| Polycyclic aromatic hydrocarbons (PAHs), listsd as persistent toxic substances (PTS), are ubiquitous in environment. With characteristics of adhesion, refractory, semivolatile and accumulation, PAHs damage the nervous, immune, endocrine and reproductive systems of organisms. The European Food Safety Authority (EFSA) introduceda system of four specific PAHs, namely, benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), benzo[b]fluoranthene (BbF) and chrysene (CHR), assessing that the sum of the four PAH compounds was the most suitable indicator for PAHs in food. The main objective of this study was three-fold:to high through-put analysis of digital gene expression of scallops exposed to PAHs, to investigate the accumulation rules of PAHs mixture and to screen useful canditors monitoring PAHs pollution in marine system. This study may intend to provide fundamental evidence of PAHs pollutin monitoring in China coastal area.1. Analysis of digital gene expression of Chlamys farreri exposed to PAHsIn this chapter, we ultimate RNA-seq technology screen gene expression of digestive gland of scallops after 10 days exposure. The data suggested that 469 genes has been differential expressed from the control group, among which 209 were up-degrated and 260 were down-dagrated. Assessing the relationship between genes and sensitivities to PAHs, CYP4502P1 and QO can be applied to estimate marine PAHs pollution. But further researches are necessary.2. Study on toxic effects of Chlamys farreri exposed to PAHsThe present study, we measured the PAHs residual quantity in tissues, detoxification metabolism enzymes (EH、DD、GST、UGT、SULT、SOD、GSH/GSSG) and related key gene (EH、DD、GST、UGT、SULT、Cu/Zn-SOD) and damage effects of biological macromolecules (MDA content, PC content and F value) of gills and digestive gland of scallops during 21 days PAHs mixture (BaP:BbF:CHR: BaA=5:3:1:1) exposure. Experimental exposure concentration is set to the control group,0.02,0.2,2μg/L, while at 0,1,3,6,10,15 and 21 day. The results showed that the accumulation order of PAHs in tissues was digestive gland>gill> soft tissue> adductor muscle, the order of PAHs ingredients accumulated was CHR≈BaA>BbF> BaP. Measuring indexes of Ⅰ-phase metabolism, EH and DD activity was induced and then kept steady. The exposure groups are significant different from the control one. The same trend was observed in the mRNA expression of EH and DD.Neither enzyme activity nor mRNA expression presented significant difference with tissue differential. As to Ⅱ-phase metabolism, all enzymes were induced at beginning, except high conctration group of GST. The genes expression showed the similar viration to related enzymes. SOD activity increased during the first 10 day, and showed significant positive relationship with pollution contration and exposure days. On the contrary, mRNA expression of SOD was decreaed at first. The difference of treated groups of GSH/GSSG ratio was non-significant. Besides that, F value was negative related with pollution contration. MDA content was different from the control group. Significant difference of PC content was observed among exposure groups. In sum, CHR and BaA with lighter molecular weight are more easy to be accumulated. The digestive gland of scallops was more sensititive to PAHs accumulaton. The indexes including GST、SOD and F value could be applied to assess the PAHs pollution in the marine eco-system. |
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