Metallothionein and glutathione in Lymnaea stagnalis determine the specificity of responses to the effects of ionising radiation

The aim of our study was to distinguish the stress-related molecular response of the pulmonate mollusc Lymnaea stagnalis from the Chernobyl area in comparison with the consequences of other harmful effects, including the short-term effects of radiation and heating. Specimens inhabiting ponds near the Chernobyl nuclear power plant, the cooling channel of the electric power station and the soil reclamation channel (groups R, T and C, correspondingly), and specimens adapted to laboratory conditions (a control group (CL), a disposable group exposed to 2 mGy X-ray radiation over the body (RL), and a group exposed to 25 deg. C for 4 days (TL)) were compared. Despite high variability of responses, Principle Component Analysis distinctly separated the laboratory and feral groups into two sets. In the feral groups, low levels of the stress-related and metal-binding protein metallothionein (MT), protein carbonyls and lactate dehydrogenase in the digestive gland were indicated. The main separating criteria selected by classification and regression tree analysis were the protein carbonyls, cholinesterase and MT. Molluscs from group R were clearly distinguished by the lowest levels of MT, Mn-superoxide dismutase and lactate dehydrogenase, and the highest level of glutathione, demonstrating that the oppression of the gene-determined stress-related response and its partially metabolic compensation can be possible markers for chronic environmental effects of irradiation. (authors)