Bacterial transposons and the mechanisms of their transposition

The published data on molecular mechanisms of transposons movement inside and between genomes are reviewed. The replicative mechanism of transposition of the family of Tn3-like elements is discussed, as well as the modes of bacteriophage Mu, Tn9, Tn10, Tn903 transposition. The factors affecting the choice of transposition pathways are analysed.     

The selective accumulation of monoclonal antibodies in the lungs after cyclophosphane administration to rats]

The study has demonstrated the possibility to use cyclophosphamide as a model of "impairment" agent for lung tissue cells to provide access of monoclonal antibodies to nuclear antigen structures. Biodistribution of monoclonal antibodies to various intracellular antigens was studied on Wistar rats pretreated with various doses of cyclophosphamide. Accumulation of 2C5 antibodies to cell nuclei was found to be dependent on the dose of cyclophosphamide administered.     

Phenotypic features of a strain of Yersinia pseudotuberculosis with the pVM82 plasmid, detected at pseudotuberculosis outbreak foci]

The phenotypic properties conferred to Yersinia pseudotuberculosis cells by the genetical determinants of a 25Md fragment of the plasmid pVM82 coding for the modified cellular immune response in the infected organism. The fragment was shown to determine the conjugative properties of the plasmid, the resistance of bacterial cells to a number of hydrophobic agents and cellular ability to absorb the Congo red dye. The latter confirms the presence of additional structural components in the cell wall of the strain harbouring the plasmid pVM82. The increased resistance of the plasmid-containing strain to bactericidal effect of the blood plasma was demonstrated as compared with the resistance of the strains harbouring the p57 plasmid lacking the 25Md fragment or no plasmid at all.     

European checkerspots (Melitaeini: Lepidoptera,Nymphalidae) are not aposematic – the point of view of great tits (Parus major)

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Isolation rate of gram negative microflora and its sensitivity to antibiotics in hemoblastosis patients

A total of 67 patients with blood system diseases and infectious complications were examined. During the period of the examination 139 microorganisms were isolated. Of these gram negative microorganisms constituted 51%, gram positive microorganisms--34.8% and fungal flora--14.2%. Most frequently the following gram negative microorganisms were isolated from the patients: Pseudomonas sp. (including P. aeruginosa), Klebsiella pneumoniae, Escherichia coli, Haemophilus influenzae. All isolated microorganisms retained sensitivity to imipenem, with the exception of individual strains of Pseudomonas sp.; the latter exhibited sensitivity to amicacin and ceftazidim. Cefotaxime was active with respect to 75% of K. pneumoniae strains and all E. coli strains, ciprofloxacin was active with respect to 43% of E. coli strains, 80% of K. pneumoniae strains and 83.4% of Pseudomonas sp. strains, cefepim was active with respect to 85.7% of Pseudomonas sp. strains and all E. coli strains, ceftazidim was active with respect to all Pseudomonas sp. and E. coli strains. 75% of K. pneumoniae strains, 77.8% of Pseudomonas sp. strains and 86% of E. coli strains retained sensitivity to amicacin. 25% of K. pneumoniae strains required testing for ESBL production.     

Effect of physicochemical parameters on the formation of chitosan-based gels

The possibility for forming physical gels based on Pchelozan (bee chitosan with a molecular weight of 230 kDa and an acetylation degree of 26-65%) has been demonstrated. Conditions for obtaining the gels (1% solution in 1% glycolic acid, 25 degrees C, pH 5.5-7.5) were selected. The effects of (1) the concentration of the original solution, (2) the degree of acetylation of Pchelozan, and (3) the value of pH on the process of gel formation, were studied. The gels obtained may be classified with reversible toxotropic systems. These gels are stable for a long time when stored within a temperature range of 18-55 degrees C. The gel with a degree of acetylation of 34% was characterized by irreversible syneresis.