Genovariants of Vibrio cholerae biovar El Tor: Construction, molecular-genetic, and proteomic analyses

Abstract

Experimental modeling of the emergence of virulent Vibrio cholerae El Tor genovariants is presented. It has been shown that the obtained genovariants differed neither in phenotypic or genotypic traits from natural genetically altered strains that emerged in populations of wild-type strains. It has been established, using the PCR and sequencing methods, that the genovariants formed in the process of conjugation carried in their genome a fragment of the CTXClassφ prophage genome with the ctxB1 gene of classical-type cholera vibrios. It has been shown that changes in the prophage’s structure led to higher levels of toxigenicity and virulence in the genovariants compared to a typical recipient strain. A proteomic analysis has also revealed changes in the expression of 26 proteins performing various functions in the cell, such as metabolism, energy exchange, transport of amino acids, etc.). These data are indicative of the effect produced by the new DNA region in the genome of the genovariants on the expression level of some house-keeping genes. The obtained results confirm the idea that horizontal gene transfer is one of the mechanisms leading to the emergence of genovariants in the populations of wild-type strains.