Abstract
The successful modulation of phenotype is essential for the colonisation and proliferation of bacteria within the complex ecosystem of the gastrointestinal tract. To accomplish this, bacteria obtain and respond to information from the environment. One important parameter is the other bacteria present. The ability to correctly sense self, and also others, must therefore be advantageous for the control of mass action processes by the bacterial population. Within the gut ecosystem that may include processes involved in colonisation including those determining biofilm formation, pathogenicity, dispersal and DNA transfer. The ability to sense other bacteria may have important consequences for competitive and nutritional strategies controlling for example, entry into stationary phase, dispersal and the production of antimicrobial compounds. The ability to interfere with the signalling of bacteria will determine the fitness of the given organism to survive in the gut and may also have therapeutic potential.