[Isolation of the new antibiotic variamycin B from the biosynthetic products of a Streptomyces olivovariabilis sp. nov. culture]. / Vydelenie novogo antibiotika variamitsina B iz produktov biosinteza kul'tury Streptomyces olivovariabilis sp. nov.

Variamycin B, a new antitumor antibiotic was isolated from metabolic products of Streptomyces olivovariabilis sp. nov. The empirical formula of variamycin B is C52H76O24, the melting point is 163-165 degrees C (dec.), (alpha)20D--30 +/- 2 degrees (C 0.5, alcohol), the UV-spectrum: lambda max 230, 279, 317, 330, 415 (lg E 4.27, 4.6, 3.83, 3.75, 3.95), IR-spectrum: 1080, 1170, 1380, 1570, 1640, 1720, 3400 cm-1. Variamycin B is classified as belonging to the group of antibiotic analogs of aureolic acid. Chromomycinone, tetrazide and residues of two 2,6-didesoxysugars, i.e. olivose and variose were obtained as a result of complete and partial acid degradation of variamycin B. It was shown with the data of quantitative analysis of the hydrolysates obtained on complete hydrolysis of variamycin B that the ratio between the residues of variose and olivose in the antibiotic molecule was 1 : 4. Oxidation of variamycin B with Fremi salt resulted in formation of chinone having chromomycinone-chinone, 2 residues of olivose and 1 residue of variose in its composition. Investigation of the products of partial hydrolysis provided isolation of a substance having aglicone-chromomycenone and 4 residues of olivose in its composition. A partial structure of variamycin B is proposed.

[Determination of the penicillin acylase activity of E. coli cultures using a method of gas-liquid chromatography]. / Opredelenie penitsillinatsilaznoi aktivnosti kul'tur E. coli s ispol'zovaniem metods gazozhidkostnoi khromatografii

Penicillinacylase activity was determined in E. coli by the product of benzylpenicillin destruction, i.e. phenylacetic acid formed under the effect of the enzyme. The determination was performed on a chromatograph. The immobile phase consisted of 10 per cent of ethylenglycol edipate on chromosorb A, modified with 2 per cent H3PO4. Nitrogen was used as the gaseous carrier. The method is rapid and handy for mass testing of the cultures with a purpose of detecting penicillinacylase-producing strains. It provided reliable determination of penicillinacylase in the cultures producing simultaneously beta-lactamase, another penicillin-destroying enzyme.