Studies on Streptomycetes

Abstract

Investigation was made on the mycological and antibacterial properties of a strain No. 46408 isolated from a soil sample collected in Shimoueda, Wakayama Prefecture. The strain No. 46408 was compared with similar strains, St. hygroscopicus and St. halstedii, and it was judged to belong to a new species and therefore named Streptomyces atratus nov. sp. Also a strain A-165-Z1, which produces ilamycin, was referred to on its mycological properties and assumed to resemble St. atratus. St. atratus was found to produce new antibiotics, rufomycin A and B, specially active against acid-fast bacteria. Investigation was made on the isolation procedure, physico-chemical properties and biological activities of antibiotic 46408 produced by Streptomyces atratus nov. sp. The solvent extract from the whole culture of this strain gave two antibiotic substances. Both are yellow, neutral and sparingly soluble in water and active against acid-fast bacteria, especially Mycobacterium tuberculosis and Mycobacterium smegmatis but inactive against most other bacteria, fungi and yeast examined. From the physico-chemical and microbiological properties they were found to be new substances and named rufomycin A and B, respectively. Recently Umezawa et al. reported on new antibiotics, ilamycins, active against acid- fast bacteria. The properties of rufomycins and ilamycins suggest that they really are very much like. Rufomycin A was nearly as effective as streptomycin in experimental tuberculosis in mice.