Changing Biosynthetic Profiles by Expressing Blda in Streptomyces Strains.

Recently we described an unusual way of activating a cryptic gene cluster when we explored the origin of the bald phenotype of Streptomyces calvus. Complementation of S. calvus with a correct copy of bldA restored sporulation and additionally promoted production of a new natural products. In this study we report on the expression of bldA in several Streptomyces strains that have been described as "poorly sporulating" strains. In seven out of 15 cases, HPLC profiling revealed the production of new compounds, and in two cases the overproduction of known compounds. Two compounds were isolated and their structures were determined.