<p>The comprehensive analysis of intact lipids (called lipidomics) can provide information about the presence of microbial communities in an ecosystem and assist in understanding the biogeochemistry in that system. In previous work we had developed a method to determine the profiles of eight phospholipid classes in a soil microorganism by direct-infusion electrospray mass spectroscopy using tandem mass spectrometry. The work done in this study encompasses first the optimization of previous methodology for use with water and sediment samples containing low concentration of phospholipids and large amounts of organic contaminants and secondly the application of this method to the analysis of phospholipids within composite tailings and recycled process water using a triple quadrupole mass spectrometer to determine the intact lipids in the bacterial community. The results are presented illustrating the phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipids present in composite tailing samples and recycled process water. This thesis begins with the optimization of a direct infusion mass spectrometry method, which allowed the analysis of intact phospholipids within both water and sediment samples. This method allows for high through-put analysis using both the separation afforded by neutral loss and precursor ion scanning modes and a database containing all possible adduct masses to identify and quantify unknown phospholipids. This method was then applied to water and sediment samples obtained from the Syncrude Sandhill Fen composite tailings site. This analysis discovered multiple differences within the water samples attributed to changes both in well temperature and the ongoing reclamation projects resulting in the change in phospholipid profiles. This thesis also outlines the shortcomings of the direct infusion lipidomics method when used for the analysis of complex samples such as composite tailings sediment samples. In summary, this thesis has demonstrated that direct infusion lipidomics can be successfully applied to the analysis of water samples and yield statistically significant differences within the microbial lipidome.</p> / Master of Science (MSc)

Mass spectrometry is a versatile, sensitive and fast technique with which to probe biophysical properties in biological systems and one of the most important analytical tools in the multidisciplinary field of proteomics. The study of nativestate proteins and their complexes in the gas-phase is well established and direct infusion electrospray ionisation mass spectrometry (DI-ESI-MS) techniques are becoming increasingly popular as a tool for screening and determining quantitative information on protein-protein and protein-ligand interactions. However, complexes retained by ESI-MS are not always representative of those in solution and care must be taken in interpreting purely gas-phase results. This thesis details modification and advancement of solution phase techniques devised by Gross et al. utilising ESI-MS and Fitzgerald et al. applying matrix assisted laser desorption ionisation (MALDI)-MS termed PLIMSTEX (protein-ligand interactions by mass spectrometry, titration and hydrogen-deuterium-exchange)[1] and SUPREX (Stability of unpurified proteins from rates of H/D exchange)[2] to quantify these interactions with regards to high throughput analysis. The first part of this thesis describes the different developmental stages of the devised HPLC-front ends and their optimisation with myoglobin and insulin. The successfully developed HPLC-front end in conjunction with PLIMSTEX and SUPREX and ESI-MS then gets tested with self expressed and purified cyclophilin A(CypA)- cyclosporin A (CsA) system, followed by a test screen with potential CypA binding ligands. Dissociation constants (Kd’s) within one order of magnitude to reported values are determined. In the third part of this thesis the application of the devised ESI-SUPREX methodology has been applied to anterior gradient 2 (AGr2) and the factor H complement control proteins module 19-20 (fH19-20) exhibiting binding potential to a taggedhexapeptide and a synthetic pentasaccharide, respectively, resulting in thermodynamical data for these protein-ligand interactions. For the AGr2 system another dimension of investigation has been added by temperature controlling the devised ESI-SUPREX approach, revealing a phase transition in the protein at higher temperatures. The final part of this thesis describes the application of the ESI-SUPREX methodology to probe folding properties of CypA in the presence of the self expressed and purified E. coli chaperonin groEL. Thereby the denaturing properties of groEL have been emphasised along with the stabilisation of a denatured CypA species.