Displaying publications 21 - 40 of 125 in total

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  1. Microarray profiling of secretory-phase endometrium from patients with recurrent miscarriage
    Othman R, Omar MH, Shan LP, Shafiee MN, Jamal R, Mokhtar NM
    Reprod Biol, 2012 Jul;12(2):183-99.
    PMID: 22850470
    The aim of the present study was to identify differentially expressed genes and their related biological pathways in the secretory phase endometrium from patients with recurrent miscarriage (RM) and fertile subjects. Endometrial samples from RM and fertile patients were analyzed using the Affymetrix GeneChip® ST Array. The bioinformatic analysis using the Partek Genomic Suite revealed 346 genes (175 up-regulated and 171 down-regulated) that were differentially expressed in the endometrium of RM patients compared to the fertile subjects (fold change ≥1.5, p<0.005). Validation step using quantitative real-time polymerase chain reaction (qPCR) confirmed a similar expression pattern of four exemplary genes: one up-regulated gene (fibroblast growth factor 9, FGF9) and three down-regulated genes: integrin β3 (ITGB3), colony stimulating factor 1 (CSF1) and matrix-metalloproteinases 19 (MMP19). The Gene Set Enrichment Analysis (GSEA) and the Pathway Studio software have found 101 signaling pathways (p<0.05) associated with the affected genes including the FGFR3 /signal transducer and activator of transcription (STAT) pathway and the CSF1R/STAT pathway. Cell adhesion, cell differentiation and angiogenesis were among biological processes indicated by this system. In conclusion, microarray technique is a useful tool to study gene expression in the secretory phase-endometrium of RM patients. The differences in endometrial gene expressions between healthy and RM subjects contribute to an increase in our knowledge on molecular mechanisms of RM development and may improve the outcome of pregnancies in high-risk women with RM.
  2. Macroporous bioceramics: a remarkable material for bone regeneration
    Lew KS, Othman R, Ishikawa K, Yeoh FY
    J Biomater Appl, 2012 Sep;27(3):345-58.
    PMID: 21862511 DOI: 10.1177/0885328211406459
    This review summarises the major developments of macroporous bioceramics used mainly for repairing bone defects. Porous bioceramics have been receiving attention ever since their larger surface area was reported to be beneficial for the formation of more rigid bonds with host tissues. The study of porous bioceramics is important to overcome the less favourable bonds formed between dense bioceramics and host tissues, especially in healing bone defects. Macroporous bioceramics, which have been studied extensively, include hydroxyapatite, tricalcium phosphate, alumina, and zirconia. The pore size and interconnections both have significant effects on the growth rate of bone tissues. The optimum pore size of hydroxyapatite scaffolds for bone growth was found to be 300 µm. The existence of interconnections between pores is critical during the initial stage of tissue ingrowth on porous hydroxyapatite scaffolds. Furthermore, pore formation on β-tricalcium phosphate scaffolds also allowed the impregnation of growth factors and cells to improve bone tissues growth significantly. The formation of vascularised tissues was observed on macroporous alumina but did not take place in the case of dense alumina due to its bioinert nature. A macroporous alumina coating on scaffolds was able to improve the overall mechanical properties, and it enabled the impregnation of bioactive materials that could increase the bone growth rate. Despite the bioinertness of zirconia, porous zirconia was useful in designing scaffolds with superior mechanical properties after being coated with bioactive materials. The pores in zirconia were believed to improve the bone growth on the coated system. In summary, although the formation of pores in bioceramics may adversely affect mechanical properties, the advantages provided by the pores are crucial in repairing bone defects.
  3. Fulltext Physiological and growth responses of six turfgrass species relative to salinity tolerance
    Uddin K, Juraimi AS, Ismail MR, Hossain A, Othman R, Abdul Rahim A
    ScientificWorldJournal, 2012;2012:905468.
    PMID: 22666166 DOI: 10.1100/2012/905468
    The demand for salinity-tolerant turfgrasses is increasing due to augmented use of effluent or low-quality water (sea water) for turf irrigation and the growing turfgrass industry in coastal areas. Experimental plants, grown in plastic pots filled with a mixture of river sand and KOSAS(R) peat (9 : 1), were irrigated with sea water at different dilutions imparting salinity levels of 0, 8, 16, 24, 32, 40, or 48 dS m⁻¹. Salinity tolerance was evaluated on the basis of leaf firing, shoot and root growth reduction, proline content, and relative water content. Paspalum vaginatum was found to be most salt tolerant followed by Zoysia japonica and Zoysia matrella, while Digitaria didactyla, Cynodon dactylon "Tifdwarf," and Cynodon dactylon "Satiri" were moderately tolerant. The results indicate the importance of turfgrass varietal selection for saline environments.
  4. Colorectal cancer and its association with the metabolic syndrome: a Malaysian multi-centric case-control study
    Ulaganathan V, Kandiah M, Zalilah MS, Faizal JA, Fijeraid H, Normayah K, et al.
    Asian Pac J Cancer Prev, 2012;13(8):3873-7.
    PMID: 23098486
    OBJECTIVE: Colorectal cancer (CRC) and the metabolic syndrome (MetS) are both on the rise in Malaysia. A multi-centric case-control study was conducted from December 2009 to January 2011 to determine any relationship between the two.

    METHODS: Patients with confirmed CRC based on colonoscopy findings and cancer free controls from five local hospitals were assessed for MetS according to the International Diabetes Federation (IDF) definition. Each index case was matched for age, gender and ethnicity with two controls (140: 280).

    RESULTS: MetS among cases was highly prevalent (70.7%), especially among women (68.7%). MetS as an entity increased CRC risk by almost three fold independently (OR=2.61, 95%CI=1.53-4.47). In men MetS increased the risk of CRC by two fold (OR=2.01, 95%CI, 1.43-4.56), demonstrating an increasing trend in risk with the number of Mets components observed.

    CONCLUSION: This study provides evidence for a positive association between the metabolic syndrome and colorectal cancer. A prospective study on the Malaysian population is a high priority to confirm these findings.

  5. Fulltext Flavonoid biosynthesis genes putatively identified in the aromatic plant Polygonum minus via Expressed Sequences Tag (EST) analysis
    Roslan ND, Yusop JM, Baharum SN, Othman R, Mohamed-Hussein ZA, Ismail I, et al.
    Int J Mol Sci, 2012;13(3):2692-706.
    PMID: 22489118 DOI: 10.3390/ijms13032692
    P. minus is an aromatic plant, the leaf of which is widely used as a food additive and in the perfume industry. The leaf also accumulates secondary metabolites that act as active ingredients such as flavonoid. Due to limited genomic and transcriptomic data, the biosynthetic pathway of flavonoids is currently unclear. Identification of candidate genes involved in the flavonoid biosynthetic pathway will significantly contribute to understanding the biosynthesis of active compounds. We have constructed a standard cDNA library from P. minus leaves, and two normalized full-length enriched cDNA libraries were constructed from stem and root organs in order to create a gene resource for the biosynthesis of secondary metabolites, especially flavonoid biosynthesis. Thus, large-scale sequencing of P. minus cDNA libraries identified 4196 expressed sequences tags (ESTs) which were deposited in dbEST in the National Center of Biotechnology Information (NCBI). From the three constructed cDNA libraries, 11 ESTs encoding seven genes were mapped to the flavonoid biosynthetic pathway. Finally, three flavonoid biosynthetic pathway-related ESTs chalcone synthase, CHS (JG745304), flavonol synthase, FLS (JG705819) and leucoanthocyanidin dioxygenase, LDOX (JG745247) were selected for further examination by quantitative RT-PCR (qRT-PCR) in different P. minus organs. Expression was detected in leaf, stem and root. Gene expression studies have been initiated in order to better understand the underlying physiological processes.
  6. Fate of napropamide herbicide in selected Malaysian soils
    Sadegh-Zadeh F, Wahid SA, Seh-Bardan BJ, Othman R, Omar D
    J Environ Sci Health B, 2012;47(2):144-51.
    PMID: 22251214 DOI: 10.1080/03601234.2012.624481
    This study was carried out to determine the sorption-desorption, degradation and leaching of napropamide in selected Malaysian soils. The sorption capacities of the selected Malaysian soils for napropamide were the following in descending order: Linau > Teringkap > Gunung Berinchang > Jambu > Rudua > Baging soil. The results indicate that napropamide degradation decreased with increasing soil sorption capacity. Napropamide was leached out earlier in the Baging soil than the other soils. Overall, the application of napropamide in the selected Malaysian soils would not pose a threat to the environment except in soil with low organic matter and clay content and high hydraulic conductivity, such as the Baging soil.
  7. Fulltext Overexpressing 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) in the lactococcal mevalonate pathway for heterologous plant sesquiterpene production
    Song AA, Abdullah JO, Abdullah MP, Shafee N, Othman R, Tan EF, et al.
    PLoS One, 2012;7(12):e52444.
    PMID: 23300671 DOI: 10.1371/journal.pone.0052444
    Isoprenoids are a large and diverse group of metabolites with interesting properties such as flavour, fragrance and therapeutic properties. They are produced via two pathways, the mevalonate pathway or the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway. While plants are the richest source of isoprenoids, they are not the most efficient producers. Escherichia coli and yeasts have been extensively studied as heterologous hosts for plant isoprenoids production. In the current study, we describe the usage of the food grade Lactococcus lactis as a potential heterologous host for the production of sesquiterpenes from a local herbaceous Malaysian plant, Persicaria minor (synonym Polygonum minus). A sesquiterpene synthase gene from P. minor was successfully cloned and expressed in L. lactis. The expressed protein was identified to be a β-sesquiphellandrene synthase as it was demonstrated to be functional in producing β-sesquiphellandrene at 85.4% of the total sesquiterpenes produced based on in vitro enzymatic assays. The recombinant L. lactis strain developed in this study was also capable of producing β-sesquiphellandrene in vivo without exogenous substrates supplementation. In addition, overexpression of the strain's endogenous 3-hydroxy-3-methylglutaryl coenzyme-A reductase (HMGR), an established rate-limiting enzyme in the eukaryotic mevalonate pathway, increased the production level of β-sesquiphellandrene by 1.25-1.60 fold. The highest amount achieved was 33 nM at 2 h post-induction.
  8. Monoterpene alcohol metabolism: identification, purification, and characterization of two geraniol dehydrogenase isoenzymes from Polygonum minus leaves
    Hassan M, Maarof ND, Ali ZM, Noor NM, Othman R, Mori N
    Biosci Biotechnol Biochem, 2012;76(8):1463-70.
    PMID: 22878188
    NADP(+)-dependent geraniol dehydrogenase (EC 1.1.1.183) is an enzyme that catalyzes the oxidation of geraniol to geranial. Stable, highly active cell-free extract was obtained from Polygonum minus leaves using polyvinylpolypyrrolidone, Amberlite XAD-4, glycerol, 2-mercaptoethanol, thiourea, and phenylmethylsulfonylfluoride in tricine-NaOH buffer (pH 7.5). The enzyme preparation was separated into two activity peaks, geraniol-DH I and II, by DEAE-Toyopearl 650M column chromatography at pH 7.5. Both isoenzymes were purified to homogeneity in three chromatographic steps. The geraniol-DH isoenzymes were similar in molecular mass, optimal temperature, and pH, but the isoelectric point, substrate specificity, and kinetic parameters were different. The K(m) values for geraniol of geraniol-DH I and II appeared to be 0.4 mM and 0.185 mM respectively. P. minus geraniol-DHs are unusual among geraniol-DHs in view of their thermal stability and optimal temperatures, and also their high specificity for allylic alcohols and NADP(+).
  9. Fulltext Scheme of obtaining β-carotene standard from pumpkin (Cucurbita moschata) flesh
    Norshazila, S., Irwandi, J., Othman, R., Yumi Zuhanis, H.H.
    International Food Research Journal, 2012;19(2):531-535.
    MyJurnal
    Characterization and quantification of carotenoid compound is complicated, costly and timeconsuming. The accuracy and reliability of the data depend solely on the standard and to High Performance Liquid Chromatography (HPLC) analysis but the major constraint is to acquire and to maintain the pure standards. Carotenoid standards are commercially available but they are expensive and are prone to isomerization and oxidation. Thus, the purpose of this study is to establish an analytical method for isolating β-carotene by using open column chromatography (OCC) from pumpkin (Cucurbita moschata) to be used as one of the carotenoid standards for determination of total and individual carotenoid. Pumpkin with orange flesh has been chosen due to the non-seasonal nature and its availability all year-round. This study demonstrated that the purity of β-carotene standard; determined by HPLC was ranged from 92.21 to 97.95%. The standard curves with five different concentrations of β-carotene extract from pumpkins in triplicate were constructed by plotting the peak area against the concentration. The coefficient of correlation was 0.9936. Therefore, this study established that pumpkin can be a reliable source of beta-carotene standard as it is cheap and commonly available throughout the year.
  10. Fulltext Boesenbergia rotunda: From Ethnomedicine to Drug Discovery
    Eng-Chong T, Yean-Kee L, Chin-Fei C, Choon-Han H, Sher-Ming W, Li-Ping CT, et al.
    Evid Based Complement Alternat Med, 2012;2012:473637.
    PMID: 23243448 DOI: 10.1155/2012/473637
    Boesenbergia rotunda is a herb from the Boesenbergia genera under the Zingiberaceae family. B. rotunda is widely found in Asian countries where it is commonly used as a food ingredient and in ethnomedicinal preparations. The popularity of its ethnomedicinal usage has drawn the attention of scientists worldwide to further investigate its medicinal properties. Advancement in drug design and discovery research has led to the development of synthetic drugs from B. rotunda metabolites via bioinformatics and medicinal chemistry studies. Furthermore, with the advent of genomics, transcriptomics, proteomics, and metabolomics, new insights on the biosynthetic pathways of B. rotunda metabolites can be elucidated, enabling researchers to predict the potential bioactive compounds responsible for the medicinal properties of the plant. The vast biological activities exhibited by the compounds obtained from B. rotunda warrant further investigation through studies such as drug discovery, polypharmacology, and drug delivery using nanotechnology.
  11. Rational discovery of dengue type 2 non-competitive inhibitors
    Heh CH, Othman R, Buckle MJ, Sharifuddin Y, Yusof R, Rahman NA
    Chem Biol Drug Des, 2013 Jul;82(1):1-11.
    PMID: 23421589 DOI: 10.1111/cbdd.12122
    Various works have been carried out in developing therapeutics against dengue. However, to date, no effective vaccine or anti-dengue agent has yet been discovered. The development of protease inhibitors is considered as a promising option, but most previous works have involved competitive inhibition. In this study, we focused on rational discovery of potential anti-dengue agents based on non-competitive inhibition of DEN-2 NS2B/NS3 protease. A homology model of the DEN-2 NS2B/NS3 protease (using West Nile Virus NS2B/NS3 protease complex, 2FP7, as the template) was used as the target, and pinostrobin, a flavanone, was used as the standard ligand. Virtual screening was performed involving a total of 13 341 small compounds, with the backbone structures of chalcone, flavanone, and flavone, available in the ZINC database. Ranking of the resulting compounds yielded compounds with higher binding affinities compared with the standard ligand. Inhibition assay of the selected top-ranking compounds against DEN-2 NS2B/NS3 proteolytic activity resulted in significantly better inhibition compared with the standard and correlated well with in silico results. In conclusion, via this rational discovery technique, better inhibitors were identified. This method can be used in further work to discover lead compounds for anti-dengue agents.
  12. Fulltext Biomolecular characterization of diazotrophs isolated from the tropical soil in Malaysia
    Naher UA, Othman R, Latif MA, Panhwar QA, Amaddin PA, Shamsuddin ZH
    Int J Mol Sci, 2013 Aug 30;14(9):17812-29.
    PMID: 23999588 DOI: 10.3390/ijms140917812
    This study was conducted to evaluate selected biomolecular characteristics of rice root-associated diazotrophs isolated from the Tanjong Karang rice irrigation project area of Malaysia. Soil and rice plant samples were collected from seven soil series belonging to order Inceptisol (USDA soil taxonomy). A total of 38 diazotrophs were isolated using a nitrogen-free medium. The biochemical properties of the isolated bacteria, such as nitrogenase activity, indoleacetic acid (IAA) production and sugar utilization, were measured. According to a cluster analysis of Jaccard's similarity coefficients, the genetic similarities among the isolated diazotrophs ranged from 10% to 100%. A dendogram constructed using the unweighted pair-group method with arithmetic mean (UPGMA) showed that the isolated diazotrophs clustered into 12 groups. The genomic DNA rep-PCR data were subjected to a principal component analysis, and the first four principal components (PC) accounted for 52.46% of the total variation among the 38 diazotrophs. The 10 diazotrophs that tested highly positive in the acetylene reduction assay (ARA) were identified as Bacillus spp. (9 diazotrophs) and Burkholderia sp. (Sb16) using the partial 16S rRNA gene sequence analysis. In the analysis of the biochemical characteristics, three principal components were accounted for approximately 85% of the total variation among the identified diazotrophs. The examination of root colonization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) proved that two of the isolated diazotrophs (Sb16 and Sb26) were able to colonize the surface and interior of rice roots and fixed 22%-24% of the total tissue nitrogen from the atmosphere. In general, the tropical soils (Inceptisols) of the Tanjong Karang rice irrigation project area in Malaysia harbor a diverse group of diazotrophs that exhibit a large variation of biomolecular characteristics.
  13. Fulltext Thymoquinone induces mitochondria-mediated apoptosis in acute lymphoblastic leukaemia in vitro
    Salim LZ, Mohan S, Othman R, Abdelwahab SI, Kamalidehghan B, Sheikh BY, et al.
    Molecules, 2013 Sep 12;18(9):11219-40.
    PMID: 24036512 DOI: 10.3390/molecules180911219
    There has been a growing interest in naturally occurring compounds from traditional medicine with anti-cancer potential. Nigella sativa (black seed) is one of the most widely studied plants. This annual herb grows in countries bordering the Mediterranean Sea and India. Thymoquinone (TQ) is an active ingredient isolated from Nigella sativa. The anti-cancer effect of TQ, via the induction of apoptosis resulting from mitochondrial dysfunction, was assessed in an acute lymphocyte leukemic cell line (CEMss) with an IC50 of 1.5 µg/mL. A significant increase in chromatin condensation in the cell nucleus was observed using fluorescence analysis. The apoptosis was then confirmed by Annexin V and an increased number of cellular DNA breaks in treated cells were observed as a DNA ladder. Treatment of CEMss cells with TQ encouraged apoptosis with cell death-transducing signals by a down-regulation of Bcl-2 and up-regulation of Bax. Moreover, the significant generation of cellular ROS, HSP70 and activation of caspases 3 and 8 were also observed in the treated cells. The mitochondrial apoptosis was clearly associated with the S phase cell cycle arrest. In conclusion, the results from the current study indicated that TQ could be a promising agent for the treatment of leukemia.
  14. Fulltext Application of potential phosphate-solubilizing bacteria and organic acids on phosphate solubilization from phosphate rock in aerobic rice
    Panhwar QA, Jusop S, Naher UA, Othman R, Razi MI
    ScientificWorldJournal, 2013;2013:272409.
    PMID: 24288473 DOI: 10.1155/2013/272409
    A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB) and organic acids (oxalic & malic) on phosphate (P) solubilization from phosphate rock (PR) and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM), and PSB strain (Bacillus sp.) were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg(-1)), plant P uptake (0.78 P pot(-1)), and plant biomass (33.26 mg). Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g(-1)) compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH.
  15. Fulltext A Novel, Homozygous c.1502T>G (p.Val501Gly) Mutation in the Thyroid peroxidase Gene in Malaysian Sisters with Congenital Hypothyroidism and Multinodular Goiter
    Lee CC, Harun F, Jalaludin MY, Heh CH, Othman R, Mat Junit S
    Int J Endocrinol, 2013;2013:987186.
    PMID: 23737781 DOI: 10.1155/2013/987186
    Congenital hypothyroidism (CH) with multinodular goiter (MNG) is uncommonly seen in children. However, CH associated with goiter is often caused by defective Thyroid peroxidase (TPO) gene. In this study, we screened for mutation(s) in the TPO gene in two siblings with CH and MNG and their healthy family members. The two sisters, born to consanguineous parents, were diagnosed with CH during infancy and received treatment since then. They developed MNG during childhood despite adequate L-thyroxine replacement and negative thyroid antibody screening. PCR-amplification of all exons using flanking primers followed by DNA sequencing revealed that the two sisters were homozygous for a novel c.1502T>G mutation. The mutation is predicted to substitute valine for glycine at a highly conserved amino acid residue 501 (p.Val501Gly). Other healthy family members were either heterozygotes or mutation-free. The mutation was not detected in 50 healthy unrelated individuals. In silico analyses using PolyPhen-2 and SIFT predicted that the p.Val501Gly mutation is functionally "damaging." Tertiary modeling showed structural alterations in the active site of the mutant TPO. In conclusion, a novel mutation, p.Val501Gly, in the TPO gene was detected expanding the mutation spectrum of TPO associated with CH and MNG.
  16. Fulltext Engineering the lactococcal mevalonate pathway for increased sesquiterpene production
    Song AA, Abdullah JO, Abdullah MP, Shafee N, Othman R, Noor NM, et al.
    FEMS Microbiol Lett, 2014 Jun;355(2):177-84.
    PMID: 24828482 DOI: 10.1111/1574-6968.12469
    Isoprenoids are a large, diverse group of secondary metabolites which has recently raised a renewed research interest due to genetic engineering advances, allowing specific isoprenoids to be produced and characterized in heterologous hosts. Many researches on metabolic engineering of heterologous hosts for increased isoprenoid production are focussed on Escherichia coli and yeasts. E. coli, as most prokaryotes, use the 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway for isoprenoid production. Yeasts on the other hand, use the mevalonate pathway which is commonly found in eukaryotes. However, Lactococcus lactis is an attractive alternative host for heterologous isoprenoid production. Apart from being food-grade, this Gram-positive prokaryote uses the mevalonate pathway for isoprenoid production instead of the MEP pathway. Previous studies have shown that L. lactis is able to produce sesquiterpenes through heterologous expression of plant sesquiterpene synthases. In this work, we analysed the gene expression of the lactococcal mevalonate pathway through RT-qPCR to successfully engineer L. lactis as an efficient host for isoprenoid production. We then overexpressed the mvk gene singly or co-expressed with the mvaA gene as an attempt to increase β-sesquiphellandrene production in L. lactis. It was observed that co-expression of mvk with mvaA doubled the amount of β-sesquiphellandrene produced.
  17. High level expression of Glomerella cingulata cutinase in dense cultures of Pichia pastoris grown under fed-batch conditions
    Seman WM, Bakar SA, Bukhari NA, Gaspar SM, Othman R, Nathan S, et al.
    J Biotechnol, 2014 Aug 20;184:219-28.
    PMID: 24910973 DOI: 10.1016/j.jbiotec.2014.05.034
    A Pichia pastoris transformant carrying the cutinase cDNA of Glomerella cingulata was over-expressed in a 5L bioreactor (2.0L working volume) under fed-batch conditions. Bioreactor experiments rely on varying selected parameters in repeated rounds of optimisation: here these included duration of induction, pH and temperature. Highest cell densities (320gL(-1) wet cell weight) with a cutinase production of 3800mgL(-1) and an activity of 434UmL(-1) were achieved 24h after induction with methanol in basal salt medium (at pH 5 and 28°C). Characterisation of the cutinase showed that it was stable between pH 6 and pH 11, had an optimum pH of 8.0 and retained activity for 30min at 50°C (optimum temperature 25°C).The preferred substrates of G. cingulata cutinase were the medium- to long-chain ρ-nitrophenyl esters of ρ-nitrophenylcaprylate (C8), ρ-nitrophenyllaurate (C12) and ρ-nitrophenylmyristate (C14), with the highest catalytic efficiency, kcat/Km of 7.7±0.7mM(-1)s(-1) for ρ-nitrophenylcaprylate. Microscopic analyses showed that the G. cingulata cutinase was also capable of depolymerising the high molecular weight synthetic polyester, polyethylene terephthalate.
  18. Co-solvent selection for supercritical fluid extraction of astaxanthin and other carotenoids from Penaeus monodon waste
    Radzali SA, Baharin BS, Othman R, Markom M, Rahman RA
    J Oleo Sci, 2014;63(8):769-77.
    PMID: 25007745
    In recent years, astaxanthin is claimed to have a 10 times higher antioxidant activity than that of other carotenoids such as lutein, zeaxanthin, canthaxanthin, and β-carotene; the antioxidant activity of astaxanthin is 100 times higher than that of α-tocopherol. Penaeus monodon (tiger shrimp) is the largest commercially available shrimp species and its waste is a rich source of carotenoids such as astaxanthin and its esters. The efficient and environment-friendly recovery of astaxanthins was accomplished by using a supercritical fluid extraction (SFE) technique. The effects of different co-solvents and their concentrations on the yield and composition of the extract were investigated. The following co-solvents were studied prior to the optimization of the SFE technique: ethanol, water, methanol, 50% (v/v) ethanol in water, 50% (v/v) methanol in water, 70% (v/v) ethanol in water, and 70% (v/v) methanol in water. The ethanol extract produced the highest carotenoid yield (84.02 ± 0.8 μg/g) dry weight (DW) with 97.1% recovery. The ethanol extract also produced the highest amount of the extracted astaxanthin complex (58.03 ± 0.1 μg/g DW) and the free astaxanthin content (12.25 ± 0.9 μg/g DW) in the extract. Lutein and β-carotene were the other carotenoids identified. Therefore, ethanol was chosen for further optimization studies.
  19. Effects of season and storage period on accumulation of individual carotenoids in pumpkin flesh (Cucurbita moschata)
    Jaswir I, Shahidan N, Othman R, Has-Yun Hashim YZ, Octavianti F, bin Salleh MN
    J Oleo Sci, 2014;63(8):761-7.
    PMID: 25007748
    Carotenoids are antioxidants with pharmaceutical potential. The major carotenoids important to humans are α-carotene, β-carotene, lycopene, lutein, zeaxanthin, and β-cryptoxanthin. Some of the biological functions and actions of these individual carotenoids are quite similar to each other, whereas others are specific. Besides genotype and location, other environmental effects such as temperature, light, mineral uptake, and pH have been found affect carotenoid development in plant tissues and organs. Therefore, this research investigated the effects of the season and storage periods during postharvest handling on the accumulation of carotenoid in pumpkin. This study shows that long-term storage of pumpkins resulted in the accumulation of lutein and β-carotene with a slight decrease in zeaxanthin. The amounts of β-carotene ranged from 174.583±2.105 mg/100g to 692.871±22.019 mg/100g, lutein from 19.841±9.693 mg/100g to 59.481±1.645 mg/100g, and zeaxanthin from not detected to 2.709±0.118 mg/100g. The pumpkins were collected three times in a year; they differed in that zeaxanthin was present only in the first season, while the amounts of β-carotene and lutein were the highest in the second and third seasons, respectively. By identifying the key factors among the postharvest handling conditions that control specific carotenoid accumulations, a greater understanding of how to enhance the nutritional values of pumpkin and other crops will be gained. Postharvest storage conditions can markedly enhance and influence the levels of zeaxanthin, lutein, and β-carotene in pumpkin. This study describes how the magnitudes of these effects depend on the storage period and season.
  20. Fulltext Biochemical and molecular characterization of potential phosphate-solubilizing bacteria in acid sulfate soils and their beneficial effects on rice growth
    Panhwar QA, Naher UA, Shamshuddin J, Jusop S, Othman R, Latif MA, et al.
    PLoS One, 2014;9(10):e97241.
    PMID: 25285745 DOI: 10.1371/journal.pone.0097241
    A study was conducted to determine the total microbial population, the occurrence of growth promoting bacteria and their beneficial traits in acid sulfate soils. The mechanisms by which the bacteria enhance rice seedlings grown under high Al and low pH stress were investigated. Soils and rice root samples were randomly collected from four sites in the study area (Kelantan, Malaysia). The topsoil pH and exchangeable Al ranged from 3.3 to 4.7 and 1.24 to 4.25 cmol(c) kg(-1), respectively, which are considered unsuitable for rice production. Total bacterial and actinomycetes population in the acidic soils were found to be higher than fungal populations. A total of 21 phosphate-solubilizing bacteria (PSB) including 19 N2-fixing strains were isolated from the acid sulfate soil. Using 16S rRNA gene sequence analysis, three potential PSB strains based on their beneficial characteristics were identified (Burkholderia thailandensis, Sphingomonas pituitosa and Burkholderia seminalis). The isolated strains were capable of producing indoleacetic acid (IAA) and organic acids that were able to reduce Al availability via a chelation process. These PSB isolates solubilized P (43.65%) existing in the growth media within 72 hours of incubation. Seedling of rice variety, MR 219, grown at pH 4, and with different concentrations of Al (0, 50 and 100 µM) was inoculated with these PSB strains. Results showed that the bacteria increased the pH with a concomitant reduction in Al concentration, which translated into better rice growth. The improved root volume and seedling dry weight of the inoculated plants indicated the potential of these isolates to be used in a bio-fertilizer formulation for rice cultivation on acid sulfate soils.
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