Scientific publications

The results of a study on the spawning-period activity of lysosomal proteases (cathepsins B and D) in the organs (muscles, liver, gills, gonads) of threespine stickleback (Gasterosteus aculeatus L.) from hydrologically and ecologically different White Sea habitats are presented. At the beginning of the spawning run, the highest activity of cathepsin B in the muscles and liver was revealed in female fish from Seldyanaya Bay, indicating a relatively high autophagy-type proteolytic potential in these fish. By the end of the spawning period, muscular and hepatic cathepsin В activity rises in stickleback from Sukhaya Lagoon and Sukhaya Salma Strait, but declines in fish from Seldyanaya Bay. The increased activity of cathepsin D in the muscles of stickleback from Seldyanaya Bay and especially from Sukhaya Salma Strait alongside its slight reduction in fish from Sukhaya Lagoon in the end of the spawning season leads to the assumption about a synergetic although differently directed pattern of change in the activity of cathepsins D and B in intracellular proteolysis in female stickleback from different habitats during spawning. The study results indicate there is a correlation between the activity of the studied enzymes in stickleback, the spawning time (May and July), and habitat conditions. The leading factor for the activity of lysosomal proteases and, accordingly, for protein hydrolysis in stickleback in this period apparently are the physiological changes the body of the fish undergoes to be able to complete the spawning and prepare for the following fertilization.