Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 18: Focus Session: Physics of Microbial Systems - organized by Tobias Bollenbach and Benedikt Sabass

BP 18.5: Vortrag

Mittwoch, 14. März 2018, 10:45–11:00, H 2013

Localized hypermutations govern competition dynamics through positioning in bacterial colonies — •Robert Zöllner, Enno Oldewurtel, Nadzeya Kouzel, and Berenike Maier — Department of Physics, University of Cologne, Zülpicher Str. 77, 50539 Köln, Germany

Cellular positioning towards the surface of bacterial colonies and biofilms can enhance dispersal, provide a selective advantage due to increased nutrient and space availability, or shield interior cells from external stresses. Little is known about the molecular mechanisms that govern bacterial positioning. Using the type IV pilus (T4P) of Neisseria gonorrhoeae, we tested the hypothesis that localized hypermutations govern positioning and thus enhance bacterial fitness in expanding gonococcal colonies. By independently tuning growth rate and T4P-mediated interaction forces, we show that the loss of T4P and the subsequent segregation to the front confers a strong selective advantage. Sequencing of the major pilin gene of the spatially segregated sub-populations and an investigation of the spatio-temporal population dynamics was carried out. Our findings indicate that localized hypermutations generate a standing variation of pilin sequences within the inoculation zone, while variants associated with a non-piliated phenotype segregate to the front of the growing colony. We conclude that tuning of attractive forces by mutations is a powerful mechanism for governing the population dynamics of bacterial colonies.