CYERCENES, NOVEL PYRONES FROM THE ASCOGLOSSAN MOLLUSK CYERCE-CRISTALLINA - TISSUE DISTRIBUTION, BIOSYNTHESIS AND POSSIBLE INVOLVEMENT IN DEFENSE AND REGENERATIVE PROCESSES

The extraordinary regenerative phenomena in the marine ascoglossan mollusc Cyerce cristallina are described here for the first time. The possible correlation between cyercenes, pyrones recently isolated from the mollusc regenerating dorsal appendages (cerata), and the processes of chemical defense and regeneration in the mollusc, was investigated by studying the tissue distribution, biological activity and biogenesis of cyercenes. Differences in distribution between the C. cristallina mantle, cerata and mucous secretion were found. Cyercenes showed activity in the Hydra vulgaris regeneration assay and the mosquito fish ichthyotoxicity assay. The de novo biosynthesis of cyercenes from propionic acid was demonstrated by means of in vivo adsorption experiments with radiolabeled propionate.