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Publications (9)0.37 Total impact

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    ABSTRACT: In this work the results of research on the influence of iron cations on the characteristics of the infectious process caused by different enterobacteria (Shigella sonnei, Shigella flexneri, Escherichia coli) are analyzed. In the experimental intraperitoneal infection of mice in the presence of saccharose and iron cations S. sonnei in phase I showed the decrease of 1g LD50 by 3-4 orders, while S. flexneri in the S-form, by not more than 1 order. The absence of correlation between the virulence of the Shigella species used for comparison, as determined in the keratoconjunctival test, and their behavior in vitro in the presence of iron was revealed. E. coli reference strains synthetizing (according to the nomenclature of I. Orskov et al.) "true" K-antigens (K1, K10) or "not true" ones (K8, K9, K27, K57) also showed different virulence in the experimental infection used in this research: the behavior of the former group corresponded to that of S. sonnei in phase I, the latter group occupied the intermediate position between the former group and S. sonnei on one hand and S. flexneri on the other hand. The sharp drop of 1g LD50 after the injection of S. sonnei in phase I in combination with iron cations can be attributed to differences in the characteristics of bacterial surface structures with antiphagocytic function and indicates that the species-specific antigen of S. sonnei in phase I should be classified with K-antigens. The experimental intraperitoneal infection of mice in the presence of trivalent iron cations can be used for making a tentative judgement on the presence of K-antigens in enterobacteria.
    Zhurnal mikrobiologii, epidemiologii, i immunobiologii 10/1983;
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    ABSTRACT: The influence of F' plasmids of different length, carrying the genetically characterized Escherichia coli K-12 chromosomal regions, on the virulence of S. sonnei has been studied. The study has revealed that in S. sonnei (in contrast to S. flexneri) the chromosome carries a recessive gene located in the area of the lactose operon; this gene is essential for the capacity of bacteria for causing keratoconjunctivitis, which has been proved by the transfer of F' plasmids of different length. The above gene is functionally independent of the influence of the F factor as such, as the transconjugants which receive the so-called "intermediate" plasmids carrying the E. coli K-12 chromosomal genes from lac I to tsx retain their virulence. The above gene (or genes) on the chromosome of S. sonnei has been localized to the left of the gene lac I.
    Zhurnal mikrobiologii, epidemiologii, i immunobiologii 10/1983;
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    ABSTRACT: Antibiotic-resistant S. typhimurium strains of different origin (isolated from patients in cases of hospital infections and enteral toxico-infections, as well as from water), when studied in experimental enteral and intranasal infection of mice showed, in comparison with antibiotic-sensitive strains, less pronounced lethal action and, accordingly, lower capacity for reproduction in the organs of the reticulo-endothelial system of mice. Multiresistant strains isolated from humans in enteral toxico-infections kill orally infected mice more frequently than strains isolated in hospital infections.
    Zhurnal mikrobiologii, epidemiologii, i immunobiologii 10/1982;
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    ABSTRACT: The possibility of obtaining Sh. sonnei donor strains in phases I and II by two methods is shown: by the transfer of the distal market lac+ from E. coli K12, Hfr-strain P4X, or by using F'ts lac+ episome. Of 5 Sh. sonnei donor strains in phase I, obtained by hybridization with E. coli K12, Hfr-strain P4X, 3 strains retained their virulence, in contrast to Sh. flexneri donor strains in the S-form, previously obtained by similar hybrizations. Of 8 Sh. sonnei donor strains in phase I, obtained by hybrididization with E. coli K12 KS 881, 6 strains were virulent. Sh. sonnei donor strains in phases I and II obtained in these experiments lost their fertility after being kept on the Dorset egg medium at 4 degrees C for 1.5--2 months.
    Zhurnal mikrobiologii, epidemiologii, i immunobiologii 01/1982;
  • I A Nastichkin, T A Lycheva
    Zhurnal mikrobiologii, epidemiologii, i immunobiologii 10/1979;
  • T A Lycheva, V G Petrovskaia
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    ABSTRACT: Episome F'13 introduced into the genome of a virulent Sh. flexneri strain brought about changes in a number of properties of the recipient strain. The expression of these properties was not connected with the chromosome area allelic to the plasmid genome. These changes seem to be induced by the mobilization of the chromosome genes of E. coli. The loss of virulence in Sh. flexneri strains carrying episome F'13 seemed to be the consequence of two reasons: the overlapping of kcpA gene by its dominant avirulent allele and abnormal synthesis of cell wall lipopolysaccharide due to the transfer of the mobilized genes from the donor strain F'13. When the preliminary mapping of genes on the chromomome was made with the use of plasmids, it was found necessary to use F-episomes which had no influence on the changes occurring in the phenotypic characteristics of the recipient.
    Zhurnal mikrobiologii, epidemiologii, i immunobiologii 06/1979;
  • T A Lycheva, V G Petrovskaia
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    ABSTRACT: The loss of virulence was observed in some of the transconjugates of E. coli O124 in the process of the transfer of the plasmids differing in length: F' 200 PS, F'x 573 and F'x 363, carrying the genes of the chromosome area lac--pur E. The genetic determinants contributing to the ability of E. coli O124 to produce keratoconjunctivitis seem to be localized near the lactose marker, and not near E as in Sh. flexneri. In E. coli O124 these genetic determinants are probably localized on both sides of the lactose operon.
    Zhurnal mikrobiologii, epidemiologii, i immunobiologii 04/1979;
  • I A Nastichkin, T A Lycheva
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    ABSTRACT: Use of selection method with R. Ffm phage offered a possibility of obtaining R-forms of Sh. sonnei from the population of bacteria of phase II with a low frequency of natural dissociation. Mono- and polyauxotrophic mutant of I, II and R-phases by hir, ilv, pro, and mtl markers were obtained by treatment of Sh. sonnei strains with nitrosoguanidine and ethyl-methanesulfonate. The frequency of mutation in two Sh. sonnei strains studied in this work (UBC and No. 941) by the same genetic regions proved to differ. The change of Sh. sonnei phase I into phase II was observed only in selection by proline marker which could be connected with the existence in this region of a gene controlling the dissociation process.
    Zhurnal mikrobiologii, epidemiologii, i immunobiologii 11/1978;
  • T A Lycheva, V G Petrovskaia
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    ABSTRACT: Genetic characteristics of Shigella flexneri virulent donor strain 3s, isolated in the laboratory, are studied. The data obtained showed that Sh. flexneri 3s 6832 is of F'protype it did not transmit even closely located chromosome markers, except pro+. The transition of pro+ marker was reproduced in recA- strain. F'pro plasmid was eliminated with a frequency similar to that of F'lac factor in the control strain of Escherichia coli. The study of virulence by means of keratoconjunktival test revealed its retaining in clones which lost F'pro plasmid. Probably, KCP-A gene retained in the chromosome of F'pro strain. Crossing with proA- and procC- C. coli strains revealed a small length of F'pro episome, enly ProA+ hybrids being obtained. A complex mechanism of F'system formation in interspecies genetic recombination between E. coli K-12 and Sh. flexneri 3s is demonstrated.
    Genetika 02/1976; 12(7):183-5. · 0.37 Impact Factor