Displaying publications 21 - 40 of 226 in total

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  1. Fulltext A simple screening test for the detection of metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter in a tertiary care hospital
    Wan Nor Amilah WA, Noor Izani NJ, Ng WK, Ashraful Haq J
    Trop Biomed, 2012 Dec;29(4):588-97.
    PMID: 23202604
    Clinical utilization of carbapenems remains under threat with the emergence of acquired carbapenemase-producing bacteria, particularly metallo-β-lactamases (MBL). Rapid detection of MBL-producing Gram-negative bacilli is essential to prevent their widespread dissemination. However, no standardized detection method is available for routine laboratory use. The purpose of the study was to evaluate a chelating-agent based double disk synergic test and disk potentiation test for MBL-producing strain detection and to determine the isolation rate of MBL-producing Pseudomonas aeruginosa and Acinetobacter from clinical samples in our tertiary teaching hospital. A total of 22 and 66 imipenem-resistant P. aeruginosa and Acinetobacter isolates respectively were tested with ceftazidime (CAZ) disk by modified double disk synergic test and disk potentiation test using ethylenediaminetetraacetic acid (EDTA) and 2-mercaptopropionic acid (as chelating agents) to detect MBL production. The tests were compared with EDTA-phenanthroline-imipenem (EPI) microdilution MIC test as gold standard. MBL positive strains were detected in 17 (77.3%) P. aeruginosa and 2 (3.5%) Acinetobacter isolates. The disk potentiation test with 2-mercaptopropionic acid (2-MPA) dilution of 1:12 provided the most acceptable sensitivities and specificities (88.2% sensitivity and 100% specificity in P. aeruginosa; 100% sensitivity and specificity in Acinetobacter) compared to other screening methods used in this study. This study provided useful information on the local prevalence of MBL-producing P. aeruginosa and Acinetobacter in our hospital. Disc potentiation test with CAZ/2-MPA disc appears to be reliable and convenient MBL detection method in the routine clinical laboratory.
    Matched MeSH terms: Bacterial Proteins/analysis*
  2. An ex vivo culture model for orthodontically induced root resorption
    Wan Hassan WN, Stephenson PA, Waddington RJ, Sloan AJ
    J Dent, 2012 May;40(5):406-15.
    PMID: 22342686 DOI: 10.1016/j.jdent.2012.02.002
    Root resorption is a ubiquitous although undesirable sequela to orthodontic treatment. Current methods to investigate the pathophysiology have certain limitations. In pursuit to understand and develop treatment modalities for orthodontically induced root resorption, the ability to manipulate cells within their natural extracellular matrix in a three dimensional organotypic model is invaluable. The study aimed to develop a laboratory-based organotypic model to investigate the effect of orthodontic forces on the periodontium.
    Matched MeSH terms: Extracellular Matrix Proteins/analysis
  3. Identification of immunoreactive secretory proteins from the stationary phase culture of Burkholderia pseudomallei
    Vellasamy KM, Mariappan V, Hashim OH, Vadivelu J
    Electrophoresis, 2011 Jan;32(2):310-20.
    PMID: 21254130 DOI: 10.1002/elps.201000355
    Bacterial secreted proteins are known to be involved in virulence and may mediate important host-pathogen interactions. In this study, when the stationary phase culture supernatant of Burkholderia pseudomallei was subjected to 2-DE, 113 protein spots were detected. Fifty-four of the secreted proteins, which included metabolic enzymes, transcription/translation regulators, potential virulence factors, chaperones, transport regulators, and hypothetical proteins, were identified using MS and database search. Twelve of these proteins were apparently reactive to antisera of mice that were immunised with B. pseudomallei secreted proteins. These proteins might be excellent candidates to be used as diagnostic markers or putative candidate vaccines against B. pseudomallei infections.
    Matched MeSH terms: Bacterial Proteins/analysis
  4. p40 in metastatic pulmonary trophoblastic tumour: potential diagnostic pitfall on histopathology
    Vallonthaiel AG, Walia R, Pramanik R, Sharma MC, Jain D
    Malays J Pathol, 2017 Aug;39(2):175-179.
    PMID: 28866701
    p40, one of the two isomers of p63, is nowadays widely used for diagnosis of squamous cell carcinoma, especially in subtyping non-small cell carcinoma on lung biopsies. We describe a case in which lung tumour was misdiagnosed as squamous cell carcinoma due to p40 immunopositivity. A 36-year-old lady presented with cough and left sided chest pain of 2 months duration. Chest imaging revealed a lesion in left lower lobe of the lung and biopsy was suggestive of squamous cell carcinoma. However, past history revealed amputation of great toe for non-healing discharging ulcer which on histopathology was diagnosed as choriocarcinoma. She also had a history of hysterectomy five years ago, details of which were not available. Post-amputation β-hCG levels were high and she had been treated with multimodality chemotherapy for choriocarcinoma. She had good response to chemotherapy initially, however became resistant later on. Review of the lung biopsy in the light of the past history along with extensive literature review led to the final diagnosis of metastatic trophoblastic tumour to lung. Hence, awareness that p40 immunopositivity can be seen in trophoblastic tumours is essential to avoid misdiagnosis, especially in sites like the lung where squamous cell carcinoma is common.
    Matched MeSH terms: Membrane Proteins/analysis
  5. Fulltext Ultrasound in the deproteinization process for chitin and chitosan production
    Vallejo-Domínguez D, Rubio-Rosas E, Aguila-Almanza E, Hernández-Cocoletzi H, Ramos-Cassellis ME, Luna-Guevara ML, et al.
    Ultrason Sonochem, 2021 Apr;72:105417.
    PMID: 33352467 DOI: 10.1016/j.ultsonch.2020.105417
    Recently, chitin and chitosan are widely investigated for food preservation and active packaging applications. Chemical, as well as biological methods, are usually adopted for the production of these biopolymers. In this study, modification to a chemical method of chitin synthesis from shrimp shells has been proposed through the application of high-frequency ultrasound. The impact of sonication time on the deproteinization step of chitin and chitosan preparation was examined. The chemical identities of chitin and chitosan were verified using infrared spectroscopy. The influence of ultrasound on the deacetylation degree, molecular weight and particle size of the biopolymer products was analysed. The microscopic characteristics, crystallinity and the colour characteristics of the as-obtained biopolymers were investigated. Application of ultrasound for the production of biopolymers reduced the protein content as well as the particle size of chitin. Chitosan of high deacetylation degree and medium molecular weight was produced through ultrasound assistance. Finally, the as-derived chitosan was applied for beef preservation. High values of luminosity, chromatid and chrome were noted for the beef samples preserved using chitosan films, which were obtained by employing biopolymer subjected to sonication for 15, 25 and 40 min. Notably; these characteristics were maintained even after ten days of packaging. The molecular weight of these samples are 73.61 KDa, 86.82 KDa and 55.66 KDa, while the deacetylation degree are 80.60%, 92.86% and 94.03%, respectively; in the same order, the particle size of chitosan are 35.70 μm, 25.51 μm and 20.10 μm.
    Matched MeSH terms: Proteins/analysis
  6. Fulltext Comparison of two assays for the detection of haemolysins of Aeromonas species
    Vadivelu J, Puthucheary SD, Navaratnam P
    Singapore Med J, 1992 Aug;33(4):375-7.
    PMID: 1411668
    The haemolysins produced by Aeromonas species were detected and compared by two assay methods--a modified blood agar plate assay and the rabbit erythrocyte haemolysin method. Both assays showed a high level of agreement (86%). The titres of the rabbit erythrocyte haemolysin assay correlated with the haemolytic zone diameter of the ox blood agar assay. In addition the agar haemolysin assay had simple media requirements, was easy to perform and results were well defined.
    Matched MeSH terms: Hemolysin Proteins/analysis*
  7. Further biological, serological and biochemical characterization of North American, European and Southeast Asian strains of bovine herpesvirus 1 compared with other alphaherpesvirinae members
    Trépanier P, Minocha HC, Ibrahim AL, Sheikh-Omar AR, Montpetit C, Lecomte J, et al.
    Vet Microbiol, 1988 Dec;18(3-4):219-31.
    PMID: 2852870
    Hemagglutination activity, structural protein profiles and neutralization assays were used in a comparative study of bovine herpesvirus 1 strains from the U.S.A., Canada, Great Britain, Denmark and Malaysia with equine, feline and human herpesviruses in order to further characterize the bovine herpesvirus 1 hemagglutinin. Bovine herpesvirus 1 strains of different geographical origins all showed hemagglutinating activity for mouse erythrocytes; furthermore, feline herpesvirus 1 was also shown to hemagglutinate mouse erythrocytes. Analyses of partly purified viruses showed that a distinctive and specific polypeptides profile is associated with each species of herpesviruses used in our study; strains of bovine herpesvirus 1 from North America, Europe and Southeast Asia however, presented a remarkable similarity as to their electrophoretic protein patterns. A protein similar to the 97-kDa bovine viral hemagglutinin was not identified with the hemagglutinating feline herpesvirus. An important neutralization epitope on the bovine viral hemagglutinin was also not found on feline, equine and human herpesviruses but was identified on all bovine strains tested from North America, Europe and Southeast Asia stressing the importance of the bovine hemagglutinin for eventual prophylactic purposes.
    Matched MeSH terms: Viral Proteins/analysis
  8. Fulltext Extracellular enzyme profiling of Stenotrophomonas maltophilia clinical isolates
    Thomas R, Hamat RA, Neela V
    Virulence, 2014 Feb 15;5(2):326-30.
    PMID: 24448556 DOI: 10.4161/viru.27724
    Matched MeSH terms: Bacterial Proteins/analysis*
  9. Similar taste-nutrient relationships in commonly consumed Dutch and Malaysian foods
    Teo PS, van Langeveld AWB, Pol K, Siebelink E, de Graaf C, Yan SW, et al.
    Appetite, 2018 06 01;125:32-41.
    PMID: 29366933 DOI: 10.1016/j.appet.2018.01.020
    Three recent studies showed that taste intensity signals nutrient content. However, current data reflects only the food patterns in Western societies. No study has yet been performed in Asian culture. The Malaysian cuisine represents a mixture of Malay, Chinese and Indian foods. This study aimed to investigate the associations between taste intensity and nutrient content in commonly consumed Dutch (NL) and Malaysian (MY) foods. Perceived intensities of sweetness, sourness, bitterness, umami, saltiness and fat sensation were assessed for 469 Dutch and 423 Malaysian commonly consumed foods representing about 83% and 88% of an individual's average daily energy intake in each respective country. We used a trained Dutch (n = 15) and Malaysian panel (n = 20) with quantitative sensory Spectrum™ 100-point rating scales and reference solutions, R1 (13-point), R2 (33-point) and R3 (67-point). Dutch and Malaysian foods had relatively low mean sourness and bitterness (
    Matched MeSH terms: Dietary Proteins/analysis
  10. Expression of recombinant proteins of Orientia tsutsugamushi and their applications in the serodiagnosis of scrub typhus
    Tay ST, Rohani MY, Ho TM, Devi S
    Diagn Microbiol Infect Dis, 2002 Oct;44(2):137-42.
    PMID: 12458119
    In this study, recombinant proteins that encompassed the AD I-AD III regions of 56 kDa immunodominant gene of 2 Orientia tsutsugamushi (OT) serotypes; Gilliam and TA763 were expressed in Escherichia coli. Both recombinant proteins exhibited serologic cross-reactivity with the rabbit antisera against various OT serotypes, as evaluated by enzyme-linked immunosorbent assay (ELISA), but not against other rickettsial species, including Rickettsia typhi, R. prowazekii and TT118 SFG rickettsiae. The feasibility of using the recombinant proteins as a diagnostic reagent was further evaluated by ELISA using sera from blood donors and scrub typhus patients. The results suggested a higher affinity of the antihuman IgM than IgG with both recombinant proteins. The IgM ELISA findings were agreeable with the results of indirect immunoperoxidase (IIP) assay especially with sera of high antibody (1:1600). However, more than one antigen are probably needed for development of an effective assay for serodiagnosis of scrub typhus in endemic areas.
    Matched MeSH terms: Recombinant Proteins/analysis*
  11. Induction and characterization of heat shock proteins of Salmonella typhi and their reactivity with sera from patients with typhoid fever
    Tang SW, Abubakar S, Devi S, Puthucheary S, Pang T
    Infect Immun, 1997 Jul;65(7):2983-6.
    PMID: 9199477
    The heat shock protein (HSP) response of Salmonella typhi following exposure to elevated growth temperatures was studied. Three major proteins with molecular sizes of 58, 68, and 88 kDa were abundantly expressed when S. typhi cells were shifted from 37 to 45 degrees C and to 55 degrees C. These proteins were also constitutively expressed at 37 degrees C. Western blotting and immunoprecipitation studies with anti-HSP monoclonal antibodies revealed that the 58- and 68-kDa proteins were analogous to the GroEL and DnaK proteins, respectively, of Escherichia coli. These HSPs are also abundantly present in the outer membrane fraction of disrupted cells and, to a lesser extent, in the cytosol. Immunoblotting experiments with sera from patients with a culture-positive diagnosis of typhoid fever showed the presence of antibodies to these HSPs. Nine of twelve sera reacted with the 58-, 68-, and 88-kDa proteins, while three sera reacted only with the 68- and 88-kDa proteins. All 10 sera from healthy individuals showed no binding to these HSPs. In light of the well-documented roles of HSPs in the pathogenesis of microbial infections and as immunodominant antigens, these findings may be relevant for a better understanding of disease processes and for the future development of diagnostic and preventive strategies.
    Matched MeSH terms: Heat-Shock Proteins/analysis*
  12. Optimization of protein extraction for proteomic analyses of fresh and frozen "Musang King" durian pulps
    Tan XY, Misran A, Daim LDJ, Lau BYC
    Food Chem, 2021 May 01;343:128471.
    PMID: 33143964 DOI: 10.1016/j.foodchem.2020.128471
    Four different methods were evaluated to extract proteins from "Musang King" durian pulps and subsequently proteins with different abundance between fresh and long term frozen storage were identified using two-dimensional polyacrylamide gel electrophoresis coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometer analyses. The acetone-phenol method was found to produce good protein yields and gave the highest gel resolution and reproducibility. Differential protein analyses of the durian pulp revealed that 15 proteins were down-regulated and three other proteins were up-regulated after a year of frozen storage. Isoflavone reductase-like protein, S-adenosyl methionine synthase, and cysteine synthase isoform were up-regulated during frozen storage. The down-regulation of proteins in frozen durian pulps indicated that frozen storage has affected proteins in many ways, especially in their functions related to carbohydrate and energy metabolisms, cellular components, and transport processes. This study will enable future detailed investigations of proteins associated with quality attributes of durians to be studied.
    Matched MeSH terms: Plant Proteins/analysis*
  13. Potential serum biomarkers associated with mild and severe leptospirosis infection: A cohort study in the Malaysian population
    Tan XT, Amran FB, Thayan R, Ahmad N, Jaafar R, Haron R, et al.
    Electrophoresis, 2017 09;38(17):2141-2149.
    PMID: 28524240 DOI: 10.1002/elps.201600471
    Leptospirosis is an emerging zoonotic infectious disease in Malaysia. The symptoms of leptospirosis vary from mild nonspecific flu-like illness to a severe condition which is usually associated with serious complication and fatality. To study the protein expression profile of mild and severe leptospirosis, 15 paired sera were collected from the patients who were mildly infected and following that progressed to severe stage. The proteome profiles of mild and severe cases were studied using 2DE analysis in combination with LC-MS/MS. The expression of proteins that were significantly different and had a fold difference of at least 2 had been identified and then validated using Western blot. Our study demonstrated apolipoprotein A-I (APOA-I), serum amyloid A (SAA), transferrin (TF), haptoglobin (HP) and transthyretin (TTR) have significantly different expression between mild and severe leptospirosis. The Ingenuity Pathway Analysis software suggested the expression of these five proteins were modulated by acute phase response signaling pathway. Besides that, a functional network of lipid metabolism, molecular transport and small molecule biochemistry that interconnects these five proteins with interactomes also had been predicted by this software. In conclusion, this finding supports the potential of these five proteins to be the biomarkers for mild and severe human leptospirosis.
    Matched MeSH terms: Acute-Phase Proteins/analysis*
  14. A physicochemical investigation of membrane fouling in cold microfiltration of skim milk
    Tan TJ, Wang D, Moraru CI
    J Dairy Sci, 2014;97(8):4759-71.
    PMID: 24881794 DOI: 10.3168/jds.2014-7957
    The main challenge in microfiltration (MF) is membrane fouling, which leads to a significant decline in permeate flux and a change in membrane selectivity over time. This work aims to elucidate the mechanisms of membrane fouling in cold MF of skim milk by identifying and quantifying the proteins and minerals involved in external and internal membrane fouling. Microfiltration was conducted using a 1.4-μm ceramic membrane, at a temperature of 6±1°C, cross-flow velocity of 6m/s, and transmembrane pressure of 159kPa, for 90min. Internal and external foulants were extracted from a ceramic membrane both after a brief contact between the membrane and skim milk, to evaluate instantaneous adsorption of foulants, and after MF. Four foulant streams were collected: weakly attached external foulants, weakly attached internal foulants, strongly attached external foulants, and strongly attached internal foulants. Liquid chromatography coupled with tandem mass spectrometry analysis showed that all major milk proteins were present in all foulant streams. Proteins did appear to be the major cause of membrane fouling. Proteomics analysis of the foulants indicated elevated levels of serum proteins as compared with milk in the foulant fractions collected from the adsorption study. Caseins were preferentially introduced into the fouling layer during MF, when transmembrane pressure was applied, as confirmed both by proteomics and mineral analyses. The knowledge generated in this study advances the understanding of fouling mechanisms in cold MF of skim milk and can be used to identify solutions for minimizing membrane fouling and increasing the efficiency of milk MF.
    Matched MeSH terms: Blood Proteins/analysis; Milk Proteins/analysis
  15. An effective placental cotyledons proteins extraction method for 2D gel electrophoresis
    Tan NJ, Daim LD, Jamil AA, Mohtarrudin N, Thilakavathy K
    Electrophoresis, 2017 03;38(5):633-644.
    PMID: 27992069 DOI: 10.1002/elps.201600377
    Effective protein extraction is essential especially in producing a well-resolved proteome on 2D gels. A well-resolved placental cotyledon proteome, with good reproducibility, have allowed researchers to study the proteins underlying the physiology and pathophysiology of pregnancy. The aim of this study is to determine the best protein extraction protocol for the extraction of protein from placental cotyledons tissues for a two-dimensional gel electrophoresis (2D-GE). Based on widely used protein extraction strategies, 12 different extraction methodologies were carefully selected, which included one chemical extraction, two mechanical extraction coupled protein precipitations, and nine chemical extraction coupled protein precipitations. Extracted proteins were resolved in a one-dimensional gel electrophoresis and 2D-GE; then, it was compared with set criteria: extraction efficacy, protein resolution, reproducibility, and recovery efficiency. Our results revealed that a better profile was obtained by chemical extraction in comparison to mechanical extraction. We further compared chemical extraction coupled protein precipitation methodologies, where the DNase/lithium chloride-dense sucrose homogenization coupled dichloromethane-methanol precipitation (DNase/LiCl-DSH-D/MPE) method showed good protein extraction efficiency. This, however, was carried out with the best protein resolution and proteome reproducibility on 2D-gels. DNase/LiCl-DSH-D/MPE was efficient in the extraction of proteins from placental cotyledons tissues. In addition, this methodology could hypothetically allow the protein extraction of any tissue that contains highly abundant lipid and glycogen.
    Matched MeSH terms: Pregnancy Proteins/analysis*
  16. The lethal and biochemical properties of Bungarus candidus (Malayan krait) venom and venom fractions
    Tan NH, Poh CH, Tan CS
    Toxicon, 1989;27(9):1065-70.
    PMID: 2799837
    Bungarus candidus venom exhibited high hyaluronidase, acetylcholinesterase and phospholipase A activities; low proteinase, 5'-nucleotidase, alkaline phosphomonoesterase and phosphodiesterase activities and moderately high L-amino acid oxidase activity. SP-Sephadex C-50 ion exchange chromatographic fractionation of the venom and Sephadex G-50 chromatography of the major lethal venom fractions indicate that the venom contains at least two highly lethal, basic phospholipases A with LD50 (i.v.) values of 0.02 micrograms/g (F6A) and 0.18 micrograms/g (F4A), respectively; as well as two polypeptide toxins with LD50 (i.v.) values of 0.17 micrograms/g and 0.83 micrograms/g, respectively. The major lethal toxin is the basic lethal phospholipase A, F6A, which accounts for approximately 13% of the venom protein and has a mol. wt of 21,000.
    Matched MeSH terms: Proteins/analysis
  17. The use of enzyme-linked immunosorbent assay for the quantitation of Calloselasma rhodostoma (Malayan pit viper) venom and venom antibodies
    Tan NH, Yeo KH, Jaafar MI
    Toxicon, 1992 Dec;30(12):1609-20.
    PMID: 1488770
    The specificity and sensitivity of an indirect and two (an 'ordinary' and a 'rapid') double sandwich enzyme-linked immunosorbent assay (ELISA) procedures for the quantitation of Calloselasma rhodostoma (Malayan pit viper) venom were examined. The three assays were equally sensitive and the accuracy of the assays was not substantially affected by individual variation in the venom composition. The specificity of the assays was examined against 26 venoms from snakes of the families Viperidae and Elapidae. While the double sandwich ELISA procedures were sufficiently specific to be used in the clinical immunodiagnosis of C. rhodostoma bite in Malaysia, the indirect ELISA procedure exhibited extensive cross-reactivity with other Malaysian pit viper venoms. Attempts were made to improve the specificity of the indirect ELISA procedure for the quantitation of C. rhodostoma venom. A 'low ELISA cross-reactivity' venom fraction (termed VF52) was isolated from C. rhodostoma venom by repeated Sephadex G-100 gel filtration chromatography. The indirect ELISA procedure using antibodies to VF52 as immunoreagent showed an improvement in specificity. The use of the indirect ELISA procedure for the detection of C. rhodostoma antibodies was also examined and the results show that the assay was sufficiently specific to be used for retrospective diagnosis of C. rhodostoma bite in Malaysia, in particular when VF52 was used as the coating antigen.
    Matched MeSH terms: Proteins/analysis
  18. Differential proteomic analysis of embryogenic lines in oil palm (Elaeis guineensis Jacq)
    Tan HS, Liddell S, Ong Abdullah M, Wong WC, Chin CF
    J Proteomics, 2016 06 30;143:334-345.
    PMID: 27130535 DOI: 10.1016/j.jprot.2016.04.039
    Oil palm tissue culture is one way to produce superior oil palm planting materials. However, the low rate of embryogenesis is a major hindrance for the adoption of this technology in oil palm tissue culture laboratories. In this study, we use proteomic technologies to compare differential protein profiles in leaves from palms of high and low proliferation rates in tissue culture in order to understand the underlying biological mechanism for the low level of embryogenesis. Two protein extraction methods, namely trichloroacetic acid/acetone precipitation and polyethylene glycol fractionation were used to produce total proteins and fractionated protein extracts respectively, with the aim of improving the resolution of protein species using two-dimensional gel electrophoresis. A total of 40 distinct differential abundant protein spots were selected from leaf samples collected from palms with proven high and low proliferation rates. The variant proteins were subsequently identified using mass spectrometric analysis. Twelve prominent protein spots were then characterised using real-time polymerase chain reaction to compare the mRNA expression and protein abundant profiles. Three proteins, namely triosephosphate isomerase, l-ascorbate peroxidase, and superoxide dismutase were identified to be potential biomarker candidates at both the protein abundant and mRNA expression levels.

    BIOLOGICAL SIGNIFICANCE: In this study, proteomic analysis was used to identify abundant proteins from total protein extracts. PEG fractionation was used to reveal lower abundant proteins from both high and low proliferation embryogenic lines of oil palm samples in tissue culture. A total of 40 protein spots were found to be significant in abundance and the mRNA levels of 12 of these were assessed using real time PCR. Three proteins namely, triosephosphate isomerase, l-ascorbate peroxidase and superoxide dismutase were found to be concordant in their mRNA expression and protein abundance. Triosephosphate isomerase is a key enzyme in glycolysis. Both l-ascorbate peroxidase and superoxide dismutase play a role in anti-oxidative scavenging defense systems. These proteins have potential for use as biomarkers to screen for high and low embryogenic oil palm samples.

    Matched MeSH terms: Plant Proteins/analysis*
  19. Proteomic profiling of mature leaves from oil palm (Elaeis guineensis Jacq.)
    Tan HS, Jacoby RP, Ong-Abdullah M, Taylor NL, Liddell S, Chee WW, et al.
    Electrophoresis, 2017 04;38(8):1147-1153.
    PMID: 28198080 DOI: 10.1002/elps.201600506
    Oil palm is one of the most productive oil bearing crops grown in Southeast Asia. Due to the dwindling availability of agricultural land and increasing demand for high yielding oil palm seedlings, clonal propagation is vital to the oil palm industry. Most commonly, leaf explants are used for in vitro micropropagation of oil palm and to optimize this process it is important to unravel the physiological and molecular mechanisms underlying somatic embryo production from leaves. In this study, a proteomic approach was used to determine protein abundance of mature oil palm leaves. To do this, leaf proteins were extracted using TCA/acetone precipitation protocol and separated by 2DE. A total of 191 protein spots were observed on the 2D gels and 67 of the most abundant protein spots that were consistently observed were selected for further analysis with 35 successfully identified using MALDI TOF/TOF MS. The majority of proteins were classified as being involved in photosynthesis, metabolism, cellular biogenesis, stress response, and transport. This study provides the first proteomic assessment of oil palm leaves in this important oil crop and demonstrates the successful identification of selected proteins spots using the Malaysian Palm Oil Board (MPOB) Elaeis guineensis EST and NCBI-protein databases. The MS data have been deposited in the ProteomeXchange Consortium database with the data set identifier PXD001307.
    Matched MeSH terms: Plant Proteins/analysis*
  20. Proteomic insights into short neurotoxin-driven, highly neurotoxic venom of Philippine cobra (Naja philippinensis) and toxicity correlation of cobra envenomation in Asia
    Tan CH, Wong KY, Chong HP, Tan NH, Tan KY
    J Proteomics, 2019 08 30;206:103418.
    PMID: 31201947 DOI: 10.1016/j.jprot.2019.103418
    The Philippine cobra, Naja philippinensis, is a WHO Category 1 venomous snake of medical importance responsible for fatal envenomation in the northern Philippines. To elucidate the venom proteome and pathophysiology of envenomation, N. philippinensis venom proteins were decomplexed with reverse-phase high-performance liquid chromatography, and protein fractions were subsequently digested with trypsin, followed by nano-liquid chromatography-tandem mass spectrometry analysis and data mining. Three-finger toxins (3FTX, 66.64% of total venom proteins) and phospholipases A2 (PLA2, 22.88%) constitute the main bulk of venom proteome. Other proteins are present at low abundances (<4% each); these include metalloproteinase, serine protease, cobra venom factor, cysteine-rich secretory protein, vespryn, phosphodiesterase, 5' nucleotidase and nerve growth factor. In the three-finger toxin family, the alpha-neurotoxins comprise solely short neurotoxins (SNTX, 44.55%), supporting that SNTX is the principal toxin responsible for neuromuscular paralysis and lethality reported in clinical envenomation. Cytotoxins (CTX) are the second most abundant 3FTX proteins in the venom (21.31%). The presence of CTX correlates with the venom cytotoxic effect, which is more prominent in murine cells than in human cells. From the practical standpoint, SNTX-driven neuromuscular paralysis is significant in N. philippinensis envenomation. Antivenom production and treatment should be tailored accordingly to ensure effective neutralization of SNTX. BIOLOGICAL SIGNIFICANCE: The venom proteome of Naja philippinensis, the Philippine cobra, is unravelled for the first time. Approximately half the protein bulk of the venom is made up of short neurotoxins (44.55% of the total venom proteins). As the only alpha-neurotoxins present in the venom, short neurotoxins are the causative toxins of the post-synaptic blockade and fast-onset neuromuscular paralysis in N. philippinensis envenomation. A substantial amount of cytotoxins (21.31%) was also detected in N. philippinensis venom, supporting that the venom can be cytotoxic although the effect is much weaker in human cells compared to murine cells. The finding is consistent with the low incidence of local tissue necrosis in N. philippinensis envenomation, although this does not negate the need for monitoring and care of bite wound in the patients.
    Matched MeSH terms: Cobra Neurotoxin Proteins/analysis
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