Response Characteristic Of CYP7A1 And AbGSTsigma Of Variously Colored Abalone(Haliotis Diversicolor Reeve, 1846) With Bacterial Chanllenge And BaP Exposure

Abalones,belonging to one of the largest marine gastropod mollusks,are economically important seafood in aquaculture worldwide.In order to study the immunological mechanisms of the abalone,a forward subtractive suppression hybridization(SSH) library from haemocytes of H.diversicolor challenged with bacteria was constructed.P450(CYP7A1) and GST(abGSTsigma) were selected.Cytochrome P450 and glutathione s-transferase(GST) are both very important enzymes which have been found in all living organisms systems examined.These two enzymatic systems are able to metabolize a phenomenal number of endogenous and exogenous compounds and have been regarded as key objects in the biology field because of their diversity in structures and functions.The research of these two enzymatic systems mostly focus on the detoxification of xenobiotics.In order to study the relationship between the abGSTsigm,CYP7A1 and the immunological system,the abalones were exposured to BaP and bacteria indepently.Real-time PCR was used to monitor the express pattern during the exposure.The following results were obtained:1.Full-length of CYP7A1 and abGSTsigma cDNA were cloned.A full-length cDNA of CYP7A1(GenBank accession number EF587282) was 2185 bp containing an open reading frame of 1494 bp,encoding 498 amino acid residues with a predicted protein molecular weight of 57557.0Da and an estimated pI of 5.56.A full-length cDNA of a sigma class GST(abGSTsigma)(GenBank accession number EF546619) was 1328 bp containing an open reading frame of 624 bp, encoding 208 amino acid residues with a predicted protein molecular weight of 23.67 kDa and an estimated pI of 5.67.2.The abGSTsigma mRNA and CYP7A1 mRNA were distributed in multiple tissues tested and was highly demonstrated in the gill,mantle and kidney of normal abalones.3.In BaP exposured abalone,the abGSTsigma gene was signigicantly expressed in the hemocytes,gill,mantle and digestive gland and the total GSTs enzyme was also induced in the four tissues.4.In bacteria-challenged abalone,the abGSTsigma gene and total GSTs enzyme were also significantly expressed in the four tissues.5.The CYP7A1 gene was only induced in hemocytes in both bacteria-challenged and BaP exposured.The preliminary work revealed that the sigma class glutathione S-transferase gene abGSTsigma,a phaseâ…¡detoxification enzyme,had a positive response to bacterial challenge,and that will lead to an insightful study on elucidating the interactions between immune responses and biotransformation exerted by abGSTsigma.