Bacterial motility provides many intriguing physics questions. The talk will focus on two of them, the interplay of magnetism and motility in magnetotactic bacteria and the patterns formed in dense monolayers of filamentous bacteria, which both study in collaboration with experimentalists.

The first part of the talk will focus on magnetotactic bacteria that swim along field lines of the geomagnetic field with the help of a chain of special organelles called magnetosomes. Combining experiments and modeling, we show that in obstacle channels mimicking sediment habitats, intermediate field strength increase swimming throughput, while high field strengths lead to trapping, which can be understood as an active version of a Kramers problem.

The second part of the talk will focus on filamentous cyanobacteria that glide on surfaces. The parameters of individual filaments can be quantified in great detail. Specifically, their self-propulsion force can be determined from buckling experiments. In dense monolayers they form patterns with nematic and polar order that can be analyzed in parallel in experiments and simulations. The simulations allow to vary parameters that cannot be easily varied experimentally and show the important role of direction reversals in these systems.

15:15 Coffee Break

15:30 Dr. Navid Khangholi (B4, AG Seemann): Photoactivation of light-sensitive membrane proteins in model cell membranes

15:45 Felix Maurer (AG Wagner): Competing aggregation and iso-density equilibrium lead to band patterns of erythrocytes

Online Link: click here