TABLE 1.
Correlation between cell speed and PF stiffness in wild type and the mutants
| Strain | Swarm diam (mm)a | Mean speed (μm/s) ± SD | Relative speedb | Helix (mean μm ± SEM)
|
Modulusc
|
||
|---|---|---|---|---|---|---|---|
| Pitch | Diam | RBM | RTM | ||||
| Wild type | 14.0 | 40.0 ± 4.0 | 1.00 | 2.84 ± 0.1 | 0.86 ± 0.06 | 1.00 | 1.00 |
| flaB3 mutant | 12.0 | 35.0 ± 2.5 | 0.87 | 2.78 ± 0.1 | 0.74 ± 0.08 | 0.93 | 1.24 |
| flaA mutant | 9.0 | 29.0 ± 3.0 | 0.72 | 2.40 ± 0.2 | 0.59 ± 0.06 | 0.76 | 0.62 |
| flaB1 mutant | 9.0 | 29.0 ± 3.5 | 0.72 | 2.70 ± 0.1 | 0.75 ± 0.04 | 0.81 | 1.02 |
| flaB2 mutant | 6.0 | 25.0 ± 4.5 | 0.62 | 2.70 ± 0.2 | 0.69 ± 0.06 | 0.87 | 1.16 |
| flaA flaB3 mutant | 9.0 | 20.0 ± 2.5 | 0.50 | 1.92 ± 0.1 | 0.44 ± 0.06 | 0.69 | 0.86 |
| flaA flaB1 mutant | 2.5 | 17.0 ± 2.0 | 0.42 | 1.77 ± 0.2 | 0.35 ± 0.05 | 0.57 | 0.64 |
| flaA flaB2 mutant | 2.5 | 16.0 ± 2.5 | 0.40 | 1.80 ± 0.1 | 0.38 ± 0.06 | 0.63 | 0.78 |
| flaB1 flaB3 mutant | 7.5 | 21.0 ± 2.5 | 0.52 | 2.70 ± 0.2 | 0.84 ± 0.07 | NA | NA |
| flaB1 flaB2 mutant | 0 | 0 | 0 | 0 | 0 | NA | NA |
a
The data are expressed as the swarm diameter of a given mutant after subtracting that of the nonmotile flaB1 flaB2 mutant.
b
Except for the flaB1 flaB3 mutant, the strains were ordered based on their decreasing relative speed. The relative speed is the mean swimming speed of the mutant bacteria divided by the mean swimming speed of the wild-type cells.
c
The relative bending modulus (RBM) and the relative twist modulus (RTM) are the stiffness of the flagellum to bending and twisting, respectively, divided by the bending or twisting modulus of the wild-type flagellum. NA, not applicable.