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Étude de la locomotion de C. elegans et perturbations mécaniques du mouvement

Abstract : This study on the locomotion of C .elegans aims at a better understanding of its nervous system and at giving birth to news ideas concerning the conception of new biometics models or objects. We first gave a description of the worm, of its physiology, and of its main modes of locomotion, that is to say the swimming – in liquid medium, and the crawling – on gel substract. When swimming, we analyzed how the dissymmetry of the movement is necessary for the worm to move on when in viscous medium. Thanks to the analysis of the velocity of the local displacements and by supposing that the forces are viscous, we balanced the forces. We thus demonstrated that transversal and longitudinal friction coefficients could be compared to the coefficients obtained theoretically from an oblong ellipsoïd. When crawling, we were able to observe a diminution of the amplitude from the head to the tail. We first studied the worm-substract interaction theorically – lubrification hypothesis, but the friction coefficients predicted were in contradiction with experimental results. This difference, according to our experiments, was due to static friction. We also measured the rigidity of the worm. By confining the worm vertically in liquid medium, we observed a continuous transition from swimming to crawling. We proved that the movement of the tail, in comparison with the movement of the head, was more and more delayed as the confinement increased. In these conditions, the global movement of the worm got slower. On substract, we were able to constrain the amplitude thanks to a horizontal confinement; we observed that wavelength decreased with amplitude.
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https://tel.archives-ouvertes.fr/tel-00178366
Contributor : Pascal Sauvage <>
Submitted on : Saturday, October 27, 2007 - 9:28:23 AM
Last modification on : Saturday, April 11, 2020 - 1:51:13 AM
Long-term archiving on: : Friday, September 24, 2010 - 11:04:58 AM

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  • HAL Id : tel-00178366, version 4

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Pascal Sauvage. Étude de la locomotion de C. elegans et perturbations mécaniques du mouvement. Biophysique [physics.bio-ph]. Université Paris-Diderot - Paris VII, 2007. Français. ⟨tel-00178366v4⟩

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