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| Research & Innovation |
Biotechnology UnitScope of research Research undertaken in the Biotechnology Unit covers the areas of tissue culture and genetic transformation, molecular markers and genetics, plant physiology, biochemistry and molecular biology, reproductive biology and latex allergy. While these areas encompass the basic and strategic biological research activities undertaken on Hevea at the Institute, a significant portion of the unit’s research has been structured to address specific needs of the rubber industry.
Major research activities Tissue culture and genetic transformationThe technique of tissue culture is being harnessed to meet the needs of genetic transformation of Hevea brasiliensis. Genes encoding for proteins that confer particular traits to the rubber tree are inserted into in vitro cultured anther callus tissue, the process being aided by a bacterium (Agrobacterium). The genetically transformed callus is subsequently regenerated into a complete plantlet though tissue culture. An important objective of genetic transformation is the enhancement of crop productivity by improving selected agronomic traits of the rubber tree. Two characteristics of the rubber tree that could benefit from transgenesis are in girth increment for timber production and in resistance to diseases, particularly Corynespora leaf disease. A second role for the transgenic rubber tree lies in the production of commercially valuable proteins in the latex. Genes encoding proteins of commercial value are inserted into rubber trees that then become natural "factories" for the production of the foreign protein. Examples of such proteins are pharmaceuticals and proteins used in personal care products. Foreign (recombinant) proteins synthesised in the latex in this manner are extracted continually and non-destructively by tapping the tree. Transgenic rubber trees require low maintenance and are environment-friendly as compared with bioreactor systems by which many pharmaceuticals are currently being manufactured. Experimental transgenic rubber trees at the Rubber Research Institute of Malaysia have successfully produced a bacterial enzyme (GUS), a mouse antibody and human serum albumin.
An aspect of genetic transformation under active research concerns the use of endogenous Hevea gene promoters (sequences of DNA which drive gene action) that function in specific tissues of the transgenic rubber tree. One promising candidate promoter for latex vessel-specific expression is the hevein gene promoter. (Hevein is one of the most abundant proteins in latex.) In a study, the DNA of the gus protein was linked to hevein promoters and used in Hevea genetic transformation. GUS expression was observed in the embryoids that were obtained.
Publications
HAMZAH S., CHAN, J.L. and YEANG, H.Y. (2002) Pollen tube growth and fruit-set success in Hevea brasiliensis hand-pollination influenced by the choice of clone and female flower. Euphytica, 123, 1-8. YEANG, H.Y. and CHEVALLIER, M.H. (1999) Range of Hevea brasiliensis pollen dispersal estimated by esterase isozyme markers. Annals of Botany, 84, 681-4. SAMSIDAR HAMZAH, CHAN, J.L. and YEANG, H.Y. (1999) Hevea brasiliensis seedlings from hand-pollination using cryo-stored pollen validated by isozymes. Journal of Rubber Research, 2(1), 62-8. SAMSIDAR HAMZAH and CHAN, J.L. (1996) Pollen storage of Hevea. Journal of Natural Rubber Research, 11(2), 115-24. Latex allergy Natural rubber latex is used in the manufacture of a wide range of latex goods, the most important being products related to healthcare such as examination gloves. In recent years, there have been many reports that certain proteins found on gloves and other surgical aids made from latex can cause an allergy in sensitised persons. The problem of latex allergy is therefore of direct concern both to the manufacturers and consumers of latex goods. To resolve the problem of latex allergy, effort has been made to quantitate the very low concentrations of proteins residual in latex goods and to understand the nature and behaviour of such residual proteins. There is ongoing research to isolate, purify and identify the specific allergenic proteins and to clone the genes (cDNA) that encode them. Once the allergens are pinpointed, it would be possible to develop diagnostics for latex allergy, immunotherapy to relieve the effects of latex allergy and immunoassays to control the quality of manufactured latex gloves.
There are 13 recognised latex allergens (proteins that cause allergy) named Hev b 1 to Hev b 13 according to the nomenclature of the International Union of Immunological Societies and the World Health Organisation. Find out more about the latex allergens…. Publications S. WAGNER, M. BUBLIN, C. HAFNER, T. KOPP, D. ALLWARDT, U. SEIFERT, S.A. ARIF, O. SCHEINER AND H. BREITENEDER (2007). Generation of Allergen-Enriched Protein Fractions of Hevea brasiliensis Latex for in vitro and in vivo Diagnosis Int Arch Allergy Immunol 2007, 143: 246–254 YEANG, H.Y., HAMILTON, R.G., BERNSTEIN, D.I., ARIF, S.A.M., CHOW, K.S., LOKE, Y.H., RAULF HEIMSOTH, M., WAGNER, S., BREITENEDER, H., BIAGINI, R.E. (2006) Allergen concentration in natural rubber latex. Clinical and Experimental Allergy 36, 1078-1086. ARIF, S.A.M., HAMILTON R.G. AND YEANG, H.Y. (2006) IgE antibody binding to the carbohydrate moiety of Hev b 13, Journal of Rubber Research 9(1), 40-49. KOLARICH, D, ALTMANN, F. AND SUNDERASAN, E. (2006) Structural analysis of the glycoprotein allergen Hev b 4 from natural rubber latex by mass spectrometry. Biochimica et Biophysica Acta, 1760(4), 715-20. SUNDERASAN, E., BAHARI, A., ARIF, S.A.M., ZAINAL, Z., HAMILTON, R.G., and YEANG, H.Y. (2005) Molecular cloning and immunoglobulin E reactivity of a natural rubber latex lecithinase homologue, the major allergenic component of Hev b 4. Clinical and Experimental Allergy, 35, 1490-5. KURUP, V.P., SUSSMAN, G.L., YEANG, H.Y., ELMS, N., BREITENEDER, H., ARIF, S.A.M., KELLY, K., BANSAL, N.K. and FINK, J.N. (2005) Specific IgE response to purified and recombinant allergens in latex allergy. Clin Mol Allergy, 3,11. JOHAR, A., LIM, D., ARIF, S.A.M., HAWARDEN, D., DU TOIT, G., WEINBERG, E.G., MOTALA, C., FIEGGEN, G., YEANG, H.Y. and POTTER, P.C. (2005) Low prevalence of latex sensitivity in South African spina bifida children in Cape Town. Pediatric Allergy and Immunology,16(2), 165-70. YEANG, H.-Y. and CHOW, K.-S. (2004) DNA cloning of Hev b 2 (Hevea latex ß-1,3-glucanase) and IgE reactivity of the recombinant protein. Journal of Rubber Research 2004 7(3):180-7. YEANG, H.-Y., ARIF, S.A.M., RAULF-HEIMSOTH, M., LOKE, Y.-H., SANDER, I., SULONG, S.H., LAU, C.-H., and HAMILTON, R.G. (2004) Hev b 5 and Hev b 13 as allergen markers to estimate the allergenic potency of latex gloves. Journal of Allergy and Clinical Immunology, 114(3), 593-8. ARIF, S.A.M., HAMILTON, R.G., YUSOF, F., CHEW, N.-P., LOKE, Y.-H., NIMKAR, S., BEINTEMA, J.J. and YEANG, H.Y. (2004) Isolation and characterization of the Early Nodule Specific Protein homologue (Hev b 13), an allergenic lipolytic esterase from Hevea brasiliensis latex. Journal of Biological Chemistry, 279(23):23933-41. YEANG, H.Y. (2004) Natural rubber latex allergens: new developments, Current Opinion in Allergy & Clinical Immunology, 4(2), 99-104. BERNSTEIN, D.I., BIAGINI, R.E., KARNANI, R., HAMILTON, R , MURPHY, K., BERNSTEIN, C., ARIF, S. A.., BRENDTS, B. and YEANG, H.Y. (2003) In vitro sensitization to purified Hevea brasiliensis proteins in health-care workers sensitized to natural rubber latex. Journal of Allergy and Clinical Immunology, 111(3), 610-6. YEANG, H.Y., LAU, C.H., SITI ARIJA M. ARIF, LOKE, Y.H., CHAN, J.L., SAMSIDAR HAMZAH and HAMILTON, R.G. (2002) Hev b 1, Hev b 2 and Hev b 3 Contents in Natural Rubber Latex and Powdered Latex Gloves. Journal of Rubber Research, 5(3), 167-78. YEANG, H.Y., ARIF, S.A.M., YUSOF, F. and SUNDERASAN, E. (2002) The allergenic proteins of natural rubber latex. Methods. 27(1), 32-45. IKRAM, A., BAHRI, A.R.S., FAUZI, M.S. and NAPI, N. (2001) Effects of added nitrogen and phosphorus on the biodegradation of NR gloves in soil. Journal of Rubber Research, 4, 102-17. YEANG, H.Y., CHOW, K.S., YUSOF, F., ARIF, S.A.M., CHEW, N.P. and LOKE, Y.H. (2000) Appraisal of latex glove proteins in the induction of sensitivity to multiple latex allergens. Journal of Investigational Allergology & Clinical Immunology, 10(4), 215-22. YEANG, H.Y. (2000) Prevalence of latex allergy may be vastly over-estimated when determined by in vitro assays. Annals of Allergy, Asthma & Immunology, 84, 628-32. KURUP,V.P., YEANG, H.Y., SUSSMAN, G.L., BANSAL, N.K, BEEZHOLD, D.H., KELLY, K.J., HOFFMAN, D.R., WILLIAMS, B. and FINK, J.N. (2000) Detection of IgE in the sera of patients using purified latex allergens. Clinical and Experimental Allergy, 30(3), 359-69. JOHNSON, B.D., KURUP, V.P., SUSMAN, G.L., ARIF, S.A.M., KELLY, K.J., BEEZHOLD, D.H. and FINK, J.N. (1999) Purified and remcombinant latex proteins stimulate peripheral blood lymphocytes of latex allergic patients. International Archives of Allergy and Immunology, 120, 270-9. WAGNER, B., KREBITZ, M., BUCK, D., NIGGEMANN, B., YEANG, H. Y., HAN, K.H., SCHEINER, O., and BREITENEDER, H. (1999). Cloning, expression and characterization of recombinant Hev b 3, a Hevea brasiliensis protein associated with latex allergy in spina bifida patients. Journal of Allergy and Clinical Immunology. 104(5), 1084-92. SOWKA, S., HAFNER, C., RADAUER, C., FOCKE, M., BREHLER, R., ASTWOOD, J. D., ARIF, S. A., KANANI, A., SUSSMAN, G. L., SCHEINER, O., BEEZHOLD, D. H., and BREITENEDER, H. (1999). Molecular and immunological characterization of new isoforms of the Hevea brasiliensis latex allergen Hev b 7: Evidence of no cross-reactivity between Hev b 7 isoforms and potato patatin and proteins from avocado and banana. Journal of Allergy and Clinical Immunology, 104, 1302-10. AIRENNE, K.J., LAITINEN, O.H., ALENIUS, H., MIKKOLA, J., KALKKINEN, N., ARIF, S.A., YEANG, H.Y., PALOSUO, T. and KULOMAA, M.S. (1999) Avidin is a promising tag for fusion proteins produced in baculovirus-infected insect cells. Protein Expression and Purification, 17(1),139-45. YEANG, H.Y., FARIDAH YUSOF and LATIFAH ABDULLAH (1998) Protein purification for the Lowry assay: Acid precipitation of proteins in the presence of SDS and other biological detergents, Analytical Biochemistry, 265, 381-384. YEANG, H.Y., WARD, M.A., ZAMRI, A.S.M., DENNIS, M.S. and LIGHT, D.R. (1998) Sequence similarity of Hev b 3 with two previously reported 27 and 23 kDa latex allergens detected by spina bifida patients. Allergy 53(5), 513-9. SOWKA, S. WAGNER, S., KREBITZ, M., SITI ARIJA MAD ARIF, FARIDAH YUSOF, KINACIYAN, T., BREHLER, R., SCHEINER, O. and BREITENEDER, H. (1998) cDNA cloning of the 43-kDa latex allergen Hev b7 with sequence similarity to patatin and its expression in the yeast Pichia pastoris. European Journal of Biochemistry, 255, 213-9. YEANG, H.Y., CHEONG, K.F., SUNDERASAN, E., SAMSIDAR HAMZAH, CHEW, N.P., SHARIFAH HAMID, HAMILTON, R.G. and CARDOSA, M.J. (1996) The 14.6kd rubber elongation factor (Hev b 1) and 24 kd (Hev b 3 rubber particle proteins are recognized by IgE from patients with spina bifida and latex allergy. Journal of Allergy and Clinical Immunology, 98(3), 628-39. SUNDERASAN, E., SAMSIDAR HAMZAH, SHARIFAH HAMID, WARD, M.A., YEANG, H.Y. and CARDOSA, M.J. (1995) Latex B-serum ? -1,3-glucanase (Hev b II) and a component of the microhelix (Hev b IV) are major latex allergens. Journal of Natural Rubber Research, 10(2), 82-99. YEANG, H.Y., SUNDERASAN, E. and HAFSAH MOHD. GHAZALY (1995) Latex allergy studies: Extraction of natural rubber latex proteins with reference to film thickness, latex d.r.c. and protein migration behaviour. Journal of Natural Rubber Research, 10(1), 46. YEANG, H.Y., FARIDAH YUSOF and LATIFAH ABDULLAH (1995) Precipitation of Hevea brasiliensis proteins with trichloroacetic acid and phosphotungstic acid in preparation for the Lowry protein assay. Analytical Biochemistry, 226, 35-43.
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