Figure 1.

Schematic model, strain background, and experimental settings

(A) A simplified view of the trade-off between growth and stress defense. Nutritional restriction affects the growth rate through metabolism and gene regulation, while the stress response and growth compete for limited resources.

(B) Schematics of the process of monitoring target protein dynamics (with fluorescent protein fusions) and the cell cycle (with the Mcm-mCherry. system) in single cells.

(C) Design of the microfluidic device. The chip consists of four identical units, each with six independent flow channels. The yellow part of a zoomed-in typical unit is the observation area, where yeast cells are fixed under a micropillar. Yeast cells were cultured independently under different glucose conditions for 8 hours and then exposed to hyperosmotic stress (0.8 M KCl).

(D) Time-lapse microscopy images of yeast cells in response to 0.8 M KCl, which was added at the 3 h time point under different culture conditions. The GFP channel indicated the osmotic-induced protein GPP1-GFP, and the mCherry channel indicated the cell cycle marker Mcm-mCherry. The scale bar is 5 μm.

(E) Examples of traces of individual cells. The left panel shows the rich-glucose condition (2%), the middle panel shows the low-glucose (0.1%) condition, and the right panel shows the poor-glucose (0.02%) condition. Highlighted are the cells with the maximum expression of Gpp1 as the population median. The numbers of cells under the 2%, 0.1%, and 0.02% glucose conditions were 29, 33, and 35, respectively.

(F) Time sequence of the cell cycle marker Mcm-mCherry. in typical cells, and the Gpp1 production rate was at the median of the population (highlighted in E).