[Electrokinetic potential of Yersinia pestis and Escherichia coli cells with an intact or defective ycaA gene (caf1M) of the fra-operon of plague pathogen].

The dependence of the amount of electrokinetic potential in cells of Escherichia coli and Yersinia pestis, which differ in the rate of reduction of lipopolysaccharide (LPS), on the presence or absence of typical and atypical capsules of Y. pestis, encoded by intact and mutant fra operons, respectively, was studied. The ycaA+ycaF+(caf1 M+caf1+) genotype was shown to be expressed in serological stability of a classical capsular antigen, irrespective of the producer strain, and a decrease in the negative charge of microbial cells compared to their noncapsular variants. Blocking of the synthesis of the product of the ycaA gene of the fra operon resulted in formation of encapsulated bacteria, whose surface electricity and serological characters varied in dependence on the LPS structure. Data obtained support the assumption that a product of the ycA gene stabilizes the conformation of the typical capsule of the plague-causing agent, which was formed from YcaF (Caf1) monomers.