Abstract
The study of differentiation in Streptomyces has been an important topic, especially in industrial microbiology, because the genus produces numerous antibiotics whose production is known to be linked to differentiation of the producing organisms. By isolating and analysing the relaxed mutants of Streptomyces spp., I have stressed the significance of the stringent response for the initiation of both differentiation and secondary metabolism of this genus. It is concluded that morphological differentiation results from a decrease in the pool of GTP, whereas antibiotic production results from a more direct function of the rel gene product (ppGpp). A-factor may render the cell sensitive to receive and respond to the specified signal molecule, presumably ppGpp (for antibiotic production), or GTP (for morphological differentiation).
