RESUMO
To determine and compare the toxic effects of Iranian heavy crude oil (IHCO) on the embryonic development of two fish species, we examined transcriptome profiles using RNA-seq. The assembled contigs were 66,070 unigenes in olive flounder embryos and 76,498 unigenes in spotted seabass embryos. In the differential gene expression (DEG) profiles, olive flounder embryos showed different up- and down-regulated patterns than spotted seabass embryos in response to fresh IHCO (FIHCO) and weathered IHCO (WIHCO). In this work, we categorized DEG profiles into six pathways: ribosome, oxidative phosphorylation, Parkinson's disease, Alzheimer's disease, Huntington's disease, and cardiac muscle contraction, validating the expression patterns of 13 DEGs using real-time quantitative RT-PCR. The expression of the CYP1A, CYP1B1, and CYP1C1 genes in spotted seabass embryos was higher than in olive flounder embryos, whereas genes related to cell processing, development, and the immune system showed the opposite trend. Orthologous gene cluster analysis showed that olive flounder embryos were sensitive (fold change of genes with cutoff P<0.05) to both FIHCO and WIHCO, but spotted seabass embryos exhibited higher sensitivity to WIHCO than FIHCO, indicating that species-specific differences are likely to be reflected in population levels after oil spills. Overall, our study provides new insight on the different embryonic susceptibilities of two marine fish species to FIHCO and WIHCO and a better understanding of the underlying molecular mechanisms via RNA-seq and DEGs.
Assuntos
Bass/embriologia , Linguado/embriologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Morfogênese/efeitos dos fármacos , Petróleo/toxicidade , Teratogênese/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Aquicultura , Bass/metabolismo , Análise por Conglomerados , Biologia Computacional , Família 1 do Citocromo P450/química , Família 1 do Citocromo P450/genética , Família 1 do Citocromo P450/metabolismo , Resistência a Medicamentos , Proteínas de Peixes/agonistas , Proteínas de Peixes/antagonistas & inibidores , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Linguado/metabolismo , Perfilação da Expressão Gênica , Ontologia Genética , Poluição por Petróleo/efeitos adversos , RNA Mensageiro/metabolismo , Distribuição Aleatória , República da Coreia , Especificidade da Espécie , Testes de ToxicidadeRESUMO
Crude oils from distinct geographical regions have distinct chemical compositions, and, as a result, their toxicity may be different. However, developmental toxicity of crude oils derived from different geographical regions has not been extensively characterized. In this study, flounder embryos were separately exposed to effluents contaminated by three crude oils including: Basrah Light (BLO), Pyrenees (PCO), and Sakhalin Vityaz (SVO), in addition to a processed fuel oil (MFO-380), to measure developmental toxicity and for gene expressions. Each oil possessed a distinct chemical composition. Edema defect was highest in embryos exposed to PCO and MFO-380 that both have a greater fraction of three-ring PAHs (33% and 22%, respectively) compared to BLO and SVO. Observed caudal fin defects were higher in embryos exposed to SVO and MFO-380, which are both dominated by naphthalenes (81% and 52%, respectively). CYP1A gene expressions were also highest in embryos exposed to SVO and MFO-380. Higher incidence of cardiotoxicity and lower nkx 2.5 expression were detected in embryos exposed to PCO. Unique gene expression profiles were observed in embryos exposed to crude oils with distinct compositions. This study demonstrates that crude oils of different geographical origins with different compositional characteristics induce developmental toxicity to different degrees.