The unsuspected ability of the human cell to oxygenate itself. Applications in cell biology

The transport of water across epithelia has remained an enigma ever since it was discovered over 200 years ago that water was transported across the isolated small intestine in the absence of osmotic and hydrostatic pressure gradients. While it is accepted that water transport is linked to solute transport, the actual mechanisms are not well understood. The movement of water and small molecules across the selectively permeable membranes of mammalian cells is a fundamental concept of physiology, which has not been resolved. Cell membranes are complexes multicomponent structures, related to many basic cellular processes, such as substance transporting, energy conversion, signal transduction, mechano-sensing, cell adhesion and so on. However, cell membranes have long been difficult to study at a single-molecule level due to their complex and dynamic properties. Cell membranes are highly permeable to water, and water follows osmotic gradients. Osmotic gradients are generated when the concentration of solutes, such as sodium, is higher on one side of the membrane than the other. But the mechanisms described are too mild to explain the control of the dynamics of the enormous amount of water that passes through the cell every minute. And since the control of the movement of water as well as solutes is fundamental for life, our observation about the presence of molecules capable of transforming the power of light into chemical energy, through the dissociation of intracellular water, as in plants, and this inside eukaryotic cells, marks a before and after in the knowledge about the mysteries of water movement and solutes inside cells.