Determination of elemental distribution and evaluation of elemental concentration in single Saccharomyces cerevisiae cells using single cell-inductively coupled plasma-mass spectrometry.

Abstract

Single-cell analysis using inductively coupled plasma mass spectrometry (SC-ICP-MS) is a method to obtain qualitative and quantitative information of the elemental content and distribution of single cells. Six intrinsic target elements were analyzed in yeast cells at different cell growth phases cultured in medium with different phosphorus concentrations (0, 7, 14\xa0mM) to study its effect on cell growth and composition. SC-ICP-MS results were compared to those obtained by the acid digestion and the average ratio was 0.81. The limits of detection of this method were 0.08, 2.54, 12.5, 0.02, 0.02 and 0.08 fg/cell for Mg, P, K, Mn, Cu and Zn, respectively. During the exponential growth phase, the cells exhibited higher elemental contents, wider distribution for most elements and larger cell size in comparison to the stationary growth phase. Phosphorus-free conditions reduced the average P content in single cells of stationary growth phase from 650 to 80 fg. Phosphorus deficiency led to decreasing intracellular concentrations not only of P, but also of K, Cu, and to increasing Zn concentration after 48\xa0h. Mg maintained its concentration at approximate 0.11 fg μm-3 and did not change significantly under the three investigated conditions after 48\xa0h. Accordingly, Mg content was successfully used to estimate the intracellular concentration of other intrinsic elements in single yeast cells. SC-ICP-MS is suited to determine target elements in single yeast cells, allows the study of heterogeneity of cell composition and effects of stressors on the elemental content, distribution and concentrations of intrinsic elements.