|
(22-12) Optimization of techniques to measure peroxisome proliferation in mussels. Orbea, Amaia*,1, Cajaraville, Miren1, 1 University of the Basque Country, Bilbao, Spain, Spain ABSTRACT- In the last decade, peroxisome proliferation in mussels emerged as a useful biomarker to assess exposure to certain environmentally relevant organic pollutants such as PAHs, PCBs and phthalate esters. Peroxisome proliferation is actually under research in the framework of the EU-funded BEEP project in order to be included in a battery of biomarkers to assess water quality in biomonitoring programs. Peroxisome proliferation is featured by increased peroxisomal volume density (Vv) and induction of enzymes of the peroxisomal Key words: Peroxisome proliferation, biomarker, catalase histochemistry, acyl-CoA oxidase |
-oxidation pathway, i.e., acyl-CoA oxidase (AOX). Since these two processes do not always parallel both endpoints need to be measured for a proper assessment of peroxisome proliferation. The aim of the present study was to improve and optimize the techniques currently used to measure peroxisomal Vv and AOX activity in mussels for application in biomonitoring programs. Peroxisomal staining to assess Vv was assayed in (a) sections of cryostat or methacrylate-embedded mussel digestive gland stained with the alkaline DAB technique for demonstration of the peroxisomal marker enzyme catalase, and (b) sections of methacrylate or paraffin-embedded material immunolabeled with polyclonal antibodies against guinea pig catalase or rat AOX. AOX activity measurements were performed in whole homogenates or peroxisome-enriched fractions of mussel digestive gland. The selected protocols were tested in mussels sampled in two locations of the Basque coast with a clear gradient of pollution by PAHs and PCBs. The inclusion of these protocols for routine assessment of peroxisome proliferation in biomonitoring programs is discussed. *Funded by project AMB99-0234 (CICYT) and BEEP (EVK3-CT-2000-00025).