Bacterial swimming speed and rotation rate of bundled flagella

FEMS Microbiol Lett. 2001 May 15;199(1):125-9. doi: 10.1111/j.1574-6968.2001.tb10662.x.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Flagella / physiology*
  • Microscopy, Confocal / instrumentation
  • Microscopy, Confocal / methods
  • Microscopy, Electron / instrumentation
  • Movement
  • Rotation
  • Salmonella typhimurium / cytology
  • Salmonella typhimurium / physiology*