A two-component regulatory system modulates twitching motility in Dichelobacter nodosus

Vet Microbiol. 2015 Aug 31;179(1-2):34-41. doi: 10.1016/j.vetmic.2015.03.025. Epub 2015 Apr 4.

Abstract

Dichelobacter nodosus is the essential causative agent of footrot in sheep and type IV fimbriae-mediated twitching motility has been shown to be essential for virulence. We have identified a two-component signal transduction system (TwmSR) that shows similarity to chemosensory systems from other bacteria. Insertional inactivation of the gene encoding the response regulator, TwmR, led to a twitching motility defect, with the mutant having a reduced rate of twitching motility when compared to the wild-type and a mutant complemented with the wild-type twmR gene. The reduced rate of twitching motility was not a consequence of a reduced growth rate or decreased production of surface located fimbriae, but video microscopy indicated that it appeared to result from an overall loss of twitching directionality. These results suggest that a chemotactic response to environmental factors may play an important role in the D. nodosus-mediated disease process.

Keywords: Chemotaxis; Dichelobacter nodosus; Footrot; Twitching motility; Type IV fimbriae.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chemotaxis
  • Dichelobacter nodosus / genetics*
  • Dichelobacter nodosus / physiology
  • Fimbriae, Bacterial / genetics*
  • Fimbriae, Bacterial / metabolism
  • Foot Rot / microbiology*
  • Gram-Negative Bacterial Infections / microbiology
  • Gram-Negative Bacterial Infections / veterinary*
  • Mutagenesis, Insertional
  • Sheep
  • Sheep Diseases / microbiology*
  • Signal Transduction*
  • Virulence