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A two-component regulatory system modulates twitching motility in Dichelobacter nodosus
Ruth M Kennan1, Carrie J Lovitt1, Xiaoyan Han1
1Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800, Australia; Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
Veterinary Microbiology
|April 21, 2015
Summary
Dichelobacter nodosus causes sheep footrot. A new system, TwmSR, regulates twitching motility, crucial for virulence, by affecting directionality, not speed.
Area of Science:
- Bacteriology
- Microbial Pathogenesis
- Signal Transduction
Background:
- Dichelobacter nodosus is the primary cause of sheep footrot.
- Type IV fimbriae-mediated twitching motility is essential for D. nodosus virulence.
Purpose of the Study:
- Identify novel virulence factors in D. nodosus.
- Investigate the role of a two-component system (TwmSR) in twitching motility and virulence.
Main Methods:
- Insertional inactivation of the twmR gene in D. nodosus.
- Comparative analysis of wild-type and mutant twitching motility rates using video microscopy.
- Assessment of bacterial growth rates and fimbriae production.
Main Results:
- Mutants lacking functional TwmR exhibited significantly reduced twitching motility rates.
- The motility defect was attributed to a loss of twitching directionality, not altered speed or fimbriae production.
- TwmSR shows similarity to bacterial chemosensory systems.
Conclusions:
- The TwmSR system regulates twitching motility directionality in D. nodosus.
- Chemosensation likely plays a role in the pathogenesis of D. nodosus-mediated footrot.
- TwmSR represents a potential target for novel footrot control strategies.
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