Table 1.

Comparison between wild-type and Δfrd strains with respect to the parameters of flagellar rotation

Parameter testeda	Wild type	Δfrd	P-value for the difference between the strainsb
Before stimulation
1. Time fraction spent in clockwise rotation±s.e.m. (%)	2.0±0.9	0.1±0.1	0.25
2. Switching frequency±s.e.m. (min−1)	2.1±0.5	0.4±0.2	<0.009
After stimulation
3. Time fraction spent in clockwise rotation±s.e.m. (%)	70±4	13±4	<0.0001
4. Switching frequency±s.e.m. (min−1)	0.7±0.2	16±2	<0.0001
5. Fraction of responsive cells (%)	96	75	0.001
aThe rotation of 46–59 tethered cells was monitored for periods of 40 s before and subsequent to stimulation with the repellent benzoate (50 mM).
bCalculated by the Mann–Whitney test, except for the fraction of responsive cells, which was calculated by the Fisher's exact test.