Westpheling 9722960 The primary long-term objective of this study is to understand the regulatory interconnection between carbon source catabolite repression, activation of antibiotic biosynthesis and morphological development in the Streptomyces bacteria. The general approach of this project has been to use catabolite controlled genes involved in complex carbohydrate utilization as tools to probe the connection between carbon utilization and morphogenesis. Using this approach, a new class of mutants was identified that are at once defective in catabolite control and morphogenesis, and also overproduce antibiotics. The most pleiotropic of the known morphological mutants of Streptomyces, bldB, was shown during the course of previous work to be pleiotropically defective in the regulation of carbon utilization. The bldB gene product is required for catabolite repression, the initiation of morphogenesis and antibiotic biosynthesis in S. coelicolor, and the study of how this gene functions in the interconnection of these processes is a major focus of the current project. To facilitate the isolation, cloning, and characterization of new mutants, transposon mutagenesis and generalized transduction methods in S. venezuelae are being developed to be used in combination with S. coelicolor for genetic analysis.