Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 15: Biopolymer Solutions and Networks
BP 15.2: Vortrag
Dienstag, 27. März 2007, 15:30–15:45, H44
Contours and Thermal Fluctuations of Individual F-actin Filaments in Entangled Networks — •Marta Romanowska1,2, Bernd Hoffmann1, Norbert Kirchgeßner1, Margret Giesen1, and Rudolf Merkel1 — 1Institute of Bio- and Nanosystems: Biomechanics, Research Centre Jüllich, 52425 Jülich, Germany — 2Marian Smoluchowski Institut of Physics, Jagiellonian University Krakow, Reymonta 4, 30-059 Krakow, Poland
Recently significant scientific interest has been focused on the contours and fluctuations of isolated actin filaments. Moreover, rheological properties of F-actin solutions were characterized in detail. However, studies of the behavior of individual filaments within F-actin solutions are scarce.
To fill this gap, we analyze F-actin filaments in entangled networks by means of Confocal Laser Scanning Microscopy. From real-time observations of the Brownian motion time-averaged filament contours and the fluctuations around them are determined. Our system comprises of fluorescently labelled and phalloidin-stabilized reporter filaments embedded in a 3-D solution of unlabelled ones. Hence, the polymer conformations are determined by a competition of intrinsic filament stiffness and steric constraints induced by surrounding filaments. We investigate the effect of actin concentration as a parameter representing the strength of the confinement. Furthermore, we evaluate some static equilibrium properties of the filaments and compare our findings to theoretical results based on the wormlike chain model and the tube concept.