Antioxidant defence parameters in tissues of some species of freshwater fish from the Gruža reservoir

Ribe mogu direktno da budu izložene toksinima cijanobakterija i zato su veoma dobri modeli za proučavanje uticaja cijanotoksina na ćelijski antioksidacioni sistem zaštite. Postoji mnogo informacija o biohemijskim i ultrastrukturnim promenama u različitim tkivima riba nakon izlaganja cijanotoksinima u laboratorijskim uslovima, ali su podaci o dejstvu cvetanja cijanobakterija u prirodnim uslovima veoma retki. Cilj ove doktorske disertacije bio je da se istraži uticaj cvetanja cijanobakterija u akumulacionom jezeru Gruža na parametre antioksidacione zaštite u jetri, škrgama i mišiću kod slatkovodnih vrsta riba Rutilus rutilus (bodorka), Blicca bjoerkna (blika), Carassius gibelio (babuška) i Perca fluviatilis (grgeč). Određivani su aktivnost enzima antioksidacione zaštite: ukupne, mangan i bakar cink sadržavajuće superoksiddismutaze (Uk SOD, Mn SOD, CuZn SOD, EC 1.15.1.1), katalaze (CAT, EC 1.11.1.6), glutation-peroksidaze (GSH-Px, EC 1.11.1.9), glutation-reduktaze (GR, EC 1.6.4.2) i enzima faze II biotransformacije glutation-S-transferaze (GST, EC 2.5.1.18), kao i koncentracija ukupnog glutationa (GSH) i sulfhidrilnih (SH) grupa. Histopatološka analiza jetre riba proučavana je na nivou svetlosne i elektronske mikroskopije. Svi ispitivani parametri mereni su pre i tokom cvetanja cijanobakterija... Dobijeni rezultati su pokazali da cvetanje cijanobakterija indukuje odgovor na oksidacioni stres u ispitivanim tkivima riba i dovodi do ultrastrukturnih promena u jetri. Rezultati ove doktorske disertacije predstavljaju prvi izveštaj o uticaju cvetanja cijanobakterija u akumulacionom jezeru Gruža na parametre antioksidacione zaštite (aktivnost SOD, CAT, GSH-Px, GR i enzima faze II biotransformacije GST, kao i koncentraciju GSH i SH grupa) u jetri, škrgama i mišiću slatkovodnih riba Rutilus rutilus, Blicca bjoerkna, Carassius gibelio i Perca fluviatilis. Biomonitoring antioksidacionih biomarkera u tkivima riba može da posluži kao rani upozoravajući signal koji ukazuje na oštećenja ćelija usled izloženosti cijanotoksinima u slatkovodnim ekosistemima. Ova disertacija pruža veliki doprinos na polju ekofiziologije akvatičnih organizama.Since fish can be directly exposed to cyanobacterial toxins, they are very good models to study the influence of cyanotoxins on the cellular antioxidant defence system. There is much information on biochemical and ultrastructural alterations in different fish tissues after exposure to cyanotoxins under laboratory conditions, however, data on the effects of cyanobacterial blooms in natural conditions are very scarce. The aim of this doctoral dissertation was to investigate the influence of the cyanobacterial bloom in the Gruža Reservoir on the antioxidant defence parameters in the liver, gills and muscle of freshwater fish Rutilus rutilus (roach), Blicca bjoerkna (white bream), Carassius gibelio (prussian carp) and Perca fluviatilis (European perch). The activity of antioxidant defence enzymes: total, manganese and copper zinc containing superoxide dismutases (Tot SOD, Mn SOD, CuZn SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), glutathione peroxidase (GSH-Px, EC 1.11.1.9), glutathione reductase (GR, EC 1.6.4.2) and the biotransformation phase II enzyme glutathione-S-transferase (GST, EC 2.5.1.18), as well as the concentrations of total glutathione (GSH) and sulphydryl (SH) groups were determined. Histopathological examination of fish liver was performed by light and electron microscopy. All investigated parameters were measured before and during cyanobacterial bloom... The presented results show that the cyanobacterial bloom-induced response to oxidative stress caused ultrastructural alterations in the liver. The results of this doctoral dissertation are a first report on the influence of the cyanobacterial bloom in the Gruža Reservoir on antioxidant defence parameters (SOD, CAT, GSH-Px, GR and biotransformation phase II enzyme GST activities, as well as concentrations of GSH and SH groups) in the liver, gills and muscle of freshwater fish Rutilus rutilus, Blicca bjoerkna, Carassius gibelio and Perca fluviatilis. Biomonitoring of antioxidant biomarkers in fish tissue could serve as an early warning signal of cellular damage resulting from exposure to cyanotoxins in freshwater ecosystems. This dissertation is an important contribution in the field of ecophysiology of aquatic organisms