INTERSPECIES DIFFERENCES IN DEVELOPMENTAL TOXICITY AND RNA-SEQ GENE EXPRESSION PROFILING ON TWO MARINE EMBRYONIC FISH EXPOSED TO IRANIAN HEAVY CRUDE OIL

Abstract

Interspecies difference of developmental toxicity of crude oil on embryonic fish allows the prediction of injury extent to a number of resident fish species in oil spill sites. This study clarifies the comparative developmental effects of Iranian Heavy crude oil (IHCO) on the differences of biouptake and toxic sensitivity between embryonic spotted bass (Lateolabrax maculates) and olive flounder (Paralichthys olivaceus). From 24 hrs after exposure to IHCO, several complex effects, including the pericardium edema, spinal curvature, developmental delay and tail fin malformation were observed in both of embryonic fish. The extent of edema, spinal curvature and developmental delay in olive flounder were stronger than those of spotted bass in oil exposed groups, whereas the levels of CYP1A expression were lower than those of spotted bass. Here, we utilized highthroughput RNA-seq to characterize the developmental toxic effects of the crude oil. The assembled contigs contained 16,942 known unigenes in flounder and 167,049 known unigenes in spotted seabass in this study. Comparison of different gene expression between exposed to crude oil and control samples revealed that the number of 97~108 genes defferentially up-regulated but 448~419 genes differentially down-regulated at 4 hrs following exposure. Gene pathway analysis of the differentially expressed gene set indicated the immune and embryonic heart tube development, cellranian Heavy crude oil (IHCO) on the differences of biouptake and toxic sensitivity between embryonic spotted bass (Lateolabrax maculates) and olive flounder (Paralichthys olivaceus). From 24 hrs after exposure to IHCO, several complex effects, including the pericardium edema, spinal curvature, developmental delay and tail fin malformation were observed in both of embryonic fish. The extent of edema, spinal curvature and developmental delay in olive flounder were stronger than those of spotted bass in oil exposed groups, whereas the levels of CYP1A expression were lower than those of spotted bass. Here, we utilized highthroughput RNA-seq to characterize the developmental toxic effects of the crude oil. The assembled contigs contained 16,942 known unigenes in flounder and 167,049 known unigenes in spotted seabass in this study. Comparison of different gene expression between exposed to crude oil and control samples revealed that the number of 97~108 genes defferentially up-regulated but 448~419 genes differentially down-regulated at 4 hrs following exposure. Gene pathway analysis of the differentially expressed gene set indicated the immune and embryonic heart tube development, cell