Fig. 1.

MotI inhibits swimming and swarming postflagellar assembly. (A) Quantitative swarm expansion assay for wild-type strain 3610 (open circles) and a MotI-inhibitory strain NPS235 (MotI^Inh) (closed circles) in which the c-di-GMP–degrading phosphodiesterase PdeH is deleted and MotI is overexpressed from a constitutive promoter. (B and C) Ten frames of time-lapse images taken over 2 s of swimming motility in wet-mount tunnel slides of individual wild-type strain 3610 (B) and MotI^Inh strain NPS235 (C) cells were combined into single averaged panels. (Magnification: 400×.) Motile cells appear as dashed lines in B and are not found in C. (D and E) Fluorescence microscopy images of wild-type strain DS9294 (D) and MotI^Inh strain NPS394 (E) expressing the P_hag-GFP reporter (false-colored green) that indicates expression of the hag gene encoding flagellin. (F and G) Fluorescence microscopy images of wild-type strain DS8062 (F) and MotI^Inh strain NPS309 (G) expressing the Hag^T209C allele and stained with a fluorescent maleimide dye (false-colored green) that indicates flagellar filament assembly. In D–G the membrane was stained with FM4-64 (false-colored red). (Scale bar: 4 µm.)