Biochemical studies on sporulation in blue-green algae. III. Effect of amino acids on glycogen accumulation

The effect of 21 amino acids was studied on glycogen accumulation during sporulation in the blue-green alga Anabaena sp. All the amino acids enhanced the initial level of glycogen on the 4th day. The maximum amount of glycogen, on the 20th day, was noticed from l-methionine, l-tyrosine, glycine, and l-histidine supplemented cultures. Others like l-serine, l-valine, l-asparagine, dl-alanine, l-glutamic acid, l-phenylalanine, l-aspartic acid, l-arginine, and dl-lysine come next in the order. On the other hand, l-cysteine and l-cystine, although upto the 16th day they exhibited higher values of glycogen, did not show much variation in glycogen content over nitrogen-free medium. Except in these two amino acids, in all others initiation of sporulation occurred on the 4th day, resulting in free spores on the 8th day. But in case of l-serine, l-asparagine, l-isoleucine, and l-phenylalanine free spores were noticed only on the 12th day while in dl-lysine they were seen on the 16th day. l-cysteine and l-cystine supplemented media showed free spores on the 20th day as in nitrogen-free control.