Mesoscopic modeling of bacterial flagellar microhydrodynamics

Area of Science:

• Biophysics
• Computational Biology
• Fluid Dynamics

Background:

• Bacterial propulsion relies on flagellar rotation within a viscous environment.
• Understanding flagellar flexibility and hydrodynamic interactions is crucial for bacterial motility.
• Existing models often simplify the complex interplay of flagellar dynamics and fluid flow.

Purpose of the Study:

• To develop a hybrid computational model for bacterial flagella propulsion.
• To investigate the roles of flagellar flexibility and hydrodynamic interactions in bacterial movement.
• To analyze flagellar deformation under viscous hydrodynamic conditions.

Main Methods:

• Employed a particle-based hybrid method combining the elastic network model (ENM) and smooth-particle hydrodynamics (SPH).
• Coarse-grained modeling of the flagellar filament, representing 11 protofilaments composed of flagellin proteins.
• Developed a computational model of a single flexible helical flagellar segment to simulate dynamics and flow fields.

Main Results:

• The hybrid model successfully described bacterial flagella propulsion in a viscous hydrodynamic environment.
• Explicitly modeled flagellar flexibility and long-range hydrodynamic interactions at low Reynolds numbers.
• Examined propulsive dynamics, generated flow fields, and the influence of hydrodynamics on flagellar deformation.

Conclusions:

• The developed hybrid method provides a robust framework for studying bacterial flagellar mechanics.
• Flagellar flexibility and hydrodynamic forces are key determinants of bacterial propulsion and deformation.
• This model offers insights into the biophysics of microbial motility and fluid dynamics.