The passive diffusion of Leptospira interrogans

TL;DR

This paper presents a theoretical study of the passive diffusion of Leptospira interrogans, using hydrodynamic modeling and Langevin simulations, achieving excellent agreement with experimental data without adjustable parameters.

Contribution

It introduces a numerical approach combining slender-body theory and Langevin dynamics to accurately model Leptospira diffusion.

Findings

Quantitative agreement with experimental diffusion measurements

Hydrodynamic resistance matrix computed numerically

No adjustable parameters needed for the model

Abstract

Motivated by recent experimental measurements, the passive diffusion of the bacterium \textit{Leptospira interrogans} is investigated theoretically. By approximating the cell shape as a straight helix and using the slender-body-theory approximation of Stokesian hydrodynamics, the resistance matrix of \textit{Leptospira} is first determined numerically. The passive diffusion of the helical cell is then obtained computationally using a Langevin formulation which is sampled in time in a manner consistent with the experimental procedure. Our results are in excellent quantitative agreement with the experimental results with no adjustable parameters.