Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 34: Statistical Physics of Biological Systems II (joint BP/DY/CPP)
BP 34.9: Vortrag
Mittwoch, 18. März 2015, 12:15–12:30, H 1028
High stress levels lead to transition from heterogeneous timing to synchronized cellular response of the E.coli Colicin E2 operon — •Andreas Mader1, Benedikt von Bronk1, Benedikt Ewald1, Sara Kesel1, Karin Schnetz2, Erwin Frey1, and Madeleine Opitz1 — 1Faculty of Physics, LMU München, Germany — 2Institute for Genetics, Universität zu Köln, Germany
The production of bacteriocins, such as colicins, is one means of bacteria to outcompete other microorganisms. In a single cell study, we analyze the heterogeneous gene expression of Colicin E2, expressed from the SOS inducible E.coli Colicin E2 operon. We quantitatively study the expression dynamics of the Colicin E2 operon in E.coli using fluorescence time-lapse microscopy. Different fluorescence reporter proteins allow us to observe heterogeneity in Colicin production and Colicin release separately. At low exogenous stress levels all cells eventually respond after a given time (heterogeneous timing), high stress levels lead to a synchronized stress response of all cells about 75 min after induction via stress. A heterogeneous response in combination with heterogeneous timing can be biologically significant. It might enable a bacterial population to endure low stress levels, while at high stress levels an immediate and synchronized response may allow elimination of closely related bacteria competing for resources. Furthermore we could demonstrate that the amount of Colicin released is dependent on cel (lysis) gene expression. Future investigations will focus on transcriptional as well as post-transcriptional regulation affecting the dynamics of Colicin expression and release.