Effects Of Antioxidant And Immune Enzymes And Transcriptomic Responses Of Typical POPs On Perna Viridis Embryo

Benzo(a)pyrene(BaP)and Dichlorodiphenyltrichloroethane(DDT)are typical Persistent Organic Pollutants(POPs),which are well known for their carcinogenic,teratogenic and mutagenic features.Therefore,the researchers have paid much attention about them.Perna viridis is widely distributed in Asian coastal waters from oceanic waters to estuarine systems,and it is a sessile and filter-feeding animal which can enrich bio-concentration pollutants.Furthermore,embryo is very sensitive and important stage in Perna viridis' life cycle.Until now,research on toxicological mechanism of Perna viridis embryo caused by POPs is still unclear,especially at molecular level.In this study,we investigated the Perna viridis embryo treated with BaP and DDT via transcriptomic and enzyme activities analysis.The results may reveal the toxic mechanism of Perna viridis embryo and provide early warning of POPs and scientific basis for ecological risk assessment.The main results are as follows:1.Antioxidant and immune enzymes effects of BaP and DDT exposure on Perna viridis embryoThe green lipped mussel Perna viridis embryo had an obvious impact on antioxidant and immune activity under BaP and DDT exposure.Compared with the control group,the results showed that the Perna viridis embryo of treated groups were subjected to a regular pattern of change,i.e.inhibition-induction,in activities of SOD and AKP,while the GPx content were rising after treated.Furthermore,the ACP activity were changed differently after BaP and DDT treated,the ACP activity was inhibited and then induced after BaP treated while it has subtle change after DDT exposed.The results showed that the Perna viridis embryo may have accommodation mechanism after BaP exposure.Based on the intergrated biomarker responses index method,we can assess toxicity about BaP and DDT quantitatively.The data suggested that RIB varied in a trend,rising firstly and then falling down and RIB of DDT group was higher than BaP group.So,we can conclude that maybe the embryo toxicity of DDT was higher than BaP.2.Transcriptomic responses of Perna viridis embryo exposed to BaP and DDTBased on the next generation sequencing(NGS)technique for high-throughput RNA-sequencing,the green mussel embryo treated with BaP and DDT with different concentration.A total of 93,362,846 raw reads were obtained.92,362,742 clean reads remained after removing adaptors,poly-N stretches and low quality reads.The values of the Q20 percentage and GC percentage of the clean reads in DGE libraries were 98.12%,37.94%,respectively.We observed that the most frequently represented functional clusters in our transcriptome on the COG database were general function prediction,translation,ribosomal structure and biogenesis.And in GO database,unique genes were assigned to three main categories,including biological process,cellular component and molecular function.The results provided rich molecular data for further study.3.Embryo's DGE analysis for relative gene expression after BaP and DDT exposureTo identify differentially expressed genes in response to BaP and DDT embryo toxicity,digital gene expression tag(DGE)have been generated from BaP and DDT treated.Based on the GO and KEGG analysis,we determined the function of many DEGs and pathways after BaP and DDT exposure.The results suggested that differential expression genes(DEGs)were related to stress response,infectious disease and innate immunity after BaP treated,while the unique genes were participated in the various molecular pathways of toxicological effects,including detoxification,oxidative stress,innate immunity,and neurobehavioral disease.Quantitative real-time PCR(qRT-PCR)measured expressional levels of candidate genes and the results proved the accuracy and reliability of the DGE data.This study reveals that RNA-seq for transcriptome profiling of P.viridis embryo can better understand the embryo toxic effects of BaP and DDT.Furthermore,it also suggests that RNA-seq is a superior tool for generating novel and valuable information for revealing the embryo toxic effects caused by POPs at transcriptional level.In this study,the transcriptome data platform constructed for Perna viridis embryo provides rich molecular information.At the same time,these data might help to lay the foundation for further research of functional genes and reveal the mechanism of Pernaviridis after POPs exposed.