Antibiotiki i meditsinskaia biotekhnologiia = Antibiotics and medical biotechnology最新文献

The general toxic and organotropic properties of azlocillin were studied in acute and chronic experiments with various animal species. By the body surface area the doses of azlocillin were equivalent to the drug average and maximum course doses for humans. The aim of the study was to determine the drug dose inducing certain side effects. It was found that only in a dose equivalent to the maximum course dose for humans i. e. 300 g the drug induced a transient increase in the blood levels of aspartate aminotransferase and alkaline phosphatase and some increase in the coagulation time. The allergenic properties of the drug were slightly pronounced. Within the tested doses azlocillin did not affect the peripheral blood indices and showed no immunomodulating embryotoxic, teratogenic or mutagenic effect. The experimental data indicated that the range between the drug therapeutic course doses and the doses inducing certain side effects was significant. This is evidence of a sufficiently high level of azlocillin safety.

Pectate lyase synthesis in the cells of Erwinia carotovora ELA 49 is induced by polypectate. This suggested that the Erwinia chromosomes carried a regulator gene responsible for negative regulation of the pectate lyase gene expression. In the present study the regulator gene controlling expression of one of the pectate lyase structural genes was cloned and designated as ptlA gene. For this purpose a genetic system with the tester plasmid pPc624 as the main element was constructed. The tester plasmid contained cat gene (resistance to chloramphenicol) controlled by the promotor of the ptlA gene cloned on vector pPD620. Plasmid pPC624 was maintained in the E. coli cells in a number of 1-2 copies and transferred resistance to chloramphenicol in concentrations up to 100 micrograms/ml to the cells. The E. carotovora cells containing pPC624 were sensitive to chloramphenicol in media containing no inductor (sodium polypectate). In media with the inductor they were resistant to chloramphenicol. Therefore, plasmid pPC624 proved to be a suitable system for testing the regulator gene product. The E. coli cells containing plasmid pPC624 were transformed by the hybrid Ptl+ plasmids identified in the clonotheque of the Erwinia DNA EcoRI fragments. The E. coli cotransformants were characterized by chloramphenicol sensitivity which provided a conclusion that the regulator ptlR gene controlling the ptlA gene expression was localized on the DNA EcoRI fragment (7.3 kb) containing the pectate lyase ptlA and ptlB genes. Deletion analysis showed that the investigated genes were localized in the EcoRI fragment (7.3 kb) of the E. carotovora chromosomal DNA in the following order: ptlA--ptlB--ptlR.(ABSTRACT TRUNCATED AT 250 WORDS)

Nisin sorption on some silica adsorbents in columns was studied. Silica gels, silochromes and sintered glass with various pore diameters, various specific surfaces, etc. were tested. Correlation between the adsorbent adsorption capacity with respect to nisin and the adsorbent pore diameter was observed. The tested silochromes, silica gels with the pore diameters of 70-80 nm and sintered glass with the pore diameters of 65-112 nm had the highest adsorption capacity with respect to nisin.

The study revealed the dominating role of aerobic-anaerobic microbial associations and in particular the specific role of anaerobic gram positive cocci in development of puerperal endometritis. The data suggested that a definite level of the uterus cavity contamination with microbes, not lower than 10(4)-10(5) CFU/ml or a large number of bacterial associates, not less than 3 was necessary for endometritis development. It was confirmed that pathogenicity of anaerobes increased in the presence of aerobic bacteria. It is concluded that quantitative methods for detecting the main causative agents of endometritis are needed. A set of antibacterial drugs for rational antibacterial therapy of puerperal endometritis is recommended.

Parameters of the oleandomycin-producing organism metabolism were studied at the stage of inoculum when intensity of the antibiotic biosynthesis was increased by treating the spores with a surface active substance (twin-21). It was shown that the inoculum producing later at the stage of fermentation higher quantities of the antibiotic was characterized by certain peculiarities. In particular, there were observed a shorter lag phase, a higher specific growth rate and a higher rate of accumulating the medium components at lower pyruvate levels in the exponential phase, higher activity of succinate dehydrogenase and higher levels of ATP in the mycelium during this period.

Laboratory informative computer systems (LICS-10 and LICS-11) for microbiological assay of antibiotics were developed. The systems are based on the ISKRA-1256 computer. As compared to the routine method with the use of the well-known V. S. Dmitrieva's Tables the LICSs provide more than a 2-fold decrease in the working hours of the assay. The data on the specific software for the LICSs are presented and the algorithms for the calculations are described.

Sensitivity of vibrios and aeromonads to vibriostatic O129 (2,4-diamino-6,7-diisopropyl pteridine) was studied. The vibrios and aeromonads were isolated in the USSR. The tests were performed with disks made in the USSR and Great Britain. The content of the drug in the disks was 10 and 150 micrograms. It was shown that V. cholerae O1 V. cholerae not O1 and V. albensis were highly sensitive to vibriostatic O129 and produced no growth in the presence of either low or high concentrations of the drug. Halophilic vibrios and 26.3 per cent of the aeromonads resistant to low concentrations of the drug were less sensitive to the vibriostatic. The aeromonads and plesiomonads were resistant to the drug. The reaction to vibriostatic O129 was found to be one of the biological features of vibrios and aeromonads which can be used for differentiation of genera Vibrio and Aeromonas and within genus Vibrio as a taxonomic criterion.

Four hundred and forty seven staphylococcal strains isolated from various anatomical areas of the mammary gland skin of healthy women were studied with respect to their sensitivity to benzylpenicillin, methicillin, tetracycline, erythromycin and lincomycin. It was shown that 87.5, 85 and 81.4 per cent of the isolates preserved their high sensitivity to lincomycin, methicillin and erythromycin respectively. Sensitivity to tetracycline and benzylpenicillin was observed in 49.9 and 57.7 per cent of the isolates respectively. No resistant forms were detected among S. intermedius and S. hyicus. The strains of S. aureus were resistant only to tetracycline. 56.52 and 39.61 per cent of the S. epidermidis strains amounting to 46.3 per cent in the species structure of Staphylococcus were resistant to tetracycline and benzylpenicillin respectively. No cultures of S. epidermidis resistant to methicillin were isolated. Among 263 strains resistant to separate antibiotics 42 (16 per cent) were polyresistant.