Regensburg 2013 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 24: Posters: Physics of Cells
BP 24.18: Poster
Mittwoch, 13. März 2013, 17:30–19:30, Poster C
High-speed video microrheology in syncytial Drosophila embryos — •Alok D. Weßel1, Mahesh.G. Reddy2, Jörg Großhans2, and Christoph F. Schmidt1 — 1Drittes Physikalisches Institut, Georg-August-Universität Göttingen, Germany — 2Zentrum für Biochemie und Molekulare Zellbiologie, Georg August-Universität Göttingen, Germany
In early development, Drosophila melanogaster embryos are in a syncytial stage, i.e. multiplying nuclei are not yet separated by membranes, but are interconnected by cytoskeletal polymer networks consisting of actin and microtubules. Between division stages 9 and 13, nuclei and the cytoskeletal network form a well-ordered 2D cortical layer.
To understand the underlying mechanical properties and dynamics of this self-organizing "pre-tissue", we measure shear moduli of the interior of the embryo and its cortical layer by high-speed video microrheology. We record position fluctuations of injected micron-sized fluorescent beads with a high-speed camera at kHz sampling frequencies.
The interior of syncytial embryos shows a homogeneous, viscously dominated behavior, whereas in the actin-rich outer parts, near the nuclear layer, we see a viscoelastic response. Furthermore we are able to resolve temporal variations of the shear modulus inside the layer during the coordinated nuclear division cycle, e.g. viscosity becomes about three times higher than during interphase.