Investigating appearance and regulation of the MXR phenotype in early embryo stages of the Mediterranean mussel (Mytilus galloprovincialis).

Multixenobiotic resistance (MXR) efflux transporters constitute a broad-spectrum physiological defense system allowing marine bivalves to cope with environmental challenges. There is, however, scarce information on the type and role that different MXR transporters may have in embryos, which represent the most sensitive stages of bivalves to environmental stress. In this study regulation of MXR-related transporters was investigated in early developmental stages of the Mediterranean mussel (Mytilus galloprovincialis).

Insights into the regulation of the MXR response in haemocytes of the Mediterranean mussel (Mytilus galloprovincialis).

This study investigated functional and transcriptional modulation of the Multixenobiotic resistance (MXR) system as a cytoprotective mechanism contributing to the physiological chemoresistance of haemocytes in the Mediterranean mussel. Basal transport activity was assessed using the model substrate rhodamine 123 and specific inhibitors for the MXR-related transporters P-glycoprotein (ABCB mRNA) and Multidrug resistance-related protein (ABCC mRNA). Results showed that MXR activity in mussel haemocytes was mainly supported by the Mrp-mediated efflux.