Berlin 2024 – scientific programme
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BP: Fachverband Biologische Physik
BP 22: Bacterial Biophysics II
BP 22.5: Talk
Wednesday, March 20, 2024, 16:00–16:15, H 0112
Global instabilities in maturing gonococcal colonies mediated by local type 4 pili interactions — •Marc Hennes1, Kai Zhou3, Benedikt Sabass2, and Berenike Maier1 — 1Institute for Biological Physics, University of Cologne, Germany — 2Institute of Infection Medicine and Zoonoses, Ludwig-Maximilians-University Munich, Germany — 3Institute of Biological Information Processing, Forschungszentrum Jülich, Germany
Mechanical forces and interactions play a pivotal role in the out-differentiation process of biofilm maturation. Active stresses in the form of swimming, growth pressure, and shear forces shape the three dimensional structure of bacterial aggregates and are linked to the metabolic activity of cells via underlying nutrient and metabolite fields. In the case of the pathogen Neisseria gonorrhoeae, initial aggregation is mediated by the short-range interaction of bound Type 4 Pili (T4P), filamentous appendages which cover the cell surfaces. Under load, pili connections continuously break, conferring dynamical and liquid-like properties to the proliferating colonies. As we discovered, the establishing nutrient gradients inside these growing aggregates entrain out-differentiation of the local interaction frequency of T4Ps, and induce at a certain aggregate size a global mechanical instability which restructures the complete colony. We discuss the physical nature of the instability, identify the underlying nutrient trigger, and present possible advantages for the colonies in the form of increased cell dispersion.
Keywords: Neisseria gonorrhoeae; Out-of-equilibrium; Biofilms; Instability; Type 4 Pili