The Effects of Altering Autoinducer-2 Concentration on Transfer Efficiencies of the F and RPI Plasmids to the Quorum Sensing Recipient Escherichia coli Strain AB1157

Many strains of bacteria constitutively produce and secrete autoinducers that allow populations to coordinate their behavior based on cell density. Previous research has shown that autoinducers are capable of up-regulating the expression of certain genes, outer membrane receptors, which are known to function in bacterial conjugation. Escherichia coli strain AB1157 is known to produce and respond to autoinducer-2 (AI-2). The purpose of this investigation was to examine the relationship between conjugation efficiency and increasing concentrations of AI-2. In this study we report a positive correlation between the conjugation efficiency of RP1 to AB1157 and increasing concentrations of AI-2, from 0% to 20% (v/v). This evidence supports the hypothesis that AI-2 provides a positive regulatory role in bacterial conjugation.