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

Abstract

Zero time addition of the autoregulator (L-factor) from S. griseue (Lkm+Amy+ ) to surface cultures of its bald mutant ZIMET 43682 (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 diffrrences indicate alterations in thc cellular architecture of substrate and aerial hyphae. The rcsults suggest that the autoregulator triggers the onset of a complex programme of differentiatlon at a very early stage.In surface cultures the streptomycetes display a complex life cycle during which the formation of both aerial inycelia and spores represent major events (KALA-KOUTSKI and AGRE 1976, CHATER and MERRICK 1976). As it has been shown earlier with blocked mutants of Streptomyces griseus and Streptomyces alboniger, formation of aerial mycelia will depend on the presence of low-molecular endogenous signals, triggers or autoregulators (KHOKHLOV et al. 1972, POGELL 1979, SZABO et al. 1967. More recently, wc reported on the inducing effect of so-called L-factors (PA: leukaemomycin production) on cyto-differentiation of the blocked strain XIMET 436822), a prototrophic derivative of the differentiating parental strain Streptomyces griseus