Superoxide Dismutase Detection in Anabaena Azollae Strasb. Isolated from Azolla Filiculoides Lam.

Abstract

Percoll and sucrose gradients were used to isolate heterocysts and vegetative cells resp. of Anabaena azollae in symbiosis with Azolla filiculoides. The distribution of the enzyme superoxide dismutase (SOD) in the heterocysts and vegetative cells was studied using activity-stained polyacrylamide gel electrophoresis. Types of SOD were determined by their different sensitivities to 2mM cyanide and 2mM hydrogen peroxide. Heterocysts contained only a faint band of both hybrid iron-manganese (Hy) and iron (Fe) SOD. Vegetative cells possessed Mn-SOD, Hy-SOD and Fe-SOD. Hy-SOD was detected for the first time in cyanobacteria. The greater activity was present as Fe-SOD in vegetative cells while total heterocysts SOD activity was only 15% with respect to vegetation cells. Source: CAB