Matrix-assisted Laser-desorption/Ionization Time-of-flight Mass Spectrometry and its Application to the Analysis of Fungal Spores

Abstract

Although much research has been completed on the application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI-MS) to the analysis of bacteria, no definitive studies have yet been performed on the analysis of fungi. Preliminary studies on the application of the MALDI-MS methodology, previously developed for the analysis of bacteria, to the analysis of intact fungal spores are described here. MALDI-MS and electrospray mass Spectrometry enable the analysis of high molecular-weight proteins, glycoproteins, oligosaccharides and oligonucleotides. Using MALDI-MS with bacteria has enabled the production of ‘fingerprints» of the intact cells; the ions observed are associated with the proteinaceous components of the cell wall. This study reports the adaptation of this technique to the direct analysis of fungal cells. Because of the large amount of carbohydrate in the fungal cell wall, the ions observed in the mass spectrometric experiments might be of carbohydrate origin. Penicillium spp., Scytalidium dimidiatum and Trichophyton rubrum have been studied in this preliminary investigation and all furnish individually distinctive spectra which seem to provide a profile of the cellular material with discrete peaks being observed over the mass range 2 to 13 kDa. The spectra obtained are reproducible within the method used but, as shown in our previous studies on bacteria, washing might selectively release components from the fungal cell wall.