7. 熱ショック処理による酵母細胞の二次ストレス耐性(平成3年度第37回凍結及び乾燥研究会研究報告)

概要

論文の詳細を見る
Cells of Saccharomyces cerevisiae were subjected to heat shock treatment at 43℃ for 30-120min, followed by secondary stress treatments and then their colony forming units (CFU) were analyzed. Enhancements of more than two orders of magnitude were observed in the secondary stress tolerances against freeze-thawing, thermal (at 50℃ ), and hydrostatic pressure (at 150 MPa) treatments assessed by the CFU. NMR investigations on the cells subjected to the heat shock treatment revealed that the treatment promoted the structuralization of intracellular water and decreased the membrane fluidity. Addition of water-structuralizing salt, i.e., Na_2SO_4, induced significant decrease in the fluidity of vesicles prepared with the phospholipids which were extracted from the yeast cells. Structural breakage of the cell was observed electronmicroscopically after the physical stresses, however, the heat shock treatment protected the membranes from the breakage. Consequently, the heat shock response promoted cell water structuralization which stabilized the membrane structure or decreased its fluidity, and as the results improved the secondary stress tolerance.
1991-10-20