engleski

Characterization of the multixenobiotic resistance mechanism (MXR) efflux activity in different tissues of crayfish Pacifastacus leniusuculus

Freshwater ecosystems are among most diverse and at the same time most endangered ecosystems today, with pollution and invasive species being among the most detrimental anthropogenic influences. The ability of aquatic organisms to adapt to pollution relies on the efficiency of primary detoxification cell machineries such as multixenobiotic resistance mechanism (MXR) which acts as first line defence. On a cellular level MXR is mediated by the ATP-binding cassette (ABC) transporter proteins that are capable to actively efflux variety of xenobiotics present in the water body. In the presented study we have characterized MXR functional efflux activity in one of the most successful crayfish invaders of European freshwater ecosystems, the signal crayfish (Pastifastacus leniusculus, Dana) and optimized conditions for MXR activity assay in this robust species. We have used a MXR fluorescent model substrate rhodamine 123 and established optimal time of its accumulation in different crayfish tissues (muscle, gills, hepatopancreas). Further, inhibitors (MK571 and verapamil) have blocked MXR efflux activity in dose dependent matter. Finally, we tested the effect of several known fresh water metal pollutants (Hg, Cd, Zn) on MXR activity. In conclusion, our results indicate that MXR efflux activity is an important and tissue specific defence mechanism for the invasive crayfish P. leniusculus. We propose MXR activity assay as a reliable method for testing pollution in freshwater ecosystems.

multixenobiotic resistance (MXR); MXR inhibitors; heavy metals; signal crayfish

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