Effect of exposure to benzo[a]pyrene on SODs, CYP1A1/1A2- and CYP2E1 immunopositive proteins in the blood clam Scapharca inaequivalvis

Abstract

The effects of water-borne exposure to benzo[a]pyrene (36 h; celite-bound 0.44 mg L(-1) B[a]P) on cytochrome P450 (CYP) and superoxide dismutases (SODs) were examined in digestive gland of the blood clam, Scapharca inaequivalvis. B[a]P accumulation and elimination were rapid, with maximum whole-body concentrations of 1.78 ng g(-1) wet wt after 12 h of treatment, followed by a progressive decline to 0.89 ng g(-1) at 36 h. The presence of B[a]P resulted in an increase in total CYP of digestive gland microsomes from 54+/-14 to 108+/-21 pmol/mg protein (mean+/-SD; p<0.05, 24 h). Increases were also seen in microsomal CYP1A1/1A2-immunopositive protein (50.5 kDa app. mol. wt; p<0.05), but not CYP2E1-immunopositive protein (49 kDa app. mol. wt.), indicating a specific response of the former isoform. Exposure to B[a]P produced a steady increase in Mn-SOD digestive gland activity (p<0.01; p<0.05) but no significant change in Cu/Zn-SOD activity. The respective proteins, measured by western blotting, were not significant induced after B[a]P exposure. Cu/Zn-SOD and Mn-SOD activities were correlated with total CYP levels (r=0.96 and 0.63, respectively), indicating a role for CYP in reactive oxygen species (ROS) production during exposure. Both 'NADPH-independent' and NADPH-dependent metabolism of B[a]P by digestive gland microsomes was seen, producing mainly 1,6-, 3,6- and 6,12-diones, with some phenols and 7,8-dihydrodiol; putative protein adducts were also formed. Redox cycling of the diones may also have contributed to ROS production, leading to the increased SOD activities.

Identification and expression of multiple CYP1-like and CYP3-like genes in the bivalve mollusk Mytilus edulis

“…In fish, CYP1A induction has been widely employed as a biomarker of exposure to AHR agonists in the aquatic environment [e.g (Bucheli and Fent, 1995; Payne, 1976; Stegeman et al, 1986)]. The prominent use of bivalve mollusks in pollution monitoring programs has prompted numerous efforts to find some CYP gene, protein or catalytic activity that would provide a similar marker of exposure in these organisms (Cravo et al, 2009; Livingstone et al, 1989; Monari et al, 2007; Monari et al, 2009; Peters et al, 1998; Porte et al, 2001; Shaw et al, 2002; Snyder et al, 2001; Sole and Livingstone, 2005; Wootton et al, 1995). There has been little success, due to lack of knowledge of specific CYP sequences, probes, or substrates [e.g.…”

“…Many studies have examined total microsomal cytochrome P450 content, levels of CYP enzyme activity, or CYP protein by immunoassay in bivalve mollusks exposed to chemicals (Canova et al, 1998; Livingstone, 1998; Livingstone et al, 1989; Monari et al, 2007; Monari et al, 2009; Shaw et al, 2002; Snyder et al, 2001; Sole and Livingstone, 2005; Wootton et al, 1995). The interpretation of those measurements has been complicated by low catalytic activity of microsomal enzymes with diagnostic substrates for CYP1A-like activity, such as ethoxyresorufin (ethoxyresorufin-O-deethylase activity, EROD) and benzo[a]pyrene (benzo[a]pyrene hydroxylase; BPH), and lack of specific cross-reactivity of antibodies for CYP1As, (Chaty et al, 2004; Jonsson et al, 2006a; Jonsson et al, 2006b).…”

Short-term dynamics of sedimentary organic matter in a littoral area of the North Adriatic Sea (Italy): Evidence from234Th and7Be

“…A possible explanation for the different penetration depths relates to the different sources of 7 Be and 234 Th; in fact, when the material is stored in the drainage basin for >200 d prior to delivery, its 7 Be signal will decay to below detection limits. The cause for the deeper penetration of 234 Th could be downward biological mixing of marine sediments with 234 Th, and this is supported by laboratory observations of specimens of the blood clam Scapharca inaequivalvis in both cores, whose presence has been recorded in the North Adriatic Sea since 1972 [17], and implying that the sediments are actively being bioturbated. However, abundance and composition of the benthic community was not investigated in this study, which has been argued to be more relevant than tracer-derived mixing rates in determining the relative influence of organisms on bioturbation [18,19].…”

Altered gene expression profiles in the lungs of benzo[ a ]pyrene-exposed mice in the presence of lipopolysaccharide-induced pulmonary inflammation

“…To gain further insight into the effect of LPS on B[ a ]P-induced carcinogenesis, a list of 57 genes were derived from published literature that indicated that these genes are involved in B[ a ]P metabolism, the cellular response to B[ a ]P and DNA repair ( Kim et al, 1998 , Ghosal et al, 2003 , Moorthy et al, 2003 , Arlt et al, 2015 , Martignoni et al, 2006 , Guo et al, 1994 , Bauer et al, 1995 , Luckert et al, 2013 , Trush et al, 1991 , Adams et al, 1995 , Shi et al, 2009 , Quinn and Penning, 2008 , Kalabus et al, 2012 , Stiborova et al, 2016b , Wada et al, 2013 , Shen et al, 2010a , Iskander et al, 2005 , Iskander et al, 2004 , Zhang et al, 2011 , Zheng et al, 2002a , Cai et al, 2010 , Buckley and Klaassen, 2007 , Shi et al, 2016a , Zhang et al, 2012 , Shi et al, 2000 , Romert et al, 1989 , Raza et al, 1991 , Alexandrov et al, 2002 , Lodovici et al, 2004 , Rojas et al, 2000 , Saunders et al, 2006 , Monari et al, 2007 , Schults et al, 2013 , Gungor et al, 2007 , Kunze et al, 2015 , Melis et al, 2013 , Christmann and Kaina, 2013 , Shen et al, 2008 , Starostenko et al, 2016 , Gibbons et al, 2014 , Kranz et al, 2014 . We divided the gene expression profiles into four categories, phase I metabolism, phase II metabolism, DNA damage response (DDR) and phase III reactions.…”