Table 1.

Bacterial strains used during the course of this study

Strain name	Phenotype	Ref.
C. crescentus NA1000	Synchronizable derivative of CB15	34
C. crescentus motA:Tn	Incomplete stator and deficient motility	32, 33
C. crescentus cheB144::Tn	Counterclockwise flagellar rotation (CCW)	31
C. crescentus cheB148::Tn	Counterclockwise flagellar rotation (CCW)	31
C. crescentus cheR::Tn (NS209)	Clockwise flagellar rotation (CW)	32
C. crescentus cheR::Tn (NS338)	Clockwise flagellar rotation (CW)	32
C. crescentus ΔtipF	Flagellum not present	32
C. crescentus ΔpilA	Pili not present	25