Uptake and biochemical response to B[a]P in the sea anemone Anthopleura elegantissima

In order to evaluate the effects of benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon (PAH) in the sea anemone Anthopleura elegantissima at the biochemical level. NADPH cytochrome P450 reductase and cytochrome P450 were assayed in A. elegantissima under toxicant. One toxicity test was performed with 75 organisms distributed in 5 groups. Animals in groups G1, G2 and G3 were given increasing B[a]P. Two groups named GC and GS were used as controls. GC was treated with seawater and GS was treated with acetone. After 72 h of exposure, enzymatic activities were determined. Microsomes were isolated from the columnar tissue and exposed in vitro to the toxicant in order to explore their ability to incorporate B[a]P. Basal activity for this enzyme was 1.69 +/- 0.18 (Mean +/- standard deviation) nmol cyt C red min(-1) mg(-1) and there was no significant effect in GS organisms compared to GC organisms. Significant increases were observed in NADPH cytochrome P450 reductase in G3 organisms. In this group, the enzyme activity was 3.53 +/- 0.40 nmol cyt C red min(-1) mg(-1). For cytochrome P450 content, a gradual increase was observed in organisms in groups G1 to G3. Basal content was 10.25 +/- 0.49 pmol mg(-1) microsomal protein. For G3 animals, P450 content was 27.51 +/- 0.32 pmol mg(-1) microsomal. For the test in vitro, it was found that microsomes isolated from G2 and G3 had the capacity to incorporate this substance when exposed to B[a]P at a level of 4 mu M in the surrounding medium. Spectrum recorded from 350 to 450 nm after a 40-min exposure for these groups showed significant difference from spectra obtained for microsomes in GC, GS and G1. It was concluded that the capacity to increase NADPH cytochrome P450 reductase activity as well as to increase NADPH cytochrome P450 reductase activity as well as to increase P450 content shows the ability of A. elegantissima to induce a mixed function oxidase activity in the presence of B[a]P.