(full paper is archived in the Miller Library)
Title: Evidence for multi-drug resistance-like activity in marine mussels Mytilus californianus and Mytilus edulis
Student Author(s): Bard, Shannon
Faculty Advisor(s): Epel, David
Location: Final Papers Biology 175H
Date: June 1992
Abstract: Marine mussels Mytilus californianus and Mytilus edulis, hardy invertebrates resistant to pollution, were found to possess a multi-xenobiotic resistance mechanism analogous to multi-drug resistance (MDR) found in resistant mammalian tumor cell lines. This MDR-like efflux pump may provide defense against natural toxins in the aquatic environment. An assay using the fluorescent dye rhodamine B was adapted to measure MDR activity in Mytilus sp. gill tissue in vivo. Four pieces of evidence support the existence of a multi-xenobiotic resistance in Mytillus sp.: 1) accumulation of rhodamine B is sensitive to known inhibitors of MDR, such as verapamil; 2) verapamil inhibits an efflux pump; 3) Western blot analysis shows the presence of a protein immunologically related and similar in molecular weight to mammalian MDR P-glycoprotein; and 4) the Mytilus sp. efflux pump is sensitive to nanomolar concentrations of rhodamine B.