| Abstract: | The nucleotide sequences of the Tc's insect toxin complex genes have been analyzed in 18 natural strains of the main and non-main subspecies of Yersinia pestis isolated in different natural foci in the Russian Federation, as well as neighboring and more remote countries, as compared to the data on Y. pestis and Y. pseudotuberculosis strains stored in the NCBI GenBank database. The nucleotide sequences of these genes in plague agent strains have been found to be highly conserved, in contrast to those of the pseudotuberculosis agent. The sequences of two genes, tcaC and tccC2, have been found to be almost identical in Y. pestis strains, whereas other three genes (tcaA, tcaB, and tccC1) contain a few mutations, which, however, are not common for all strains of the plague agent. Exceptions are only strains of the Y. pestis biovar orientalis, whose tcaB gene is in a nonfunctional state due to a nucleotide deletion. The results suggest that the formation of the species Y. pestis as an agent of a natural focal infection with a transmissive mechanism has not resulted in degradation of the Tc's complex genes. Instead, these genes are likely to have been altered as the plague agent have been adapting to the new environment. |
