Dresden 2020 – wissenschaftliches Programm
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BP 35.3: Vortrag
Donnerstag, 19. März 2020, 15:30–15:45, HÜL 386
Super-resolution structured illumination microscopy of MreB dynamics and cell wall synthesis in B. subtilis — •Julian Roth, Johanna Mehl, and Alexander Rohrbach — Albert-Ludwigs-Universität, Freiburg
Total internal reflection fluorescent structured illumination microscopy (TIRF-SIM) is a unique approach combining high acquisition speeds with a two-fold increased lateral resolution at very high contrast. Our TIRF-SIM implementation enables simultaneous dual-color super-resolution imaging of dynamic, low fluorescent samples at several Hertz. The design is based on mechanical beam steering and phase shifting devices as well as a Michelson interferometer, thus avoiding diffractive elements. The fast TIRF-SIM setup is employed to gain a clearer view on the dynamics of cell wall synthesis machinery proteins in Bacillus subtilis, as we still lack fundamental knowledge of how bacteria build, expand and maintain their cell wall. The cytoskeletal proteins MreB, RodA and PbpH are essential components of the bacterial cell-shape generation system. By imaging these proteins with TIRF-M and TIRF-SIM, directional movement and non-continuous motion patterns could be analyzed in enhanced details. Based on a multi-motor transport model, a mechanistic Brownian dynamics simulation was developed that was able to reproduce measured transport quantities like velocity and number of transport pauses and direction reversals. These new insights support the model of MreB being transported by several motors, where PbpH and RodA are likely candidates for synthesis motors based on their measured and simulated motion patterns.