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Biomedical subjects

Z Zainal

Publications and source records attributed to Z Zainal.

9 recordsLinked to original sources
PubMed2005

Molecular cloning and immunoglobulin E reactivity of a natural rubber latex lecithinase homologue, the major allergenic component of Hev b 4.

BACKGROUND: Hev b 4 is an allergenic natural rubber latex (NRL) protein complex that is reactive in skin prick tests and in vitro immunoassays. On SDS-polyacrylamide gel electrophoresis (SDS-PAGE), Hev b 4 is discerned predominantly at 53-55 kDa together with a 57 kDa minor component previously identified as a cyanogenic glucosidase. Of the 13 NRL allergens recognized by the International Union of Immunological Societies, the 53-55 kDa Hev b 4 major protein is the only candidate that lacks complete cDNA and protein sequence information. OBJECTIVE: We sought to clone the transcript encoding the Hev b 4 major protein, and characterize the native protein and its recombinant form in relation to IgE binding. METHODS: The 5'/3' rapid amplification of cDNA ends method was employed to obtain the complete cDNA of the Hev b 4 major protein. A recombinant form of the protein was over-expressed in Escherichia coli. The native Hev b 4 major protein was deglycosylated by trifluoromethane sulphonic acid. Western immunoblots of the native, deglycosylated and recombinant proteins were performed using both polyclonal antibodies and sera from latex-allergic patients. RESULTS: The cDNA encoding the Hev b 4 major protein was cloned. Its open reading frame matched lecithinases in the conserved domain database and contained 10 predicted glycosylation sites. Detection of glycans on the Hev b 4 lecithinase homologue confirmed it to be a glycoprotein. The deglycosylated lecithinase homologue was discerned at 40 kDa on SDS-PAGE, this being comparable to the 38.53 kDa mass predicted by its cDNA. Deglycosylation of the lecithinase homologue resulted in the loss of IgE recognition, although reactivity to polyclonal rabbit anti-Hev b 4 was retained. IgE from latex-allergic patients also failed to recognize the non-glycosylated E. coli recombinant lecithinase homologue. CONCLUSION: The IgE epitopes of the Hev b 4 lecithinase homologue reside mainly in its carbohydrate moiety, which also account for the discrepancy between the observed molecular weight of the protein and the value calculated from its cDNA.

Allergens↗
PubMed2003

Sorption of Cr(VI) and Cu(II) in aqueous solution by ethylenediamine modified rice hull.

The sorption characteristics of Cr(VI) and Cu(II) by ethylenediamine modified rice hull from single and binary metal ion solutions were evaluated under various experimental conditions. Optimal Cr(VI) and Cu(II) removal from single metal ion solutions occurred at pH 2.0 and 5.5, respectively. Simultaneous removal of Cr(VI) and Cu(II) occurred at pH greater than 3.0. The sorption kinetics of Cr(VI) and Cu(II) from single and binary metal ion solutions were studied with reference to metal concentration, agitation rate and particle size. Sorption of Cr(VI) was more rapid than Cu(II). The kinetics of metal ion sorption fitted a pseudo-second order expression. The variation in the initial uptake rates was very small at an agitation rate beyond 150 rpm and sorption was generally independent of particle size. Equilibrium sorption data could be fitted into the Langmuir isotherm equation. Maximum sorption capacities of ethylenediamine modified rice hull for Cr(VI) at pH 2 and Cu(II) at pH 4 in single metal solutions were 0.45 and 0.06 mmol g(-1), respectively. This corresponds to an enhancement factor of 2.6 and 3 fold for Cr(VI) and Cu(II), respectively, compared to natural rice hull. A synergistic effect was observed for sorption of these ions in binary metal solutions.

Adsorption↗
PubMed2001

Microwave-assisted synthesis of Zn/Al layered double hydroxide-(anthraquinone-2,6-disulfonate) nanocomposite.

Nanocomposites of Zn/Al-layered double hydroxide(anthraquinone-2,6-disulfonate) were synthesized by spontaneous direct assembly of inorganic and organic phases from aqueous solution. Powder X-ray diffraction patterns showed that a pure, single nanocomposite phase of good crystallinity was obtained using 1.0 M antraquinone-2,6-disulfonate ion (AQ26) and aging at 80 degrees C using conventional heating for 7 days or 0.5 h under microwave radiation, and these samples are denoted as ZAAN26C or ZAAN26MH, respectively. Zn/Al-nitrate-layered double hydroxide synthesized by a conventional method (ZANLC) showed a basal spacing of 8.3 A while both the nanocomposites showed 18.8 A as a result of AQ26 intercalation. FTIR study showed that the resulting nanocomposites are free from nitrate, the co-anion present in the mother liquor, indicating that only AQ26 is preferred during intercalation for the formation of the nanocomposite. The Brunauer, Emmet and Teller (BET) and micropore surface areas for ZAAN26C decreased relative to the ZANLC from 16.2 to 4.7 and 1.6 to 1.3 m2/g, respectively. These results indicate that AQ26 can be rapidly interdcalated in layered double hydroxide using microwave-aging resulting in a nanocomposite.

Aluminum Compounds↗
PubMed2001

The use of Mg/Al layered double hydroxide for color removal of textile wastewater.

Layered double hydroxide of Mg-Al-carbonate system (MACH) was prepared and its heat-treated product (MACHT) was obtained by calcination at 500 degrees C. The resulting materials were used as an adsorbent for removal of color from synthetic textile wastewater (STW) and textile wastewater (TWW). Batch kinetic study showed that these materials are an efficient adsorbent for textile dye. The maximum adsorption capacities between 16 to 32 mg of dyes per g of adsorbent was obtained by fitting the adsorption data to the Langmuir adsorption Isotherm. It was found that the adsorption capacity of MACHT is higher than MACH.

Adsorption↗
PubMed2001

Developmental abnormalities and reduced fruit softening in tomato plants expressing an antisense Rab11 GTPase gene.

A cDNA clone from tomato fruit encodes a protein with strong homology with the rab11/YPT3 class of small GTPases that is thought to be involved in the control of protein trafficking within cells. The gene, LeRab11a, showed a pattern consistent with a single copy in DNA gel blots. The corresponding mRNA was developmentally regulated during fruit ripening, and its expression was inhibited in several ripening mutants. Its reduced expression in the Never-ripe mutant indicates that it may be induced by ethylene in fruit. The ripening-induced expression in tissues that are undergoing cell wall loosening immediately suggests a possible role in trafficking of cell wall-modifying enzymes. The message also was produced in leaves and flowers but not in roots. Antisense transformation was used to generate a "mutant phenotype." Antisense fruit changed color as expected but failed to soften normally. This was accompanied by reduced levels of two cell wall hydrolases, pectinesterase and polygalacturonase. There were other phenotypic effects in the plants, including determinate growth, reduced apical dominance, branched inflorescences, abnormal floral structure, and ectopic shoots on the leaves. In some plants, ethylene production was reduced. These data suggest an alternative or additional role in exocytosis or endocytosis of homeotic proteins, hormone carriers, or receptors.

Base Sequence↗
PubMed1987

Pneumococcal infection in hospitalized patients: a four-year study in Malaysia.

A total of 90 cases of pneumococcal infections were identified at a major referral hospital in Kuala Lumpur, Malaysia during a study period of four years. Pneumonia was the most common clinical presentation (41 cases) followed by meningitis (19 cases). Of 48 patients who were followed-up during the microbiology consultation round, 11 died, 9 were children below two years old. Capsular typing was carried out on 57 strains of Streptococcus pneumoniae isolated from blood and body fluids of 43 children and 14 adults. 38 strains isolated from pharyngeal specimens were also typed. Types 6A (11 strains), 6B (7 strains), 14 (8 strains) and 19A (8 strains) predominated in children. The strains from older patients comprised 3 isolates from cerebrospinal fluid (types 18B, 6B and 14), five from blood (4 strains, type 1 and 1 strain, type 4) and six from pus (1 strain, type 14, 3 strains type 23F and 2 strains type 34). The isolates from pharyngeal specimens belonged to capsular type similar to those implicated in infections. 90% of the types reported in this study are included in the 23 valent pneumococcal vaccines. Minimum inhibitory concentrations of penicillin, cefuroxime, chloramphenicol and rifampicin were determined for selected strains. 4.1% of isolates were resistant to penicillin (3/74), 4.5% to cefuroxime (2/44), 6.5% to chloramphenicol (3/46) and 14.6% to rifampicin (6/41).

Age Factors↗