Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 22: Posters: Cytoskeletal filaments
BP 22.18: Poster
Tuesday, March 17, 2015, 14:00–16:00, Poster A
Scanning nanobeam SAXS on cryogenic and living Dictyostelium discoideum — •Marius Priebe1, Marten Bernhardt1, Christoph Blum2, Marco Tarantola2, Eberhard Bodenschatz2, and Tim Salditt1 — 1Georg-August-Universität Göttingen, Institut für Röntgenphysik — 2Max-Planck-Institut für Dynamik und Selbstorganisation, Göttingen
The amoeba Dictyostelium discoideum is a model system for amoeboid migration, that is enabled by a reorganization of cytoskeletal biopolymers in the cell cortex.
We have performed scanning x-ray nanobeam diffraction on single cells of Dictyostelium discoideum in different preparation states (freeze-dried, frozen hydrated and initially alive). The spatially resolved small angle x-ray diffraction signal shows characteristic streaklike patterns in reciprocal space, which we attribute to fibre bundles of the actomyosin network. We introduced an anisotropy parameter to characterize the pronounced local variations within the cell. The x-ray differential phase contrast is evaluated in terms of the projected electron density and additional x-ray fluorescence aquisitions provide information on the spatially resolved distribution (2D) of elements within the cell.
The x-ray results are correlated with optical microscopy (phase contrast and fluorescence microscopy of strains with labelled actin and myosin II) on live, fixed, and cryogenic cells.