PARENT SESSION
TP7 The use of biomarkers for assessing ecosystem damage
3:00 PM to 6:30 PM, Tuesday, 08 May 2001
Session Chair: L. Guilhermino
Room 7

(271) Studies on CYP1A-immunopositive protein in mussel (Mytilus sp.) as a biomarker of organic pollution.

Livingstone, David¹, Peters, Laurence ¹, S., Arun², Shaw, Jenny¹, ^{1 2}

ABSTRACT- No robust biomarker of organic pollution, equivalent to CYP1A in fish, exists for aquatic invertebrates. However, molecular biological and immunochemical recognition analyses, coupled with enzymological and exposure studies, indicate the presence of an inducible cytochrome P4501A (CYP1A)-like enzyme in digestive gland of Mytilus sp.. Northern and Western analyses of digestive gland tissue, microsomes or partially purified cytochrome P450 (CYP) indicate the existence of mRNA and protein with sequence/epitope similarities to fish CYP1A. Involvement of the CYP1A-like enzyme in the biotransformation of benzo[a]pyrene (BaP), in particular metabolism to phenols, is indicated from i) seasonal correlation between CYP1A-like mRNA and microsomal BaP metabolism; ii) field correlation between CYP1A-immunopositive protein and microsomal BaP hydroxylase activity; and iii) laboratory induction of CYP1A-immunopositive protein correlated with a shift in microsomal BaP metabolism to increased phenol formation. Elevated levels of digestive gland CYP1A-immunopositive protein, using anti-perch (P. fluviatilis) CYP1A antibody, have been seen in field studies with exposure of mussels to oil spill and industrial PAH and PCB pollution. Recently, we have examined the cross-reactivity of M. edulis digestive gland microsomes and partially purified CYP with commercial antibodies to fish CYP1A (Biosense, Norway). Compared to polyclonal anti-perch CYP1A which recognises a mussel protein of 48 to 52 kDa app. mol. wt., polyclonal anti-fish CYP1A1 peptide (antibody to synthetic peptides of conserved fish CYP1A1 amino acid sequence 190-204 and 282-296) recognised proteins at ~ 45, 132 and 202 kDa, and monoclonal anti-fish CYP1A1 peptide (antibody to conserved amino acid sequence 277-294 of trout O. mykiss) recognised a protein at 52 kDa. The results indicate the presence of conserved fish CYP1A sequences/epitopes in the mussel CYP1A-like protein.

Key words: mussel, cyp1a-immunopositive protein, biomarker, pollution