Motor-Driven Bacterial Flagella and Buckling Instabilities

Details Motor-Driven Bacterial Flagella and Buckling Instabilities Motor-Driven Bacterial Flagella and Buckling Instabilities

2012-01-03

arxiv.org/abs/1201.0628v1

Physics

Biological Physics

15 pages, 11 figures

Scientific paper

Many types of bacteria swim by rotating a bundle of helical filaments also called flagella. Each filament is driven by a rotary motor and a very flexible hook transmits the motor torque to the filament. We model it by discretizing Kirchhoff's elastic-rod theory and develop a coarse-grained approach for driving the helical filament by a motor torque. A rotating flagellum generates a thrust force, which pushes the cell body forward and which increases with the motor torque. We fix the rotating flagellum in space and show that it buckles under the thrust force at a critical motor torque. Buckling becomes visible as a supercritical Hopf bifurcation in the thrust force. A second buckling transition occurs at an even higher motor torque. We attach the flagellum to a spherical cell body and also observe the first buckling transition during locomotion. By changing the size of the cell body, we vary the necessary thrust force and thereby obtain a characteristic relation between the critical thrust force and motor torque. We present a sophisticated analytical model for the buckling transition based on a helical rod which quantitatively reproduces the critical force-torque relation. Real values for motor torque, cell body size, and the geometry of the helical filament suggest that buckling should occur in single bacterial flagella. We also find that the orientation of pulling flagella along the driving torque is not stable and comment on the biological relevance for marine bacteria.

Affiliated with

Also associated with

No associations

Rating

Motor-Driven Bacterial Flagella and Buckling Instabilities does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Motor-Driven Bacterial Flagella and Buckling Instabilities, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Motor-Driven Bacterial Flagella and Buckling Instabilities will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-183797