title: [Caffeine as an inhibitor of the conjugation transfer of R-factors. A study of certain aspects of the mechanism of action of caffeine on the conjugation transfer of R-factors].
abstract: Some aspects of the inhibitory effect of caffeine on conjugation transfer of R-factors described by the authors earlier were studied. The effect of the above substance on the donor and recipient competence was tested in experiments with cultivation of the parent strains for 18 hours in the presence of caffeine. For this purpose the effect of caffeine on reduction of the donor and recipient cell competence after starvation in a physiological solution was investigated. It was shown that caffeine markedly decreased the donor competence of strain 15-3Mdrd of E. coli in the experiments of both types. Caffeine also inhibited reduction of the recipient competence of strain C600 of E. coli after starvation without its changing on 18-hour treatment. For the study of the caffeine effect on formation of the conjugation pairs experiments were carried out with dilution of the conjugation mixture after definite intervals which practically stopped formation of new conjugation pairs and eliminated further effect of caffeine on conjugation. Under such conditions transfer of R-factors may occur in the conjugation pairs after elimination of caffeine by dilution, if they were formed in the presence of caffeine before the mixture dilution. The experiments showed that caffeine inhibited not the formation of the conjugation pairs but the genetic transfer of R-factors. In addition, it was found that the substance insignificantly inhibited the process of phenotypic manifestation of the resistance markers. Inhibition of conjugation R-transfer by caffeine was associated with its eliminating effect, since the concentrations used did not induce elimination of the resistance markers in R+ strains.
mesh_terms: D002110:Caffeine / Q000494:pharmacology*; D003227:Conjugation, Genetic / Q000187:drug effects*; D003470:Culture Media; D004269:DNA, Bacterial / Q000037:antagonists & inhibitors; D003864:Depression, Chemical; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects; D005111:Extrachromosomal Inheritance / Q000187:drug effects*; D010641:Phenotype; D014170:Transformation, Genetic / Q000187:drug effects
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D002110:Caffeine
vernacular_title: Kofein kak ingibitor kon''iugatsionnoĭ peredachi R-faktorov. Izuchenis nekotorykh storon mekhanizma deĭstvii kofeina na kon''iugatsionnuiu perdachu R-faktorov