When cells proliferate in confined space, they build up a compressive, growth-induced, mechanical stress, through the accumulation of osmolytes with limited cell volume expansion. This limited cell expansion also favors the increase of intracellular density through continued biomass accumulation. Osmotic stresses allow the control cell volume by adding extracellular osmolytes, which result in water efflux, and increased intracellular concentration. Cells actively regulate their osmolarity by activating a signaling kinase. The purpose of this internship is to investigate what happens to intracellular density and kinase activity when the rate of osmotic stress is changed from acute stress (instantaneous, to the scale of the cells) down to slow increase, at the rate of cell volume growth.