Inhibition of N-acyl-homoserine lactone quorum sensing
Quorum-sensing amongst Gram-negative bacteria is an important method of intercellular communication required for conveying information about population density. The extracellular accumulation of the signal molecule involved, N-acyl homoserine lactone (AHL), leading to increases in internal physiological concentration, allows phenotypic switching to occur that is beneficial to the bacterial population. In our laboratory, analysis of the effect of AHL on phenotype currently involves creating null mutants unable to produce AHL, then reintroducing the signal molecule exogenously. With the increasing number of human, animal and plant pathogens utilising AHL quorum-sensing for regulating viirulence, AHLs have become prime targets for anti-infective therapy and crop-protection. The research described here has investigated methods of inhibition of quorum-sensing through the AHL signal molecule. These include the application of extremes of temperature and pH, and isolation and characterisation of the first recombinant human antibody fragment specific to AHLs from a naive phage display library, which could be used to examine cell-cell communication without the need for gene manipulation.