Fluorescent measurement of the intracellular pH during sporulation of Saccharomyces cerevisiae

This work reports the intracellular pH (pH(i)) dynamics of Saccharomyces cerevisiae cells in sporulation medium. Cells loaded with the pH-sensitive dye carboxy-seminaphthorhodafluor-1 (C.SNARF-1) exhibited an alkalization of the pH(i) following the extracellular pH during sporulation in the absence of buffer and almost no change in pH(i) or ΔpH when sporulation was carried out in buffered medium. The results indicate that the pH gradient does not appear to be directly involved in the regulation of acetate uptake during sporulation. However, the alkalization of pH(i) by eliciting a decrease in metabolic fluxes could account for a lower demand for acetate.