Quantitative Biology of Non-growing Microbes

Coordinators: Nathalie Balaban, Thomas Julou, and Roberto Kolter

This program intends to give a quantitative biology look at non-growing microbes. Although several of the best characterised living organisms are microbes, they are almost always studied in steady-state conditions of growth, which are known to be more the exception than the rule in their natural habitats. There, microbes are expected to grow very slowly if at all and to face higher mortality. Beyond that observation, even our most basic assumptions on how cells work when growing must be reassessed for growth-arrested cells. For instance, the average concentration of intracellular compounds is not set anymore by the ratio of production to dilution due to growth, but by the ratio of production to decay. Notably, several laboratory conditions – such as stationary phase or nutrient depletion – are relevant to study non-growing microbes, and such studies have recently gained in popularity.

This program will bring together experimentalists and theoreticians, and consider laboratory as well as environmental studies in order to address important questions of this emerging field:

  • What are distinctive features of arrested cells? In particular, are there recurrent patterns in how antagonistic requirements are achieved (e.g. reduced metabolism / survival)?
  • How are cellular resources re-allocated during growth arrest and what are the trade-offs governing this allocation?
  • Are growth-arrested populations homogeneous or are they driven by rare events in single cells?
  • What are the different types of slow growth and growth arrest?
  • What information can be learned from transitions into and out of growth arrest to understand dynamics during growth arrest?
  • What are the determinants of growth resumption?
  • How do slow- and non-growing cells become insensitive to antibiotic treatments?