Regensburg 2002 – scientific programme
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SYBM: Physik biologischer Materie
SYBM 401: Physics of biological matter: Poster
SYBM 401.45: Poster
Tuesday, March 12, 2002, 18:00–19:30, H37
MEASUREMENT OF FLEXURAL RIGIDITY OF MICROTUBULES OF DICTYOSTELIUM DISCOIDEUM CELLS IN VIVO — •Andreas Reuter1, Günther Gerisch2, Winfried Möller3, and Erich Sackmann1 — 1Lehrstuhl für Biophysik E22, Technische Universität München, James-Franck-Strasse, D-85747 Garching, Germany — 2Max-Planck-Institut für Biochemie, Am Klopferspitz 18a, D-82152 Martinsried, Germany — 3Institut für Inhalationsbiologie, GSF-Forschungszentrum, Robert-Koch-Allee 8, D-82131 Gauting, Germany
We apply a recently developed magnetic bead microrheometer (Magnetic Tweezers) to investigate the flexibility of microtubules (MTs) in vivo and compare the results with values obtained by in vitro experiments. In our experiments on Dictyostelium discoideum (Dd) we concentrate on the question whether this difference is due to extremely high intracellular forces generated by motor proteins of the cell or due to a change of the flexibility of the MTs themselves. The experimental method consists of phase contrast and fluorescence microscopy to visualize the GFP-labelled MTs combined with magnetic tweezers. Dd cells phagocytose ferromagnetic beads of a diameter of 1 µm. Via an external magnetic coil we can apply forces of up to 1 nN to these beads. The displacement is measured in real time by a single particle tracking algorithm. To characterize the flexural rigidity of MTs we analyze the geometric shape of single MTs with a single filament tracing algorithm.