Displaying publications 281 - 300 of 1723 in total

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  1. Taxonomy and toxicity of a bloom-forming Ostreopsis species (Dinophyceae, Gonyaulacales) in Tahiti island (South Pacific Ocean): one step further towards resolving the identity of O. siamensis
    Chomérat N, Bilien G, Viallon J, Hervé F, Réveillon D, Henry K, et al.
    Harmful Algae, 2020 09;98:101888.
    PMID: 33129466 DOI: 10.1016/j.hal.2020.101888
    Among dinoflagellates responsible for benthic harmful algal blooms, the genus Ostreopsis primarily described from tropical areas has been increasingly reported from subtropical and temperate areas worldwide. Several species of this toxigenic genus produce analogs of palytoxin, thus representing a major threat to human and environmental health. The taxonomy of several species needs to be clarified as it was based mostly on morphological descriptions leading in some cases to ambiguous interpretations and misidentifications. The present study aims at reporting a benthic bloom that occurred in April 2019 in Tahiti island, French Polynesia. A complete taxonomic investigation of the blooming Ostreopsis species was realized using light, epifluorescence and field emission electron microscopy and phylogenetic analyses inferred from LSU rDNA and ITS-5.8S rDNA regions. Toxicity of a natural sample and strains isolated from the bloom was assessed using both neuroblastoma cell-based assay and LC-MS/MS analyses. Morphological observations showed that cells were round to oval, large, 58.0-82.5 µm deep (dorso-ventral length) and 45.7-61.2 µm wide. The cingulum was conspicuously undulated, forming a 'V' in ventral view. Thecal plates possessed large pores in depressions, with a collar rim. Detailed observation also revealed the presence of small thecal pores invisible in LM. Phylogenetic analyses were congruent and all sequences clustered within the genotype Ostreopsis sp. 6, in a subclade closely related to sequences from the Gulf of Thailand and Malaysia. No toxicity was found on the field sample but all the strains isolated from the bloom were found to be cytotoxic and produced ostreocin D, a lower amount of ostreocins A and B and putatively other compounds. Phylogenetic data demonstrate the presence of this species in the Gulf of Thailand, at the type locality of O. siamensis, and morphological data are congruent with the original description and support this identification.
    Matched MeSH terms: Chromatography, Liquid
  2. Fulltext Development of Isocratic RP-HPLC Method for Separation and Quantification of L-Citrulline and L-Arginine in Watermelons
    Ridwan R, Abdul Razak HR, Adenan MI, Md Saad WM
    Int J Anal Chem, 2018;2018:4798530.
    PMID: 29853897 DOI: 10.1155/2018/4798530
    Watermelons (Citrullus lanatus) are known to have sufficient amino acid content. In this study, watermelons grown and consumed in Malaysia were investigated for their amino acid content, L-citrulline and L-arginine, by the isocratic RP-HPLC method. Flesh and rind watermelons were juiced, and freeze-dried samples were used for separation and quantification of L-citrulline and L-arginine. Three different mobile phases, 0.7% H3P04, 0.1% H3P04, and 0.7% H3P04 : ACN (90 : 10), were tested on two different columns using Zorbax Eclipse XDB-C18 and Gemini C18 with a flow rate of 0.5 mL/min and a detection wavelength at 195 nm. Efficient separation with reproducible resolution of L-citrulline and L-arginine was achieved using 0.1% H3P04 on the Gemini C18 column. The method was validated and good linearity of L-citrulline and L-arginine was obtained with R2 = 0.9956, y = 0.1664x + 2.4142 and R2 = 0.9912, y = 0.4100x + 3.4850, respectively. L-citrulline content showed the highest concentration in red watermelon of flesh and rind juice extract (43.81 mg/g and 45.02 mg/g), whereas L-arginine concentration was lower than L-citrulline, ranging from 3.39 to 11.14 mg/g. The isocratic RP-HPLC method with 0.1% H3P04 on the Gemini C18 column proved to be efficient for separation and quantification of L-citrulline and L-arginine in watermelons.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  3. Fulltext Determination of polycyclic aromatic hydrocarbons in human blood samples using solid phase extraction and gas chromatography mass spectrometry- a review
    Samer Al-Battawi, Yu Bin Ho, Mohd Talib Latif, Vivien How, Karuppiah Thilakavathy
    Malaysian Journal of Medicine and Health Sciences, 2019;15(204):165-169.
    MyJurnal
    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants with toxic effects and adverse health impacts on general population. Several methods of extraction had been applied to extract PAHs from human blood samples such as solid phase extraction (SPE). The SPE represents one of the most common techniques for extraction and clean-up procedures as it needs low quantity of solvents with less manual efforts. Similarly, various analytical instruments like gas chromatography coupled to mass spectrometry (GC-MS) was used to measure the PAHs levels. Gas chromatog- raphy is a simple, fast, and very efficient method for solvents and small organic molecules. This review provides an overview of the measured concentrations of PAHs in human blood samples through the application of SPE and GC- MS during the last ten years. While these studies used various solvents, their application of SPE method and GC-MS revealed rewarding results about the determination of PAHs levels in the human samples.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  4. Fulltext Surface Thermo-Dynamic Characterization of Poly (Vinylidene Chloride-Co-Acrylonitrile) (P(VDC-co-AN)) Using Inverse-Gas Chromatography and Investigation of Visual Traits Using Computer Vision Image Processing Algorithms
    Kakani V, Kim H, Basivi PK, Pasupuleti VR
    Polymers (Basel), 2020 Jul 23;12(8).
    PMID: 32717780 DOI: 10.3390/polym12081631
    The Inverse Gas Chromatography (IGC) technique has been employed for the surface thermo-dynamic characterization of the polymer Poly(vinylidene chloride-co-acrylonitrile) (P(VDC-co-AN)) in its pure form. IGC attributes, such as London dispersive surface energy, Gibbs free energy, and Guttman Lewis acid-base parameters were analyzed for the polymer (P(VDC-co-AN)). The London dispersive surface free energy ( γ S L ) was calculated using the Schultz and Dorris-Gray method. The maximum surface energy value of (P(VDC-co-AN )) is found to be 29.93 mJ·m - 2 and 24.15 mJ·m - 2 in both methods respectively. In our analysis, it is observed that the γ S L values decline linearly with an increase in temperature. The Guttman-Lewis acid-base parameter K a , K b values were estimated to be 0.13 and 0.49. Additionally, the surface character S value and the correlation coefficient were estimated to be 3.77 and 0.98 respectively. After the thermo-dynamic surface characterization, the (P(VDC-co-AN)) polymer overall surface character is found to be basic. The substantial results revealed that the (P(VDC-co-AN)) polymer surface contains more basic sites than acidic sites and, hence, can closely associate in acidic media. Additionally, visual traits of the polymer (P(VDC-co-AN)) were investigated by employing Computer Vision and Image Processing (CVIP) techniques on Scanning Electron Microscopy (SEM) images captured at resolutions ×50, ×200 and ×500. Several visual traits, such as intricate patterns, surface morphology, texture/roughness, particle area distribution ( D A ), directionality ( D P ), mean average particle area ( μ a v g ) and mean average particle standard deviation ( σ a v g ), were investigated on the polymer's purest form. This collective study facilitates the researches to explore the pure form of the polymer Poly(vinylidene chloride-co-acrylonitrile) (P(VDC-co-AN )) in both chemical and visual perspective.
    Matched MeSH terms: Chromatography, Gas
  5. Fulltext Contribution of aroma compounds to the antioxidant properties of roasted white yam (Dioscorea rotundata)
    Lasekan O, Teoh LS
    BMC Chem, 2019 Dec;13(1):133.
    PMID: 31891159 DOI: 10.1186/s13065-019-0650-3
    Background: The aroma chemistry and the contribution of the aroma compounds to the anti-oxidative properties of roasted yam have yet to be characterized. The growing popularity of roasted yam in regions where they are being consumed calls for a concerted effort to elucidate their aroma chemistry as well as their anti-oxidative properties.

    Results: The aroma compounds in roasted white yam (Dioscorea rotundata) were isolated and identified using static headspace-gas chromatography-mass spectrometry (SH-GC-MS) and gas chromatography-olfactometry (GC-O). In addition, the anti-oxidative activities of the most abundant volatile heterocyclic compounds (2 pyrroles, 4 furans and 3 pyrazines) were evaluated on their inhibitory effect towards the oxidation of hexanal for a period of 30 days. Twenty-nine aroma-active compounds with a flavour dilution (FD) factor range of 2-256 and an array of odour notes were obtained. Among them, the highest odour activities (FD ≥ 128) factors were determined for 2-acetyl furan and 2-acetylpyrrole. Other compounds with significant FD factors ≥ 32 were; 2-methylpyrazine, ethyl furfural, and 5-hydroxy methyl furfural.

    Conclusion: Results of the anti-oxidative activity showed that the pyrroles exhibited the greatest antioxidant activity among all the tested heterocyclic compounds. This was followed by the furans and the pyrazines which had the least antioxidant activity.

    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  6. Fulltext Partial purification and characterization of polyphenol oxidase from Chinese parsley (Coriandrum sativum)
    Lin H, Ng AWR, Wong CW
    Food Sci Biotechnol, 2016;25(Suppl 1):91-96.
    PMID: 30263491 DOI: 10.1007/s10068-016-0103-x
    Purification and characterization of polyphenol oxidase (PPO) from Chinese parsley (Coriandrum sativum) were achieved. Crude PPO exhibited an enzyme activity of 1,952.24 EU/mL. PPO was partially purified up to 6.52x with a 10.89% yield using gel filtration chromatography. Maximal PPO activity was found at 35°C, pH 8.0 for 4-methylcatechol and at 40°C, pH 7.0 for catechol. PPO showed a higher affinity towards 4-methylcatechol, but a higher thermal stability when reacting with catechol. LCysteine was a better inhibitor than citric acid for reducing PPO activity at concentrations of 1 and 3mM in the presence of either substrate. Two 46 kDa isoenzymes were identified using SDS-PAGE. Isolation and characterization of Chinese parsley serves as a guideline for prediction of enzyme behavior leading to effective prevention of enzymatic browning during processing and storage, including inhibition and inactivation of PPO.
    Matched MeSH terms: Chromatography, Gel
  7. Potassium Alum [KAl(SO4)2∙12H2O] solid catalyst for effective and selective methoxylation production of alpha-pinene ether products
    Wijayati N, Lestari LR, Wulandari LA, Mahatmanti FW, Rakainsa SK, Cahyono E, et al.
    Heliyon, 2021 Jan;7(1):e06058.
    PMID: 33553744 DOI: 10.1016/j.heliyon.2021.e06058
    Methoxylation is a relevant technological process applied in the production of high-value α-pinene derivatives. This report investigates the use of potassium alum [KAl(SO4)2 · 12H2O] as a catalyst in the methoxylation of α-pinene. In this study, the methoxylation reaction was optimized for the highest conversion of α-pinene and selectivity, assessed for the factors, catalyst loading (0.5; 1.0; and 1.5 g), volume ratio of α-pinene: methanol (1:4, 1:7, 1:10), reaction temperature (50, 55, 60 and 65 °C), and reaction time (72, 144, 216, 288, 360 min). The highest selectivity of KAl(SO4)2∙12H2O in the methoxylation of α-pinene was achieved under an optimal condition of 1 g of catalyst loading, volume ratio of 1:10, as well as the reaction temperature and incubation time of 65 °C and 6 h, respectively. GC-MS results revealed the yields of the methoxylated products from the 98.2% conversion of α-pinene, to be 59.6%, 8.9%, and 7.1% for α-terpinyl methyl ether (TME), fenchyl methyl ether (FME), bornyl methyl ether (BME), respectively. It was apparent that a lower KAl(SO4)2∙12H2O loading (0.5-1.5 g) was more economical for the methoxylation reaction. The findings seen here indicated the suitability of the KAl(SO4)2 · 12H2O to catalyze the methoxylation of α-pinene to produce an commercially important ethers.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  8. Fulltext Metabolome analysis and chemical profiling of Indonesian royal jellies as the raw material for cosmetic and bio-supplement products
    Sari E, Mahira KF, Patel DN, Chua LS, Pratami DK, Sahlan M
    Heliyon, 2021 May;7(5):e06912.
    PMID: 34013079 DOI: 10.1016/j.heliyon.2021.e06912
    Royal jellies (RJs) possess moisturizing, emulsifying, and stabilizing properties, and several pharmacological activities have also been found to be present, which make them an ideal component for cosmetic and skin care products. However, despite the abundant efficacies, there is a lack of studies that explore the chemical composition of RJ using metabolome analysis. Furthermore, an evaluation of the chemical composition of Indonesian RJs collected from different regions has yet to be carried out. Therefore, the main objective of this study was to identify any differences in the chemical composition of such RJs. Chemical profiling was also carried out to enable more targeted utilization based on the actual compositions. Chemical profiling is also important given the rich Indonesian biodiversity and the high dependence of the RJ compositions on the botanical source. In this research, ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used as part of an untargeted metabolomics approach. From the chemical profiling, >30 compounds were identified across four RJ samples. The major constituents of the samples were found to be oligosaccharides, fatty acids, and adenosine monophosphate derivatives. Meanwhile, sucrose and planteose were found to be highest in the samples from Banjarnegara and Kediri, whereas dimethyloctanoic acid was found to be unique to the sample from Banjarnegara. It was also discovered that the RJs from Demak and Tuban contained more organic fatty acids and oligosaccharides than the other samples. Although the sample from Demak demonstrated good potential for use in the cosmetic, skin care, and bio-supplement industries, the higher abundance of fatty acids and oligosaccharides in the sample from Tuban indicated that it is perhaps the most suitable RJ for use in this field.
    Matched MeSH terms: Chromatography, Liquid
  9. Fulltext Detection of Haemoglobin S using multiplex ligation-dependent probe amplification and flow-through hybridization techniques: experience in a tertiary hospital
    Wee, S.Y., Hafiza, A., Azma, R.Z., Azlin, I., Norunaluwar, J., Malisa, M.Y., et al.
    Medicine & Health, 2020;15(1):106-118.
    MyJurnal
    Hemoglobin S (HbS, α2β26GluVal) merupakan variasi hemoglobin yang terbentuk hasil daripada mutasi GAG GTG pada kodon 6 gen β-globin. Hemoglobinopati haemoglobin S (HbS) jarang ditemui di kalangan penduduk Malaysia tetapi selalunya dijumpai di kalangan pendatang asing dari Afrika. Walau bagaimanapun beberapa kes didapati dalam kaum India dan Melayu. Kajian ini meninjau keputusan makmal pesakit HbS dan penggunaan “multiplex ligation-dependent probe amplification” (MLPA) dan “flow-through hybridization” (FTH) dalam mengesan mutasi HbS. HbS dikenalpasti melalui kromatografi cecair prestasi tinggi (HPLC) dan/atau elektroforesis kapilari serta elektroforesis hemoglobin. Analisis molekul dijalankan menggunakan kaedah MLPA, FTH dan penjujukan Sanger. Dua warga Afrika, tiga Melayu dan dua India berusia antara 2-31 tahun telah dikenalpasti. Lima pesakit adalah HbS homozigot, seorang kompaun heterozigot HbS/β-talasemia dan seorang lagi pembawa HbS. Tahap hemoglobin (Hb) kes HbS homozigot adalah antara 7.4-10.2 g/dL dengan aras HbS dan HbF diantara 58.3-94.7% dan 1.5-35.5%. Hb untuk kes kompaun heterozigot HbS/β-talasemia adalah 5.8 g/dL dan normal pada pembawa HbS. Aras HbS, HbF dan HbA2 untuk HbS/β-talasemia dan pembawa HbS adalah 67%, 27.2% dan 4.2%, dan 38.6%, 0.1% and 2.8% setiap satu. Kedua-dua kaedah MLPA dan FTH berjaya mengesan mutasi HbS dalam semua kes, manakala cuma FTH dapat menentukan zygositi mutasi HbS dan β-talasemia dalam satu ujian yang sama.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  10. Fulltext Entamoeba histolytica: Proteomics Bioinformatics Reveal Predictive Functions and Protein-Protein Interactions of Differentially Abundant Membrane and Cytosolic Proteins
    Azmi N, Othman N
    Membranes (Basel), 2021 May 21;11(6).
    PMID: 34063994 DOI: 10.3390/membranes11060376
    Amoebiasis is caused by Entamoeba histolytica and ranked second for parasitic diseases causing death after malaria. E. histolytica membrane and cytosolic proteins play important roles in the pathogenesis. Our previous study had shown several cytosolic proteins were found in the membrane fraction. Therefore, this study aimed to quantify the differential abundance of membrane and cytosolic proteins in membrane versus cytosolic fractions and analyze their predicted functions and interaction. Previous LC-ESI-MS/MS data were analyzed by PERSEUS software for the differentially abundant proteins, then they were classified into their functional annotations and the protein networks were summarized using PantherDB and STRiNG, respectively. The results showed 24 (44.4%) out of the 54 proteins that increased in abundance were membrane proteins and 30 were cytosolic proteins. Meanwhile, 45 cytosolic proteins were found to decrease in abundance. Functional analysis showed differential abundance proteins involved in the molecular function, biological process, and cellular component with 18.88%, 33.04% and, 48.07%, respectively. The STRiNG server predicted that the decreased abundance proteins had more protein-protein network interactions compared to increased abundance proteins. Overall, this study has confirmed the presence of the differentially abundant membrane and cytosolic proteins and provided the predictive functions and interactions between them.
    Matched MeSH terms: Chromatography, Liquid
  11. Glycerol Waste Valorization to Mesoxalic Acid Over a Bimetallic Pt-Pd/CNT Catalyst in Alkaline Medium
    Ahmad MS, Cheng CK, Singh S, Ong HR, Abdullah H, Hong CS, et al.
    J Nanosci Nanotechnol, 2020 09 01;20(9):5916-5927.
    PMID: 32331197 DOI: 10.1166/jnn.2020.18549
    Glycerol electro-oxidation offers a green route to produce the high value added chemicals. Here in, we report the glycerol electro-oxidation over a series of multi walled carbon nano tubes supported monometallic (Pt/CNT and Pd/CNT) and bimetallic (Pt-Pd/CNT) catalysts in alkaline medium. The cyclic voltammetry, linear sweep voltammetry and chronoamperometry measurements were used to evaluate the activity and stability of the catalysts. The Pt-Pd/CNT electrocatalyst exhibited the highest activity in terms of higher current density (129.25 A/m²) and electrochemical surface area (382 m²/g). The glycerol electro-oxidation products formed at a potential of 0.013 V were analyzed systematically by high performance liquid chromatography. Overall, six compounds were found including mesoxalic acid, 1,3-dihydroxyacetone, glyceraldehyde, glyceric acid, tartronic acid and oxalic acid. A highest mesoxalic acid selectivity of 86.42% was obtained for Pt-Pd/CNT catalyst while a maximum tartronic acid selectivity of 50.17% and 46.02% was achieved for Pd/CNT and Pt/CNT respectively. It was found that the introduction of Pd into Pt/CNT lattice facilitated the formation of C3 products in terms of maximum selectivity achieved (86.42%) while the monometallic catalysts (Pd/CNT and Pt/CNT) showed a poor performance in comparison to their counterpart.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  12. Direct Analysis of Glyphosate, Glufosinate, and Their Metabolites in Palm Oil Using Liquid Chromatography with Tandem Mass Spectrometry
    Shinde R, Halim N, Banerjee AK
    J AOAC Int, 2020 Nov 01;103(6):1528-1533.
    PMID: 33247748 DOI: 10.1093/jaoacint/qsaa066
    BACKGROUND: Glyphosate and glufosinate are broad-spectrum herbicides which are frequently used in palm oil plantations for weed control. Metabolites of these herbicides are known to have environmental and food safety implications. As there is no validated method for multiresidue testing of these herbicides and their metabolites in palm oil products, a new method was needed for the purpose of regulatory analysis.

    OBJECTIVE: In this study, we endeavored to develop a rapid method for multiresidue analysis of glyphosate (+aminomethylphosphonic acid) and glufosinate (+3-methylphosphinicopropionic acid and N-acetyl-glufosinate) in refined and crude palm oil matrices using liquid chromatography (LC) tandem mass spectrometry (MS/MS).

    METHOD: The optimized sample preparation workflow included extraction of refined or crude palm oil (10 g) with acidified water (0.1 M HCl), cleanup by phase separation with dichloromethane, and analysis by LC-MS/MS with multiple reaction monitoring.

    RESULTS: The use of a Torus-DEA LC column ensured simultaneous analysis of these compounds within a runtime of 10 min. The LOQ of these analytes was 0.01 mg/kg, except that of aminomethylphosphonic acid which was 0.02 mg/kg. The method sensitivity complied with the national maximum residue limits of Malaysia and the European Union. Also, the method selectivity, sensitivity, accuracy, and precision were aligned with the SANTE/12682/2019 guidelines of analytical quality control.

    CONCLUSIONS: The potentiality of the optimized method lies in a high throughput direct analysis of glyphosate and glufosinate with their metabolites in a single chromatographic run. The method is fit for purpose for regulatory testing of these residues in a broad range of palm oil matrices.

    HIGHLIGHTS: The study reports for the first time a validated method for simultaneous analysis of glyphosate, glufosinate, and their metabolites in a range of palm oil products. The method did not require a derivatization step and provided a high throughput analysis of these compounds with satisfactory selectivity, sensitivity, accuracy, and precision.

    Matched MeSH terms: Chromatography, Liquid
  13. Fulltext Insecticide Residues on Poultry Manures: Field Efficacy Test on Selected Insecticides in Managing Musca Domestica Population
    Ong SQ, Ab Majid AH, Ahmad H
    Trop Life Sci Res, 2017 Jul;28(2):45-55.
    PMID: 28890760 MyJurnal DOI: 10.21315/tlsr2017.28.2.4
    In this study, bifenthrin (Maxxthor SC, Ensystex Australasia Pty Ltd), imidacloprid (Prothor SC, Ensystex Australasia Pty Ltd) and fipronil (Regent(®)50SC, Bayer) were applied on the natural infest manures according to the manufacturer rate during a broiler breeding cycle. Solvent direct-immersion extraction (SDIE) was used in detecting the target compound and later, quantification of the insecticide residues in field condition was investigated. The samples were prior cleaned up by solid-phase extraction (SPE) and analysed by Ultra-Performance Liquid Chromatography (UPLC) - photodiode array (PDA) system. In the field trial, three insecticides were showed accumulation during the broiler breeding period and it is suggested that they acted as adulticides when applied on the poultry manures, this is supported by the significant correlation between the increment of insecticide residues to the reduction percentage of adult flies (<0.05). Fipronil showed significantly greater reduction on the adult fly compared to the other insecticides, in which the reduction rate compared to control population at the end of the broiler breeding period; fipronil, imidaclopril and bifenthrin reduced 51.51%, 28.30% and 30.84% of adult flies, respectively.
    Matched MeSH terms: Chromatography, Liquid
  14. Fulltext A Review of Gelatin Source Authentication Methods
    Hameed AM, Asiyanbi-H T, Idris M, Fadzillah N, Mirghani MES
    Trop Life Sci Res, 2018 Jul;29(2):213-227.
    PMID: 30112151 MyJurnal DOI: 10.21315/tlsr2018.29.2.15
    Gelatin is a very popular pharmaceutical and food ingredient and the most studied ingredient in Halal researches. Interest in source gelatin authentication is based on religious and cultural beliefs, food fraud prevention and health issues. Seven gelatin authentication methods that have been developed include: nucleic acid based, immunochemical, electrophoretic analysis, spectroscopic, mass-spectrometric, chromatographic-chemometric and chemisorption methods. These methods are time consuming, and require capital intensive equipment with huge running cost. Reliability of gelatin authentication methods is challenged mostly by transformation of gelatin during processing and close similarities among gelatin structures. This review concisely presents findings and challenges in this research area and suggests needs for more researches on development of rapid authentication method and process-transformed gelatins.
    Matched MeSH terms: Chromatography
  15. Fumonisin B1 Production by Fusarium Species and Mycotoxigenic Effect on Larval Zebrafish
    Azman N, Zainudin NAIM, Ibrahim WNW
    Trop Life Sci Res, 2020 Oct;31(3):91-107.
    PMID: 33214858 DOI: 10.21315/tlsr2020.31.3.7
    Fumonisin B1 (FB1) is a common mycotoxin produced by Fusarium species particularly F. proliferatum and F. verticillioides. The toxin produced can cause adverse effects on humans and animals. The objectives of this study were to detect the production of FB1 based on the amplification of FUM1 gene, to quantify FB1 produced by the isolates using Ultra-fast Liquid Chromatography (UFLC) analysis, to examine the embryotoxicity effect of FB1 and to determine EC50 toward the larvae of zebrafish (Danio rerio). Fifty isolates of Fusarium species were isolated from different hosts throughout Malaysia. Successful amplification of the FUM1 gene showed the presence of this gene (800 bp) in the genome of 48 out of 50 isolates. The highest level of FB1 produced by F. proliferatum isolate B2433 was 6677.32 ppm meanwhile F. verticillioides isolate J1363 was 954.01 ppm. From the assessment of embryotoxicity test of FB1 on larvae of zebrafish, five concentrations of FB1 (0.43 ppm, 0.58 ppm, 0.72 ppm, 0.87 ppm and 1.00 ppm) were tested. Morphological changes of the FB1 exposed-larvae were observed at 24 to 168 hpf. The mortality rate and abnormality of zebrafish larvae were significantly increased at 144 hpf exposure. Meanwhile, the spontaneous tail coiling showed a significant difference. There were no significant differences in the heartbeat rate. As a conclusion, the presence of FUM1 in every isolate can be detected by FUM1 gene analysis and both of the species produced different concentrations of FB1. This is the first report of FB1 produced by Fusarium species gave a significant effect on zebrafish development.
    Matched MeSH terms: Chromatography, Liquid
  16. Enzymatic activities of Malayan cobra (Naja naja sputatrix) venoms
    Tan NH, Tan CS
    Toxicon, 1987;25(11):1249-53.
    PMID: 3433296
    The enzymatic activities of four samples of Malayan cobra venom were investigated. There was significant variation in the contents of L-amino acid oxidase, alkaline phosphomonoesterase, acetylcholinesterase, phospholipase A, 5'-nucleotidase and hyaluronidase. The phosphodiesterase content was, however, constant. Storage of the lyophilized venom powder at 25 degrees C for 1 month did not affect the enzymatic activities. The venom enzymatic activities were generally also stable at 4 degrees C in 0.85% saline solution. After incubation at 37 degrees C for 39 days in 0.85% saline solution, the venom still retained considerable amounts of enzymatic activities. SP-Sephadex C-25 ion-exchange chromatography of the venom showed that the phospholipase A, L-amino acid oxidase, 5'-nucleotidase, phosphodiesterase and alkaline phosphomonoesterase exist in multiple forms.
    Matched MeSH terms: Chromatography, Ion Exchange
  17. Determination of pyronaridine in blood plasma by high-performance liquid chromatography for application in clinical pharmacological studies
    Jayaraman SD, Ismail S, Nair NK, Navaratnam V
    J Chromatogr B Biomed Sci Appl, 1997 Mar 07;690(1-2):253-7.
    PMID: 9106050
    A method is described for the determination of pyronaridine in plasma using high-performance liquid chromatography with fluorescence detection. The method involves liquid-liquid extraction with phosphate buffer (pH 6.0, 0.05 M) and diethyl ether-hexane (70:30%, v/v) and chromatographic separation on a C18 column (Nucleosil, 250 x 4.6 mm I.D., 5 microns particle size) with acetonitrile-0.05 M phosphate buffer pH 6.0 (60:40%, v/v) as the mobile phase (1 ml/min) and detection by fluorescence (lambda ex = 267 nm, lambda em = 443 nm). The detector response is linear up to 1000 ng and the overall recoveries of pyronaridine and quinine were 90.0 and 60.3%, respectively. The assay procedure was adequately sensitive to measure 10 ng/ml pyronaridine in plasma samples with acceptable precision (< 15% C.V.). The method was found to be suitable for use in clinical pharmacological studies.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  18. Fulltext Trans fatty acids in selected bakery products and its potential dietary exposure
    Siti Nurshahbani, S., Azrina, A.
    International Food Research Journal, 2014;21(6):2175-2181.
    MyJurnal
    High intake of trans fatty acids (TFA) may cause adverse changes in blood lipids as shown in many epidemiological studies. The major sources of TFA in human diet come from bakery products such as cookies, cakes, muffins, breads and pastries. In this study, total fat of baked products was determined using Soxhlet method while TFA content was determined on gas chromatograph using a highly polar capillary column and flame ionization detector. Exposure to TFA from the baked product was estimated based on Food Consumption Statistics of Malaysia 2003. High level of TFA was observed in muffins (3.21-7.34 g per 100 g food) followed by pastries (2.90-6.03 g per 100 g food) and cakes (2.26-8.36 g per 100 g food) regardless of products having brand name or not. Among the TFA isomers, trans 18:1 6t was the most abundant followed by trans 18:1 9t, trans 16:1 9t, trans 18:2 and small quantities of trans 18:1 11t. Exposure to TFA based on the Malaysian Food Consumption Statistics 2003 of the baked products was ranging from 0.14-0.18 g/day. Even with the low estimated exposure, actual intake of baked products must be monitored closely as other high fat food as these products is one of main contributor to TFA in the diet following their high frequency of daily intake.
    Matched MeSH terms: Chromatography, Gas
  19. Fulltext Liquefaction of Mukah Balingian Coal via Semi-continuous Two-stage Solvent Flow Reactor System
    M.A.M. Ishak, M.T. Safian, Z.A. Ghani, K. Ismail
    ASM Science Journal, 2013;7(1):7-17.
    MyJurnal
    Solvent flow reactor system was introduced into the extraction system to increase the system efficiency and enhance the extraction yield by adding fresh solvent during the extraction processes. The liquefaction experiment was carried out at various flow-rates (1, 3 and 5 ml/min), reaction times (30, 45 and 60 min) and reaction temperatures (300ºC, 350ºC, 400ºC, 420ºC and 450ºC) with tetralin as solvent. Despite the ability of adding fresh solvent into the extraction process, the conversion of oil+gas was still considered to be low as there was ~25% of coal extracts left to be converted into low molecular weight compounds. One possible option to increase the oil yield is by applying catalyst that will further break up the coal extracts into small molecular weight compounds. In this study, a second reactor was introduced consisting of catalyst (NiSiO2) assuming that the catalyst would interact more effectively with coal extracts rather than the coal itself. In the
    absence of catalyst, the oil yield was 55%. By introducing the Ni catalyst, the oil yield increased by 15%. Further analysis of GCMS showed that the oil from catalytic liquefaction gave out more low molecular weight compounds in comparison to the un-catalytic liquefaction oil.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  20. Fulltext Percentage of haemoglobin variants detected during HbA1c analysis in Hospital Kuala Lumpur
    Intan Nureslyna, S., Sabariah, M.N., Lim, C.R., Wan Nor Syafiqah, W.S., Chen, D.R., Choy, S.Y., et al.
    Malaysian Journal of Medicine and Health Sciences, 2013;9(2):13-17.
    MyJurnal
    HbA1c is an established index of glycaemic control and correlates strongly with risk of chronic diabetic complications. However, the accuracy of HbA1c measurement can be affected by many factors, among which is the presence of haemoglobin (Hb) variants. The aim of the study was to determine the percentage of Hb variant detected during HbA1c monitoring in Hospital Kuala Lumpur. The study also analysed non-reportable HbA1c results in the presence of Hb variants. A cross-sectional study using retrospective data of HbA1c results over five months’ period was analysed on Biorad Variant II Turbo, a high performance liquid chromatography (HPLC) assay. The Hb variants were grouped either as HbS, HbC, others (Hb variant apart from HbS or C), and a combination of HbS or C with Others. A total of 11,904 patients were included. Only 2.3% (273) had Hb variants; HbS trait (10.3%), others (89%), and the combination of HbS trait with others (0.7%). No patient with HbC variant or its combination was found. Only 2.2% of those with Hb variant had non-reportable HbA1c. Although the percentage of Hb variants detected during HbA1c analysis and non-reportable HbA1c results were low, their presence should be noted.
    Matched MeSH terms: Chromatography, High Pressure Liquid
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