Among many antifungal antibiotics, there are polyene antibiotics which can be classified into four groups¹⁾ by means of ultraviolet absorption spectrum, that is, fungicidin-rimocidin-chromin group, eurocidin group, mediocidin group and trichomycin²⁾-ascosin-candicidin group. Trichomycin-ascosin-candicidin group is insoluble in nonpolar solvents such as ether and chloroform. Trichomycin-ascosin-candicidin group is soluble in many organic solvents such as acetone and methanol. Especially, this group is easily soluble in basic or acidic solvents such as pyridine, phenol, and in some organic solvents comprising many hydroxyl groups. In spite of the insolubility in water in free form of trichomycin group, many solvents need water to dissolve them.

Antibiotics belonging to this group, being almost same in their nature, can not be distinguished one from another, and their solubility in various solvents is also same. The purpose of this paper is to describe a new solvent system to purify this group of antibiotics using trichomycin as the representative.

It has been reported by Middlebrook and Cohn (1953), Barnett, et al. (1953), and several other investigators ^(1–7) that isoniazid-resistant Mycobacterium tuberculosis are usually attenuated for guinea pigs. It has also been reported that such isoniazid-resistant strains manifest little or no catalase activity in vitro^(8–10) and that certain isoniazid-resistant strains require, for the initiation of growth on agar, hemin, alpha-keto acids, or under certain conditions, inorganic iron, comparing with isoniazid-susceptible parent strains^(9–11). These reports indicate that isoniazid-resistant strains of Mycobacterium tuberculosis have significantly different properties from isoniazid-susceptible parent strains.

This paper is concerned with the viability of isoniazid-resistant mutants of Mycobacterium avium.

Soil actinomycetes have been screened for their production of antitumor substances in our laboratory by using experimental animal tumors and HeLa cells in the tissue culture. The test meterial, the culture liquid, was daily injected to animals which had been inoculated with an appropriate number of tumor cells, or added to the tissue culture medium of HeLa cells, and the inhibition on the development of tumors or on the growth of HeLa cells was examined. By these studies, it was confirmed that miscellaneous antitumor substances are produced by soil actinomycetes. For instance, culture liquids of about 10% of soil actinomycetes screened exhibited antitumor effect and prolonged the survival period of mice bearing Ehrlich carcinoma. However, in the further studies isolating the active agents, there were many difficulties owing to the fact that there was not a suitable rapid quantitative method of testing the antitumor activity. The authors presented a cylinder plate method in this paper. This method is not applicable to all antitumor substances, depending on their speed of diffusion in the agar or their modus of the antitumor action. However, in the case of the substance to which this method is applicable, this method is very helpful for the isolation. This method can also be used for the screening of microorganisms for the production of antitumor substances.

Schrek⁽¹⁾ has indicated that the following four principles can be used for the in vitro test of anti-cell effect: (1) counting the number of eosin-unstained cells; (2) testing the capacity of excised viable tissues to react histologically to reagents; (3) testing the capacity of cells to ferment substrates; (4) testing the capacity of redoxy activity of cells. He showed dilution methods of testing the anti-cell activity depending on these principles. As it has been known in the antibiotic studies, the cylinder plate method is more quantitative than the dilution method. If the conditions to keep the cells alive in the agar medium is found, according to these principles a suitable cylinder plate method can be devised.

Among these principles, that of testing the redoxy activity has been utilized in the rapid cylinder plate method of testing the antibacterial activity⁽²⁾. In the case when on the plate, where the bacteria had not grown enough to exhibit visible turbidity, methylene blue was placed, then the clear blue inhibition zone could be observed. The principle of testing the capacity of redoxy activity of cells was considered to be most easily applicable to the cylinder plate method.

The authors’ preliminary experiments indicated that the cells of Ehrlich carcinoma of mice, when they were placed in Hanks salt agar or mouse Ringer agar, maintained the dye-reducing activity at least for 48 hours at 37°C. This time lemz;th has been known to be enough to permit the diffusion of the antibiotics. Among retloxy dyes, Schrek used 2, 6-dichlorophenolindophenol and Kikuchi⁽³⁾ used 2, 3, 5-triphenyl tetrazolium chloride. The author’s preliminary tests indicated that these dyes and also methylene blue could be used for the detection of the reducing activity of cells of Ehrlich carcinoma. In the case of methylene blue, some devices were necessary to prevent the reoxidation by air. 2, 3, 5-Triphenyl tetrazolium chloride was expensive. Therefore, the authors used...Please see the PDF file for the full Abstract.

A research for new anti-tumor substances produced by soil actinomycetes has been carried in our laboratory for the past several years. As a result, several aspects of cazinophilin were found and are reported in the preceding papers^(1)(2)(3). Recently, the fermentation broth of a strain, isolation #V621, having growth-inhibitory activity against gram positive and gram negative bacteria, was found to exert destructive effect upon the cells of Ehrlich carcinoma and Yoshida sarcoma which resulted in the prolongation of the survival period of the host animals. The broth also showed virucidal activity in vitro against Newcastle disease virus and influenza virus and parasitocidal activity against ascaris.

Then, isolation of active principles from the fermentation broth was tried and at least several substances were obtained. A group of these active substances which were found to be previously underscribed compounds was named Mitomycin. It is the purpose of this paper to describe generally antibiotic producing strain, assay, cultivation and properties of mitomycin.

Mitomycin, a new antibiotic which is active against bacteria as well as Ehrlich carcinoma and Yoshida sarcoma, is produced by a species of Streptomyces heretofore undescribed. The species was isolated from a soil sample collected at Jōchi-machi, Shibuya-ku, Tokyo.

In our screening program of antiviral antibiotics from streptomyces, a few strains manifesting some antiohage activities were found. Studies on phagomycin⁽⁴⁾ isolated from one of them were reported by M. Miura (1956).

In the present paper, the author describes another new antiphage substance produced by Streptomyces sp. No. C-930. The organism was isolated from soil samples collected at Ryōzen, Hukushima Prefecture.

The antibiotic was obtained from a culture filtrate of the strain in a pure crystalline form. Its physico-chemical and biological properties seemed to differ from those of known antiphage antibiotics derived from Streptomyces species: phagolessin A₅₈⁽¹⁾, cardicin⁽²⁾, crysomycin⁽³⁾, and phagomycin⁽⁴⁾. The substance was thus recognized as a new antibiotic and named phagocidin. Of the Streptomyces species already announced, this organism closely resembles Streptomyces antibioticus. Its mycological aspects will be dicussed in detail later on.

Phagocidin⁽¹⁾ is a new antiviral antibiotic isolated by N. Higo in 1956. This antibiotic is produced from Streptomyces sp. No. C^-930 which possesses an unique biological property showing a strong antiphage- but no antibacterial activity. About 0.3mcg/ml of it is capable of inactivating 5096 of a T₃ phage population, while no bacterial population tested was injured even with 200mcg/ml. Phagocidin seems to be an acidic substance, is soluble in various organic solvents and weak alkaline water, and is stable in a weak alkaline, but not in an acidic solution. Though several streptomyces antiphage-antibiotics ^(2)(3)(4)(5) have been already reported, the modes of their actions have been described only in a few cases. Among them, phagolessin A₅₈⁽²⁾ and phagomycin⁽⁴⁾ were shown to be active against free phages, but not against intracellular viral growth.

The present paper deals with the problem of how phagocidin is active against bacterial virus. It is noteworthy that phagocidin indicates not only a high activity against free phages but also an activity against phages adsorbed onto host cells.

Orientomycin^(1,2) is an antibiotic produced by a strain of streptomyces (K-300),^(3,4) upon which several reports have been published already. In those papers the antibiotic was called Special Substance No. 2^(3,5) or K-300 substance^(6,7). At that time, we could not obtain it in a pure form, although we were interested in its characteristic properties.

In those previous papers, it was reported that the antibiotic was soluble in water but insoluble in almost all organic solvents, scarcely adsorbed on carbon and alumina, and it showed an amphoteric behavior on electrophoretic papergram. It was also described that the antibiotic gave ninhydrin reaction in yellowish tinge, and among the degradation products of the antibiotic a substance migrated as glutamic acid or serine on the paperchromatography. Furthermore, it was recognized that the antibiotic inhibited gram positive bacteria, gram negative bacteria and tubercle bacilli in vitro, and its toxicity for mice was very low.

Thereafter, several laboratories reported the isolation of new antibiotics (oxamycin^(8,9,10) , cycloserinem^(11,12) , and PA-94⁽¹³⁾) which were identical with each other, and the structure of these antibiotics was determined as D-4-amino-3-isoxazolidone. The resemblance between characteristic properties of our orientomycin and that of D-4-amino-3-isoxazolidone came into our notice. Therefore, we carried out the purification of orientomycin according to the almost similar procedure as that used in oxamycin. Consequently, orientomycin was prepared in a pure form and identified as D-4-amino-3-isoxazolidone. The present paper deals with the purification, physico-chemical and biological properties and the identification of orientomycin.