MXR response in sea anemones: Effect of temperature, salinity and copper

Multixenobiotic resistance (MXR) phenotype is a cellular defense which can eliminate toxic substances from cells. Several studies describe the MXR activity after pollutant exposure, but little is known about the interference of abiotic factors in this mechanism. The present study aimed to evaluate MXR activity in sea anemones Bunodosoma cangicum after in vivo and in vitro exposures to different temperatures (15, 20 and 25C) and salinities (15, 30 and 45‰) associated or not with copper (0, 7.8 and 15.6 μg/L). Results showed that low temperature inhibited the MXR activity in vivo and in vitro, while salinity did not alter this activity. Copper could change the response, mainly at different temperatures (15 and 25 °C) - 7.8 μg/L Cu activated in vivo and in vitro and 15.6 μg/L Cu in vitro inhibited MXR activity in relation to same copper concentrations at 20 °C. Results for MXR activity found between in vivo and in vitro exposures were similar among temperature treatments and salinities; however, under hyperosmotic shock, in vivo exposure showed that animals has different response than isolated cells. The animals exposed to salinity 45‰ produced a mucus layer as a defense mechanism, because of this protection the response was different between in vivo and in vitro exposures. Concluding, temperature affects MXR activity independently of the presence of copper and each model of exposure contributes with different type of knowledge (cellular mechanism/systemic response).