Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 19: Multi-cellular systems
BP 19.4: Talk
Tuesday, March 17, 2015, 10:30–10:45, H 1058
Microcolony Merging of Neisseria Gonorrhoeae is driven by Pili-mediated Cell-Cell Interactions — •Wolfram Pönisch1, Christoph Weber1, Khaled Alzurqa2, Hadi Nasrollahi2, Nicolas Biais2, and Vasily Zaburdaev1 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2Brooklyn College, NY, USA
The bacterium Neisseria gonorrhoeae is the causative agent of the second most common sexually transmitted disease gonorrhea. During the infection process bacteria form microcolonies consisting of a few hundreds to a few thousands of individual cells. The attractive cell-cell interactions required for colony formation are mediated by type IV pili, thin and long filaments emerging from the cell membrane. Recently it has been shown how multiple retractile pili coordinate their forces to propel the cells on a surface. While there is evidence that a closely related process causes the cell-cell-interactions, the physical principles driving the formation of the colonies are poorly understood. We examine a key mechanism of colony assembly, the coalescence of two microcolonies, by performing experiments and developing a theoretical microscopic model of individual cells interacting solely by their pili. The comparison of the experimental data and results of our model exhibits an excellent quantitative agreement. Initially two colonies show a fast approach within a few minutes that is followed by a relaxation of the colony shape towards a sphere with a characteristic time of hours. Our findings suggest that pili-mediated interactions are the major mechanism required to explain the merging of microcolonies.