Effect of Temperature on Glycerol Retention in the Halotolerant Algae Dunaliella and Asteromonas

Abstract

Algae of the genera Dunaliella and Asteromonas can maintain extremely high concentration gradients (>10(4)) of glycerol between the intracellular space and the medium. This unique ability is highly temperature-dependent. Treating the algae for several minutes at temperatures exceeding 60 C causes complete release of all the internally held glycerol; 50% release occurs around 50 C, but essentially none is released below 40 C. A similar behavior was observed in several species of Dunaliella, and one of Asteromonas and is independent of the salt concentration of the medium. The underlying mechanism may involve a temperature-dependent conformational transition of a component of the cellular membrane which is essential for glycerol impermeability.