Cytochrome P450 and dependent activities in unexposed and PAH-exposed terrestrial annelids

The cytochrome P450 system of the oligochaetes Eisenia f. fetida (tiger wor m) and Enchytraeus crypticus (pot worm) was analysed using ethoxy-, pentoxy - and benzoxyresorufin as substrates for monooxygenase activity. Whole body microsomes of the earthworm E.f. fetida displayed PentROD activity in the range from 0.26 to 1.05 pmol mg protein(-1) min(-1) and BenzROD activity in the range from 0.14 to 0.30 pmol mg protein(-1) min(-1). Exposure of the a nimals for up to four weeks to 100 mg fluoranthene or benzo[a]pyrene kg(-1) soil (dry weight) did not induce significant changes in the activity of th ese monooxygenases. In E. crypticus EROD activity was in the range from 2.1 0 to 6.18 pmol mg protein(-1) min(-1) and PentROD activity in the range fro m 1.75 to 4.78 pmol mg protein(-1) min(-1). Short-term exposure to BaP by f eeding reduced the EROD activity significantly by 45%, but did not effect P entROD activity. After long-term (8 weeks) exposure to BaP in the agar-agar medium EROD activity was not changed but PentROD had decreased to zero. In both species cytochrome P420 and NADPH-cytochrome C reductase activity wer e present. In E.f. fetida microsomes are associated with the giant haemoglo bin. Both can be separated by gel filtration on a Sepharose B2 column or by hydrophobic interaction chromatography after solubilisation with cholate. NADPH-cytochrome C reductase elutes together with haemoglobin. Cytochrom P4 20 is eluted with Emulgen 911 and can be further purified by ion exchange c hromatography using HA-Ultrogel. By SDS-PAGE of the purified microsomal pro teins three protein bands are visualised in the range of cytochrome P450 di splaying an apparent molecular mass of 54, 56 and 58 kDa. Only the 54-kDa p rotein interacts weakly with perch (Perca fluviatilis) CYP1A antibodies, wh ile two proteins with an apparent molecular mass of 65 and 71 kDa give a st rong antibody signal. (C) 1998 Elsevier Science Inc. All rights reserved.