Regensburg 2016 – wissenschaftliches Programm
BP 29.3: Vortrag
Dienstag, 8. März 2016, 10:15–10:30, H45
Differential motility of Neisseria gonorrhoeae within bacterial micro-colonies determines the dynamics of colony merging — •Wolfram Pönisch1, Christoph Weber1, Khaled Alzurqa2, Hadi Nasrollahi2, Nicolas Biais2, and Vasily Zaburdaev1 — 1Max Planck Institut für Physik Komplexer Systeme, Dresden, Germany — 2Brooklyn College, New York, USA
Many bacteria possess type IV pili, several microns long filaments that protrude out of the cell membrane. Retraction of pili can generate pulling forces of up to 180 pN. These forces allow cells to attach and move over surfaces. Pili also mediate attractive cell-to-cell interactions that lead to the formation of microcolonies. In this project we examine microcolonies of Neisseria gonorrhoeae, the causative agent of the second most common sexually transmitted disease, gonorrhea. By tracking single cells inside of a microcolony, we were able to measure the mean square displacement of cells as a function of their position in a colony and to characterize their motility. We observe that cells close to the surface of the colony are considerably more motile than cells in the inner bulk. A simulation model of individual cells interacting via pili is used to unravel the mechanisms that cause this observation, for example by identifying differences in the number of interacting pili. We suggest that the position-dependent motility of cells in a colony determines the peculiar dynamics of merging microcolonies. The coalescence process is characterized by a fast approach of the colonies that is followed by a slow relaxation to the spherical shape.