IDENTIFICATION OF 2 METABOLITES INDUCED BY A BUTYROLACTONE AUTOREGULATOR IM-2 IN STREPTOMYCES SP FRI-5

IM-2, one of the butyrolactone autoregulators of Streptomyces, trigger s blue pigment production in Streptomyces sp. FRI-5 at a concentration of 0.6 ng/ml. Two IM-2-induced metabolites were identified by compari son of the HPLC profiles of extracellular metabolites produced in the absence and presence of IM-2. The two compounds were purified to homog eneity from the culture broth, and assigned as tryptophol and guanosin e, respectively. With respect to the IM-2-induced production of guanos ine, the intracellular and extracellular nucleotide contents were inve stigated in the absence and presence of IM-2. No difference in nucleot ide content, including that of ppGpp, was observed, indicating that pp Gpp does not participate in the induction pathway of IM-2. It was ther efore concluded that IM-2 is an independent regulator of Streptomyces metabolism, which not only induces blue pigment but also affects metab olism of tryptophan and guanosine.