THE ROLE OF TREHALOSE IN CELL STRESS

Water is usually thought to be required for the living state, but many organisms can withstand anhydrobiosis when essentially all of their b ody water has been removed. The mechanisms for survival to this kind o f stress could be similar in microbes, plants and animals. One common feature is the accumulation of sugars by anhydrobiotic organisms. Treh alose, which is one of the most effective saccharides in preventing ph ase transition events in the lipid bilayer, is accumulated by anhydrob iotic organisms in large amounts. It lowers membrane phase transitions in dry yeast cells, thus preventing imbibitional damages when cells a re rehydrated. Yeast cells have a trehalose carrier in the plasma memb rane which endows them with the ability to protect both sides of the m embrane. Kinetic analysis of the trehalose transport activity in Sacch aromyces cerevisiae cells revealed the existence of a multicomponent s ystem with a constitutive low-affinity uptake component and a high-aff inity H+-trehalose symporter regulated by glucose repression.