Determination of Acyl Homoserine Lactone and Tetramic Acid Concentrations in Biological Samples

Within environmental communities, there is a constant struggle for survival, as nutrients are often limited. In response, bacteria have developed elaborate methods to deal with competitors. One such mechanism is the coordination of behaviors and function via the exchange of small chemical signals in a process known as quorum sensing. This process is especially prominent in the pathogenicity of Pseudomonas aeruginosa , an opportunistic human pathogen that forms sessile communities known as biofilms. These biofilms play an important role in the lifestyle of P. aeruginosa , either in their natural environment or during establishment and maintenance of infection in human hosts; thus, they often have grievous effects on human health. As such, a method for the detection of these QS signals may provide insights into the pathogenicity and survival of P. aeruginosa . In this chapter, we present a method for the extraction and quantitation of the P. aeruginosa QS signal N -3-oxo-dodecanoyl-homoserine lactone, and its rearranged tetramic acid product, C₁₂ -TA, which itself has implications as a survival tactic used by P. aeruginosa .