The Synthetic Organic Chemistry Program is supporting the research of Dr. Paul J. Scheuer of the Department of Chemistry at the University of Hawaii at Manoa. This research will continue the studies of the chemical communication system used by marine organisms in their interactions with each other. These studies will help us to understand better our impact on the marine environment. Investigation will continue into the source of cyanide ion and into the pathways of terpene biosynthesis for the production of isocyanoterpenes in sponges. Ciocalypta sp. and Acanthella sp. will be analyzed for free amino acids and labelled amorphane prepared to carry out incorporation experiments. Cell-free extracts will continue as the method of choice. Other biosynthesis experiments are planned to trace the origin of the alkaloid, shermilamine A, in a tunicate, Trididemnum sp. Metamorphosis of larvae of the nudibranch Phestilla sibogae is induced by a substance elaborated by the prey of the nudibranch, the stony coral Porites compressa. Attempts to isolate, purify, and characterize the inducer will be continued in a collaborative effort with Professor M. G. Hadfield and his research group. Specific predator-prey relationships are common among coral reef invertebrates. The molecular basis of a number of these systems is now known. However the substance(s) which provide the initial attraction and/or the feeding stimuli are unknown. These questions will be addressed with the sponge-nudibranch pair Dysidea fragilis-Hypselodoris infucata.