EFFECT OF CA2+ ON THE RETENTION OF GLYCEROL AND AMINO-ACIDS IN DUNALIELLA-TERTIOLECTA

When D. tertiolecta cells, previously incubated in a 0.5 kmol m(-3) NaCl medium with 1 mol m(-3) Ca2+, were transferred to an isotonic NaCl medium without Ca2+, the intracellular glycerol, as well as intracellular amino acids, was transiently lost to the medium within 30 min. The transient leakage of glycerol and amino acids was enhanced by the addition of EGTA (1 mol m(-3)), while the addition of SrCl2 (1 mol m(-3)) or polyamines such as spermidine (5 mol m(-3)) and spermine (5 mol m(-3)) restrained the leakage caused by the lack of external Ca2+ of intracellular glycerol and amino acids.