Appears in collection : 2022 - T1 - WS3 - Mathematical models in ecology and evolution

Joint work with Christophe Anjard, Vincent Calvez, Jean-Paul Rieu et Olivier Cochet-Escartin.

Using a self-generated hypoxic assay, it is shown that Dictyostelium discoideum displays a remarkable collective aerotactic behavior: when a cell colony is covered, cells quickly consume the available oxygen and form a dense ring moving outwards at constant speed and density. We propose a simple, yet original PDE model, that enables an analytical qualitative and quantitative study of the phenomenon and reveals that the collective migration gives rise to traveling wave solutions, whose propagation can be explained through the interplay between cell division and the modulation of aerotaxis. The modeling and its conclusions supplement and are confirmed by an experimental investigation of the cell population behavior. This approach also gives rise to an explicit and novel formula of the collective migration speed of cells that encapsulates a surprising combination of expansion by cell division, such as described by the Fisher/KPP equation, and aerotaxis. The conclusions of this model appear to extend to more complex models.