Requirement for pantothenate for filament formation by Erwinia carotovora

Pantothenate is required for the formation of filaments by Erwinia carotovora. This has been demonstrated for the following division-inhibiting agents: D-serine, D-cycloserine, penicillin, vancomycin, fluoride ion, and ultraviolet light. D-Serine inhibits pantothenate synthesis in an ammonia-glucose or an ammonia-pyruvate medium; therefore, it is necessary to add pantothenate to obtain filament formation in these media, using D-serine as the division-inhibiting agent. Under conditions in which pantothenate synthesis is not inhibited by the agent producing filaments, the need for it for filamentation was shown by the use of salicylate, an inhibitor of endogenous pantothenate synthesis. Evidence is presented that the production of filaments is a specific response to pantothenate, rather than a nonspecific growth stimulation.