Interpopulational variability of molecular responses to ionizing radiation in freshwater bivalves Anodonta anatina (Unionidae).
Freshwater ecosystems are exposed to multiple anthropogenic stressors including chemical pollution and warming that can affect health of the resident organisms and their responses to novel challenges. We investigated the of in situ exposure history on molecular responses to a novel stressor, ionizing radiation, in unionid mollusks Anodonta anatina. Males from pristine (F-), agricultural (A-) sites and a cooling reservoir of a nuclear power plant (N-site) were exposed to acute low dose (2mGy) X-ray radiation followed by 14days of recovery (R-groups) or to control conditions (C-groups). Biomarkers of oxidative stress, geno-, cyto- and neurotoxicity were used to assess cellular injury and stress. Control group from the cooling reservoir (CN) had higher background levels of caspase-3 activity, metallothionein concentrations and nuclear lesions and lower levels of superoxide dismutase (SOD) and glutathione in the gills compared to other control groups (CF and CA). Irradiation induced cellular damage in mussels from all three sites including increased levels of nuclear lesions in hemocytes, depletion of caspase-3, suppression of superoxide dismutase and catalase activities, an increase of the lipid peroxidation and oxidized glutathione levels, as well as down-regulation of cholinesterase indicating neurotoxicity. The up-regulation of ethoxyresorufin-O-deethylase activity in the digestive gland and vitellogenin-like protein level in gonads were also found in radiation-exposed groups indicating feminization of males and disturbances of xenobiotic metabolism. The RA-group showed the greatest magnitude of radiation-induced stress responses compared to the other two groups. Overall, unionid mollusks, particularly those from a chronically polluted agricultural site, were highly sensitive to low-dose radiation (2mGy) indicating limitations of stress protection mechanisms to deal with multiple stressors.
Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, Kryvonosa Str, Ternopil 46027, Ukraine; Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA; Department of General Chemistry, I.Ya. Horbachevsky Ternopil State Medical University, 1, Maidan Voli, Ternopil 46001, Ukraine.
H
H
Falfushynska
Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, Kryvonosa Str, Ternopil 46027, Ukraine; Department of General Chemistry, I.Ya. Horbachevsky Ternopil State Medical University, 1, Maidan Voli, Ternopil 46001, Ukraine.
L
L
Gnatyshyna
Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, Kryvonosa Str, Ternopil 46027, Ukraine.
I
I
Yurchak
Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, Kryvonosa Str, Ternopil 46027, Ukraine.
O
O
Stoliar
Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA. Electronic address: isokolova@uncc.edu.
I M
IM
Sokolova
D000818:Animals; D049877:Anodonta / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects*; D008297:Male; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000009:adverse effects*; D011839:Radiation, Ionizing; D014455:Ukraine
Bivalve mollusk; Caspase-3; Genotoxicity; Irradiation; Oxidative stress; Stress tolerance