| In recent years,the ecotoxicological effects of nanomaterials on aquatic organisms have attracted wide attention,but the mechanism of metal nanoparticles on the immune system of bivalves is still unclear.In this thesis,the immune response of oysters exposed to different concentrations(0,1,10,100 mg / L)of nano-nickel oxide(nNiO)and the clearance mechanism of oysters exposed to different concentrations of nNiO(0,0.1,1,10,50,100 mg /L)under different time(3,12,24,48,96 h)were studied.The main results are as follows:1.A total of 1541 immune-related genes and 17 immune pathways were enriched after transcriptome analysis(RNA-seq)of gill and digestive gland of oyster.The most enriched immune pathways was appeared in the 1 mg/L nNiO treatment group,including Toll and Imd,signaling pathway,NOD-like signaling pathway,Platelet activation,Leukocyte transendothelial migration and Chemokine signaling pathway etc.The maximum number of differentially enriched genes(DEGs)was found in the 10 mg/L treatment group.The number of DEGs in gill tissue(51)was higher than that in digestive gland(42).2.Among all the enriched immune pathways,the differential genes in the immune recognition pathway were the most(70 DEGs),including 44 up-regulated genes and 26down-regulated genes.Among them,the largest number of differential genes were enriched in the 10 mg/L treatment group with 36 DEGs.3.TLR(Toll-like receptor)pathway in Toll and Imd signaling pathway recognized nNiO,through bacterial recognition ligands in My D88-dependent pathway,and induced immune effectors such as IFN to response the exposure of nickel oxide nanoparticles.4.P-gp and MRP are important proteins in oyster MXR system,which transported intracellular nNiO to extracellular.The transport activities of both P-gp and MRP proteins were in dose and time-dependent manner with nNiO exposure.The transport activity in gill was 3.61 times higher than that in digestive gland.Accordingly,gill is the main clearance organ of oysters for nNiO esposure.The transport activity of MXR system decreased to39.31 % after the transport activity of P-gp was specific inhibited which indicated that P-gp was the main clearing protein of MXR system after nNiO exposure.In summary,nNiO exposure activated the immune system of oysters.The nanoparticles were identified mainly through the response of My D88-dependent pathway in gills,response to nano-nickel oxide stress by inducing immune effect factors such as interferon.And the nanoparticles were cleared by transporters on membranes such as P-gp.The results provide insight for the study on the immunotoxicity mechanism of nanotoxicology in bivalves. |
