Soft Condensed Matter Group
print


Breadcrumb Navigation


Content

Single Cell Response and Decision Making

One of the most prominent phenomena in biological systems is their capability to adopt to environmental changes. The underlying signaling networks provide strategies of optimal response. A common observation is the fact that cell decisions are heterogeneous among a isogenic population. This fact can be traced back to natural number fluctuations in signalling elements and can be treated as noise in biochemical networks.

We are interested the timing and dynamics of single cell gene expression using single cell time-lapse microscopy. We studied various bacterial model systems the (1) arabinose utilization, (2) the competence state and (3) the onset of biofilm formation.

Current research focuses on

Optimization of sugar utilization strategies

Sonja Westermayer, Judith Mergerle, Georg Fritz, Uli Gerland, Joachim Rädler

Bacteria can rapidly react to environmental changes by adapting gene expression of certain genes. We investigate the time-dependent response of sugar utilization systems in Escherichia coli on the single-cell level. We study both individual systems and the situation of two competing sugar utilization systems, with the goal to characterize properties that may have been optimized by evolution. Using microfluidic set-ups we expose bacterial cultures to systematically variable environments and use time-lapse microscopy and single cell tracking to acquire single-cell expression kinetics. In mathematical models using cost-benefit analysis and game theoretical concepts, we compare different regulatory schemes as strategies to cope with variable environments.

This work is supported by the DFG through the priority program SPP

related publications:

  • S. A. Westermayer, G. Fritz, J. Gutiérrez, J. A. Megerle, M. P. S. Weißl, K. Schnetz, U. Gerland & J. O. Rädler
    "Single-cell characterization of metabolic switching in the sugar phosphotransferase system of Escherichia coli"
    Molecular Microbiology (2016) doi:10.1111/mmi.13329
  • J.A. Megerle, G. Fritz, U. Gerland, K. Jung, J.O. Rädler
    "Timing and dynamics of single cell gene expression in the arabinose utilization system"
    Biophysical Journal 95, p. 2103-2115 (2008)
  • M. Leisner, J.-T. Kuhr, J.O. Rädler, E. Frey, and B. Maier
    "Kinetics of genetic switching into the state of bacterial competence" 
    Biophys. Journal 96(3) pp. 1178 - 1188 (2009)
  • A. Meyer, J. Megerle, C. Kuttler, J. Müller, C. Aguilar, L. Eberl, B. Hense, J.O. Rädler
    "Dynamics of AHL mediated quorum sensing under flow and non-flow conditions"
    Physical Biology, 9 (2012) 026007.

Collaborations:

  • Prof. Dr. Ulrich Gerland, LMU
  • Prof. Dr. Karin Schnetz, Universität zu Köln
  • Prof. Dr. Kirsten Jung, LMU

Stem cell decision making

FURTHER READING

  • A. Meyer, J. Megerle, C. Kuttler, J. Müller, C. Aguilar, L. Eberl, B. Hense, J.O. Rädler
    "Dynamics of AHL mediated quorum sensing under flow and non-flow conditions"
    Physical Biology, 9 (2012) 026007.
  • M. Leisner, J.-T. Kuhr, J.O. Rädler, E. Frey, and B. Maier
    "Kinetics of genetic switching into the state of bacterial competence" 
    Biophys. Journal 96(3) pp. 1178 - 1188 (2009)
  • J.A. Megerle, G. Fritz, U. Gerland, K. Jung, J.O. Rädler
    "Timing and dynamics of single cell gene expression in the arabinose utilization system"
    Biophysical Journal_ 95, p. 2103-2115 (2008)
  • Leisner, M., K. Stingl, J.O. Rädler, and B. Maier
    "Basal expression rate of comK sets a 'switching-window' into the K-state of Bacillus subtilis"
    Molecular Microbiology, 63(6), 1806-1816 (2007).