Changes in Metabolic Activity of Proteus mirabilis during Swarming

Proteus mirabilis in the long, swarming form had altered metabolic activity compared with bacteria in non-swarming phases on solid media. During swarming the rates of incorporation of precursors into DNA, RNA and protein, as measured in broth cultures immediately after harvesting from swarm plates, were lowered. The rates of uptake of these precursors into the bacteria were also lowered, and at the same time the rate of oxygen uptake was reduced to less than 20% of the normal rate, although intracellular ATP concentrations remained constant. The return of macromolecular synthesis and oxygen uptake to preswarming rates corresponded to the end of the active swarm period. The results indicate that in the multiflagellate swarmers of P. mirabilis metabolic activity was lowered to a level necessary to maintain flagella activity but not bacterial growth.