The structure of cirramycin A1, C31H51NO10, has been determined. It consists of a basic sugar, mycaminose, and a 16-membered ketolactone. Cirramycin A1 is the first macrolide antibiotic which has been shown to have mycaminose as a sole sugar moiety.
A variety of cirramycin derivatives has been prepared by modifying the hydroxyl groups, aldehyde function, dimethylamino group of mycaminose or the conjugated carbonyl system of the cirramycin A1 molecule. Among the derivatives evaluated, disuccinylcirramycin A1 (III) was found to possess some improved biological properties with respect to oral absorption, local tissue irritability as well as general toxicity.
A new iron-containing peptide which inhibits the growth of Gram-positive and some Gram-negative bacteria was isolated from the broth of Streptomyces AS-K-753. The antibiotic was obtained as light buff plates. On acid hydrolysis eight amino acids, three organic acids and one keto acid could be detected.ASK-753 is similar in many properties to the sideromycin but differs from it in certain crucial characteristics.
A new antibiotic, citromycin, was isolated from cultures of two strains of Streptomyces. It was concluded to be a new water-soluble, basic antibiotic related to the streptothricin-like group. The isolation and purification as well as the physical, chemical and biological properties of the antibiotic are described. The differences of citromycin to various new streptothricin-like antibiotics are examined and discussed.
A new species of Actinoplanes designated as Actinoplanes brasiliensis nov.sp. is described. Its taxonomic relationship with other species of Actinoplanes as well as the cultural, physiological and biochemical characteristics, are also discussed. The antibiotic A/672 produced by the new isolate is described and its in vitro and in vivo data are given.
Lomofungin is a new antibiotic which is extracted from the fermentation broth of Streptomyces lomondensis var. lomondensis with methyl ethyl ketone and purified by crystallization. It is an acidic olive-yellow colored compound with a molecular formula C15H10N2O6 and a molecular weight of 314. It exhibits ultraviolet and visible absorption maxima at 221, 270, 311, 375 and 439mμ in 0.01N methanolic hydrochloric acid, and at 239, 265, 299, 342, 478 in 0.01N aqueous sodium hydroxide. Lomofungin does not melt below 320°C.It is soluble in dimethylformamide, alkaline water, acidic acetone and acidic methyl ethyl ketone but only slightly soluble in water, methanol, cyclohexane, acetone, ether or ethyl acetate.