Modelling Vibrio fischeri’s behaviour Using P Systems

Abstract

Quorum sensing is a cell density dependent gene regulation system that allows an entire population of bacterial cells to communicate in order to regulate the expression of certain or specific genes in a coordinated way depending on the size of the population. In this paper we present a model of the Quorum Sensing System in Vibrio fischeri using a variant of membrane systems called P systems. In this framework each bacterium and the environment are represented by membranes and the rules are applied according to probabilities computed using mass action law. This approach allows us to examine the individual behaviour of each bacterium as an agent as well as the behaviour of the colony as a whole and the processes of swarming and recruitment. Our simulations show that at low cell densities the bacteria remain dark while at high cell densities some bacteria start to produce light and a recruitment process takes place that makes the whole colony of bacteria to emit light. The above mentioned behaviour of our in silico bacteria maps well experiments and in vitro observations.