INDUCTION OF PEROXISOMAL OXIDASES IN MUSSELS - COMPARISON OF EFFECTS OF LUBRICANT OIL AND BENZO(A)PYRENE WITH 2 TYPICAL PEROXISOME PROLIFERATORS ON PEROXISOME STRUCTURE AND FUNCTION IN MYTILUS-GALLOPROVINCIALIS

Marine mussels are used as bioindicators of water pollution in marine and estuarine environments in the so-called ''Mussel Watch'' programs because of their capacity to accumulate numerous organic xenobiotics i ncluding aromatic hydrocarbons. in this study, we have analyzed the ef fects of two xenobiotics [benzo(a)pyrene and the water accommodated fr action of a lubricant oil] and two typical (rodent) peroxisome prolife rators (clofibrate and dioctyl phthalate) on structure and function of peroxisomes in digestive glands of mussels Mytilus galloprocincialis, either following water exposure (for 1, 7, and 21 days) or after dire ct injection through the adductor muscle (for 1 and 7 days). The activ ities of catalase (CAT), acyl-CoA oxidase (AOX), and D-amino acid oxid ase were determined in whole homogenates of digestive glands. In addit ion, stereological methods were applied on sections stained histochemi cally for demonstration of catalase activity in order to quantify the morphological changes of peroxisomes. The peroxisomal acyl-CoA oxidase and D-amino acid oxidase were increased in mussels injected for 7 day s with benzo(a)pyrene, phthalate, and clofibrate and a similar trend w as noted for benzo(a)pyrene and lubricant oil in water exposure experi ments (21 days). The catalase activity was reduced or unchanged depend ing on the mode of exposure of animals. By stereology, significant inc reases of numerical and volume densities of peroxisomes were found in animals injected for 7 days with lubricant oil or clofibrate. These ob servations indicate that peroxisomal oxidases in mussels are induced a t moderate rates in response to different xenobiotics and that their d etermination could provide a (sensitive) marker for detection of effec ts of some toxic pollutants, particularly the lubricant oils which in addition induce significant structural alterations of mussel peroxisom es. (C) 1998 Academic Press.