[Structure of a Shigella flexneri population in the process of forming microcolonies]

The study of the adaptation period of the S- and R-forms of S. flexneri in a nutritionally sufficient medium has revealed that the population structure characteristic of the S-form and Ra-chemotype comprises two classes of cells: actively growing and nonviable. Besides these two classes, the class of spontaneously lysing bacteria is present in the population of mutants with various degrees of lipopolysaccharide (LPS) lesions. The number of bacteria subject to autolysis increases with the progress of the degradation of the R-nucleus of LPS and depends on age of the inoculate. Morphological analysis has revealed that lysis affects mainly cells 2-3 microns long, which were in the middle of the growth stage at the moment of their inoculation.