Bacterial swimming speed and rotation rate of bundled flagella

Yukio Magariyama, Shigeru Sugiyama, Seishi Kudo

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)


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 μm (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.

Original languageEnglish
Pages (from-to)125-129
Number of pages5
JournalFEMS Microbiology Letters
Issue number1
Publication statusPublished - 2001 May 15
Externally publishedYes


  • Flagellar rotation rate
  • Laser dark-field microscopy
  • Salmonella typhimurium
  • Swimming speed

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Genetics


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