Osmotic stress refers to the physiological effects of changes in osmotic pressure on cells and organisms. This can occur when cells are exposed to high or low concentrations of solutes in their external environment, leading to water movement into or out of the cell to maintain osmotic balance. Osmotic stress can have a range of effects on cellular processes, including alterations in protein folding, enzyme activity, and cell membrane integrity. Understanding how cells respond to osmotic stress is important for a variety of fields, including microbiology, physiology, and biotechnology. Research in osmotic stress often involves studying the mechanisms by which cells sense and respond to changes in osmolarity and developing strategies to improve cell survival under osmotic stress conditions.