Together with Streptomyces for Thirty-five Years.

Findings on Streptomyces through the author’s 35-years studies were outlined. 1. On the basis of the morphological characteristics of aerial mycelia and sporiferous hyphae, the genus Streptomyces was divided into eight morphological types. The four of them were further subdivided by the morphological features of spirals. 2. Streptomycin 6-phosphate was produced in the cell of Streptomyces griseus. This compound had no antibiotic activity and was transformed to streptomycin by dephosphorylation with the specific alkaline phosphatase at the periplasmic space or outside of the cell. 3. S. griseus produced streptomycin-6-kinase in the cell. This enzyme contributed to self-protection of the streptomycin producer by inactivating streptomycin and liberating ribosome-bound streptomycin. 4. Suppression of the phospholipid cycle of cell wall synthesis enhanced streptomycin production.