Beneficial Effects of Calcium Chloride on Two Cyanobacterial Species under Sodium Chloride Stress

EXPOSURE of Anabaena constricta and Nostoc linckia to 0.2M NaCl induced a significant decrease in cell number, dry weight and pigments (chlorophyll “a” and carotenoids,). Also, there was a decrease in glucose, protein and nitrogen contents. The addition of two different concentrations of CaCl2 (40 and 60 mM) to the salinized cultures with both organisms induced a significant increase in growth and metabolites activities. Protein electrophoretic patterns of the culture of A. constricta exposed to 0.2 M NaCl showed the disappearance of one protein band at 77 KDa and appearance of two protein bands at 171 and 70 KDa. The addition of 40 mM CaCl2 to the salinized culture of A.constricta showed disappearance of one protein at 77 KDa and appearance of three protein bands at 17, 61 and 162 KDa, while addition of 60 mM CaCl2 to salinized culture caused appearance of three protein bands at 18, 58 and 138 KDa as compared with control (salinized culture of 0.2 M NaCl alone). Addition of 0.2 M NaCl to culture of N.linckia and addition of 40 mM or 60 mM CaCl2 to salinized culture showed no change of protein patterns as compared with control (culture without NaCl) but differed in the percentage of intensity of proteins