Dresden 2006 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 22: Sensory Biophysics and Signal Transduction
AKB 22.4: Vortrag
Donnerstag, 30. März 2006, 15:30–15:45, ZEU 255
Dictyostelium discoideum Chemotaxis: Threshold for Directed Motion — •Carsten Beta1,2, Loling Song1,3, Sharvari Nadkarni1, Hendrik Boedeker1,4, Albert Bae1,2, Carl Franck1, Wouter-Jan Rappel5, William Loomis6, and Eberhard Bodenschatz1,2 — 1LASSP, Department of Physics, Cornell University — 2Max Planck Institute for Dynamics and Self-Organisation, Göttingen — 3Harvard Medical School, Department of Cell Biology — 4Institut für Angewandte Physik, WWU Münster — 5Department of Physics, University of California at San Diego — 6Division of Biological Sciences, University of California at San Diego
The chemotactic response of Dictyostelium discoideum cells to stationary, linear gradients of cyclic adenosine 3’,5’-monophosphate (cAMP) was studied using microfluidic devices. In shallow gradients of less than 10−3 nM/µm, the cells showed no directional response and exhibited a constant basal motility. In steeper gradients, cells moved up the gradient on average. The chemotactic speed and the motility increased with increasing steepness up to a plateau at around 10−1 nM/µm. In very steep gradients, above 10 nM/µm, the cells lost directionality and the motility returned to the sub-threshold level. In the regime of optimal response the difference in receptor occupancy at the front and back of the cell is estimated to be only about 100 molecules.