Background

Yeast has been extensively used to study the ionic response after gene deletion, modification of the extracellular environment, or heterologous protein production for example. In this context, having methods to monitor the ionic status of yeast cells is of high interest. ICP-AES uses high-energy plasma from an inert gas like argon to burn analytes very rapidly. The color that is emitted from the analyte is indicative of the elements present, and the intensity of the spectral signal is indicative of the concentration of these elements. Compared with other techniques (for example spectrophotometric methods, atomic absorption spectrometry and atomic fluorescence spectrometry), ICP-AES is a multi-ion analysis method involving simple and fast procedure with relatively low detection limits (Dahlquist and Knoll, 1978). The method described here applies to concentration determination of Ba²⁺, Ca²⁺, Cd²⁺, Co²⁺, Cu²⁺, Fe²⁺, K⁺, Mg²⁺, Mn²⁺, Na⁺, Ni²⁺, and Zn²⁺, with the possibility of measurement of numerous cellular ionic concentrations from one 100 ml yeast culture (Eide et al., 2005; Thines et al., 2018). While this protocol has been tested in our laboratory for these twelve ions, this protocol could most likely be transferred to other elements. Besides, although described here for whole-cell measurement of the yeast ionic content, this method could be transferred to other cell types or to isolated organelles by fractionation on sucrose gradient for instance.