High Pressure Bioscience : Basic Concepts, Applications and Frontiers

Iwahashi, Hitoshi, Hitoshi Iwahashi

Hydrostatic pressure is one of the physical factors affecting cellular physiology. Hydrostatic pressure of a few tens MPa decreases the growth rate and a few hundred MPa decreases the cellular viability. To find clues to understand how such pressure effects on living cells relating to damages on protein molecules, we employed yeast DNA microarrays and analyzed genome-wide gene-expression levels in yeast cells which have been exposed to different levels of hydrostatic pressure. These include the cells temporarily adapted to a high pressure (from 0.1 to 30 MPa) and to a low pressure (from 30 to 0.1 MPa). These conditions cause yeast cells decreases of growth rate. We also analyzed gene expression profiles from the cells recovering after the sublethal pressure treatment at 180 MPa at 4 °C for 0 min and at 40 MPa at 4 °C for 16 h. These conditions cause yeast cells decreases of cellular viability. The activated genes by the temporary adaptations to both of the high pressure and the low pressure suggest that proteins related to membrane biosynthesis and cell wall biosynthesis can be crucial targets of pressure-induced damages, whereas the activated genes under recovering conditions after exposure to the sublethal high pressure suggest that proteasome activity and proteins localized in endoplasmic reticulum can be the crucial targets or the essential factors to survive.