Single-Cell Biophysics: Measurement, Modulation, and Modeling

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Monday Speaker Abstracts

How Fast Can Bacteria Grow Their Flagella?

Chien-Jung Lo

National Central University, Taoyuan, Taoyuan, Taiwan.

Chien-Jung Lo

Department of Physics and Graduate Institute of Biophysics, National Central University,

Jhongli, Taoyuan, Taiwan

Bacterial flagella are self-assembled external tubular filaments for swimming. During the

assembly process, flagellins are transported unfolded through the central channel in the flagellum

to the growing tip. We develop in vivo single-cell fluorescent imaging to monitor in real time the

Vibrio alginolyticus polar flagella growth. The flagellar growth rate is found to be highly length-

dependent. We characterized the key factors controlling the flagellar growth rate. We modeled

flagellin transport inside the channel as a one-dimensional diffusive process. When the flagellum

is short, its growth rate is determined by the loading speed at the base. Only when the flagellum

grows longer does diffusion of flagellin become the rate-limiting step, dramatically reducing the

growth rate. Our results and model shed new light on the dynamic building process of this

complex extracellular structure.

Reference: M.T. Chen, Z.Y. Zhao, J.Yang, P. Kai, M.A.B. Baker, F. Bai and C.-J. Lo*, (2017)

Length-dependent flagellar growth rate of Vibrio alginolyticus revealed by real time fluorescent

imaging. eLife. e22140