Hydrodynamics and direction change of tumbling bacteria.

The bacterium Escherichia coli (E. coli) swims in viscous fluids by rotating several helical flagellar filaments, which are gathered in a bundle behind the cell during 'runs' wherein the cell moves steadily forward. In between runs, the cell undergoes quick 'tumble' events, durin...

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Autores principales:	Mariia Dvoriashyna, Eric Lauga
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/35ad0fc9560f4dfcb684b1a185e357ef
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spelling	oai:doaj.org-article:35ad0fc9560f4dfcb684b1a185e357ef2021-12-02T20:09:07ZHydrodynamics and direction change of tumbling bacteria.1932-620310.1371/journal.pone.0254551https://doaj.org/article/35ad0fc9560f4dfcb684b1a185e357ef2021-01-01T00:00:00Zhttps://doi.org/10.1371/journal.pone.0254551https://doaj.org/toc/1932-6203The bacterium Escherichia coli (E. coli) swims in viscous fluids by rotating several helical flagellar filaments, which are gathered in a bundle behind the cell during 'runs' wherein the cell moves steadily forward. In between runs, the cell undergoes quick 'tumble' events, during which at least one flagellum reverses its rotation direction and separates from the bundle, resulting in erratic motion in place and a random reorientation of the cell. Alternating between runs and tumbles allows cells to sample space by stochastically changing their propulsion direction after each tumble. The change of direction during a tumble is not uniformly distributed but is skewed towards smaller angles with an average of about 62°-68°, as first measured by Berg and Brown (1972). Here we develop a theoretical approach to model the angular distribution of swimming E. coli cells during tumbles. We first use past experimental imaging results to construct a kinematic description of the dynamics of the flagellar filaments during a tumble. We then employ low-Reynolds number hydrodynamics to compute the consequences of the kinematic model on the force and torque balance of the cell and to deduce the overall change in orientation. The results of our model are in good agreement with experimental observations. We find that the main change of direction occurs during the 'bundling' part of the process wherein, at the end of a tumble, the dispersed flagellar filaments are brought back together in the helical bundle, which we confirm using a simplified forced-sphere model.Mariia DvoriashynaEric LaugaPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 16, Iss 7, p e0254551 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Mariia Dvoriashyna Eric Lauga Hydrodynamics and direction change of tumbling bacteria.
description	The bacterium Escherichia coli (E. coli) swims in viscous fluids by rotating several helical flagellar filaments, which are gathered in a bundle behind the cell during 'runs' wherein the cell moves steadily forward. In between runs, the cell undergoes quick 'tumble' events, during which at least one flagellum reverses its rotation direction and separates from the bundle, resulting in erratic motion in place and a random reorientation of the cell. Alternating between runs and tumbles allows cells to sample space by stochastically changing their propulsion direction after each tumble. The change of direction during a tumble is not uniformly distributed but is skewed towards smaller angles with an average of about 62°-68°, as first measured by Berg and Brown (1972). Here we develop a theoretical approach to model the angular distribution of swimming E. coli cells during tumbles. We first use past experimental imaging results to construct a kinematic description of the dynamics of the flagellar filaments during a tumble. We then employ low-Reynolds number hydrodynamics to compute the consequences of the kinematic model on the force and torque balance of the cell and to deduce the overall change in orientation. The results of our model are in good agreement with experimental observations. We find that the main change of direction occurs during the 'bundling' part of the process wherein, at the end of a tumble, the dispersed flagellar filaments are brought back together in the helical bundle, which we confirm using a simplified forced-sphere model.
format	article
author	Mariia Dvoriashyna Eric Lauga
author_facet	Mariia Dvoriashyna Eric Lauga
author_sort	Mariia Dvoriashyna
title	Hydrodynamics and direction change of tumbling bacteria.
title_short	Hydrodynamics and direction change of tumbling bacteria.
title_full	Hydrodynamics and direction change of tumbling bacteria.
title_fullStr	Hydrodynamics and direction change of tumbling bacteria.
title_full_unstemmed	Hydrodynamics and direction change of tumbling bacteria.
title_sort	hydrodynamics and direction change of tumbling bacteria.
publisher	Public Library of Science (PLoS)
publishDate	2021
url	https://doaj.org/article/35ad0fc9560f4dfcb684b1a185e357ef
work_keys_str_mv	AT mariiadvoriashyna hydrodynamicsanddirectionchangeoftumblingbacteria AT ericlauga hydrodynamicsanddirectionchangeoftumblingbacteria
_version_	1718375115372101632

Hydrodynamics and direction change of tumbling bacteria.

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