Effect of the autoregulator from Streptomyces griseus JA 5142 on surface cultures of blocked mutant ZIMET 43682.

Zero time addition of the autoregulator (L-factor) from S. griseus (Lkm+Amy+) to surface cultures of its bald mutant ZIMET 43 682 (Amy-Lkm-) restored the capacity to form both anthracycline-type antibiotic leukaemomycin and aerial mycelium. The pertinent mycelia displayed the same growth rate and cellular levels of nucleic acids as the asporogeneous phenotype but the composition of fatty acids and phospholipids as well as the ratio of cytochromes b and c were altered. These differences indicate alterations in the cellular architecture of substrate and aerial hyphae. The results suggest that the autoregulator triggers the onset of a complex programme of differentiation at a very early stage.