Studio proteico della parete cellulare di saccharomyces cerevisiae in condizioni di stress

Wine yeasts during alcoholic fermentation and ageing are subjected to several stresses and cell wall is the first compartment involved in the stress response. This PhD thesis deals with the study of the variation in cell wall protein composition in 6 different strains of Saccharomyces cerevisiae (flor/no flor wine strains and laboratory strains). We developed a mass spectrometric method (ESI-Q-TOF) to identify CWPs, unbiased with respect to the covalent linkages to the cell wall carbohydrates. We analysed cell wall protein (CWPs) composition in the studied strains in three different conditions: logarithmic phase and stationary phase in a rich fermenting medium and a flor phase in a minimal medium added with ethanol. In all conditions tested we identified overlapping sets of 20 different proteins. Among them 14 are predicted GPI-modified proteins and 6 are ASL proteins. We choose 5 interesting GPI-proteins and we used qRT-PCR to study related genes in order to identify variation in gene expressions related to different phases.