Analysis of cell wall mutants ofSaccharomyces cerevisiaeby pyrolysis mass spectrometry

The main constituents of the cell wall of Saccharomyces cerevisiae, i.e. β-1,3-glucan, β-1,6-glucan and mannan, could be distinguished by pyrolysis ammonia chemical ionization mass spectrometry or Py(CI)MS. Cell walls extracted with alkali, which removes the mannan fraction and part of the glucan from the cell wall, yielded mass spectra that differed clearly from nonextracted cell walls. Multivariate analysis of these spectra showed a shift from ‘mannan-like’ towards ‘glucan-like’ cell walls. Known cell wall mutants, such as mnn9 and kre1, were recognized by this technique. Py(CI)MS in combination with multivariate analysis of the spectra is therefore a useful tool for identifying and characterizing cell wall mutants in yeast.