PhD defense Antrea Pavlou, July 12

The PhD defense of Antrea Pavlou will be on Tuesday 12th of July at 2pm in the conference room of LIPhy, Saint-Martin d’Hères. It is also possible to follow the defence via Zoom.
The defense will be in English.

Title : Quantification of bacterial resource allocation in changing environments on the single-cell level.

Abstract : The ability of microbes to colonize the most improbable places can be partly attributed to the efficient coordination between growth and metabolism. Over the last 50 years, the relationship between growth and the environment has been intensely studied, and has lead to general empirical relationships or ’growth laws’. In most studies, however, bacteria are maintained at steady-state growth even though such conditions are rarely found in a natural environment. To investigate bacterial adaptation in changing environments, we have tracked growth and gene expression of single cells of Escherichia coli bacteria growing in a microfluidics device in changing environments. We have examined the behavior of key ribosomal and metabolic genes using fluorescent protein tags. Using inference algorithms, along with models accounting for the maturation kinetics of reporters, we were able to derive dynamic resource allocation profiles of each protein of interest from the time-lapse measurements. The experimental results provide a detailed view of resource allocation strategies of individual bacteria in dynamically changing environments. Even though the average behavior of the bacteria precisely matches known growth laws during steady-state, resource allocation deviates from the classical growth laws during growth transitions. Furthermore, we identified a considerable heterogeneity between bacteria that manifests itself by different strategies for adapting to a new environment. Our results reveal new principles of dynamical resource allocation and could be helpful in improving biotechnological processes involving microorganisms.

Jury composition:
Wolfram Liebermeister, INRAE, rapporteur
Pascal Hersen, Institut Curie, rapporteur
Rosalind Allen, University of Jena, examinatrice
Franz Bruckert, Université Grenoble-Alpes, examinateur
Eugenio Cinquemani, Inria, invité
Hans Geiselmann, directeur de thèse
Hidde de Jong, directeur de thèse

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