Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 9: Posters - Cell Mechanics
BP 9.9: Poster
Montag, 20. März 2017, 17:30–19:30, P3
passive and active response of bacteria under mechanical compression — •renata garces1, samantha miller2, and christoph f. schmidt1 — 1Georg-August-Universität Göttingen, Göttingen, Germany — 2The University of Aberdeen, Aberdeen, United Kingdom
Bacteria display simple but fascinating cellular structures and geometries. Their shapes are the result of the interplay between osmotic pressure and cell wall construction. Typically, bacteria maintain a high difference of osmotic pressure (on the order of 1 atm) to the environment. This pressure difference (turgor pressure) is supported by the cell envelope, a composite of lipid membranes and a rigid cell wall. The response of the cell envelope to mechanical perturbations such as geometrical confinements is important for the cells survival. Another key property of bacteria is the ability to regulate turgor pressure after abrupt changes of external osmotic conditions. This response relies on the activity of mechanosensitive (MS) channels: membrane proteins that release solutes in response to excessive stress in the cell envelope. We here present experimental data on the mechanical response of the cell envelope and on turgor regulation of bacteria subjected to compressive forces. We indent living cells with micron-sized beads attached to the cantilever of an atomic force microscope (AFM). This approach ensures global deformation of the cell. We show that such mechanical loading is sufficient to gate mechanosensitive channels in isosmotic conditions.