Cellular and molecular consequences of reduced cell water content

Cell volumes, viability, ultrastructure, and metabolism have been studied in mouse L cells at reduced water contents. Dehydration was achieved by addition of sorbitol to the incubation medium at concentrations of 0.15, 0.3, and 0.6 m. In 0.3 m sorbitol, cell volume was reduced to about 35% of the initial control level and cell ultrastructure was markedly altered. Nevertheless, such cells retained viability and their metabolism was much the same as that of control cells, evaluated by [U-14C]glucose. Except for a lesser volume reduction, cells in 0.15 m sorbitol behaved similarly. However, when placed in 0.6 m sorbitol the cells exhibited quantitative and qualitative differences in their metabolism compared with controls, and grew very poorly or not at all. Their ultrastructure was not obviously different from cells in 0.3 m sorbitol although cell volume was slightly reduced. These results are considered in the context of different conceptions of the properties and metabolic activities of the aqueous intracellular compartments (cytosol, nucleoplasm, and interiors of cytoplasmic membrane-bound-organelles). We interpret the data as additional evidence for the existence of extensive spatial organization of enzyme and the pathways they catalyze in the aqueous compartments. On this basis it is also suggested that at least part of the damage that occurs in severely dehydrated mammalian cells could result from the irreversible disruption of this organization and loss of metabolic control. We speculate about the evolutionary involvement of intracellular water and how it might have participated in the development of structure and function in contemporary cells.