Transcripts level responses in a marine medaka (Oryzias javanicus) exposed to organophosphorus pesticide.

The differential expression of a set of genes encoding antioxidant enzymes and stress-responsive proteins was investigated by real-time quantitative PCR in intestine, liver, and muscle tissues extracted from Oryzias javanicus after exposure to the organophosphorus pesticide, Iprobenfos (IBP). After IBP exposure, transcriptional changes in all the tested genes were prominent in the liver and moderate in the intestine, but unpredictable in the muscle. In the liver, CAT transcription increased after exposure to IBP at all concentrations (P<0.05). CYP1A mRNA was induced in the intestine and liver at the two higher concentrations. G6PD transcription was induced in the liver at the three higher IBP concentrations, but was suppressed in muscle at the same concentrations. GPx expression in the liver increased at three higher concentrations of IBP. In the intestine and liver, GR expression was induced at two higher and three higher concentrations, respectively. However, no significant changes were observed in the muscle. GST and SOD transcription was induced in the liver at all IBP concentrations. IBP exposure induced UB expression in the intestine and liver in a concentration-dependent manner. The transcriptional changes in these genes in the liver could be good biomarkers for stress levels in O.javanicus, and be used as critical biomarkers for environmental quality assessment.