Parametri antioksidacionog zaštitnog sistema i koncentracija teških metala u visceralnoj masi odabranih vrsta puževa i školjki Dunava, Tise i Velike Morave

Abstract

Slatkovodni mekušci su dobri model organizmi za proučavanje uticaja faktora sredine u biomonitoring studijama zbog svojih karakteristika: slabe pokretljivosti, načina ishrane, brojnosti, veličine tela i dr. Oni imaju sposobnost da u svom telu akumuliraju znatne količine zagađujućih materija. Na osnovu analize sadržaja ovih materija u mekušcima moguće je zaključivati o kvalitetu sredine. Cilj ove doktorske disertacije bio je da se ispita uticaj različitih lokaliteta: reka Dunav, Tisa i Velika Morava na promene u parametrima antioksidacionog zaštitnog sistema: superoksid-dismutaze (SOD, EC 1.15.1.1), katalaze (CAT, EC 1.11.1.6), glutationperoksidaze (GSH-Px, EC 1.11.1.9), glutation-reduktaze (GR, EC 1.6.4.2), enzima faze II biotransformacije glutation-S-transferaze (GST, EC 2.5.1.18), kao i koncentraciju glutationa (GSH). Parametri su ispitivani u visceralnoj masi puža Viviparus acerosus i školjke Corbicula fluminea. Interspecijske razlike su praćene analizom parametara antioksidacionog zaštitnog sistema u visceralnoj masi puževa V. acerosus, Amphimelania holandrii i školjki C. fluminea i Sinanodonta woodiana iz Velike Morave. Uticaj sezonskih faktora određivan je tokom aprila i septembra u visceralnoj masi vrste V. acerosus iz Dunava, Tise i Velike Morave. Analizirane su koncentracije 15 metala u visceralnoj masi sve četiri vrste slatkovodnih mekušaca u aprilu. Značajne razlike aktivnosti SOD u visceralnoj masi puža V. acerosus iz različitih reka čine ovaj enzim pogodnim biomarkerom u ekofiziološkim studijama. Varijacije aktivnosti GST u visceralnoj masi školjke C. fluminea iz različitih reka, ukazuju na to da se i ovaj enzim može koristiti kao biomarker. Uporedni pregled parametara antioksidacionog zaštitnog sistema četiri vrste slatkovodnih mekušaca izdvajaju A. holandrii kao potencijalnu bioindikatorsku vrstu. Odsustvo jasnog sezonskog uticaja na GST u visceralnoj masi V. acerosus izdvaja ovaj enzim kao potencijalno dobar biomarker. Sposobnost bioakumulacije metala slatkovodnih mekušaca nije dovoljno istražena. Prema podacima dobijenim u ovoj doktorskoj disertaciji V. acerosus predstavlja potencijalno dobrog indikatora zagađenosti rečnih sistema metalima. Biomarkeri imaju važno mesto u programima monitoringa i proceni biološkog efekta različitih ksenobiotika. Biomarkeri otkrivaju stres prouzrokovan dejstvom zagađivača kao i drugim promenama u životnoj sredini. Integracija biomarkera i hemijske analize neophodna je kako bi se uspostavila veza između stresa i zagađenja. Dosadašnji literaturni podaci koji se odnose na odgovor enzimskih i neenzimskih komponenti antioksidacionog zaštitnog sistema kod slatkovodnih vrsta puževa su ograničeni što ukazuje na značaj podataka dobijenih u ovoj studiji.

Freshwater molluscs are a good model organism for studying the effects of environmental factors in biomonitoring studies due to their following characteristics: poor mobility, diet, numbers, size. They have the ability to accumulate in their body significant amounts of pollutants. By analysing the contents of these substances in molluscs we can draw conclusions about the quality of the environment. The aim of this PhD thesis was to investigate the effects of different localities, the Danube, Tisa and Velika Morava Rivers, on changes in the parameters of the antioxidative defence system: the enzymatic activities of superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), glutathione-peroxidase (GSH-Px; EC 1.11.1.9), glutathionereductase (GR; EC 1.6.4.2), and phase II biotransformation enzyme glutathione-S-transferase (GST; EC 2.5.1.18), and glutathione (GSH) concentration. The parameters were investigated in the visceral mass of the snail Viviparus acerosus and mussel Corbicula fluminea. Interspecies differences were followed by analysing the parameters of the antioxidative defense system in the visceral mass of snails, V. acerosus, Amphimelania holandrii, and mussels, C. fluminea and Sinanodonta woodiana, from the Velika Morava River. Seasonal changes were determined during April and September in the visceral mass of species, V. acerosus from the Danube, Tisa and Velika Morava. We analyzed the concentrations of 15 metals in the visceral mass of all four species of freshwater molluscs in April. Significant differences in SOD activities in the visceral mass of the snail V. acerosus from different rivers render this enzyme a suitable biomarker for ecophysiological studies. Variations in GST activities in the visceral mass of the mussel C. fluminea from different rivers can also be considered as a good biomarker. A comparative review of the parameters of the antioxidative defence system in four species of freshwater molluscs distinguish A. holandrii as a potential bioindicator species. The absence of a clear seasonal impact on GST in the visceral mass of V. acerosus makes this enzyme a good biomarker. The potential of freshwater molluscs to bioaccumulate metals studied in this dissertation showed that V. acerosus is a good indicator of metal pollution in river systems. Biomarkers have an important role in monitoring programs and assessments of the biological effects of various xenobiotics. Biomarkers reveal the influence of stress caused by pollution and other changes in the environment. The integration of biomarkers and chemical analyses is necessary to establish a connection between stress and pollution. Previous literature data related to the responses of enzymatic and nonenzymatic components of the antioxidant defence system in freshwater snail species have been limited. This points to the importance of the data obtained in this dissertation.