RESUMEN
Y. pestis high repeated sequences DNA (HRS) used as probes in the blot hybridization procedure made it possible to reveal some tendencies of their location on the chromosome, namely, the correlation with the regions where Y. pestis strains were isolated, correlation with the stability of their properties and, perhaps, with the variation of individual strains.
Asunto(s)
ADN Bacteriano/genética , Secuencias Repetitivas de Ácidos Nucleicos , Yersinia pestis/genética , Dermatoglifia del ADNRESUMEN
A conceptual model of the Yersinia pestis Ca(2+)-dependence mechanism is proposed. The model is based on data from analyses of peculiarities of recombinant cells of this plague-causing agent carrying the cloned first Bg/II fragment of the Ca(2+)-dependence plasmid (pCaD) and a combination of this fragment and other plasmid pCaD fragments. The data obtained also allowed a revision of the role of the lcr GVH locus of pCaD in this phenomenon.
Asunto(s)
Calcio/farmacología , ADN Recombinante/genética , Regulación Bacteriana de la Expresión Génica/fisiología , Yersinia pestis/genética , División Celular/efectos de los fármacos , División Celular/genética , Mapeo Cromosómico , Medios de Cultivo , Calor , Fenotipo , Plásmidos , Virulencia , Yersinia pestis/efectos de los fármacos , Yersinia pestis/patogenicidadRESUMEN
This paper was prepared on the basis of a report presented at the first Congress of the All-Russian Society of Geneticists and Breeders (December 1994, Saratov, Russia). Analysis of published data and the authors' own investigations enabled them to propose a concept of evolution of pathogenicity within the Yersinia genus. They concluded that phenotypic features conferred by yersinia plasmids should be considered taxonomic traits.
Asunto(s)
Evolución Biológica , Yersinia/genética , Marcadores Genéticos , Fenotipo , Plásmidos/genética , Yersinia/clasificación , Yersinia/patogenicidadRESUMEN
The bank of the HindIII, EcoRI and PstI fragments of Yersinia pestis Ca(2+)-dependence plasmid (pCaD) was constructed and used as molecular probes, combined with the restriction analysis to map pCaD. Experiments on laboratory animals showed two subfragments of the fifth HindIII fragment to impart virulence, invasiveness to the plasmidless avirulent strains of Y. pestis, Y. pseudotuberculosis and Escherichia coli, and the protective activity to Y. pestis clones, while the original fifth HindIII fragment possessed no such property.
Asunto(s)
Calcio/metabolismo , Plásmidos , Yersinia pestis/genética , Clonación Molecular , Escherichia coli/genética , Escherichia coli/patogenicidad , Genes Bacterianos , Mapeo Restrictivo , Virulencia/genética , Yersinia pestis/patogenicidad , Yersinia pseudotuberculosis/genética , Yersinia pseudotuberculosis/patogenicidadRESUMEN
Two replicons, pOX38 (in F-factor derivative lacking all IS elements) and pCT105 (containing cholera toxin operon cloned in pBR322) have been fused to produce recombinant plasmid, pCO109, which was then introduced into Vibrio cholerae eltor by conjugation. Restriction analysis showed pCO109 to dissociate in V. cholerae cells at a higher frequency than in Escherichia coli strains, its pOX38 component being lost, while the pCT105 component demonstrated relative stability. V. cholerae eltor RV79 (pCT105) produced 4-5 micrograms/ml of cholera toxin. Occasional insertion of cloned vctA, B operon into RV79 chromosome was also observed.
Asunto(s)
Toxina del Cólera/genética , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Plásmidos , Vibrio cholerae/genética , Toxina del Cólera/biosíntesis , Conjugación Genética , Recombinación Genética , Vibrio cholerae/metabolismoRESUMEN
Plasmid DNA was isolated from Yersinia pestis strains containing pesticin I or fraction I antigen and "mouse" toxin determinants. Specificity of DNA preparations was studied by using them for transformation of plague agent strains carrying no plasmids. pPstI plasmid (molecular weight 7,0-7,8 MD) encoded pesticin I, fibrinolysin and plasmacoagulase synthesis. Fraction I antigen and "mouse" toxin production determinants were borne on pFraI/Tox plasmid (molecular weight about 50 MD). The observation that some Y. pestis cultures, having lost the ability to synthesize one of pFraI/Tox products, still retained this plasmid in their cells, is regarded as an evidence for a complicated regulation of pFraI/Tox function.