<xhtml:span xmlns:xhtml="http://www.w3.org/1999/xhtml" xml:lang="en">Takeo Miki, Ph.D.&#160; Alteration in fatty acid composition by short term hypertonic stress of GPD gene disrupted yeast. </xhtml:span>

Saccharomyces cerevisiae, commonly referred to as yeast, is a staple in the fermentation industry. During fermentation, yeast encounters various forms of stress, including inadequate nitrogen sources, suboptimal pH levels, elevated temperatures, and hyperosmotic conditions derived from the fermentation substrate. Osmotic stress causes physical damage to cells. A model was presented in which yeast rapidly synthesizes glycerol as a compatible solute in response to hypertonic shock and adapts to changes in the external environment. However, given the membrane permeability of glycerol, some aspects of the osmotic adaptation mechanism in yeast are not well understood. Considering the physical effects of osmotic stress, the cell membrane was expected to be the first to suffer severe damage. Furthermore, this damage is thought to have a critical impact on intercellular organ membranes. Despite the importance of cell membranes, there is little information on the relationship between membrane robustness and osmotic resistance. The objective of this study was to ascertain the correlation between fluctuations in fatty acid composition and the yeast's capacity to withstand short-term hypertonic shock using GPD gene knockout strains as an osmotically stress-damped yeast. The result, S. cerevisiae OCM-2 ΔGPD1 strain exhibited weaker osmotic stress resistance than the parent strain. OCM-2 ΔGPD1 markedly increased C18:1 expression under osmotic stress. Meanwhile, OLE1 mRNA reduction was observed in all strains by osmotic stress, and it was estimated that the C18:1 increase in OCM-2 ΔGPD1 was derived from the intracellular elongation of C16:1.