Matched MeSH terms: Diabetes Mellitus, Experimental/enzymology*; Diabetes Mellitus, Type 2/enzymology*; Liver/enzymology
  6. Chandramathi S, Suresh K, Kuppusamy UR
    Ann Trop Med Parasitol, 2010 Jul;104(5):449-52.
    PMID: 20819313 DOI: 10.1179/136485910X12743554760423
    Matched MeSH terms: Nematode Infections/enzymology*; Blastocystis Infections/enzymology*; Microsporidiosis/enzymology*
  7. Tay SP, Cheong SK, Hamidah NH, Ainoon O
    Malays J Pathol, 1998 Dec;20(2):91-4.
    PMID: 10879268
    A study was undertaken to evaluate the ability of flow cytometric analysis of intracellular myeloperoxidase (MPO) in differentiating populations of lymphocytes (L), monocytes (M) and granulocytes (G), by means of lysed whole blood method. Anticoagulated blood from 23 normal individuals was lysed with FACS lysing solution and permeabilized with FACS permeabilizing solution before subjected to direct immunofluorescence staining. The geometric means of the fluorescence intensity were measured using FACSCalibur flow cytometer (Becton Dickinson). Populations of L, M and G were gated based on their light scatter characteristics and expression of CD14 and CD45. Then, the fluorescence intensity of MPO expression was studied in these individual cell populations. The results showed that fluorescence intensity of MPO was the strongest in G and weakest in L, whereas M showed intermediate fluorescence intensity. Our findings reveal that discrimination of these three cell types is achievable based upon the sole expression of intracellular MPO.
    Matched MeSH terms: Granulocytes/enzymology*; Lymphocytes/enzymology*; Monocytes/enzymology*
  8. Iyngkaran N, Yadav M, Boey CG
    Med J Malaysia, 1995 Mar;50(1):21-4.
    PMID: 7752971
    The effect of cow's milk protein (CMP) challenge on the levels of alkaline phosphatase (ALP) in the upper jejunal mucosa and the serum were studied in 25 infants clinically suspected to have cow's milk allergy. Following CMP provocation 3 groups were identified. Group 1 consisted of 10 infants who had clinical and histological reaction to CMP challenge. All 10 infants had significant depletion in the levels of tissue and serum ALP. Group 2 consisted of 5 infants who had histological reaction but no clinical reaction. Tissue ALP was depressed in 3 but not in 2 following CMP challenge. Serum ALP were essentially unaltered in all 5. Group 3 consisted of 10 infants who clinically and histologically tolerated CMP challenge. Tissue and serum ALP were not depressed in any. Estimation of sucrase levels in the mucosa and xylose absorption before and after CMP challenge were also performed for comparison with changes of tissue and serum ALP levels. The clinical significance of the changes in serum ALP level is discussed.
    Matched MeSH terms: Intestinal Mucosa/enzymology*; Jejunum/enzymology*; Milk Hypersensitivity/enzymology*
  9. Yusof YA, Yan KL, Hussain SN
    Anal. Quant. Cytol. Histol., 2003 Dec;25(6):332-8.
    PMID: 14714299
    To determine whether tumor marker pi glutathione transferase (GST-pi) is expressed in hepatocellular carcinoma (HCC) and other chronic liver diseases and to compare its expression with that of alpha-fetoprotein (AFP).
    Matched MeSH terms: Hepatitis B/enzymology; Carcinoma, Hepatocellular/enzymology; Liver Cirrhosis/enzymology; Liver Neoplasms/enzymology
  10. Wiesmann UN, DiDonato S, Herschkowitz NN
    Biochem Biophys Res Commun, 1975 Oct 27;66(4):1338-43.
    PMID: 4
    Matched MeSH terms: Fibroblasts/enzymology; Leukodystrophy, Metachromatic/enzymology; Lysosomes/enzymology*; Skin/enzymology
  11. Muhamad N, Simcock DC, Pedley KC, Simpson HV, Brown S
    PMID: 21296180 DOI: 10.1016/j.cbpb.2011.01.008
    Like other nematodes, both L(3) and adult Teladosagia circumcincta secrete or excrete NH(3)/NH(4)(+), but the reactions involved in the production are unclear. Glutamate dehydrogenase is a significant source NH(3)/NH(4)(+) in some species, but previous reports indicate that the enzyme is absent from L(3)Haemonchus contortus. We show that glutamate dehydrogenase was active in both L(3) and adult T. circumcincta. The apparent K(m)s of the L(3) enzyme differed from those of the adult enzyme, the most significant of these being the increase in the K(m) for NH(4)(+) from 18mM in L(3) to 49mM in adults. The apparent V(max) of the oxidative deamination reaction was greater than that of the reductive reaction in L(3), but this was reversed in adults. The activity of the oxidative reaction of the L(3) enzyme was not affected by adenine nucleotides, but that of the reductive reaction was stimulated significantly by either ADP or ATP. The L(3) enzyme was more active with NAD(+) than it was with NADP(+), although the activities supported by NADH and NADPH were similar at saturating concentrations. While the activity of the oxidative reaction was sufficient to account for the NH(3)/NH(4)(+) efflux we have previously reported, the reductive amination reaction was likely to be more active.
    Matched MeSH terms: Haemonchus/enzymology; Larva/enzymology*; Ostertagia/enzymology*; Ostertagiasis/enzymology
  12. Eng LI, Loo M, Fah FK
    Br J Haematol, 1972 Oct;23(4):419-25.
    PMID: 5084807
    Matched MeSH terms: Erythrocytes/enzymology*; Infant, Newborn, Diseases/enzymology; Metabolism, Inborn Errors/enzymology; Methemoglobinemia/enzymology
  13. Iyngkaran N, Yadav M, Boey CG
    Acta Paediatr Scand, 1991 May;80(5):549-50.
    PMID: 1678569
    Matched MeSH terms: Intestinal Mucosa/enzymology*; Jejunum/enzymology*; Microvilli/enzymology; Protein-Losing Enteropathies/enzymology*; Milk Hypersensitivity/enzymology*
  14. Saed Taha R, Ismail I, Zainal Z, Abdullah SN
    J Plant Physiol, 2012 Sep 01;169(13):1290-300.
    PMID: 22658816 DOI: 10.1016/j.jplph.2012.05.001
    The stearoyl-acyl-carrier-protein (ACP) desaturase is a plastid-localized enzyme that catalyzes the conversion of stearoyl-ACP to oleoyl-ACP and plays an important role in the determination of the properties of the majority of cellular glycerolipids. Functional characterization of the fatty acid desaturase genes and their specific promoters is a prerequisite for altering the composition of unsaturated fatty acids of palm oil by genetic engineering. In this paper, the specificity and strength of the oil palm stearoyl-ACP desaturase gene promoter (Des) was evaluated in transgenic tomato plants. Transcriptional fusions between 5' deletions of the Des promoter (Des1-4) and the β-glucuronidase (GUS) reporter gene were generated and their expression analyzed in different tissues of stably transformed tomato plants. Histochemical analysis of the Des promoter deletion series revealed that GUS gene expression was confined to the tomato fruits. No expression was detected in vegetative tissues of the transgenic plants. The highest levels of GUS activity was observed in different tissues of ripe red fruits (vascular tissue, septa, endocarp, mesocarp and columella) and in seeds, which harbored the promoter region located between -590 and +10. A comparison of the promoter-deletion constructs showed that the Des4 promoter deletion (314bp) produced a markedly low level of GUS expression in fruits and seeds. Fluorometric analysis of the GUS activity revealed a 4-fold increase in the activity of the full-length Des promoter compared to the CaMV35S promoter. RNA-hybridization analyses provided additional evidence of increased GUS expression in fruits driven by a Des fragment. Taken together, these results demonstrate the potential of the Des promoter as a tool for the genetic engineering of oil palms and other species, including dicots, in improving the quality and nutritional value of the fruits.
    Matched MeSH terms: Fruit/enzymology*; Seeds/enzymology*; Lycopersicon esculentum/enzymology*; Arecaceae/enzymology*; Plants, Genetically Modified/enzymology
  15. Deris ZZ, Akter J, Sivanesan S, Roberts KD, Thompson PE, Nation RL, et al.
    J Antibiot (Tokyo), 2014 Feb;67(2):147-51.
    PMID: 24169795 DOI: 10.1038/ja.2013.111
    Polymyxin B and colistin were examined for their ability to inhibit the type II NADH-quinone oxidoreductases (NDH-2) of three species of Gram-negative bacteria. Polymyxin B and colistin inhibited the NDH-2 activity in preparations from all of the isolates in a concentration-dependent manner. The mechanism of NDH-2 inhibition by polymyxin B was investigated in detail with Escherichia coli inner membrane preparations and conformed to a mixed inhibition model with respect to ubiquinone-1 and a non-competitive inhibition model with respect to NADH. These suggest that the inhibition of vital respiratory enzymes in the bacterial inner membrane represents one of the secondary modes of action for polymyxins.
    Matched MeSH terms: Cell Membrane/enzymology; Escherichia coli/enzymology; Gram-Negative Bacteria/enzymology*; Klebsiella pneumoniae/enzymology; Acinetobacter baumannii/enzymology
  16. Mat Yusoff M, Gordon MH, Ezeh O, Niranjan K
    Food Chem, 2016 Nov 15;211:400-8.
    PMID: 27283648 DOI: 10.1016/j.foodchem.2016.05.050
    This paper reports on the extraction of Moringa oleifera (MO) oil by using aqueous enzymatic extraction (AEE) method. The effect of different process parameters on the oil recovery was discovered by using statistical optimization, besides the effect of selected parameters on the formation of its oil-in-water cream emulsions. Within the pre-determined ranges, the use of pH 4.5, moisture/kernel ratio of 8:1 (w/w), and 300stroke/min shaking speed at 40°C for 1h incubation time resulted in highest oil recovery of approximately 70% (goil/g solvent-extracted oil). These optimized parameters also result in a very thin emulsion layer, indicating minute amount of emulsion formed. Zero oil recovery with thick emulsion were observed when the used aqueous phase was re-utilized for another AEE process. The findings suggest that the critical selection of AEE parameters is key to high oil recovery with minimum emulsion formation thereby lowering the load on the de-emulsification step.
    Matched MeSH terms: Moringa oleifera/enzymology*
  17. Yaacob MA, Hasan WA, Ali MS, Rahman RN, Salleh AB, Basri M, et al.
    Acta Biochim. Pol., 2014;61(4):745-52.
    PMID: 25337608
    Genome mining revealed a 1011 nucleotide-long fragment encoding a type I L-asparaginase (J15 asparaginase) from the halo-tolerant Photobacterium sp. strain J15. The gene was overexpressed in pET-32b (+) vector in E. coli strain Rosetta-gami B (DE3) pLysS and purified using two-step chromatographic methods: Ni(2+)-Sepharose affinity chromatography and Q-Sepharose anion exchange chromatography. The final specific activity and yield of the enzyme achieved from these steps were 20 U/mg and 49.2%, respectively. The functional dimeric form of J15-asparaginase was characterised with a molecular weight of ~70 kDa. The optimum temperature and pH were 25°C and pH 7.0, respectively. This protein was stable in the presence of 1 mM Ni(2+) and Mg(2+), but it was inhibited by Mn(2+), Fe(3+) and Zn(2+) at the same concentration. J15 asparaginase actively hydrolysed its native substrate, l-asparagine, but had low activity towards l-glutamine. The melting temperature of J15 asparaginase was ~51°C, which was determined using denatured protein analysis of CD spectra. The Km, Kcat, Kcat/Km of J15 asparaginase were 0.76 mM, 3.2 s(-1), and 4.21 s(-1) mM(-1), respectively. Conformational changes of the J15 asparaginase 3D structure at different temperatures (25°C, 45°C, and 65°C) were analysed using Molecular Dynamic simulations. From the analysis, residues Tyr₂₄ , His₂₂, Gly₂₃, Val₂₅ and Pro₂₆ may be directly involved in the 'open' and 'closed' lid-loop conformation, facilitating the conversion of substrates during enzymatic reactions. The properties of J15 asparaginase, which can work at physiological pH and has low glutaminase activity, suggest that this could be a good candidate for reducing toxic effects during cancer treatment.
    Matched MeSH terms: Photobacterium/enzymology*
  18. Abd Rahman RN, Ali MS, Sugiyama S, Leow AT, Inoue T, Basri M, et al.
    Protein Pept Lett, 2015;22(2):173-9.
    PMID: 25329331
    Geobacillus zalihae sp. nov., which produces a putative thermostable lipase, represents a novel species, with type strain T1. The characterisation of this intrinsically thermostable T1 lipase either physicochemically or structurally is an important task. The crystallisation of T1lipase in space was carried out using a High-Density Protein Crystal Growth (HDPCG) apparatus with the vapour diffusion method, and X-ray diffraction data were collected. The microgravity environment has improved the size and quality of the crystals as compared to earth grown crystal. The effect of microgravity on the crystallisation of T1 lipase was clearly evidenced by the finer atomic details at 1.35 A resolution. Better electron densities were observed overall compared with the Earth-grown crystals, and comparison shows the subtle but distinct conformations around Na(+) ion binding site stabilized via cation-π interactions. This approach could be useful for solving structure and function of lipases towards exploiting its potentials to various industrial applications.
    Matched MeSH terms: Geobacillus/enzymology*
  19. Maiangwa J, Ali MS, Salleh AB, Rahman RN, Shariff FM, Leow TC
    Extremophiles, 2015 Mar;19(2):235-47.
    PMID: 25472009 DOI: 10.1007/s00792-014-0710-5
    Psychrophilic microorganisms are cold-adapted with distinct properties from other thermal classes thriving in cold conditions in large areas of the earth's cold environment. Maintenance of functional membranes, evolving cold-adapted enzymes and synthesizing a range of structural features are basic adaptive strategies of psychrophiles. Among the cold-evolved enzymes are the cold-active lipases, a group of microbial lipases with inherent stability-activity-flexibility property that have engaged the interest of researchers over the years. Current knowledge regarding these cold-evolved enzymes in psychrophilic bacteria proves a display of high catalytic efficiency with low thermal stability, which is a differentiating feature with that of their mesophilic and thermophilic counterparts. Improvement strategies of their adaptive structural features have significantly benefited the enzyme industry. Based on their homogeneity and purity, molecular characterizations of these enzymes have been successful and their properties make them unique biocatalysts for various industrial and biotechnological applications. Although, strong association of lipopolysaccharides from Antarctic microorganisms with lipid hydrolases pose a challenge in their purification, heterologous expression of the cold-adapted lipases with affinity tags simplifies purification with higher yield. The review discusses these cold-evolved lipases from bacteria and their peculiar properties, in addition to their potential biotechnological and industrial applications.
    Matched MeSH terms: Bacteria/enzymology*
  20. Sabullah MK, Sulaiman MR, Abd Shukor MY, Syed MA, Shamaan NA, Khalid A, et al.
    ScientificWorldJournal, 2014;2014:571094.
    PMID: 25401148 DOI: 10.1155/2014/571094
    Crude extract of ChE from the liver of Puntius javanicus was purified using procainamide-sepharyl 6B. S-Butyrylthiocholine iodide (BTC) was selected as the specific synthetic substrate for this assay with the highest maximal velocity and lowest biomolecular constant at 53.49 µmole/min/mg and 0.23 mM, respectively, with catalytic efficiency ratio of 0.23. The optimum parameter was obtained at pH 7.5 and optimal temperature in the range of 25 to 30°C. The effect of different storage condition was assessed where ChE activity was significantly decreased after 9 days of storage at room temperature. However, ChE activity showed no significant difference when stored at 4.0, 0, and -25°C for 15 days. Screening of heavy metals shows that chromium, copper, and mercury strongly inhibited P. javanicus ChE by lowering the activity below 50%, while several pairwise combination of metal ions exhibited synergistic inhibiting effects on the enzyme which is greater than single exposure especially chromium, copper, and mercury. The results showed that P. javanicus ChE has the potential to be used as a biosensor for the detection of metal ions.
    Matched MeSH terms: Liver/enzymology*
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