DEVELOPMENT OF THE CELL-DIVISION SITE IN FTSA(-) FILAMENTS

Early changes at cell-division sites were studied in non-septate filam ents induced by growth of ftsATs mutant cells under non-permissive con ditions. The positions of localized regions of plasmolysis were used a s markers for the locations of partial and complete annular structures that are thought to be precursors of the periseptal annuli that flank the septum during cytokinesis. The results confirmed that these struc tures were localized at potential division sites and suggested a model in which older division sites play a role in the generation of new si tes for future use, with each older site being used only once for this purpose. The results also suggest that the details of division-site d evelopment can profitably be studied in cells in which early events in the differentiation process are uncoupled from the septation event.