Filamentous growth in Saccharomyces cerevisiae is a stress response commonly induced under nutrient deprivation and by certain alcohols. It is a compound phenotype characterized by pseudohyphal growth, invasion and a shift to more polarized budding. Previous methods have not allowed the time-resolved determination of filamentous growth. Here we present a new method for budding pattern characterization that enables the measurement of filamentous growth and metabolite concentration during yeast cell growth at precise time intervals. By combining chemical cell immobilization and single-cell imaging using an oCelloScope (TM), this method provides more accurate budding pattern classification compared with previous methods. The applications of the method include, for example, investigation of quorum sensing-controlled yeast filamentous growth and metabolism under stress and identification of toxic metabolites.

METHOD SUMMARY An accurate method for yeast budding pattern determination is presented using a combination of oCelloScope (TM) imaging, chemical cell immobilization and proton (H-1) NMR analysis. This new method furthermore enables the measurement of time-resolved metabolite concentration in parallel with monitoring yeast budding patterns.