title: Amoeboid swimming: a generic self-propulsion of cells in fluids by means of membrane deformations.
abstract: Microorganisms, such as bacteria, algae, or spermatozoa, are able to propel themselves forward thanks to flagella or cilia activity. By contrast, other organisms employ pronounced changes of the membrane shape to achieve propulsion, a prototypical example being the Eutreptiella gymnastica. Cells of the immune system as well as dictyostelium amoebas, traditionally believed to crawl on a substratum, can also swim in a similar way. We develop a model for these organisms: the swimmer is mimicked by a closed incompressible membrane with force density distribution (with zero total force and torque). It is shown that fast propulsion can be achieved with adequate shape adaptations. This swimming is found to consist of an entangled pusher-puller state. The autopropulsion distance over one cycle is a universal linear function of a simple geometrical dimensionless quantity A/V(2/3) (V and A are the cell volume and its membrane area). This study captures the peculiar motion of Eutreptiella gymnastica with simple force distribution.
authors: Laboratory of Interdisciplinary Physics, UMR 5588, Université Joseph Fourier and CNRS, F-38041 Grenoble, France.
authors: Alexander
authors: A
authors: Farutin
authors: Laboratory of Interdisciplinary Physics, UMR 5588, Université Joseph Fourier and CNRS, F-38041 Grenoble, France.
authors: Salima
authors: S
authors: Rafaï
authors: Physics of Geological Processes, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, Norway.
authors: Dag Kristian
authors: DK
authors: Dysthe
authors: Centre de Recherche INSERM U823 Institut Albert Bonniot, BP170 38042 Grenoble Cedex 9, France.
authors: Alain
authors: A
authors: Duperray
authors: Laboratory of Interdisciplinary Physics, UMR 5588, Université Joseph Fourier and CNRS, F-38041 Grenoble, France.
authors: Philippe
authors: P
authors: Peyla
authors: Laboratory of Interdisciplinary Physics, UMR 5588, Université Joseph Fourier and CNRS, F-38041 Grenoble, France.
authors: Chaouqi
authors: C
authors: Misbah
mesh_terms: D022081:Cell Surface Extensions / Q000502:physiology*; D016822:Euglenida / Q000502:physiology*; D008954:Models, Biological; D013550:Swimming / Q000502:physiology*