[Development of technology for isolation and purification of gentamicin using sorption without filtration].

A technology for isolation and purification of gentamicin from nonfiltered fermentation broth with the use of sorption-pulsory columns was developed as a result of the research work. The practical application of the technology will increase the yield from 30 to 57 per cent and reduce the content of the minor admixtures in the final product up to 5 per cent in comparison to the currently used process.

[Sorption of aminoglycoside antibiotics from unfiltered culture fluid].

Sorption of aminoglycosides such as sisomicin, gentamicin, kanamycin and streptomycin from the non-filtrated fermentation broth by carboxylic cation exchange resins under the static conditions was studied. The optimal conditions for the sorption of the aminoglycosides and their subsequent desorption were determined (the ratio of the volumes of the sorbent and fermentation broth and the time of the sorption and desorption).

[Selection and physiological study of culture of Bacillus circulans-- producer of butirosin].

For isolating a highly active variant of the butirosin-producing culture, a strain forming trace amounts of the antibiotic substance was used. Exposure to nitrosomethylbiuret and nitrosoguanidine and the use of selective media containing streptomycin and butirosin resulted in a 30-fold increase in the strain productivity. Thin layer chromatography of the produced antibiotic substance in the solvent system developed by the authors, mass spectrometry and assay of the antimicrobial spectrum in regard to ++gram-positive and ++gram-negative bacteria by using the known aminoglycosidine-inactivating enzymes revealed that the substance was identical to butirosin.

[Study of possible biological transformation of kanamycin to amikacin].

For transformation of kanamycin A (Km) to amikacin (Ak) with acylating enzymes from B. circulans, a culture producing butirosin (Btn), cellular and acellular conversion systems and methods for chemical and biological identification of Km, Ak and Btn were developed. The level of conversion of Km to Ak in vivo and in vitro did not exceed 2 per cent.

[Use of mass spectrometry with chemical ionization in screening antibacterial antibiotics with a broad spectrum of action (aminoglycosides and macrolides)].

It is shown that mass-spectrometry with ammonia desorption chemical ionization (ADCI) can be used for identification of aminoglycosides and macrolides at the initial stages of screening. ADCI can also be used for selection of strains which form the lowest amounts of by-products, as well as for optimization of biosynthetic conditions.

[Structure of the antineoplastic antibiotic variamycin].

The results of the structural study of antitumor antibiotic variamycin and its peracetyl derivative by 1H-and 13C-NMR spectroscopy are reported. Structures of carbohydrate chains of the antibiotics molecule are revised. Variamycin is shown to be 2-[beta-cymmarosyl(1-3)-beta-oliosyl (1-3)-beta-olivosyl]-6-[beta-olivosyl (1-3)-beta-olivosyl] chromomycinone.

[Production of lincomycin by Micromonospora halophytica culture].

A Micromonospara culture designated as 991/78 with activity against gram-positive cocci and bacteria was isolated from samples of silt-covered substrates from the Amu-Darya. Directed screening on a selective medium supplemented with lincomycin in an amount of 50-100 micrograms/ml was used. Identification of the antibiotic produced by the culture showed it to be lincomycin.

[Study of conformation structure and molecular interactions of rosamycin by infrared spectrum analysis].

IR spectra of rosamycin and its solutions in inert (CCl4 and C2Cl4), proton acceptor (tetrahydrofuran, hexametapol and diethylamine) and proton donor (CHCl3 and CH3OD) solvents were studied at various concentrations (0.1 to 0.001 mol/l) and temperatures (20 to 100 degrees C) in the region of the vC = O and vOH absorption bands (1600-1800 and 3200 3650 sm 1).

[Identification of idiotrophs for 3'-deoxykanamycin B synthesis in Streptomyces tenebrarius (Higgens a. Kastner)].

Mutants of Streptomyces tenebrarius with the blocked synthesis of 3'-deoxykanamycin B were obtained by treating the producer with NTG and chloramphenicol, or after gamma-irradiation. These mutants (idiotrophs) were distributed into three groups by means of the cosynthesis experiments on agar plates: convertors, secretors and "neutral" strains. Five idiotrophs represented five complementation groups for biosynthesis of the antibiotic.

[Infrared spectra and the molecular conformations of macrolide-group antibiotics in solution].

IR spectra (1,600-1,800, 3,100-3,700 cm-1) of tetrachlorethylene solutions of macrolide antibiotics such as erythromycin monohydrate and dihydrate, oleandomycin, erythrolose amine and anhydroerythromycin were obtained. The atoms and atomic groups included into the hydrogen bond were determined. It was shown that the antibiotic molecule conformations were stabilized by the intramolecular hydrogen bonds.

[IR spectral research on erythromycin mono- and dihydrates].

The IR spectra of crystalline and amorphous forms of erythromycin monohydrate and dihydrate were investigated and their characteristic spectral features were described. Differences in the system of the intermolecular hydrogen bonds and in the level of perfection of the crystalline structures of the monohydrate and dihydrate were detected. It was shown that both crystallohydrates of erythromycin might exist in two polymorphous modifications.

[Formation of antibiotic JI-20B by a culture of Streptomyces flavovirens].

An actinomycetous culture having an antibiotic action on gram-positive and gram-negative bacteria was isolated from a soil sample collected in the region of the Balaton Lake. As a result of the taxonomic study the culture was classified as Str. flavovirens.

[Isolation of the new antibiotic variamycin B from the biosynthetic products of a Streptomyces olivovariabilis sp. nov. culture].

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.

[Use of selective media with lincomycin for the directed screening of antibiotic producers].

Relation between lincomycin resistance of Micromonospora cultures freshly isolated from soil samples and their capacity for production of antibiotics related to lincomycin by the structure or mode of action was shown. 32 cultures of Micromonospora were isolated from soil platings containing 50--100 microgram/ml of lincomycin. Crude antibiotic substances were recovered with the method of organic solvent extraction from 10 cultures possessing pronounced antibiotic activity.