title: [Oscillations in population densities of the bacterial prey-predator couple Escherichia coli-Bdellovibrio bacteriovorus: experimental study and theoretical model].
abstract: Oscillations in population densities in the bacterial predator-prey Bdellovibrio bacteriovorus-Escherichia coli system were investigated both experimentally and theoretically. Experimental conditions for observing (damped) oscillations were first determined in a closed system and then used in an open system, i.e. in a chemostat, when an adequate flux of nutritive medium was added. The experimentally observed oscillations were always unstable with poorly reproducible amplitude and period. A theoretical model was used in order to explain this behaviour. It was first presented and satisfactorily tested for the same bacterial couple operating in a closed system, and allowed an experimental determination of its kinetic parameters. When adapted to open system conditions, it yielded computer-simulations which showed oscillations of the population densities in good agreement with those experimentally observed. It also showed that stable oscillations were not possible, the only "focus" in the predator-prey-density plane being an unstable one with no surrounding limit cycle.
mesh_terms: D001501:Bdellovibrio / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D003470:Culture Media; D004926:Escherichia coli / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D013997:Time Factors
chemical_list: D003470:Culture Media
vernacular_title: Oscillations des densités de population du couple bactérien proie-prédateur escherichia coli-Bdellovibrio bacteriovorus: étude expérimentale et modèle théorique.