Testing the Ability of Compounds to Induce Swarming.

One of the most distinctive features of Proteus mirabilis is its ability to undergo differentiation from short, rod-shaped vegetative cells with peritrichous flagella to massively elongated swarm cells that express hundreds to thousands of flagella. The unique bull's-eye pattern that forms from cycles of active swarming and consolidation back to the vegetative state has long been a distinguishing characteristic of this species. Many factors involved in regulation of flagellar synthesis and swarm cell differentiation have been characterized, but the exact conditions sensed by P. mirabilis that send a signal to initiate differentiation and motility have yet to be fully elucidated. Here we describe a method for using several types of media to investigate compounds that induce swarming motility under conditions that would not normally be permissive.