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Auto-organisation des microtubules sous l'action de champs externes faibles. Comparaisons entre expériences et simulations numériques

Nicolas Glade 1
1 TIMB
TIMC - Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525
Abstract : This work is concerned with the physical chemical processes underlying biological self-organisation by which an initially homogenous solution of reacting chemicals spontaneously self-organises so as to give rise to a preparation of macroscopic order and form. Theoreticians have predicted that self-organisation can arise from a coupling of reactive processes with molecular diffusion. In addition, the presence or absence of an external field, such as gravity, at a critical moment early in the self-organising process may determine the morphology that subsequently develops. The formation in-vitro of microtubules, a major element of the cellular skeleton, shows this type of behaviour. The microtubule preparations spontaneously self-organise by way of reaction and diffusion and the morphology of the state that forms depends upon the presence of gravity at a critical moment early in the process. In our experiments, I have shown that an associated phenomenon in living cells, the transport and organisation of subcellular particles, arises when microtubules self-organise in vitro. The principal objective of the experiments presented is the effect of weak external fields on microtubule self-organisation. I have shown that it is possible to reproduce the results of experiment carried in space using ground-based apparatus. Under these conditions there is no self-organisation. Self-organisation can be restablished with other external fields and factors. In addition, we have developed a numerical reaction-diffusion scheme, based on the chemical dynamics of a population of microtubules, that simulates the experimental self-organisation. In this work we outline the main features of these simulations and discuss the manner by which a permanent dialogue with experiment has helped develop a microscopic understanding of the collective behaviour. The numerical simulations predict the major features of the experimental observations.
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Nicolas Glade. Auto-organisation des microtubules sous l'action de champs externes faibles. Comparaisons entre expériences et simulations numériques. Autre [q-bio.OT]. Université Joseph-Fourier - Grenoble I, 2002. Français. ⟨tel-00005407⟩

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