SUPEROXIDE-DISMUTASE IN SYMBIOTIC, FREE-LIVING AND WILD ANABAENA AND NOSTOC (NOSTOCALES, CYANOPHYTA)

Symbionts and isolates of Anabaena azollae Strasburger (Cyanophyta) from various Azolla species, an Arthrobacter globiformis Conn et Dimmick isolate, Azolla filiculoides Lamarck plants (Pteridophyta), isolates of Nostoc species from cycad coralloids, and free-living Anabaena and Nostoc from the wild were tested for the presence of iron, manganese and iron-manganese superoxide dismutase. The three isoenzymes were found in symbionts and isolates of Anabaena and Nostoc, and in free-living Nostoc species from the wild. Only iron superoxide dismutase was found in Azolla filiculoides, in Arthrobacter globiformis and in free-living Anabaena from the wild. The presence of similar superoxide dismutase isoenzymes in Anabaena azollae and Nostoc isolates suggests the possibility that the Azolla phycobiont may be a species of Nostoc rather than a species of Anabaena.