Obtaining of Intrapopulational Dissociants of Some Bacilli and the Use of DIR-PCR for Their Identification

The paper is the first to suggest methods for rapid obtaining and genotypic identification of phenotypic (colonial–morphological) dissociants of bacterial cultures. For revealing the potential dissociation ability and obtaining dissociants, the use of bacterial cystlike refractile cells (CRC) is recommended. These cells are characterized by enhanced variability; upon their first passage, an abrupt increase in the dissociation index is observed as a result of the emergence of cells that form morphologically different types of colonies. The approaches elaborated were tested with Bacillus cereus, B. subtilis, and B. licheniformis, for which colonial–morphological dissociants of various types were obtained after the first passage of CRC (both of those formed in the developmental cycle of the bacteria and of those arising as a result of an artificial increase in the concentration of anabiosis autoinducers in the cultivation medium). The genomic distinctions between dissociants of B. cereus and B. subtilis were estimated using polymerase chain reaction with a primer system designed based on the analysis of nucleotide sequences of complete prokaryotic genomes available in the GenBank database (DIR-PCR). The application of the proposed method allowed distinctions to be revealed between the genomes of dissociants of Bacillus cereus and B. subtilis, which is in agreement with the hypothesis that assumes reversible intragenomic rearrangements to be the basis of bacterial dissociation into subpopulations.