Nuclear and cell division in Bacillus subtilis. Antibiotic-induced morphological changes.

Incubation of Bacillus subtilis after outgrowth from spores in the presence of four different antibiotics in two different concentrations, showed that septation can occur without termination of nuclear division. Septation is then only partially uncoupled from the normal division cycle. Observations on location and development of mesosomes in the presence of the antibiotics, made in three-dimensional cell reconstructions, suggest that the mesosome plays a role in the normal coordination between nuclear and cell division, and may explain the partial independence between these two processes in B. subtilis.