Luis GOMEZ NAVA – Modelling intermittent biological systems at microscopic scales: from bacteria to cells.

Laboratoire Matière et Systèmes Complexes (MSC), Université Paris Cité.

Many microscopic biological systems behave in an intermittent way. Examples range from microswimmers (like bacteria, microalgae or amoeba) up to cellular tissues, where the individual constituents display different behaviors over time. In this talk I will talk about the modelization of such systems. First, I will talk about the dynamics at the interface of two cellular tissues when, in each of them, cells can divide and die. Using numerical simulations implemented with the cellular Potts model, together with a population dynamics description, we studied the stability of the interface between the two tissues and showed that when the cell apoptosis is a process regulated by the pressure in the system, but the cell division is not, then the system is unstable. In the second part of the presentation, I will talk about the modelization of intermittent biased motion of microswimmers in the presence of an external signal c(x) and discuss the minimal requirements that such a model needs in order to allow the particles to move towards (or away from) the source of the external signal.