Dresden 2014 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 7: Posters: Cell adhesion, mechanics and migration

BP 7.35: Poster

Montag, 31. März 2014, 17:30–19:30, P3

Probing the potential landscape of a bacterial protein chain motor used for self-propulsion — •Julian Roth, Matthias Koch, and Alexander Rohrbach — Lab for Bio- and Nano-Photonics, University of Freiburg, Georges-Koehler- Allee 102, 79110 Freiburg, Germany

The locomotion of swimming bacteria is normally related to rotary motors as e.g. flagella motors. This study concentrates on the helical bacterium Spiroplasma melliferum, a plant pathogen which lacks a stiff cell wall in contrast to most other bacteria. It is able to deform itself intensively, a property that is used for propulsion by generating a pair of kinks propagating down the length of the cell body - thus representing a linear motor. Kinks are generated by a cytoskeletal ribbon made of the unique protein Fibril, whose subunits can change their length through conformational changes. However, the functional principle and the mechanics of the Fibril ribbon have not yet been completely understood. In order to advance the understanding of contraction and relaxation of the Fibril ribbon our experiments are supported by a model, which we developed to describe the switching of the subunits of this ribbon according to Kramers rate theory. To test the validity of the model, we fix the ends of the cell by attaching optically trapped beads and probe its response to different external forces and environmental conditions as e.g. the addition of drugs. Additionally, we use the recently developed object-adapted optical trapping and shape-tracking technique [1] to image and analyze the complex cell movement. [1] Koch, M. & A. Rohrbach (2012). Nature Photonics 6(10): 680-686