Section: New Results

Qualitative modeling of gene regulatory networks in food-borne pathogens

Bacteria are able to respond to a variety of environmental stresses, which poses food safety problems when these bacteria are food-borne pathogens. Addition of salt, one of the most ancient and common way of preserving food, subjects the bacteria to an osmotic stress to which some may survive. However, the molecular mechanisms of adaptation in food-born pathogens are largely unknown. As a first step towards better understanding these adaptation processes on the molecular level, Delphine Ropers and Aline Métris from the Institute for Food Research in Norwich (UK), invited researcher in IBIS last year, developed a qualitative model of the osmotic stress response in the model bacterium Escherichia coli. The qualitative dynamics of the network has been analyzed using the tool Genetic Network Analyzer (GNA) . The model has allowed to reproduce the behavior of E. coli cells adapting to an osmotic stress by including the regulatory mechanisms involved in the process. This work has been published in the International Journal of Food Microbiology [21]. It paves the way to modelling stress responses of other foodborne pathogens like Salmonella to stresses relevant for the food industry, for which much less is known.