Omic Studies On The Toxicological Effects Of Cadmium And Arsenic In Juvenile Flounder Paralichthys Olivaceus

As environmental contaminants,heavy metals are of great concern due to their high risk to the environment and human health.Cadmium and arsenic are two common heavy metals in the Chinese coastal waters.In this study,the two ?-omic? approaches including metabolomics and proteomics were used to elucidate the toxic effects of Cd and As(?)on the juvenile flounder Paralichthys olivaceus.The major results were summarized as following:1.NMR-based metabolomic data preprocessing method on the extracts of whole tissue from flounder Paralichthys olivaceusThe juvenile flounder Paralichthys olivaceus was exposed to a reduced salinity(50% normal salinity,15.6 psu).After exposure for 48 h,the one dimensional 1H NMR spectroscopy was used to analyze the metabolomes of flounder samples.To investigate the influences of data preprocessing,the metabolomic data of founder samples were subjected to three different data preprocessing methods(unit variance scaling,Pareto scaling and generalized log transformation-mean centering)before pattern recognition analysis.Results indicated that the concentration of osmolyte,trimethylamine N-oxide,was approximately 200 times higher than other metabolites in flounder samples.The reduced salinity induced significant metabolic responses in juvenile flounder.After orthogonal partial least squares-discriminant analysis(OPLS-DA),generalized log transformation-mean centering was found to be the best data preprocessing method,presenting 8 significantly altered metabolites induced by reduced salinity,which was consistent with the quantitative analysis of metabolites.Overall,this study provided a suitable data preprocessing method to analyze the metabolomic data of flounder P.olivaceus.2.Omic analyses reveal toxicological effects of Cd on flounder P.olivaceusThe present study aimed at evaluating the toxicological effects of cadmium(5 ? g/L and 50 ? g/L)in P.olivaceus.After exposure for 14 days,24 spots in all which were significantly expressed in P.olivaceus with cadmium exposures.These proteins can be categorized into diverse functional classes,related to material and energy etabolism?signal transduction and transport?transcription and translation?production and development ? cytoskeleton ? apoptosis and defense mechanisms.Metabolic profiling indicated that Cd2+-treatment enhanced proteolysis and disturbed osmotic regulation and energy metabolism in juvenile flounder P.olivaceus.Furthermore,the enhanced anaerobic metabolism indicated by the elevated lactate in flounder tissue extracts.Gene expression profiles exhibited that Cd could induce immune stress and oxidative stress and disturb energy metabolism in juvenile flounder P.olivaceus.In addition,Cd might promote the growth and gonadal differentiation in juvenile flounder P.olivaceus.3.Omic analyses reveal toxicological effects of As(?)on flounder P.olivaceusThe present study aimed at evaluating the toxicological effects of arsenic(As(?),5 ? g/L and 50 ? g/L)in P.olivaceus.After exposure for 14 days,30 spots in all which were significantly expressed in P.olivaceus with arsenic exposures.These proteins can be categorized into diverse functional classes,related to material and energy etabolism?signal transduction and transport?transcription and translation?protein folding and assembly and cytoskeleton.Metabolic profiling indicated that As(?)-treatment enhanced proteolysis and disturbed osmotic regulation and energy metabolism in juvenile flounder P.olivaceus.Furthermore,the enhanced anaerobic metabolism indicated by the elevated lactate?glucose and glycogen in flounder tissue extracts.Gene expression profiles exhibited that arsenic could induce immune stress and oxidative stress and disturb energy metabolism and promote the growth in juvenile flounder P.olivaceus.