INDUCTION OF ONLY LIMITED ELONGATION INSTEAD OF FILAMENTATION BY INHIBITION OF CELL-DIVISION IN CORYNEBACTERIUM-GLUTAMICUM

In order to characterize the cell-division mechanism of coryneform bac teria, we tried to isolate cell-division mutants from Corynebacterium glutamicum after N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis, suc h as Escherichia coli fts mutants, which form long filaments at the re strictive temperatures. At the nonpermissive temperature; most of the mutants formed club-shaped or dumbbell-shaped, elongated rod cells, bu t no filament formers were isolated. Then we examined the effects of c ell division inhibitors on this organism. Cephalexin and sparfloxacin, which are the inhibitors of septation and DNA synthesis respectively, and are known to cause cell filamentation in E. coli, did not cause f ilamentation in C. glutamicum but induced morphological changes that w ere similar to those observed with the temperature-sensitive ts mutant s of C. glutamicum. These, results suggest that C. glutamicum has a un ique regulation mechanism, that is, the inhibition of cell division le ads to cessation of cell elongation.