Synthetic Organic Chemistry Program is supporting the research of Dr. John D. Faulkner of the Ocean Research Division of the Scripps Institution of Oceanography, a part of the University of San Diego. Dr. Faulkner will be studying the nature of the compounds used by marine organisms in controlling their interactions with one another. In particular he will be studying the Mollusca phylum. This will improve understanding of the impact of man's activities on the marine biosphere. The observations of marine biologists and ecologists have implicated chemical messengers as an important means of communication in the marine environment. Many soft-bodied marine animals rely upon chemical defense mechanisms for their survival. Within the phylum Mollusca there exists a wide range of defensive strategies. The majority of molluscs are protected by hard shells into which the animal can retreat. At the other end of the range, the dorid nudibranchs have a dietary-derived chemical defense mechanism that has compensated for the loss of the shell. Molluscs living in the intertidal zone require a shell for protection against physical damage but may also have a chemical defense against predators. This research will continue on the structural elucidation of marine natural products from marine molluscs, particularly those from unusual environments and relatively unstudied locations. There is strong support for the hypothesis that nudibranchs concentrate only the most effective chemical deterrents from dietary sources. In addition, they may modify dietary metabolites to obtain deterrents with increased feeding inhibitory activity or, in a few instances, perform de novo synthesis of feeding inhibitors. This research will characterize the structure of the novel feeding inhibitors from nudibranchs and to investigate structure-activity relationships. The detection and selective acquisition of chemicals from dietary sources, their storage and functions will be investigated. Molluscs that have a shell and produce a chemical secretion will be further studied with the goal of defining the relative importance of physical and chemical defenses to marine molluscs. In particular, specimens of Bullomorphs and Lamellariids in addition to the Siphnoariids will be examined further.
