Abstract

Genetically-identical bacterial cells commonly display different phenotypes, especially in response to environmental stress. What causes phenotypic heterogeneity and how does it affect adaptation of bacterial populations during stress? We address these questions using a combination of single-molecule imaging, single-cell analysis via microfluidics, machine-learning, and quantitative modelling. We currently focus on three major stress responses in E. coli bacteria; the adaptive response to alkylation stress, the SOS response to DNA damage, and the oxidative stress response. We observe substantial phenotypic heterogeneity for each type of response, but uncover that the underlying mechanisms are fundamentally different and have unexpected consequences for the behaviour of the cell population under stress.