Dynamics and force generation of flagellum and pili in Caulobacter crescentus

Surface attachment of bacteria is the first step of biofilm formation and biofilms are associated with infections and bacterial resistance. Surface attachment of bacteria is often mediated by extracellular appendages, for example flagellum and pili. The flagellum is a cork-screw like structure used for swimming and surface sensing. Pili are filamentous structures and have a wide variety of functions, among them attachment on surfaces. Because of the small diameter of flagellum and pili, direct observations of flagellum and pili are challenging under physiological conditions. C. crescentus, a model organism for biofilm formation, has an asymmetric life cycle. The sessile and stalked mother cell produces a motile daughter cell that is equipped with a flagellum and pili at the free pole. In this work we investigated the dynamics and force generation of the flagellum and pili of C. crescentus under physiological conditions employing a label-free method