Therapeutic results of four months’ chemotherapy on 400 cases were already published by Tuberculosis Research Committee supported by Ministry of Health and Welfare on July 18, 1953, in “Nihon Iji Shinpo” (Japan Medical News), No. 1525. Further investigations showed that 4-month chemotherapy was insufficient in the majority of the cases of pulmonary tuberculosis, and so we began clinical trials of 9-month chemotherapy in September, 1953. We have consolidated the individual case reports on the results of the trials, which are reviewed below.
During a systematic search for new antibiotics produced by Streptomyces, in which Candida albicans was employed as test organism, a crystalline antibiotic substance has been isolated from a previously undescribed species of Streptomyces No. 278 which inhibits only Candida species. Since the physical appearance of this organism and its growth characteristics on various media were not in accordance with the description of any Streptomyces species described in the standard references, Bergey(1) and Waksman and Lechevalier(2), it was given the name Streptomyces toyocaensis. The description of the organism will be reported elsewhere. The following paper contains an account of production, isolation, physical and chemical properties and activities of the new antibiotic for which the name toyocamycin is proposed.
During the course of searching new antibiotics effective against fungi, the authors isolated a new Streptomyces strain No. 21-A-2 from the soil at Higashi-Kitazawa, Shibuya-ku, Tokyo. The taxonomic studies of this strain was carried out by one of the authors(1) and this strain was named Streptomyces kitazawaensis nov. sp. This strain produces a substance which shows a specific activity against yeast and fungi especially against Piricularia oryzae. The authors succeeded in obtaining this active substance in crystalline form and this crystal was identified with antimycin A2 3 4 5 6 7 8 9 10 according to its physical, chemical and biological properties.
The present paper deals with its isolation, comparison of its physical and chemical properties with Antimycin-A and some biological properties.
As shown in the previous paper, Takeuchi, Nitta, and Umezawa(1) obtained a crude powder of pluramycin and they studied the effect on Ehrlich carcinoma of mice. When it was daily injected to mice to which one million tumor cells had been intraperitoneally inoculated, and the daily injection was started 5 days after the inoculation, it inhibited the ascites increase and prolonged the survival period. When it was daily intraperitoneally injected to mice to which one million tumor cells had been subcutaneously inoculated, and the daily injection was started 5 days after the inoculation, it inhibited the growth of the subcutaneous mild tumor. The ratio of the minimum effective daily dose to the daily tolerable dose was observed to be 1/6, when the injection was started 5 days after the inoculation. Among known antitumor substances, pluramycin was considered to be the strongest in the antitumor activity to Ehrlich carcinoma.
The pluramycin-producing strain was isolated from the soil sample obtained at Nagano Prefecture and it was assigned to a new specieis, Streptomyces pluricolorescens. The antitumor activity the cultured liquid was first found by testing the effect on ascites type of Ehrlich carcinoma. The active agent was extracted by testing each extract on the antitumor effect and the anti-HeLa cell effect. Then, the active agent in the crude powder was found to exhibit the bacteriostatic effect. The existence of two antitumor agents was confirmed by the countercurrent distribution studies. The one which was the major part of the antitumor activity in the cultured liquid and which was considered to be stronger in the antitumor activity than another was named pluramycin A, and another was mimed pluramycin B. The existence of pluramycins A and B was confirmed also by the paper chromatography. Pluramycin A was further purified and obtained in the crystalline form.
In this paper, the isolation and characters of pluramycins are presented.
Three antibiotics have been obtained from a culture liquid of a streptomyces, characters of which will be reported in another paper. The one of them inhibited the growth of fungi and its ultraviolet absorption was similar to that of trichomycin, ascosin, or candicidin. According to the classification of polyene antifungal substances made by Utahara and others(1), it was one of trichomycin-ascosin-candicidin group substances. The others inhibited the growth of bacteria. The one of the antibacterial substances was extracted and found to inhibit the growth of B. subtilis and to be strongly toxic. Another was extracted and purified. It was found to be a new antibiotic and named phleomycin by the authors.
Phleomycin was adsorbed by the cation exchange resin and eluted by sodium chloride solution. It was purified as its reineckate. It was stable in neutral and weakly alkaline solutions, but very unstable in acid. It inhibited the growth of mycobacteria and weakly the growth of various kinds of other bacteria. It did not have the delayed toxicity.
In this paper, the production, isolation, and characters of phleomycin are presented.