Yadetie Fekadu

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  • Article
    Transcriptome responses in polar cod (Boreogadus saida) liver slice culture exposed to benzo[a]pyrene and ethynylestradiol: insights into anti-estrogenic effects
    (Elsevier, 2021-05-17) Yadetie, Fekadu ; Brun, Nadja R. ; Vieweg, Ireen ; Nahrgang, Jasmine ; Karlsen, Odd André ; Goksøyr, Anders
    Polar cod (Boreogadus saida) is a key species in the arctic marine ecosystem vulnerable to effects of pollution, particularly from petroleum related activities. To facilitate studying the effects of those pollutants, we adapted a precision-cut liver slice culture protocol for this species. Using this system on board a research vessel, we studied gene expression in liver slice after exposure to the polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (BaP), ethynylestradiol (EE2), and their mixtures, to map their molecular targets and examine possible anti-estrogenic effects of BaP. The exposure experiments were performed with BaP alone (0.1, 1, and 10 μM) or in combination with low concentrations of EE2 (5 nM) to mimic physiological estradiol levels in early vitellogenic female fish. Transcriptome analysis (RNA-seq) was performed after 72 h exposure in culture to map the genes and cellular pathways affected. The results provide a view of global transcriptome responses to BaP and EE2, which resulted in enrichment of many pathways such as the aryl hydrocarbon (Ahr) and estrogen receptor pathways. In the mixture exposure, BaP resulted in anti-estrogenic effects, shown by attenuation of EE2 activated transcription of many estrogen target genes. The results from this ex vivo experiment suggest that pollutants that activate the Ahr pathway such as the PAH compound BaP can result in anti-estrogenic effects that may lead to endocrine disruption in polar cod.
  • Article
    Transcriptome responses in copepods Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus exposed to phenanthrene and benzo[a]pyrene
    (Elsevier, 2022-08-12) Yadetie, Fekadu ; Brun, Nadja R. ; Giebichenstein, Julia ; Dmoch, Katarzyna ; Hylland, Ketil ; Borgå, Katrine ; Karlsen, Odd André ; Goksøyr, Anders
    Arctic and sub-arctic pelagic organisms can be exposed to effluents and spills from offshore petroleum-related activities and thus it is important to understand how they respond to crude oil related contaminants such as polycyclic aromatic hydrocarbons (PAHs). The copepod species Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus represent key links in the arctic marine food web. We performed a transcriptome analysis of the three species exposed to phenanthrene (Phe) and benzo[a]pyrene (BaP) representing low and high molecular weight PAHs, respectively. Differential expression of several genes involved in many cellular pathways was observed after 72 h exposure to Phe (0.1 μM) and BaP (0.1 μM). In C. finmarchicus and C. glacialis, the exposure resulted in up-regulation of genes encoding enzymes in xenobiotic biotransformation, particularly the phase II cytosolic sulfonation system that include 3′-phosphoadenosine 5′-phosphosulfate synthase (PAPSS) and sulfotransferases (SULTs). The sulfonation pathway genes were more strongly induced by BaP than Phe in C. finmarchicus and C. glacialis but were not affected in C. hyperboreus. However, a larger number of genes and pathways were modulated in C. hyperboreus by the PAHs including genes encoding xenobiotic biotransformation and lipid metabolism enzymes, suggesting stronger responses in this species. The results suggest that the cytosolic sulfonation is a major phase II conjugation pathway for PAHs in C. finmarchicus and C. glacialis. Some of the biotransformation systems affected are known to be involved in metabolism of endogenous compounds such as ecdysteroids, which may suggest potential interference with physiological and developmental processes of the copepod species.[Display omitted]•Characterized transcriptome responses in three Calanus species exposed to phenanthrene (Phe) and benzo[a]pyrene (BaP).•Many xenobiotic biotransformation genes and pathways were affected by Phe and BaP in the three species.•Genes in sulfonation system were up-regulated by Phe and BaP in C. finmarchicus and C. glacialis.•A larger number of other pathways such as lipid metabolism were modulated in Phe and BaP exposed C. hyperboreus.