Beitrag
Superoxide dismutase in cyanobacteria of the Baltic Sea
Canini, Antonella; Albertano, Patrizia; Leonardi, Donatella; Di Somma, Daniela; Grilli Caiola, Maria
Algological Studies/Archiv für Hydrobiologie, Supplement Volumes No. 83 (1996), p. 129 - 143
32 Literaturangaben
veröffentlicht: Dec 19, 1996
DOI: 10.1127/algol_stud/83/1996/129
ArtNo. ESP142011700010, Preis: 29.00 €
Abstract
Iron superoxide dismutase (Fe-SOD) isoenzyme was detected in extracts of mixed, bloom-forming, nitrogen-fixing cyanobacteria N odularia sp. and Aphanizomenon sp., freshly collected from the Baltic Sea, and in cultures of previously isolated Nodularia sp. The enzyme pattern of activity showed three bands and was similar to that found in Anabaena cylindrica. By immunogold labelling, Fe-SOD was localized on both vegetative cells and heterocysts of Nodularia sp. and Aphanizomenon sp. The level of gold particles present in heterocyst cytoplasm was similar to that found in vegetative cells of both cyanobacteria examined. Moreover, the ratio of Fe-SOD labelling between heterocysts and vegetative cells was very similar for both cyanobacteria in the cytoplasmic region, whereas some differences were observed in the cell wall. Fe-SOD particle labelling showed the highest density in heterocysts of Nodularia sp. that also showed highest nitrogenase activity when exposed to the highest sunlight irradiance. These results support the positive correlation between Fe-SOD and nitrogenase activity observed in other nitrogen-fixing cyanobacteria, suggesting a role for the isoenzyme in the protection of nitrogenase from damage by reactive oxygen-derived species.
Schlagworte
Cyanobacteria • Nodularia • Aphanizomenon • Fe-SOD activity • Fe-SOD immunogold labelling • nitrogen fixation