[Transformation of glycyrrhizinic acid. XV. Synthesis of triterpene saponins with monosaccharide residues, attached through complex ester bonds]. / Transformatsii glitsirrizinovoi kisloty. XV. Sintez triterpenovykh saponinov s monosakharidnymi ostatkami, prikreplennymi slozhnoéfirnymi sviaziami.

Triterpene saponins, glycoside analogues of glycyrrhizic acid with a modified carbohydrate chain containing monosaccharide residues attached through ester bonds, were synthesized. To this end, peracetylated glycyrrhizic acid or its 30-methyl ester were glycosylated by 2,3,4,6-tetra-O-acetyl-alpha-D-gluco-or-alpha-D-galactopyranosyl bromide in dichloroethane in the presence of Ag2CO3. Glycerrhetinic acid saponin with D-Galp residues exhibited a higher antiulcer activity than glycyrrhizic acid in rats at a dose of 25 mg/kg. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2003, vol. 29, no. 6; see also http://www.maik.ru.

[Standardized nutrient medium for determining the biological activity of antibiotics of the aminoglycoside group]. / Unifitsirovannaia pitatel'naia sreda dlia opredeleniia biologicheskoi aktivnosti nekotorykh antibiotikov aminoglikozidnoi gruppy.

The possibility of the use of nutrient media containing only salt components in addition to agar-agar in determination of the biological activity of aminoglycoside antibiotics was confirmed. The optimal results were obtained on the medium including ammonium acetate, disubstituted sodium phosphate and agar-agar. Glucose was added to the medium simultaneously with the test microbe. The medium is simple by its composition. It provides satisfactory growth of B. subtilis ATCC 6633 as the test microbe and clear inhibition growth zones of sufficient size. The results of the assay of the biological activity of neomycin, monomycin, streptomycin and kanamycin on the medium of this composition were reproducible.

[Nutrient medium for determining the biological activity of heliomycin]. / Pitatel'naia sreda dlia opredeleniia biologicheskoi aktivnosti geliomitsina.

It was shown that a nutrient medium containing only salt components except agar-agar could be used for assay of the biological activity of heliomycin. The optimal results were observed on the medium containing ammonium chloride, urea, disubstituted sodium phosphate, glucose and agar-agar. The medium provided satisfactory growth of Bac. subtilis ATCC 6633 as the test culture and formation of clear inhibition growth zones of the sufficient size. The medium is standard and its use allows obtaining reproducible results in assay of the heliomycin biological activity.

[Growth of test microorganisms used in determining antibiotic activity on synthetic nutrient media]. / Rost test-mikroorganizmov, ispol'zuemykh pri opredelenii aktivnosti antibiotikov, na sinteticheskikh pitatel'nykh sredakh.

The growth of gram-negative sporulating bacteria and yeast-like fungi used in a microbilogical assay of antibiotic activity was studied on solid synthetic media of simple composition. Their reproduction with the microbial growth of different density was shown to be possible on media containing available and strictly standardized components, such as salts, glucose and disubstituted sodium phosphate. The cultures tested were not similar by their growth requirements.

[Standardization of the nutrient medium for determining the biological activity of a number of antibiotics by the diffusion-in-agar method]. / Unifikatsiia pitatel'noi sredy dlia opredeleniia biologicheskoi aktivnosti riada antibiotikov metodom diffuzii v agar.

The possibility of using 2 variants of a unified nutrient medium containing no Hottinger's broth for determination of the biological activity of a large number of antibacterial antibiotics was shown. The medium provided satisfactory reproducibility of the results. It contained yeast extract as a source of nitrogen. The medium was selected with the method of the fractional factor experiment. Clear inhibition growth zones and the slope of the dose-response curve were used as the criteria for estimation of the optimal medium. The described nutrient medium allowed a 2-time increase in the sensitivity of the method used for determination of the biological activity of neomycin, monomycin, streptomycin, oxytetracycline, chlortetracycline and erythromycin.

[Effect of the nutrient medium components on the formation of growth inhibition zones of the test microbe in determining the biological activity of mycoheptin]. / Vliianie komponentov pitatel'noi sredy na obrazovanie zon zaderzhki rosta test-mikroba pri opredelenii biologicheskoi aktivnosti mikogeptina.

The effect of the nutrient medium components on the diffusion properties of mycoheptin and the growth of Candida utilis as the test-microbe was studied. It was found that the content of various amounts of sodium and potassium chlorides, disubstituted sodium phosphate, glucose, yeast extract, peptone, agar-agar and the value of pH in the medium had a significant effect on the size of the inhibition growth zones of the test-culture, clearance of their margin and the angle of the dose-response curve. The nutrient medium composition considered to be optimal for determination of the mychoheptin activity is proposed.

[Study of the possibility of stabilizing a levorin microbiological standard]. / Izuchenie vozmozhnosti stabilizatsii mikrobiologicheskogo standarta levorina.

The effect of a number of factors, providing increased stability of the levorin microbiological standard was studied. It was shown that air-tight packing and inert gas atmosphere (antibiotic storage in ampoules sealed under nitrogen) significantly increased the antibiotic stability. It was also shown that hydrochinone had the highest positive effect on levorin stability.

[Effect of the cultivation conditions of Candida species yeast-like fungi on their sensitivity to levorin]. / Vliianie uslovii kul'tivirovaniia drozhzhepodobnykh gribov roda Candida na ikh chuvstvitel'nost' k levorinu

The effect of levorin on yeast-like fungi under (different) cultivation conditions was studied. It was shown that the medium composition and incubation temperature affected the results of determination of the test-culture sensitivity to levorin. There was correlation between the time of the population lag-phase and the critical time of the zone formation and these values depended on the temperature of the test-microbe vegetation. Strain 037 of C. utilis was more sensitive to levorin and had a longer lag-phase as compared to the other species of the yeast-like fungi, which provided favourable conditions for formation of the growth inhibition zones.

[Use of paper discs in determining the biological activity of mycoheptin by the agar diffusion method]. / Ispol' zovanie bumazhnykh diskov pri opredelenii biologicheskoi aktivnosti mikogeptina metodom diffuzii v agar

Diffusion of mycoheptin from the discs into agar was studied. A procedure providing practical use of the discs for quantitative estimation of mycoheptin activity was developed. A possibility of using the discs in the assay of solutions containing significant amounts of an organic solvent was shown.

[Effect of gamma-irradiation on some biological and physico-chemical properties of polyene antibiotics]. / Vliianie gamma-oblucheniia na nekotorye biologicheskie i fiziko-khimicheskie svoistva polienovykh antibiotikov

Deep effect of gamma-rays on polyenic antibiotics was studied. It was shown that gamma-radiation induced radiation-chemical oxidation of the substances. The chromatographic analysis showed that the levorin degradation products were identical to the polyenic products of the antibiotic oxidative destruction. As for mycoheptin and amphotericin B, destruction of their molecules to non-polyenic products was observed. It was found that toxicity of the levorin aromatic heptaen did not practically change after gamma-irradiation in high doses. The toxicity of mycoheptin and amphotericin B, non-aromatic heptaens increased after exposure to high doses of gamma-rays.