Variations in the Antioxidant Defense System of the Black Sea Mussel, Mytilus galloprovincialis (Lamarck, 1819)

Lachezar P. Yakimov1*, Elina R. Tsvetanova2, Almira P. Georgieva2, Nesho H. Chipev1, Albena V. Alexandrova2
1 - Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Science, 2 Gagarin str., 1113 Sofia, BULGARIA
2 - Institute of Neurobiology, Bulgarian Academy of Science,
23 Acad. G. Bonchev str., 1113 Sofia, BULGARIA
*Corresponding author:
Abstract. The study aimed at assessing changes in the pro-antioxidant balance in gills, foot and digestive gland, of the mussels, Mytilus galloprovincialis Lam., gathered in June and September in two successive years (2017 – 2018) from 11 different habitats with various environmental conditions of the Bulgarian Black Sea coastal area. The glutathione (GSH) concentration and enzyme activity of catalase (CAT), glucose-6-phosphate dehydrogenase (G6PDH), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione-S-transferase (GST), superoxide dismutase (SOD), together with the lipid peroxidation (LPO) level and concentrations of selected trace metals (Cd, Cu, Pb, Ni, Zn) were measured in each organ. Significant, although not high, correlations were established between different tissue biomarkers and Cu, Pb and Cd. In gills the highest degree of oxidative stress (OS) was present, compared to the other tissues, as evidenced by the significantly higher LPO levels along with activated antioxidant enzymes CAT, GPX, GST, SOD and extremely high G6PDH. Among the organs, the lowest levels of OS were detected in the foot, indicated by the lowest LPO and the highest GSH concentrations. The digestive gland showed a relatively low degree of OS, indicated by the significantly lower LPO and antioxidant enzyme activities, with exception of the high CAT activity. In conclusion, the established significant variability in the tested OS parameters indicated their different sensitivity towards environmental pro-oxidants and reaction of the antioxidant defense system in different organs of the mussels. The gills seemed to be most suitable for biomonitoring of oxidative stress in the mussels.
Key words:  lipid peroxidation, antioxidants, heavy metals, Mytilus galloprovincialis.

Ecologia Balkanica, 2019, Special Edition 2, pp. 71-80
Article № eb.19SE207 [Full text - PDF]pdf

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