Dr. Bill Baker
Ph.D., University of Hawaii, 1986
Postdoctoral Fellow, Rice University, 1987-88
Stanford University, 1988-89
Natural product isolation and characterization from marine invertebrates; biosynthesis and synthesis of secondary metabolites from marine invertebrates; chemical ecology.
Marine invertebrates such as sponges, corals and mollusks have evolved a variety of defenses to protect themselves in the hostile environment of the ocean.Some of these defense mechanisms are physical. More common in these organisms is chemical defense, production of toxic secondary metabolites that deter predation, fouling, infection or otherwise promote the welfare of the organism.
The study of secondary metabolites in marine invertebrates is a multifaceted endeavor. Our major emphasis is the isolation and identification of new secondary metabolites using the techniques of organic structure determination: high-field 1H and 13C NMR in one- and two-dimensions (COSY, RCT, HETCOR, HMBC, etc.); mass spectrometry (electron impact, fast atom bombardment, etc.); IR; and UV; as well as traditional wet chemistry(derivatization, hydrolysis, ozonolysis, Baeyer-Villiger oxidation, etc.). Once we have identified a new metabolite, we can broaden the scope of our investigation to biosynthetic and ecological aspects and investigate its biological activity.
Biosynthesis addresses the fundamentals of metabolism in an organism. Our investigation of how an organism makes secondary metabolites from primary metabolites (amino acids, carbohydrates, etc.) involves the synthesis of stable- and/or radioactively labeled precursors that are either fed to a live organism or treated with an enzyme preparation from that organism. The location of the label in the product is identified by spectroscopy or chemical degradation. An accumulation of precursor/product data allows the elucidation of the mechanism.
In collaboration with biologists, we study the role of new metabolites both in the organism (i.e., feeding deterrents) and in the environment that the organism is found (i.e., allelopathy). Other biological and ecological aspects of interest include the distribution of a metabolite in the food chain (some nudibranchs, for example, sequester defensive agents from the sponge they prey on) and chemotaxonomy.
Nature is an important source of new pharmaceuticals.Compounds that an organism has developed for its own defense can be used for man's defense as antiviral agents (AIDS, Herpes), antineoplastic agents (cancer), or other pharmaceuticals. In collaboration with pharmacologists, we screen our new isolates in assays that will identify their potential as drugs.