Geometry of cell division in Staphylococcus aureus.

The process of division in Staphylococcus aureus was examined by phase-contrast microscopy. The organisms appeared to divide in three alternating perpendicular planes, with sister cells remaining attached to each other after division. The resulting point of attachment was usually not exactly at the point corresponding to the center of the previous septal disk. Moreover, sister cells often changed position with respect to one another while still remaining attached. These factors are apparently responsible for the irregularity of staphylococcal clumps. Studies with penicillin and the examination of thin sections in the electron microscope confirm the conclusion, based upon light microscopy, that successive divisions in S. aureus occur in perpendicular planes.     

Regulation of cell division in E. coli

Recent investigation of some old cell division mutants of E. coli suggests that genes playing central roles in the regulation of division have been identified. The results suggest that cell division is triggered when a critical level of a single protein, FtsZ, is attained. The activity of this protein is channelled to the new division site by the activity of the min locus, which blocks access to old sites. Continued study of these genes should yield further insights into the cell division process.