Makamycin is a member of a group of antibiotics including streptogramin^1,17), PA 114^2,18) staphylomycin^3,19), and ostreogricin (E 129)^4,20), and was isolated from a cultured material of Streptomyces mitakaensis in our laboratory⁵⁾. Later two mikamycins, mikamycins A and B, were extracted and purified, and their strong synergistic relation was reported ⁶⁾. Structures of these two mikamycins were studied and they were confirmed to be quite different each other. Mikamycin B is a cyclic peptide, having lactone linkage and being constituted of 3-hydroxypicolinic acid, L-threonine, L-4-oxopipecolic acid, D-α-aminobutylic acid, L-phenylglycine, L-proline, and L-p-dimethylamino-N-methyl-phenylalanine^7,8). The formula of A, C₃₁H₃₉O₉N₃, and hydrolysis studies by Okabe⁹⁾ indicated its quite different structure from B. These different structures of A and B suggested their different action mechanisms. It is an interesting problem, whether A and B showing such a strong synergism would inhibit different steps in a same series of metabolism, or they would depress those in different series of metabolism .

In this paper, studies on effects of mikamycins A and B on synthesis of protein and nucleic acids are presented.

In the previous paper,¹⁾ the substances produced by Streptomyces No. 732 and No. 1752 were described to be mixtures of three components and each component coincided with one another, although the ratios of content of components were different in the two strains.

The three components shall be named quinomycins A, B and C, respectively. In the present publication, the production of the quinomycins and the purification procedures of quinomycins A and C are described. Quinomycin A was isolated from Streptomyces No. 1752 and quinomycin C from Streptomyces No. 732. The physical, chemical and biological properties of the quinomycins are also described in comparison with those of echinomycin. Quinomycin A is identical with echinomycin²⁾ according to the paperchromatogram, but quinomycins B and C are considered to be new antibiotics.

As described in the first report¹⁾ of this series, a Streptomyces S-2-210 resembling Str. aureus was found to produce antibiotics that seemed to belong to quinoxaline antibiotics. From culture of the strain, a mixture of antibiotics was easily crystallized, and the main component named as triostin C was isolated by column chromatography. Two other minor components named as triostins A and B were detected on paperchromatogram, but they have not been isolated yet.

It seemed that triostins A, B and C were quite closely related to one another. They also had many similar properties to those of other quinoxaline antibiotics, but they differed from others in some properties. The crystal preparation of a mixture of triostins A, B and C obtained on the way of isolating triostin C is designated as “triostin complex” in this paper.

This paper deals with the isolation procedures, the physical and chemical properties, and the biological properties of triostin C.

In the course of searching for new antibiotic effective against pathogenic fungi, the culture broth of a streptomycete showed high activities against Piricularia oryzae, etc., and two antifungal substances were isolated in crystalline forms. One of them was proved to be identical with blasticidin S by comparing ultraviolet and infrared absorption spectra and other properties, but another one was found to be a new antibiotic and named as pathocidin. In this report, its isolation and purification, physical and chemical properties as well as antibiotic activities are described. The taxonomic study of the strain will be reported later.

From the culture broth of an unidentified species of streptomyces, a crystalline antibiotic, active against Candida albicans and Mycobacterium B. C. G., was isolated and was found to be identical with toyocamycin which have been reported by Nishimura et al¹⁾.

The present paper deals with the structural study of toyocamycin and evidence for ithe total structure (XVIII) of the antibiotic is presented.

In the previous paper¹⁾ of this series, ayamycin A complex has been reported to reveal a characteristic cytotoxicity in HeLa cells and to possess an inhibitory activity against Ehrlich ascites carcinoma in mice. As a result of further purification procedures ayamycin A₂ was obtained as needle crystals and its physico-chemical properties were described²⁾.

In this paper the studies on an anti-tumor activity of ayamycin A₂ are presented.

The medical mycology has been progressed remarkably in recent years. Candida can be found rather frequently in vagina. Some of them are only saprophytic, but not infrequently the development of symptoms of vulvo-vaginal candidiasis is observed. We have been studying this subject from various points of view, and have reported the therapeutic effect of various kinds of drugs such as trichomycin and nystatin in vulvovaginal candidiasis.

We are reporting here the results of experimental treatment of vulvo-vaginal candidiasis with amphotericin B (Squibb).