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A macroscopic scale model of bacterial flagellar bundling.

ABSTRACT: Escherichia coli and other bacteria use rotating helical filaments to swim. Each cell typically has about four filaments, which bundle or disperse depending on the sense of motor rotation. To study the bundling process, we built a macroscopic scale model consisting of stepper motor-driven polymer helices in a tank filled with a high-viscosity silicone oil. The Reynolds number, the ratio of viscous to elastic stresses, and the helix geometry of our experimental model approximately match the corresponding quantities of the full-scale E. coli cells. We analyze digital video images of the rotating helices to show that the initial rate of bundling is proportional to the motor frequency and is independent of the characteristic relaxation time of the filament. We also determine which combinations of helix handedness and sense of motor rotation lead to bundling.

SUBMITTER: Kim M

PROVIDER: S-EPMC307593 | biostudies-literature | 2003 Dec

REPOSITORIES: biostudies-literature

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A macroscopic scale model of bacterial flagellar bundling.

Kim MunJu M Bird James C JC Van Parys Annemarie J AJ Breuer Kenneth S KS Powers Thomas R TR

Proceedings of the National Academy of Sciences of the United States of America 20031211 26

Escherichia coli and other bacteria use rotating helical filaments to swim. Each cell typically has about four filaments, which bundle or disperse depending on the sense of motor rotation. To study the bundling process, we built a macroscopic scale model consisting of stepper motor-driven polymer helices in a tank filled with a high-viscosity silicone oil. The Reynolds number, the ratio of viscous to elastic stresses, and the helix geometry of our experimental model approximately match the corre ...[more]

PMID: 14671319

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