Inducement Of The CYP1A1 MRNA Expression And EROD Activity Of Black Porgy(Sparus Macrocephalus) Exposed To Benzo(a)pyene

CYP1A gene is highly inducible by polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCB's),dioxins and related compounds.Induction of CYP1A1 in fish has been evaluated as a sensitive method in monitoring contamination in aquatic systems. The research detect the effect of BaP, typical representative of PAHs, on the caged black porgy by measure of liver organs CYP1A1 mRNA expression and the activity of EROD. It is expected to screen a biomarker in molecule level to indicate the pollution in the aquatic ecosystem. The following result were obtained:1. A CYP1A1 cDNA was cloned from the liver tissue of black porgy(Genebank accession number DQ898145). Sequence alinement shows that CYP1A1 sequence is highly homologized with those cloned from other sparid fishes, the identity is more than 90%.This sequence contains an unique sequence of CYP gene family and an unique sequence of the CYP1A gene subfamily.It demonstrates the sequence we cloned belongs to the subfamily of CYP1A in fish.2. The effect of BaP upon CYP1A1 mRNA level in liver was detected using a semi-quantified RT-PCR method. 6hrs after exposed to BaP, CYP1A1 mRNA is induced, and the time to reach the Maximum expression depends on the concentration of BaP. The fish was exposed to 5μg/L and 0.2μg/L of BaP,and after 6hrs the CYP1A1 expression in liver reaches the maximum and then decreases to basal level. While 1μg/L , it needs 24hrs..3. Using Dot blot hybridization method to detect the induction of BaP on CYP1A1 mRNA level in liver. The fish was exposed to BaP,and after 6hrs CYP1A1 mRNA level in liver is induced. Statistical analysis(One-way ANOVA and Dunnett t-test) shows that 12hrs after exposure to 5ug/L BaP, CYP1A1 expression in liver is remarkable induced (p<0.05)compared to control ,and exposure to 1ug/L, the CYP1A1 mRNA level is highly induced (p<0.01)4. Using Dot blot hybridization method to detect the induction of BaP on CYP1A1 mRNA level in gill. After exposure to BaP, CYP1A1 mRNA level in gill is strongly induced. 6hrs and 12hrs after exposure , CYP1A1 mRNA in gill is strongly induced compared to the control group and independent on...