Heteromorphism of the corynebacteria. III. D- (dark) and C- (clear) cell types and multiseptate specimens]

A population of Corynebacterium diphtheriae may consist of cells with accented (osmiophilic) cytoplasm (cells of the "dark" type, or D type) and cells with cytoplasm having no pronounced osmiophilic properties (cells of the "clear" type, or C type). The divergence of the population into cells of the D and C types occurs at the stage of cell division, the original mother cell being able to divide into 2 or more individual cells belonging to different types (elongated multiseptate cells). At the same time no morphological disturbances in septation may be observed. The ability of each type of cells for division into the corresponding individual daughter cells indicates their being biologically valid. The mixed (D--C) population of Corynebacterium diphtheriae is considered to be a sign of the dissociation of bacterial culture.