Imaging mass spectrometry applied to the study of metabolites synthesized during microbial interactions and pathogen-host interactions

Identifier:  TFG:2974

Handle: https://hdl.handle.net/20.500.11797/TFG2974

Authors:  Les Bueno, Laura

Abstract:
Imaging mass spectrometry (IMS) is an analytical technique based on the ionization and detection of compounds present in a sample. It allows to determine the molecular mass, the spatial distribution and the relative abundance of the compounds, generating a mass spectrum of each measurement point and an ion image of each detected compound. In this work, IMS is presented as a powerful tool for the study of interactions between microorganisms, and pathogenic microorganisms during the colonization phase of their host. To this end, several relevant examples are highlighted where the utility of matrix-assisted desorption / ionization (MALDI) imaging spectrometry in microbiological investigations is demonstrated. To corroborate the efficacy of this technique, the data obtained from a culture of the bacterium Pseudomonas tolaasii and a co-culture of it with Mycetocola tolaasinivorans, both originally isolated from mushrooms, are analyzed and discussed. The results demonstrate that MALDI-IMS is a rapid hypothesis generator that allows to putatively identify compounds synthesized by P. tolaasii, such as tolaasin and pseudodesmin, among others. Furthermore, thanks to this analysis, it is speculated that M. tolaasinivorans is capable of linearizing tolaasin, a virulence factor in a mushroom disease, opening the way for future research into its detoxification mechanism. In addition, MALDI-IMS is compared to surface-assisted laser desorption ionization (SALDI) using a nanostructured silicon substrate coated with gold nanoparticles. SALDI-IMS can overcome some of the disadvantages of MALDI, especially the substitution of the organic matrix, therefore both techniques could complement each other.