[Ultrastructure of cells comprising an intact population of several strains of S. typhimurium and E. coli].

The authors describe the ultrastructure of cells composing the intact population of several S. typhimurium and E. coli strains. Four morphological cell variants were revealed in the population of three salmonella strains. Cells of the first variant had the structure characteristic of all the Gram negative bacteria, and smooth contour surface structures, among which the membrane of the cell wall, its rigid component and the cytoplasmic membrane were differentiated readily. The second variant differed from the first one by the presence of deep individual folds of the surface structures invaginating into the cell. In comparison with the former two types of cells, the two latter variants were characterized by a lesser size, dense cytoplasm and a marked tortuosity of the cell contours in which only the wall components could be revealed. It is supposed that the fourth variant had a structure characteristic of the R-form of cells, the first one--of the S-form, and the second and third variants could be referred to the transitional S leads to R-forms. Increased density of the cytoplasm and rugose character of the surface structures could be attributed to increased dehydration of the cytoplasm of the dissociating cells. No marked polymorphism was revealed in the E. coli cells.