In the course of new antibiotics screening, a complex of new basic macrolide antibiotics collectively named YL-704 was isolated from the culture broth of a streptomycete designated MCRL 0388. This complex consisted of two major components designated YL-704 A1 and YL-704 B1 and eleven other minor components. The antibiotic YL-704 complex-producing strain was characterized by the formation of hygroscopic masses of smooth-walled spores on aerial mycelia and by the production of diffusible and substrate pigment behaving as a pH indicator in glycerol-asparagine agar, inorganic salts-starch agar and tyrosine agar media. Progeny of the type strain have been deposited in the collections of the Northern Regional Research Laboratory, Agricultural Research Service, U. S. Department of Agriculture, Peoria, Illinois, U. S. A. as NRRL 3761, and the Fermentation Research Institute Chiba, Japan, as FERM-P No. 289. In the course of selecting for mutant strains, a mutant (strain MCRL 0393) was obtained with ultra-violet irradiation. This mutant produced dark green diffusible pigment. In contrast to the wild-type strain, the pigment was not a pH indicator. The mutant strain did not form hygroscopic masses of spores on any agar medium. The present paper concerns taxonomic studies on strain MCRL 0388 and multant strain MCRL 0393. Based on the results, strain MCRL 0388 is considered as a new subspecies of Streptomyces platensis, and the name Streptomyces platensis subsp. malvinus FURUMAI and OKUDA subsp. nov. is proposed. The type strain is MCRL 0388 (NRRL 3761) by virtue of its being a single isolate. The fermentative production of antibiotic YL-704 complex also is dealt with in this paper. Isolation and characterization of the components of the complex will be reported in another papery.
Characterizationof Strain MCRL 0388The media used for morphological, cultural and physiological studies were those described by SHIRLING and GOTTLIEB2), and WAKSMAN3) . Taxonomic studies were generally carried out according to procedures described for the International Streptomyces Project (ISP)2) . Color names
A new complex of phleomycin-bleomycin group antibiotics, YA-56, was isolated from the culture broth of a streptomycete designated as strain MCRL 0387 and identified as a new variety of Streptomyces humidus Nakazawaand Shibata in Imamura et al.9 1956. Ultraviolet irradiation of strain MCRL0387 gave a high-yielding mutant which formed blue aerial mycelium instead of the grayish aerial mycelium of the original strain. Fermentative production of the antibiotics YA-56 complex is described. In the course of screening for new antibiotics, a complex of antibacterial and antitumor antibiotics was obtained from the culture broth of a streptomycete. This complex, named YA-56, consisted of two main components designated YA-56 X and XA-56Y and at least three other minor components. Further investigation indicated these belonged to the phleomycin-bleomycin group. The present paper deals with the taxonomy and antibiotic production of the producing strain. Isolation and characterization of the main components of the antibiotic YA-56 complex will be reported in a succeeding paper. The antibiotic YA-56 complex-producing strain was characterized by the formation of hygroscopic masses of smooth-walled spores in coils on aerial mycelia. As a result of taxonomic study, the strain was considered as a new variety of Streptomyces humidus, for which the name Streptomyces humidus var. antitumoris Furumai and Okuda var. nov. is proposed. The type strain has been deposited in the Northern
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