A multixenobiotic transporter in Urechis caupo embryos: protection from pesticides?

Much is known about how adult organisms protect themselves from exposure to foreign compounds (xenobiotics), but for a population to successfully colonize a habitat, all life stages of the organism must be able to grow and develop normally in that habitat. In this study, a multixenobiotic transporter is described which is similar to the multidrug transporter in mammalian cells, used by some embryos as protection from natural xenobiotics they may encounter in their environment. It is shown that some moderately hydrophobic pollutants — but not very hydrophobic pollutants — are competitive substrates of the multixenobiotic transporter in the embryos of a marine worm. Multixenobiotic resistance may protect Urechis caupo embryos from certain toxic substances by preventing their entry into cells. In this way the xenobiotics cannot interfere with cellular processes that are crucial for normal development, such as DNA synthesis, cell division, and gene transcription.