POTTS, Malcolm; Virginia Tech, Blacksburg: The Desiccome: Humble Beginnings

The loss of water from cells is a stress that was likely imposed very early in evolution. An understanding of the sensitivity or tolerance of cells to depletion of intracellular water is relevant to the study of quiescence, longevity and aging, because one consequence of air-drying is full metabolic arrest, sometimes for extended periods. When considering the adaptation of cells to physiological extremes of pH, temperature or pressure, it is generally assumed that evolution is driven toward optimum function rather than maximum stability. However, adaptation to desiccation has the singular and crucial distinction that dried cells do not grow, and the time the cell is dried may represent the greater part of the life (the time the cell remains viable) of that cell and its component macromolecules. Is a consideration of �function� relevant in the context of desiccated cells? The response of prokaryotic cells to desiccation, and the mechanisms they employ to tolerate this stress at the level of the genome and proteome, are considered using the cyanobacteria Nostoc commune, Gloeocapsa alpina and Chroococcidiopsis spp., as model systems. The data are compared and contrasted with the responses of the transcriptomes of yeast and human to drying in air