Abstract: | The comparative analysis of the production of the main pathogenicity factors by toxigenic and non-toxigenic clones of V. cholerae natural classical strain Dacca 35 Ogawa has been carried out. The data obtained in this analysis indicate that the appearance of turbid colonies, not synthesing cholera toxin, is linked with the production of an exopolysaccharide layer on the outer surface of the cells, which determines their morphology. The suggestion has been made that the regulatory gene toxR controls the expression of not only cholera toxin, protein OmpU, but also exopolysaccharide. |