Effects of Growth-Permissive Pressures on the Physiology ofSaccharomyces cerevisiae

Abstract

This chapter discusses the recent advances in explorations of the effects of growth-permissive pressures on the growth and physiology of Saccharomyces cerevisiae. The simplest and most convenient system for high-pressure cultivation of S. cerevisiae is a pressure syringe, generally made of stainless steel or titanium, with a diameter of approximately 10 cm, length of 30 cm, and internal volume of about 500 ml, which can typically be used at pressures up to 200 MPa. Tryptophan uptake in S. cerevisiae is mediated by high-affinity-type tryptophan permease Tat2 and low-affinity-type tryptophan permease Tat1. The high-pressure-growth (HPG) mutants are classified into four semidominant linkage groups designated HPG1, HPG2, HPG3, and HPG4. It is worthwhile to examine the isolation of HPG mutants from nutrient-prototrophic strains. Hydrostatic pressure causes intracellular acidification in a manner analogous to that of weak acid treatment. Therefore, intracellular acidification may cause HSP30 induction with hydrostatic pressure. Organic osmolytes such as amino acids and their derivatives, polyols, sugars, and methylamines are used by the cells of water-stressed organisms to maintain cell volume. By exploiting genomic information and powerful tools for genetic manipulation, the effects of hydrostatic pressure on S. cerevisiae have been analyzed by investigators in a broad range of experimental fields, including physiology, biochemistry, molecular biology, and food sciences. Using hydrostatic pressure as a parameter, piezophysiology can uncover novel biological phenomena that are accompanied by large volume changes, not only in S. cerevisiae but also in many other organisms.