标题：SEASONAL CHANGES IN ISOENZYME PATTERN AND THE ACTIVITIES OF SUPEROXIDE DISMUTASE AND CATALASE IN THE LIVER OF GREEN FROGS PELOPHYLAX ESCULENTA COMPLEX AS PART OF TOLERANCE TO FREEZING AND THAWING
摘要：Paper deals with green frog Pelophylax esculenta complex seasonal changes in isoenzyme pattern and activities of liver antioxidative enzymes: superoxide dismutases (SOD, EC 1.15.1.1) and catalase (CAT, EC 1.11.1.6) as a response to freezing and thawing. Frogs were sampled in autumn and spring in the area of Bardaca wetlands (B&H). After the exposure to subzero temperatures (-2°C) for 8h, frogs were thawed at different time intervals. Activities and isoforms of liver SOD and CAT were determined using native PAGE. The presence of three SOD isoforms was observed in autumn frogs (Rf SOD1= 0.156, RfSOD2= 0.311, RfSOD3= 0.650), while in the isoenzyme pattern of spring frogs SOD1 isoform was absent. Only one CAT isoform (Rf=0.179) was detected in all samples. The results indicate that the most significant changes in SOD and CAT activities occurred in the first hours of thawing for both autumn and spring frogs. Alternation in activities of SOD and CAT suggests key role of these enyzmes in antioxidative defence of the Pelophylax esculenta complex in the state of excessive generation of reactive oxygen species associated with thawing. On the other hand, alternation of isoform expression of SOD before and after hibernation suggests possible redox modulation related with hibernation.
