The yeast osmostress response is carbon source dependent

Abstract

Adaptation to altered osmotic conditions is a fundamental property of living cells and has been studied in detail in the yeast Saccharomyces cerevisiae. Yeast cells accumulate glycerol as compatible solute, controlled at different levels by the High Osmolarity Glycerol (HOG) response pathway. Up to now, essentially all osmostress studies in yeast have been performed with glucose as carbon and energy source, which is metabolised by glycolysis with glycerol as a by-product. Here we investigated the response of yeast to osmotic stress when yeast is respiring ethanol as carbon and energy source. Remarkably, yeast cells do not accumulate glycerol under these conditions and it appears that trehalose may partly take over the role as compatible solute. The HOG pathway is activated in very much the same way as during growth on glucose and is also required for osmotic adaptation. Slower volume recovery was observed in ethanol-grown cells as compared to glucose-grown cells. Dependence on key regulators as well as the global gene expression profile were similar in many ways to those previously observed in glucose-grown cells. However, there are indications that cells re-arrange redox-metabolism when respiration is hampered under osmostress, a feature that could not be observed in glucose-grown cells.

Correlative single-molecule fluorescence barcoding of gene regulation in Saccharomyces cerevisiae

“…3A), the only nonfermentable substrate in our study. Indeed, multiple studies that involve ethanol-grown yeast cultures in minimal media, used either a YPE medium (a standard YPD with ethanol instead of glucose) or a glycerol-ethanol mixture [21][22][23][24]. However, we did not change the conditions to be consistent with our single-molecule experiments.…”

Kinetic models application on glycerol production from glucose by the marine yeast Candida orthopsilosis

“…Kinetics of carbon source effect on glycerol production by C. orthopsilosis HH52: Data presented in Figure 3 showed that C. orthopsilosis HH52 could accumulate glycerol at variable concentrations using different carbons, the reason could be that various carbon sources used in fermentation might exhibit different degrees of osmotic pressure on the yeast cells (Leandro et al, 2011). Glycerol synthesis is essential for yeast cells to recompense an osmotic stress which is carbon source dependent (Ansell, 1997;Babazadeh et al, 2017). The current study indicated that the monosaccharides hexoses such as glucose and fructose exhibit the highest glycerol production yield.…”

Ask yeast how to burn your fats: lessons learned from the metabolic adaptation to salt stress

“…Osmotolerance is lower upon growth on the less fermentable carbon source galactose accompanied by a reduced accumulation of glycerol (Vanacloig-Pedros et al 2015). Moreover, in the absence of a fermentable carbon source, yeast cells do no longer accumulate glycerol, and the adjustment of osmotic balance is further delayed (Babazadeh et al 2017). Taken together, we hypothesize that high salinity causes a nutritional stress in yeast cells, which is counteracted by different metabolic adjustments.…”