Streptomyces No. 455D1, which was isolated from the soil of Chichibu district in Saitama Prefecture, was found to produce 2 antifungal substances. One of them was confirmed to be a polyene antibiotic belonging to fungicidin-rimocidin- chromin group11).
The other was studied in detail and confirmed to be a new antibiotic on the basis of its physical, chemical and biological properties. This antibiotic was named blastmycin. It shows specifically strong inhibition against Piricularia oryzae which causes a terrible disease on the rice plant. The strain No. 455D1 seemed to be a new species of streptomyces and was named Streptomyces blastmyceticus.
One of the present authors has reported inhibitory action of sarkomycin on Ehrlich’s ascites carcinoma ionculated to the mice of ddN strain in the 6th week of life. A natural history and histological sequence of growth of Ehrlich’s mouse carcinoma after intraperitoneal inoculation to the particular mouse strain were well established in the above study.
The present paper reports some data from a similar series of experiments using Actinomycin J. Irrespective of the younger age of the animals used and slight difference of season, the control groups showed almost exact repetition of the natural history.
In the previous paper, some fundamental aspects of the possible oncostatic activity of actinomycin J upon Ehrlich’s ascites cacinoma in mice was reported. The present study was attempted in order to compare the effects of the same preparation upon Yoshida ascites sarcoma in rats. Following two points were of particular interest in the study to be reported. (1) Determination of the optimal oncostatic dosage if there is any such effect in the antibiotic preparation upon Yoshida sarcoma. (2) Detection of a characteristic cytologic effect if there is any. It has been our experience that often a cytologic effect of a chemotherapeutic agent is more apparent in Yoshida ascites sarcoma than in Ehrlich’s ascites carcinoma.
Previously we reported1) that the oily concentrate containing sarkomycin free acid (Sy), purified by the solvent extraction method from the cultured broth, reacts with isonicotinic acid hydrazide (INAH) to form biologicaly active and low toxic solid substance (SI) under some conditions. This substance was stable in antibacterial activity in short period of storage. In the present paper, we report the optimum condition for its preparation and its stabilities in long period of storage under various conditions not only in antibacterial activities but also in antitumor activities. Materials, bioassays and animal tests are the same as reported in the previous paper1).
In this laboratory, studies on antiphage agents produced by Streptomyces is carried out as a part of antiviral screening program concomitantly with the screening of the antibacterial substances. As already reported, phagomycin1) and phagocidin2),3) were isolated and investigated on the mode of actions. In the present paper, the author described a new antiphage substance, phagostatin, isolated from the mycelial mat of a strain of a streptomyces sp. (Our collection No. F-300). The antibiotic was obtained in a crystalline form, which was active against the growth of T3 and T7 phage without the inactivation of their free phage particles. It was also somewhat effective against organisms such as E. coli B, Sal. enteritidis, S. lutea, M. citreus and B. anthracis, but the antibacterial action was much lower than that against phage. The present report deals with the mycological characteristics of the strain, isolation and physicochemical properties of crystalline phagostatin. The results of the studies on the mode of action of the antibiotic will be described later.