Quantitative measurement of signal processing by the chemosensory system of Escherichia coli

• Applicant: Professor Dr. Victor Sourjik
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2012 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 216694921

• Final Report Year: 2017

Final Report Abstract

Chemotaxis of the gut bacterium Escherichia coli is one of the most studied models of simple behavior. In this project, we investigated several important but so far poorly understood aspects of E. coli chemotaxis, namely (i) chemoeffector preferences and their relation to physiology, (ii) mechanisms of tactic responses to unconventional stimuli such as sugars and pH, and (iii) detailed performance of the adaptation system. The results of the project demonstrated the correlation between the chemotactic and physiological preferences of E. coli, suggesting that chemotaxis evolved to locate environment with optimal growth conditions. We further elucidated how bacteria utilize taxis to locate intermediate points in gradients of pH and to aggregate at low cell densities. We also characterized several important properties of the adaptation system of E. coli chemotaxis pathway, such as the universal relation between the response strength and adaptation time, the importance of multiple methylation sites, and the physiological significance of imprecise adaptation to several attractants. Finally, we established the assay to systematically map ligand specificities of receptors from various bacterial species, including those of medical or agricultural relevance.

Publications

• Opposite responses by different chemoreceptors set a tunable preference point in Escherichia coli pH taxis. Mol Microbiol, 2012. 86(6): p. 1482-9
  Yang, Y. and V. Sourjik
  
• Imprecision of adaptation in Escherichia coli chemotaxis. PLoS One, 2014. 9(1): p. e84904
  Neumann, S., N. Vladimirov, A.K. Krembel, N.S. Wingreen, and V. Sourjik
  
• Importance of Multiple Methylation Sites in Escherichia coli Chemotaxis. PLoS One, 2015. 10(12): p. e0145582
  Krembel, A., R. Colin, and V. Sourjik
  
• Relation between chemotaxis and consumption of amino acids in bacteria. Mol Microbiol, 2015. 96(6): p. 1272-82
  Yang, Y., P. A., C. Hofler, G. Poschet, M. Wirtz, R. Hell, and V. Sourjik,
  
• Universal response-adaptation relation in bacterial chemotaxis. J Bacteriol, 2015. 197(2): p. 307-13
  Krembel, A.K., S. Neumann, and V. Sourjik
  
• Chemotaxis towards autoinducer 2 mediates autoaggregation in Escherichia coli. Nat Commun, 2016. 7: p. 12984
  Laganenka, L., R. Colin, and V. Sourjik