Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 10: Postersession II

BP 10.31: Poster

Montag, 12. März 2018, 17:30–19:30, Poster C

Probing C. Elegans Micromechanics in vivo — •Peter Weist, Renata Garces, Eugenia Butkevich, and Christoph F. Schmidt — Drittes Physikalisches Institut - Biophysik, Fakultät für Physik, Georg-August-Universität Göttingen

To perform undulatory locomotion, C. elegans generate forces acting not only on the surrounding environment but also against its own-body bending resistance. The decoupling of body passive-active responses during the bending is crucial to quantify the forces generated by the worms muscles. To date, a direct measurement of the stresses involved in the worms deformation is lacking. In this contribution, we present an experimental set-up that monitors the global response of individual worms to bending and pulling forces in a simple geometry. Living worms are kept straight by clamping their extremities onto agar plates. We pull and move the center of the worm with a custom-made cantilever of known spring constants (values around 1 N/m). We measure the loading forces and displacement profiles. Describing the worm body as a purely elastic material, we are able to determine bending and stretching contributions to the global stiffness and to derive material parameters. Furthermore, to separate the passive response of the body from the muscle activity, we vary the contraction-relaxation state of the muscles using pharmacological treatments. We provide a synthesis of the typical range of magnitudes of the worm's material parameters for different muscles states. The characterization technique for the mechanics of wild-type worms we propose can be used as a standard test for muscle functioning, including genetically modified species.