Bacterial swimming speed and rotation rate of bundled flagella.
Swimming speed (v) and flagellar-bundle rotation rate (f) of Salmonella typhimurium, which has peritrichous flagella, were simultaneously measured by laser dark-field microscopy (LDM). Clear periodic changes in the LDM signals from a rotating bundle indicated in-phase rotation of the flagella in the bundle. A roughly linear relation between v and f was observed, though the data points were widely distributed. The ratio of v to f (v-f ratio), which indicates the propulsive distance during one flagellar rotation, was 0.27 microm (11% of the flagellar pitch) on average. The experimental v-f ratio was twice as large as the calculated one on the assumption that a cell had a single flagellum. A flagellar bundle was considered to propel a cell more efficiently than a single flagellum.
Magariyama
Y
Y
National Food REsearch Institute, Tsukuba, Japan. maga@affrc.go.jp
Sugiyama
S
S
Kudo
S
S
D005407:Flagella / Q000502:physiology*; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods; D008854:Microscopy, Electron / Q000295:instrumentation; D009068:Movement; D012399:Rotation; D012486:Salmonella typhimurium / Q000166:cytology / Q000502:physiology*