ACCUMULATION OF TREHALOSE AS A COMPATIBLE SOLUTE UNDER OSMOTIC-STRESSIN EUGLENA-GRACILIS-Z

The photosynthetic protozoon Euglena gracilis, accumulated a large amo unt of trehalose in the cells under salt or osmotic stresses. Radioact ivity of [C-14] paramylon, a beta-1,3-polyglucan which was stored in t he cells of E. gracilis, was degraded rapidly and this radioactivity w as almost stoichiometrically incorporated into trehalose. The intercon version of trehalose from paramylon by salt or osmotic stresses was de pendent on the concentrations or osmotic pressures, suggesting that E. gracilis accumulate trehalose as an osmoprotectant. After the removal of salt or osmotic stresses, trehalose was gradually degraded, howeve r, it was not converted into paramylon.