ACCUMULATION OF MANNOSYLGLYCERATE AND DI-MYO-INOSITOL-PHOSPHATE BY PYROCOCCUS-FURIOUS IN RESPONSE TO SALINITY AND TEMPERATURE

C-13 and H-1 nuclear magnetic resonance spectroscopy was used to ident ify and quantify organic solutes accumulated by the hyperthermophilic archaeon Pyrococcus furiosus in response to temperature and salinity, Di-myo-inositol-phosphate and 2-O-beta-mannosylglycerate were the majo r organic solutes accumulated in these cells. The total intracellular organic solutes increased significantly in response either to an incre ase in temperature or to an increase in Salinity, but beta-mannosylgly cerate accumulated mainly at high salinities, whereas the concentratio n of di-myo-inositol-phosphate increased dramatically at supraoptimal growth temperatures, Glutamate was present at concentrations detectabl e by nuclear magnetic resonance only in cells grown in low salinity me dia, The intracellular levels of K+ are clearly dependent on the salin ity of the medium, and the concentrations of this cation are high enou gh to counterbalance the negative charges of beta-mannosyl-glycerate a nd di-myo-inositol-phosphate in the cell, The results presented here t ogether with those previously reported for Pyrococcus woesei (S, Schol z, J, Sonnenbichler, W, Schafer, and R, Hensel, FEBS Lett, 306:239-242 , 1992) Strongly support a role for di-myo-inositol-phosphate in therm oprotection.