FIG. 7.

Suspension-clearing assays comparing the abilities of the wild-type (WT) and mutant strains to maintain themselves dispersed in suspension by active swimming. Aliquots of a bacterial suspension were withdrawn at regular intervals from the top of the suspension, which was maintained without agitation under microaerophilic conditions, and the OD₆₀₀ was recorded as an estimation of the cell density. This is a representative example of three independent experiments performed with different cultures.