Therefore, unlike magnesium, an increase of resistance to dehydration–rehydration treatments of stationary-phase growth cells appears to be correlated with calcium bioavailability. We attempted to reveal whether the dehydration–rehydration stability

of yeast cells taken from stationary growth phases can be increased by preincubating these cells in water with elevated levels of magnesium. Cells were grown with 0.15 g L−1 of Mg2+ as well as without magnesium. In these experiments, yeast cells that were grown in the medium without magnesium were subsequently incubated with 0.15 g L−1 of Mg2+ or with 0.3 g L−1 of Mg2+ and were not incubated in the solution without Mg2+ (indicated as ‘−’ in the Table 1). Correspondingly, yeast cells that were grown in media with 0.15 g L−1 of Mg2+ were incubated without magnesium or with 0.3 g L−1 of Mg2+ and were not incubated in the solution with 0.15 g L−1 of http://www.selleckchem.com/ATM.html Mg2+ (indicated as ‘−’ in the Table 1). Results, shown in the Table 1, show that when yeast cells were grown in media without addition of magnesium, their subsequent incubation in water containing Mg2+

ions led to an increase of cellular resistance to dehydration–rehydration. RO4929097 molecular weight In this case, the increase of Mg2+ availability during preincubation was accompanied by an increase of cell resistance. If yeast was grown in molasses with 0.15 g L−1of Mg2+ their subsequent incubation in water without magnesium or with a higher concentration of magnesium (0.30 g L−1) resulted in the decrease of cell resistance to dehydration–rehydration when compared with cultures without preincubation. Taken together, it is clear that magnesium availability, either in nutrient medium at the culture growth stage or in incubation media, is very important and plays a role in yeast anhydrobiosis phenomena. It was shown previously that one of the main factors that determined the resistance of yeast cells to dehydration–rehydration

was the maintenance of the structural integrity Bay 11-7085 of the plasma membrane (Rapoport et al., 1995; Simonin et al., 2007b). Therefore, we studied the effects of Mg2+ and Ca2+ supplementations on yeast membrane stability. We used a test on the changes of the viability of dry yeast cells upon slow gradual rehydration in water vapour. This test is based on a hypothesis linking changes in membrane molecular organization during dehydration–rehydration of cells (Beker & Rapoport, 1987; Crowe et al., 1987). In accordance with this model, cell dehydration results in the increase of membrane phospholipid temperature of phase transition (Tm) from a gel to a liquid-crystalline phase. Correspondingly, when such ‘dry’ phospholipids are transferred into water at room temperatures, they undergo a phase transition from a gel to a liquid-crystalline phase.