RESUMO
A collection of 363 V. cholerae strains isolated from different sources were studied by the spectrum of their hemolytic activity in combination with biovar-associated properties. The strains were analyzed for the presence of the cholera toxin (CT) gene (vct) and the hemolysin gene (hly) with the use of the CT probe and a previously cloned 6.56 kb fragment of V. eltor DNA coding the synthesis of hemolysin. The study revealed that all V. cholerae strains had the hly gene irrespective of the spectrum of their hemolytic activity, biovar, 01 agglutinability and the presence of the vct gene in their genome, while other species of the genus Vibrio and related groups contained no hly gene sequence. The results of the comparative study of the hemolytic activity of V. cholerae and V. eltor are discussed.
Assuntos
Fatores de Hemolisina/genética , Vibrio cholerae/genética , Animais , Técnicas de Tipagem Bacteriana , Genes Bacterianos , Cobaias , Hemólise/genética , Fenótipo , Coelhos , Recombinação Genética , Vibrio cholerae/classificação , Vibrio cholerae/patogenicidadeRESUMO
A 6.56-kb V. cholerae eltor DNA fragment encoding hemolysin synthesis was cloned in pUC18. The resultant recombinant plasmid pES4H (9.25 kb) was mapped by restriction analysis and shown to express in different E. coli strains as well as in nonhemolytic V. cholerae strains. Application of the cloned fragment as a molecular probe revealed homologous sequences in all V. cholerae strains tested independently on their biotypes, hemolytic activity and presence of vct-genes in their genomes while none of other Vibrio species and related microorganisms contained such sequences. A recombinant E. coli strain, a V. cholerae eltor hemolysin producer, was constructed. The simultaneous expression of hemolytic and toxinogenic properties by the same V. cholerae strains is discussed.
