engleski

The multidrug resistance-like mechanism in the marine sponge Tethya aurantium

The purpose of this study was to investigate the presence of a verapamilsensitive, multidrug resistance(MDR)-like mechanism for binding and accumulation of xenobiotics in the marine sponge Tethya aurantium. Incubation of sponge membrane vesicles with radiolabelled 2-acetylaminofluorene (AAF) or vineristine (VCR) led to binding of the radiolabel to the membranes. In the absence of ATP, the amount of radiolabelled AAF or VCR bound to membranes was decreased, demonstrating the energy-defendence of the binding process. Verapamil (10 μ /ml) lowers the binding of AAF and VCR by 41 and 63%. respectively. Sponge cubes exposed to seawater polluted with radiolabelled benzo(a)pyrene accumulated 73% more radiolabel in the presence than in the absence of verapamil (5 μ /ml). These results demonstrate that verapamil-sensitive. MDR-like binding of xenobiotics found in cell-free vesicle preparations from sponge tissue in vitro is operative also in in-vivo conditions. The knowlegde that the presence of one xenobiotic may block the pumping out, and hence accelerate accumulation of other(s), may help us to understand and interpret our present and past data on different environmental parameters.

multidrug resistance ; marine sponge ; Tethya aurantium

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