Oxidative stress in response to xenobiotics in the blue mussel Mytilus edulis L.: evidence for variation along a natural salinity gradient of the Baltic Sea.
ABSTRACT Blue mussels (Mytilus edulis L.) collected at three sampling sites in each of three geographical regions (South, Middle, North) along the permanent longitudinal South-North salinity gradient of the Baltic Sea, were exposed for 10 days to copper (35ppb) or 95 octane petrol (0.3 per thousand). During the experiment, they were maintained at the respective sampling site salinity. Scope for growth (SFG) was determined, and biochemical stress markers (protein carbonyl groups, disulfide bond formation, and glutathione transferase (GST), and catalase (CAT) activities) were investigated in gill tissue upon termination of the experiment. Treatment and regional effects for SFG and protein carbonyl groups were all significant for petrol. The largest increase in protein carbonyl groups was observed in the North. Mussels from the southern, more saline ( approximately 7 per thousand) region had the highest SFG, and displayed the largest SFG decrease in response to treatment, indicating that they had the most energy available for allocation to stress response. They also displayed the least increase in the level of protein carbonyl groups. Mussels from the Northern, less saline ( approximately 5%) region had the highest degree of protein carbonyl groups in response to both treatments, and lowest average SFG. Silver stained diagonal gels for samples from one sampling site in South and North, respectively, demonstrated differences in disulfide bond profiles for both stress treatments. There was also a regional difference in the number of protein disulfides observed on diagonal gels. The most diverse protein disulfide response was found in South. No treatment related effects on GST and CAT activities were observed. We suggest that both SFG and protein carbonyl groups show that geographical difference in stress susceptibility, previously established between the North and the Baltic Seas, also apply on a regional scale within the Baltic Sea, along the salinity gradient.
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ABSTRACT: The Baltic Sea suffers from extensive blooms of the toxic cyanobacteria Nodularia spumigena that produces nodularin toxin (NOD). Additionally, intensification of oil transportation and related activities in the area increase the risk of oil spills. The current experiment was designed to mimic a situation where an oil spill occurs during a cyanobacterial bloom by exposing the amphipod Gammarus oceanicus to a NOD-rich cyanobacterial extract and the polycyclic aromatic hydrocarbon compound benzo[a]pyrene (B[a]P), a common constituent of oil. The activity of the antioxidant enzymes glutathione S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) were examined after 48 and 96 h of exposure. Exposure to low and high levels of the NOD-rich extract produced a time-dependent activation of GST, GPx and SOD. CAT levels were elevated only by high NOD treatment. Also the toxicity of B[a]P was indicated by significantly elevated antioxidant response. In the combined exposures treatment-dependent additive increases in the activity of GPx and SOD were observed as well as inhibitory (antagonistic) effects on GST, CAT and GPx. Rapid concentration-dependent accumulation of NOD by G. oceanicus was observed. The addition of B[a]P reduced the accumulation of NOD and resulted in different biomarker response patterns compared to single exposures demonstrating the effects of mixture toxicity.Toxicon 02/2014; 78:68-77. · 2.92 Impact Factor
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ABSTRACT: Oxidative stress is considered one of the main ecological and evolutionary forces. Several environmental stressors vary geographically and thus organisms inhabiting different sites face different oxidant environments. Nevertheless, there is scarce information about how oxidative damage and antioxidant defences vary geographically in animals. Here we study how oxidative stress varies from lowlands (300-700m asl) to highlands (2200-2500m asl) in the lizard Psammodromus algirus. To accomplish this, antioxidant enzymatic activity (catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione transferase, DT-diaphorase) and lipid peroxidation were assayed in tissue samples from the lizards' tail. Lipid peroxidation was higher in individuals from lowlands than from highlands, indicating higher oxidative stress in lowland lizards. These results suggest that environmental conditions are less oxidant at high elevations with respect to low ones. Therefore, our study shows that oxidative stress varies geographically, which should have important consequences for our understanding of geographic variation in physiology and life-history of organisms.Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 03/2014; · 2.20 Impact Factor
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ABSTRACT: This study investigated the uptake and effects of a common human pharmaceutical, propranolol, on the structure and function of a coastal Baltic Sea model community consisting of macroalga (Ceramium tenuicorne), mussels (Mytilus edulis trossulus), amphipods (Gammarus spp.), water and sediment. The most sensitive species, the mussel, was affected to the same extent as in previous single species studies, while the effects on the amphipod and alga were smaller or even positive compared to experiments performed in less complex test systems. The observed cascade of beneficial effects was a result of inter-specific species interactions that buffered for more severe effects. The poor condition of the mussel led to a feeding shift from alga to mussel by the amphipods. The better food quality, due to the dietary shift, counteracted the effects of the exposure. Less amphipod grazing, together with increased levels of nutrients in the water was favourable for the alga, despite the negative effects of propranolol. This microcosm study showed effects on organisms on different organizational levels as well as interactions among the different components resulting in indirect exposure effects of both functional and structural nature. The combination of both direct and indirect effects would not have been detected using simpler single- or even two-species study designs. The observed structural changes would in the natural environment have a long-term influence on ecosystem function, especially in a low-biodiversity ecosystem like the Baltic Sea.PLoS ONE 01/2014; 9(4):e93774. · 3.53 Impact Factor