Characterization of a Novel Mechanism for Xenobiotic Resistance in MarineInvertebrates

摘要

This research describes a first line of defense against toxins in marineorganisms, which utilizes the multidrug transporter family to keep the toxin out of the cell in the first place. We have studied the embryos of a marine worm and an adult mussel. Both organisms possess a high titer of this protein, and the activity of the transporter provides protection from toxins by reducing the toxin concentration in the cell. Evidence for involvement of the transport protein in toxin protection is based on the properties of the transport activity, immunological cross reactivity and isolation of a partial gene sequence. Evidence for protection includes accumulation studies and toxicity studies in the presence of inhibitors of the transport activity. This research reveals that these transporters are potent first lines of defense against toxins. The results also reveal that assessing toxins in the environment by examining tissue levels of toxins may be an inaccurate indicator of environmental contamination; if the test organisms possess the transporter protein, its activity will reduce the amount of toxin in the tissues and result in an underestimation of toxin load. These results suggest the widely used Mussel Watch Program will underestimate the environmental level of some pollutants.