C-5-5

STABLE ISOTOPE INCORPORATION EVIDENCE FOR DE NOVOBIOSYNTHESIS OF SECONDARY METABOLITES IN BRITISH COLUMBIA NUDIBRANCHS.

Julia Kubanek and Raymond J. Andersen
Departments of Chemistry and Earth & Ocean Sciences, Universityof British Columbia, Vancouver, Canada V6T 1Z4


The skin extracts of nudibranchs, or sea slugs, have yielded to chemistsa vast and structurally-complex array of organic compounds. It hasbeen shown that many nudibranchs depend upon these compounds for chemicalprotection from potential predators in competitive environments like thesubtidal waters of coastal British Columbia. Using stable isotopeincorporation methodology, biosynthetic investigations into the de novobiosynthesis of selected nudibranch natural products (eg 1, 2) have beenundertaken. Resultant labeling in isolated metabolites has proventhat the compounds studied are synthesized in the nudibranch and not derivedfrom any food source. Furthermore, these experiments have offeredinsight into the pathways of molecular assembly, particularly into modesof ring formation and the origin of oxygen atoms in terpenoid productsof B.C. nudibranchs Acanthodoris nanaimoensis, Acanthodoris hudsoniand Cadlina luteomarginata, and into patterns of carbon-carbonbond formation in the polyketide portions of metabolites from Triophacatalinae and Diaulula sandiegensis.



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