Intracellular Macromolecules in Cell Volume Control and Methods of Their Quantification.

The traditional theories of cell volume regulation focus on monovalent ions and small organic osmolytes. The main subject of this review is macromolecular content of the cell and its role in cell volume. We start by reviewing general information about cellular macromolecules and present some quantitative relationships. Next, we review a wide range of methods for measuring intracellular macromolecular concentration and related parameters; in particular, a large section is devoted to the so-called quantitative phase imaging methods based on transmission light microscopy. In the last part, we discuss three specific biological examples where quantitative analysis of macromolecular concentrations is expected to generate valuable insights into biological processes: the biology of organelles, long-term cell volume maintenance and apoptotic volume decrease.