Metabolites and Proteins of Pseudomonas aeruginosa Biofilms

Bacterial biofilms are structurally and physiologically heterogenous communities of bacterial cells embedded in a self-produced extracellular polymeric substance. Current studies aim to understand the dynamics and responses of biofilms to various environmental factors especially since they play a pathogenic role in chronic wounds preventing wound healing. One approach to studying biofilms is through mass spectrometry (MS), a versatile analytical tool that provides qualitative and quantitative analyses and has been utilized for various biological applications such as biofilms. This dissertation describes the development of two mass spectrometric strategies for the detection of metabolites and proteins from a biofilm-forming Pseudomonas aeruginosa chronic wound clinical isolate. Two laser-based ion sources were implemented: atmospheric pressure matrix assisted laser desorption ionization MS and laser diode thermal desorption atmospheric pressure photoionization MS. The latter was demonstrated for the analysis of metabolites within intact P. aeruginosa biofilms. A bottom-up proteomic workflow for planktonic and biofilm cultures was also developed based upon liquid chromatography tandem mass spectrometry. This proteomic protocol was then used to compare the effect of lactate nutrient supplementation on cellular metabolism in both P. aeruginosa planktonic and biofilm cultures.