Mitochondrial volume changes induced by the antibiotic showdomycin and energized by ATP require the addition of the respiratory inhibitor antimycin A [HADLER, H. L; B. E. Claybourn and T. P. TSCHANG ; Biochem. Biophys. Res. Comm., 31 : 25 (1968)]. The requirement for the antibiotic antimycin A may be replaced by the uncoupling agent 2, 4-dinitrophenol. Indeed, damped oscillatory ATP energized mitochondrial volume changes may be induced by the combination of showdomycin plus dinitrophenol. It is proposed that both antimycin A and dinitrophenol expose the same strategically located mitochondrial thiol group which conjugates with the maleimide moiety present in showdomycin. This unexpected flux of useful chemical energy dependent upon dinitrophenol is contrary to several suggestions in the literature regarding the mode of action of dinitrophenol. The postulated high energy intermediate cleaved or not formed because of the action of dinitrophenol [LARDY, H. A. and C. A. ELVEHJEM; Ann. Rev. Biochem. 14:1 (1945), Slater, E. C. ; Proc. Int. Congr. Biochem. 5th Moscow, 1961, 5 : 325, (1963)] is now indicated to be a thiol conjugate which meshes with the respiratory chain.
A new antibiotic, 1-(p-hydroxyphenyl)-2, 3-diisocyano-4-(p-methoxyphenyl)-buta-l, 3-diene, was isolated from the mycelium of Dichotomomyces albus Saito in crystalline form by utilizing the paper disc-agar diffusion plaque inhibition method. The antibiotic inhibits the plaque formation of Newcastle disease virus infected on primary chick embryo fibroblast cell monolayer. It is active against some gram-positive and gram-negative bacteria, including Shigella flexneri and Proteus vulgaris.
In our screening for antiviral antibiotics using the agar diffusion-plaque inhibition method, a new antibiotic was obtained in crystalline form from the filter cake of the fermented broth of Dichotomomyces albus SAITO. The structure of the antibiotic was determined to be l-(p-hydroxyphenyl)-2, 3-diisocyano-4 (p-methoxyphenyl)-buta-l, 3-diene from the interpretation of the ultraviolet absorption, infrared absorption, nuclear magnetic resonance and mass spectra.
Details of the effect on Ehrlich carcinoma of the individual bleomycins A1, A2, A2', A5, B2, B4 and B6 and their distribution in organs of mice are reported. In this study, A1, A2, A5 were found to have properties which might make them useful for treatment of tumors in skin of squamous cell carcinomas. The copper-free bleomycins had almost the same activities as the copper-containing forms against bacteria and Ehrlich carcinoma. Copper in the copper-containing bleomycins was shown to increase the toxicity and to increase the effect on vascular permeability by comparing copper-free and copper-containing A2 and B2. These observations suggest that copper-free bleomycins would be more useful for treatment of human tumors than copper-containing bleomycins.
A series of 29 derivatives was obtained from the ditetrahydropyranyl ether of coumermycin A1 by treatment with 3- and 3, 5-substituted 4-acetoxy and 4-methoxy benzoyl chlorides. Many of the required acids were hitherto unknown and three were obtained from novobiocin by published procedures. Although all of the semisynthetic coumermycins so obtained were potent antibiotics, they showed significant differences in activity depending on the nature of the substituents in the benzamido portion of the molecules.
Trienine, a new antitumor antibiotic, was isolated from the fermentation broth of Streptomyces SC3725. The substance, which contains three conjugated double bonds in a molecule weighing approximately 1, 400, is active in vitro against gram-positive bacteria, as well as against several yeast and fungi. Trienine is also active as an inhibitor of the growth of the 5 WM tumor.
In the course of isolating soil microorganisms four strains of actinomycetes were isolated. Based on the morphological studies these organisms were found to belong to a new genus in the family Actinoplanaceae. These organisms produced abundant aerial mycelia as Streptomycetaceae, and produced a clubshaped sporangium and a motile zoospore. With these characters it was designated as Kitasatoa gen. nov., belonging to the family Actinoplanaceae. Among four strains, Kitasatoa purpurea is the type genus. The three other strains are: K. kauaiensis, K. nagasakiensis and K. diplospora.
In studies of biological effects of the antibiotic cyanein1) inhibition of the growth of Allium cepa roots and of mitosis in root tips of Vicia faba were observed2, 3). This communication is concerned with effects of cyanein, amphotericin B and fusaric acid on permeability of the beet root.
Narrowing effects of citrinin on representatives of major groups of the fungi were reported recently1). Besides the narrowing of growing hyphae, growth of short side branches in almost at right angles to the hyphal tips of Botrytis cinerea and also yeast-like growth of the the dimorphic fungus Paecilomyces viridis, can be induced by citrinin2). The present report is con cerned with the effects of the antibiotic on permeability of Eremothecium ashbyi which is known to produce riboflavin.