Skip to Main content Skip to Navigation
Journal articles

Chemotaxis in external fields: Simulations for active magnetic biological matter

Abstract : The movement of microswimmers is often described by active Brownian particle models. Here we introduce a variant of these models with several internal states of the swimmer to describe stochastic strategies for directional swimming such as run and tumble or run and reverse that are used by microorganisms for chemotaxis. The model includes a mechanism to generate a directional bias for chemotaxis and interactions with external fields (e.g., gravity , magnetic field, fluid flow) that impose forces or torques on the swimmer. We show how this modified model can be applied to various scenarios: First, the run and tumble motion of E. coli is used to establish a paradigm for chemotaxis and investigate how it is affected by external forces. Then, we study magneto-aerotaxis in magnetotactic bacteria, which is biased not only by an oxygen gradient towards a preferred concentration, but also by magnetic fields, which exert a torque on an intracellular chain of magnets. We study the competition of magnetic alignment with active reorientation and show that the magnetic orientation can improve chemotaxis and thereby provide an advantage to the bacteria, even at rather large inclination angles of the magnetic field relative to the oxygen gradient, a case reminiscent of what is expected for the bacteria at or close to the equator. The highest gain in che-motactic velocity is obtained for run and tumble with a magnetic field parallel to the gradient, but in general a mechanism for reverse motion is necessary to swim against the magnetic field and a run and reverse strategy is more advantageous in the presence of a magnetic torque. This finding is consistent with observations that the dominant mode of directional changes in magnetotactic bacteria is reversal rather than tumbles. Moreover, it provides guidance for the design of future magnetic biohybrid swimmers. Author summary In this paper, we propose a modified Active Brownian particle model to describe bacterial swimming behavior under the influence of external forces and torques, in particular of a magnetic torque. This type of interaction is particularly important for magnetic biohybrids (i.e. motile bacteria coupled to a synthetic magnetic component) and for magnetotactic
Document type :
Journal articles
Complete list of metadatas

Cited literature [59 references]  Display  Hide  Download

https://hal-cea.archives-ouvertes.fr/cea-02459617
Contributor : Véronique Lamare <>
Submitted on : Wednesday, January 29, 2020 - 3:03:38 PM
Last modification on : Thursday, January 30, 2020 - 1:41:04 AM
Long-term archiving on: : Thursday, April 30, 2020 - 4:57:29 PM

File

Codutti-2019-journal.pcbi.1007...
Publisher files allowed on an open archive

Licence


Distributed under a Creative Commons Attribution 4.0 International License

Identifiers

Collections

Citation

Agnese Codutti, Klaas Bente, Damien Faivre, Stefan Klumpp. Chemotaxis in external fields: Simulations for active magnetic biological matter. PLoS Computational Biology, Public Library of Science, 2019, 15 (12), pp.e1007548. ⟨10.1371/journal.pcbi.1007548⟩. ⟨cea-02459617⟩

Share

Metrics

Record views

115

Files downloads

165