Displaying publications 1 - 20 of 101 in total

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  1. Sabri MZ, Abdul Hamid AA, Sayed Hitam SM, Abdul Rahim MZ
    Adv Bioinformatics, 2019;2019:6912914.
    PMID: 31346332 DOI: 10.1155/2019/6912914
    Aptamer has been long studied as a substitute of antibodies for many purposes. However, due to the exceeded length of the aptamers obtained in vitro, difficulties arise in its manipulation during its molecular conjugation on the matrix surfaces. Current study focuses on computational improvement for aptamers screening of hepatitis B surface antigen (HBsAg) through optimization of the length sequences obtained from SELEX. Three original aptamers with affinity against HBsAg were truncated into five short hairpin structured aptamers and their affinity against HBsAg was thoroughly studied by molecular docking, molecular dynamics (MD) simulation, and Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) method. The result shows that truncated aptamers binding on HBsAg "a" determinant region are stabilized by the dynamic H-bond formation between the active binding residues and nucleotides. Amino acids residues with the highest hydrogen bonds hydrogen bond interactions with all five aptamers were determined as the active binding residues and further characterized. The computational prediction of complexes binding will include validations through experimental assays in future studies. Current study will improve the current in vitro aptamers by minimizing the aptamer length for its easy manipulation.
  2. Sakai S, Momose K, Yumoto T, Nagamitsu T, Nagamasu H, Hamid AA, et al.
    Am J Bot, 1999 Oct;86(10):1414-36.
    PMID: 10523283
    The first systematic observation of a general flowering, a phenomenon unique to lowland mixed-dipterocarp forests in Southeast Asia, is presented. During general flowering, which occurs at irregular intervals of 3-10 yr, nearly all dipterocarp species together with species of other families come heavily into flower. We monitored reproductive phenology of 576 individual plants representing 305 species in 56 families in Sarawak, Malaysia. Observations continued for 53 mo from August 1992 and covered one episode of a general flowering cycle. Among 527 effective reproductive events during 43 mo, 57% were concentrated in the general flowering period (GFP) of 10 mo in 1996. We classified 257 species into flowering types based on timing and frequency of flowering. The most abundant type was "general flowering" (35%), which flowered only during GFP. The others were "supra-annual" (19%), "annual" (13%), and "sub-annual" (5%) types. General flowering type and temporal aggregation in reproductive events were commonly found among species in various categories of taxonomic groups, life forms, pollination systems, and fruit types. Possible causes for general flowering, such as promotion of pollination brought about by interspecific synchronization and paucity of climatic cues suitable for flowering trigger, are proposed, in addition to the predator satiation hypothesis of Janzen (1974).
  3. Nasser Al-Shorgani NK, Kalil MS, Wan Yusoff WM, Shukor H, Hamid AA
    Anaerobe, 2015 Dec;36:65-72.
    PMID: 26439644 DOI: 10.1016/j.anaerobe.2015.09.008
    Improvement in the butanol production selectivity or enhanced butanol:acetone ratio (B:A) is desirable in acetone-butanol-ethanol (ABE) fermentation by Clostridium strains. In this study, artificial electron carriers were added to the fermentation medium of a new isolate of Clostridium acetobutylicum YM1 in order to improve the butanol yield and B:A ratio. The results revealed that medium supplementation with electron carriers changed the metabolism flux of electron and carbon in ABE fermentation by YM1. A decrease in acetone production, which subsequently improved the B:A ratio, was observed. Further improvement in the butanol production and B:A ratios were obtained when the fermentation medium was supplemented with butyric acid. The maximum butanol production (18.20 ± 1.38 g/L) was gained when a combination of methyl red and butyric acid was added. Although the addition of benzyl viologen (0.1 mM) and butyric acid resulted in high a B:A ratio of 16:1 (800% increment compared with the conventional 2:1 ratio), the addition of benzyl viologen to the culture after 4 h resulted in the production of 18.05 g/L butanol. Manipulating the metabolic flux to butanol through the addition of electron carriers could become an alternative strategy to achieve higher butanol productivity and improve the B:A ratio.
  4. Taha EM, Omar O, Yusoff WM, Hamid AA
    Annals of microbiology, 2010 Dec;60(4):615-622.
    PMID: 21125005
    Lipid biosynthesis and fatty acids composition of oleaginous zygomycetes, namely Cunninghamella bainieri 2A1, cultured in media with excess or limited nitrogen were quantitatively determined at different times of culture growth. Accumulation of lipids occurred even when the activity of NAD(+)-ICDH (β-Nicotinamide adenine dinucleotide-isocitrate dehydrogenase) was still detectable in both media. In C. bainieri 2A1, under nitrogen limitation, the ratio of lipids was around 35%, whereas in nitrogen excess medium (feeding media supplemented with ammonium tartarate), the lipid ratio decreased. The amount of this decrease depended on the level of ammonium tartarate in the media. The main findings in this paper were that C. bainieri 2A1 has the ability to accumulate lipid although nitrogen concentration detected inside the media and that NAD-ICDH was active in all culture periods. These results proved that the strain C. bainieri 2A1 has an alternative behavior in lipid biosynthesis that differs from yeast. According to the old hypotheses, yeasts could not accumulate lipid more than 10% when nitrogen was detected inside the media. Nitrogen-limited and excess media both contained the same fatty acids (palmitic acid, stearic acid, olic acid, linoleic acid and γ-linolenic acid), but at different concentrations. The C:N ratio was also studied and showed no effects on total lipid accumulation, but a significant effect on γ-linolenic acid concentration.
  5. Hamid AA, Dek MS, Tan CP, Zainudin MA, Fang EK
    Antioxidants (Basel), 2014;3(3):502-15.
    PMID: 26785067 DOI: 10.3390/antiox3030502
    Changes in antioxidant properties and degradation of bioactives in palm oil (PO) and rice bran oil (RBO) during deep-frying were investigated. The alpha (α)-tocopherol, gamma (γ)-tocotrienol and γ-oryzanol contents of the deep-fried oils were monitored using high performance liquid chromatography, and antioxidant activity was determined using 2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Results revealed that the antioxidant activity of PO decreased significantly (p < 0.05), while that of RBO was preserved after deep-frying of fries. As expected, the concentration of α-tocopherol in PO and γ-tocotrienol in both PO and RBO decreased significantly (p < 0.05) with increased frying. Results also showed that γ-tocotrienol was found to be more susceptible to degradation compared to that of α-tocopherol in both PO and RBO. Interestingly, no significant degradation of α-tocopherol was observed in RBO. It is suggested that the presence of γ-oryzanol and γ-tocotrienol in RBO may have a protective effect on α-tocopherol during deep-frying.
  6. Bachok MF, Yusof BN, Ismail A, Hamid AA
    Asia Pac J Clin Nutr, 2014;23(3):369-76.
    PMID: 25164446 DOI: 10.6133/apjcn.2014.23.3.01
    Ulam refers to a group of traditional Malaysian plants commonly consumed as a part of a meal, either in the raw form or after a short blanching process. Many types of ulam are thought to possess blood glucose-lowering properties, but relatively little is known on the effectiveness of ulam in modulating blood glucose levels in humans. This review aims to systematically evaluate the effectiveness of ulam in modulating blood glucose levels in humans. A literature review was conducted using multiple databases with no time restriction. Eleven studies were retrieved based on a priori inclusion and exclusion criteria. In these 11 studies, only Momordica charantia, locally known as "peria katak", was extensively studied, followed by Centella asiatica, locally known as "daun pegaga", and Alternanthera sessilis, locally known as "kermak putih". Of the 11 studies, 9 evaluated the effectiveness of M. charantia on blood glucose parameters, and 7 of which showed significant improvement in at least one parameter of blood glucose concentration. The remaining 2 studies reported nonsignificant improvements in blood glucose parameters, despite having high-quality study design according to Jadad scale. None of the studies related to C. asiatica and A. sessilis showed significant improvement in blood glucose-related parameters. Current clinical evidence does not support the popular claim that ulam has glucose-lowering effects, not even for M. charantia. Hence, further clinical investigation is needed to verify the glucose modulation effect of M. charantia, C. asiatica, and A. sessilis.
  7. Cheng SH, Ismail A, Anthony J, Ng OC, Hamid AA, Yusof BN
    BMC Complement Altern Med, 2016 Feb 27;16:84.
    PMID: 26920910 DOI: 10.1186/s12906-016-1047-7
    BACKGROUND: Type 2 diabetes mellitus is a major health threat worldwide. Cosmos caudatus is one of the medicinal plants used to treat type 2 diabetes. Therefore, this study aims to determine the effectiveness and safety of C. caudatus in patients with type 2 diabetes. Metabolomic approach will be carried out to compare the metabolite profiles between C. Caudatus treated diabetic patients and diabetic controls.

    METHODS AND DESIGN: This is a single-center, randomized, controlled, two-arm parallel design clinical trial that will be carried out in a tertiary hospital in Malaysia. In this study, 100 patients diagnosed with type 2 diabetes will be enrolled. Diabetic patients who meet the eligibility criteria will be randomly allocated to two groups, which are diabetic C. caudatus treated(U) group and diabetic control (C) group. Primary and secondary outcomes will be measured at baseline, 4, 8, and 12 weeks. The serum and urine metabolome of both groups will be examined using proton NMR spectroscopy.

    DISCUSSION: The study will be the first randomized controlled trial to assess whether C. caudatus can confer beneficial effect in patients with type 2 diabetes. The results of this trial will provide clinical evidence on the effectiveness and safety of C. caudatus in patients with type 2 diabetes.

    TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02322268.

  8. Rahman HA, Sahib NG, Saari N, Abas F, Ismail A, Mumtaz MW, et al.
    BMC Complement Altern Med, 2017 Feb 22;17(1):122.
    PMID: 28228098 DOI: 10.1186/s12906-017-1640-4
    BACKGROUND: Obesity is a major health concern both in developed and developing countries. The use of herbal medicines became the subject of interest for the management of obesity due to its natural origin, cost effectiveness and minimal side effects. The present study aimed at investigating anti-obesity potential of ethanolic extract from Cosmos caudatus Kunth leaf (EECCL).

    METHODS: In this study, the rats were randomly divided into six groups i.e., (1) Normal Diet (ND); (2) Normal Diet and 175 mg/kgBW of EECCL (ND + 175 mg/kgBW); (3) Normal Diet and 350 mg/kgBW of EECCL (ND + 350 mg/kgBW); (4) High Fat Diet (HFD); (5) High Fat Diet and 175 mg/kgBW of EECCL (HFD + 175 mg/kgBW); (6) High Fat Diet and 350 mg/kgBW of EECCL (HFD + 350 mg/kgBW). The anti-obesity potential was evaluated through analyses of changes in body weight, visceral fat weight, and blood biochemicals including total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), leptin, insulin, adiponectin, ghrelin and fecal fat content. In addition, metabolite profiling of EECCL was carried out using NMR spectroscopy.

    RESULTS: Rats receiving EECCL together with HFD showed significant (p  0.05) different with those of ND rats. Other related obesity biomarkers including plasma lipid profiles, insulin, leptin, ghrelin and adiponectin levels also showed significant improvement (p 

  9. Wan-Nadilah WA, Akhtar MT, Shaari K, Khatib A, Hamid AA, Hamid M
    BMC Complement Altern Med, 2019 Sep 05;19(1):245.
    PMID: 31488132 DOI: 10.1186/s12906-019-2655-9
    BACKGROUND: Cosmos caudatus is an annual plant known for its medicinal value in treating several health conditions, such as high blood pressure, arthritis, and diabetes mellitus. The α-glucosidase inhibitory activity and total phenolic content of the leaf aqueous ethanolic extracts of the plant at different growth stages (6, 8. 10, 12 and 14 weeks) were determined in an effort to ascertain the best time to harvest the plant for maximum medicinal quality with respect to its glucose-lowering effects.

    METHODS: The aqueous ethanolic leaf extracts of C. caudatus were characterized by NMR and LC-MS/MS. The total phenolic content and α-glucosidase inhibitory activity were evaluated by the Folin-Ciocalteu method and α-glucosidase inhibitory assay, respectively. The statistical significance of the results was evaluated using one-way ANOVA with Duncan's post hoc test, and correlation among the different activities was performed by Pearson's correlation test. NMR spectroscopy along with multivariate data analysis was used to identify the metabolites correlated with total phenolic content and α-glucosidase inhibitory activity of the C. caudatus leaf extracts.

    RESULTS: It was found that the α-glucosidase inhibitory activity and total phenolic content of the optimized ethanol:water (80:20) leaf extract of the plant increased significantly as the plant matured, reaching a maximum at the 10th week. The IC50 value for α-glucosidase inhibitory activity (39.18 μg mL- 1) at the 10th week showed greater potency than the positive standard, quercetin (110.50 μg mL- 1). Through an 1H NMR-based metabolomics approach, the 10-week-old samples were shown to be correlated with a high total phenolic content and α-glucosidase inhibitory activity. From the partial least squares biplot, rutin and flavonoid glycosides, consisting of quercetin 3-O-arabinofuranoside, quercetin 3-O-rhamnoside, quercetin 3-O-glucoside, and quercetin 3-O-xyloside, were identified as the major bioactive metabolites. The metabolites were identified by NMR spectroscopy (J-resolve, HSQC and HMBC experiments) and further supported by dereplication via LC-MS/MS.

    CONCLUSION: For high phytomedicinal quality, the 10th week is recommended as the best time to harvest C. caudatus leaves with respect to its glucose lowering potential.

  10. Al-Zuaidy MH, Mumtaz MW, Hamid AA, Ismail A, Mohamed S, Razis AFA
    BMC Complement Altern Med, 2017 Jul 10;17(1):359.
    PMID: 28693595 DOI: 10.1186/s12906-017-1849-2
    BACKGROUND: Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by continuous hyperglycemia associated with insulin resistance and /or reduced insulin secretion. There is an emerging trend regarding the use of medicinal plants for the treatment of diabetes mellitus. Melicope lunu-ankenda (ML) is one of the Melicope species belonging to the family Rutaceae. In traditional medicines, its leaves and flowers are known to exhibit prodigious health benefits. The present study aimed at investigating anti-diabetic effect of Melicope lunu-ankenda (ML) leaves extract.

    METHODS: In this study, anti-diabetic effect of ML extract is investigated in vivo to evaluate the biochemical changes, potential serum biomarkers and alterations in metabolic pathways pertaining to the treatment of HFD/STZ induced diabetic rats with ML extract using 1H NMR based metabolomics approach. Type 2 diabetic rats were treated with different doses (200 and 400 mg/kg BW) of Melicope lunu-ankenda leaf extract for 8 weeks, and serum samples were examined for clinical biochemistry. The metabolomics study of serum was also carried out using 1H NMR spectroscopy in combination with multivariate data analysis to explore differentiating serum metabolites and altered metabolic pathways.

    RESULTS: The ML leaf extract (400 mg/kg BW) treatment significantly increased insulin level and insulin sensitivity of obese diabetic rats, with concomitant decrease in glucose level and insulin resistance. Significant reduction in total triglyceride, cholesterol and low density lipoprotein was also observed after treatment. Interestingly, there was a significant increase in high density lipoprotein of the treated rats. A decrease in renal injury markers and activities of liver enzymes was also observed. Moreover, metabolomics studies clearly demonstrated that, ML extract significantly ameliorated the disturbance in glucose metabolism, tricarboxylic acid cycle, lipid metabolism, and amino acid metabolism.

    CONCLUSION: ML leaf extract exhibits potent antidiabetic properties, hence could be a useful and affordable alternative option for the management of T2DM.

  11. Nordin N, Hairon SM, Yaacob NM, Hamid AA, Isa SAM, Hassan N
    BMC Public Health, 2021 02 02;21(1):268.
    PMID: 33568119 DOI: 10.1186/s12889-021-10320-y
    BACKGROUND: People with type 2 diabetes mellitus (T2DM) are best managed by a chronic care model that is associated with enhanced quality of care and improved patient outcome. Assessing patients' perceived quality of care is crucial in improving the healthcare delivery system. Hence, this study determined the perceived quality of care among people with T2DM and explored its associations with (i) sociodemographic and clinical characteristics and (ii) types of healthcare clinics to guide future planning.

    METHODS: A cross-sectional study involving 20 primary healthcare clinics in the North East Region of Peninsular Malaysia and people with T2DM as the sampling unit was conducted from February to May 2019. The pro forma checklist, interview-guided Skala Kepuasan Interaksi Perubatan-11, and Patient Assessment of Chronic Illness Care (Malay version; PACIC-M) questionnaire were used for data collection. Univariate analysis and linear regression were used to determine the status of perceived quality of care and the factors associated with the perceived quality of care, respectively.

    RESULTS: Overall, data from 772 participants were analyzed. The majority was from the Malay ethnic group (95.6%) with a mean (standard deviation [SD]) glycated hemoglobin A1c (HbA1c) level of 8.91% (2.30). The median (interquartile range [IQR]) of the number of medical officers available at each clinic was 6 (7), with Family Doctor Concept (FDC) clinics having a higher number of medical officers than non-FDC clinics (p = 0.001). The overall mean (SD) PACIC-M score was 2.65 (0.54) with no significant difference between scores of patients treated in the two clinic types (p = 0.806). Higher perceived quality of care was associated with lower number of medical officers (adjusted regression coefficient [Adj.β], - 0.021; p-value [p], 0.001), and greater doctor-patient interaction in all domains: distress relief (Adj.β, 0.033; p,

  12. Prabhakaran P, Raethong N, Thananusak R, Nazir MYM, Sapkaew C, Soommat P, et al.
    PMID: 36907245 DOI: 10.1016/j.bbalip.2023.159306
    Aurantiochytrium sp. SW1, a marine thraustochytrid, has been regarded as a potential candidate as a docosahexaenoic acid (DHA) producer. Even though the genomics of Aurantiochytrium sp. are available, the metabolic responses at a systems level are largely unknown. Therefore, this study aimed to investigate the global metabolic responses to DHA production in Aurantiochytrium sp. through transcriptome and genome-scale network-driven analysis. Of a total of 13,505 genes, 2527 differentially expressed genes (DEGs) were identified in Aurantiochytrium sp., unravelling the transcriptional regulations behinds lipid and DHA accumulation. The highest number of DEG were found for pairwise comparison between growth phase and lipid accumulating phase where a total of 1435 genes were down-regulated with 869 genes being up-regulated. These uncovered several metabolic pathways that contributing in DHA and lipid accumulation including amino acid and acetate metabolism which involve in the generation of crucial precursors. Upon applying network-driven analysis, hydrogen sulphide was found as potential reporter metabolite that could be associated with the genes related to acetyl-CoA synthesis for DHA production. Our findings suggest that the transcriptional regulation of these pathways is a ubiquitous feature in response to specific cultivation phases during DHA overproduction in Aurantiochytrium sp. SW1.
  13. Prabhakaran P, Nazir MYM, Thananusak R, Hamid AA, Vongsangnak W, Song Y
    PMID: 37625782 DOI: 10.1016/j.bbalip.2023.159381
    Aurantiochytrium sp., a marine thraustochytrid possesses a remarkable ability to produce lipid rich in polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA). Although gene regulation underlying lipid biosynthesis has been previously reported, proteomic analysis is still limited. In this study, high DHA accumulating strain Aurantiochytrium sp. SW1 has been used as a study model to elucidate the alteration in proteome profile under different cultivation phases i.e. growth, nitrogen-limitation and lipid accumulation. Of the total of 5146 identified proteins, 852 proteins were differentially expressed proteins (DEPs). The largest number of DEPs (488 proteins) was found to be uniquely expressed between lipid accumulating phase and growth phase. Interestingly, there were up-regulated proteins involved in glycolysis, glycerolipid, carotenoid and glutathione metabolism which were preferable metabolic routes towards lipid accumulation and DHA production as well as cellular oxidative defence. Integrated proteomic and transcriptomic data were also conducted to comprehend the gene and protein regulation underlying the lipid and DHA biosynthesis. A significant up-regulation of acetyl-CoA synthetase was observed which suggests alternative route of acetate metabolism for acetyl-CoA producer. This study presents the holistic routes underlying lipid accumulation and DHA production in Aurantiochytrium sp. SW1 and other relevant thraustochytrid.
  14. Alam MA, Juraimi AS, Rafii MY, Hamid AA, Aslani F, Hakim MA
    Biol Res, 2016 Apr 18;49:24.
    PMID: 27090643 DOI: 10.1186/s40659-016-0084-5
    This study was undertaken to determine the effects of varied salinity regimes on the morphological traits (plant height, number of leaves, number of flowers, fresh and dry weight) and major mineral composition of 13 selected purslane accessions. Most of the morphological traits measured were reduced at varied salinity levels (0.0, 8, 16, 24 and 32 dS m(-1)), but plant height was found to increase in Ac1 at 16 dS m(-1) salinity, and Ac13 was the most affected accession. The highest reductions in the number of leaves and number of flowers were recorded in Ac13 at 32 dS m(-1) salinity compared to the control. The highest fresh and dry weight reductions were noted in Ac8 and Ac6, respectively, at 32 dS m(-1) salinity, whereas the highest increase in both fresh and dry weight was recorded in Ac9 at 24 dS m(-1) salinity compared to the control. In contrast, at lower salinity levels, all of the measured mineral levels were found to increase and later decrease with increasing salinity, but the performance of different accessions was different depending on the salinity level. A dendrogram was also constructed by UPGMA based on the morphological traits and mineral compositions, in which the 13 accessions were grouped into 5 clusters, indicating greater diversity among them. A three-dimensional principal component analysis also confirmed the output of grouping from cluster analysis.
  15. Shukor H, Abdeshahian P, Al-Shorgani NK, Hamid AA, Rahman NA, Kalil MS
    Bioresour Technol, 2016 Feb;202:206-13.
    PMID: 26710346 DOI: 10.1016/j.biortech.2015.11.078
    In this work, hydrolysis of cellulose and hemicellulose content of palm kernel cake (PKC) by different types of hydrolytic enzymes was studied to evaluate monomeric sugars released for production of biobutanol by Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564) in acetone-butanol-ethanol (ABE) fermentation. Experimental results revealed that when PKC was hydrolyzed by mixed β-glucosidase, cellulase and mannanase, a total simple sugars of 87.81±4.78 g/L were produced, which resulted in 3.75±0.18 g/L butanol and 6.44±0.43 g/L ABE at 168 h fermentation. In order to increase saccharolytic efficiency of enzymatic treatment, PKC was pretreated by liquid hot water before performing enzymatic hydrolysis. Test results showed that total reducing sugars were enhanced to 97.81±1.29 g/L with elevated production of butanol and ABE up to 4.15±1.18 and 7.12±2.06 g/L, respectively which represented an A:B:E ratio of 7:11:1.
  16. Shukor H, Al-Shorgani NK, Abdeshahian P, Hamid AA, Anuar N, Rahman NA, et al.
    Bioresour Technol, 2014 Oct;170:565-73.
    PMID: 25171212 DOI: 10.1016/j.biortech.2014.07.055
    Palm kernel cake (PKC) was used for biobutanol production by Clostridium saccharoperbutylacetonicum N1-4 in acetone-butanol-ethanol (ABE) fermentation. PKC was subjected to acid hydrolysis pretreatment and hydrolysates released were detoxified by XAD-4 resin. The effect of pH, temperature and inoculum size on butanol production was evaluated using an empirical model. Twenty ABE fermentations were run according to an experimental design. Experimental results revealed that XAD-4 resin removed 50% furfural and 77.42% hydroxymethyl furfural. The analysis of the empirical model showed that linear effect of inoculums size with quadratic effect of pH and inoculum size influenced butanol production at 99% probability level (P<0.01). The optimum conditions for butanol production were pH 6.28, temperature of 28°C and inoculum size of 15.9%. ABE fermentation was carried out under optimum conditions which 0.1g/L butanol was obtained. Butanol production was enhanced by diluting PKC hydrolysate up to 70% in which 3.59g/L butanol was produced.
  17. Shukor H, Abdeshahian P, Al-Shorgani NK, Hamid AA, Rahman NA, Kalil MS
    Bioresour Technol, 2016 Oct;218:257-64.
    PMID: 27372004 DOI: 10.1016/j.biortech.2016.06.084
    Catalytic depolymerization of mannan composition of palm kernel cake (PKC) by mannanase was optimized to enhance the release of mannan-derived monomeric sugars for further application in acetone-butanol-ethanol (ABE) fermentation. Efficiency of enzymatic hydrolysis of PKC was studied by evaluating effects of PKC concentration, mannanase loading, hydrolysis pH value, reaction temperature and hydrolysis time on production of fermentable sugars using one-way analysis of variance (ANOVA). The ANOVA results revealed that all factors studied had highly significant effects on total sugar liberated (P<0.01). The optimum conditions for PKC hydrolysis were 20% (w/v) PKC concentration, 5% (w/w) mannanase loading, hydrolysis pH 4.5, 45°C temperature and 72h hydrolysis time. Enzymatic experiments in optimum conditions revealed total fermentable sugars of 71.54±2.54g/L were produced including 67.47±2.51g/L mannose and 2.94±0.03g/L glucose. ABE fermentation of sugar hydrolysate by Clostridium saccharoperbutylacetonicum N1-4 resulted in 3.27±1.003g/L biobutanol.
  18. Sudi IY, Hamid AA, Shamsir MS, Jamaluddin H, Wahab RA, Huyop F
    Biotechnology, biotechnological equipment, 2014 Jul 04;28(4):608-615.
    PMID: 26740767
    Halogenated compounds are recalcitrant environmental pollutants prevalent in agricultural fields, waste waters and industrial by-products, but they can be degraded by dehalogenase-containing microbes. Notably, 2-haloalkanoic acid dehalogenases are employed to resolve optically active chloropropionates, as exemplified by the d-specific dehalogenase from Rhizobium sp. RCI (DehD), which acts on d-2-chloropropionate but not on its l-enantiomer. The catalytic residues of this dehalogenase responsible for its affinity toward d-2-chloropropionate have not been experimentally determined, although its three-dimensional crystal structure has been solved. For this study, we performed in silico docking and molecular dynamic simulations of complexes formed by this dehalogenase and d- or l-2-chloropropionate. Arg134 of the enzyme plays the key role in the stereospecific binding and Arg16 is in a position that would allow it to activate a water molecule for hydrolytic attack on the d-2-chloropropionate chiral carbon for release of the halide ion to yield l-2-hydroxypropionate. We propose that within the DehD active site, the NH group of Arg134 can form a hydrogen bond with the carboxylate of d-2-chloropropionate with a strength of ∼4 kcal/mol that may act as an acid-base catalyst, whereas, when l-2-chloropropionate is present, this bond cannot be formed. The significance of the present work is vital for rational design of this dehalogenase in order to confirm the involvement of Arg16 and Arg134 residues implicated in hydrolysis and binding of d-2-chloropropionate in the active site of d-specific dehalogenase from Rhizobium sp. RC1.
  19. Nakagawa M, Itioka T, Momose K, Yumoto T, Komai F, Morimoto K, et al.
    Bull. Entomol. Res., 2003 Oct;93(5):455-66.
    PMID: 14658448
    Insect seed predators of 24 dipterocarp species (including the genera ot Dipterocarpus, Dryobalanops and Shorea) and five species belonging to the Moraceae, Myrtaceae, Celastraceae and Sapotaceae were investigated. In a tropical lowland dipterocarp forest in Sarawak, Malaysia, these trees produces seeds irregularly by intensely during general flowering and seeding events in 1996 and/or 1998. Dipterocarp seeds were preyed on by 51 insect species (11 families), which were roughly classified into three taxonomic groups: smaller moths (Trotricidae, Pyralidae, Crambidae, Immidae, Sesiidae, and Cosmopterigidae), scolytids (Scolydae) and weevils (Curdulionidae, Apionidae, Anthribidae, and Attelabidae). Although the host-specificity of invertebrate seed predators has been assumed to be high in tropical forests, it was found that the diet ranges of some insect predators were relatively wide and overlapped one another. Most seed predators that were collected in both study years changes their diets between general flowering and seeding events. The results of cluster analyses based on the number of adult of each predator species that emerged from 100 seeds of each tree species, suggested that the dominant species was not consistent, alternating between the two years.
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