Effect Of Cd-PCB153,Humic Acid And Cd-PCB153 On RNA/DNA And Expression Of Sonic Hedhehog Gene Of Marin Med Aka Larva

An experiment was conducted to study:(1)the effect of different doses(0-200μg/L)of mixed cadmium(Cd),2,2’,4,4’,5,5’-hexachlorobiphenyl(PCB153)on the RNA/DNA and relative transcript level of Sonic hedgehog gene(Shh)of marine medaka(Oryzias melastigma)larva;(2)the effect of different doses of fulvic acid(FA)and Cd-PCB153(200-200μg/L)on the RNA/DNA and relative transcript level of Shh of marine medaka larva.The larvae were bred in a simulation ecosystem using a suitable sea water(pH 8.1,28℃,salinity 30,dissolved oxygen 6.0mg/dm3)prepared by high-grade sea crystal imported from Germany.The larvae with 10d of age,healthy and similar size were chosen for experiment.After exposing experiments and FA experiments,we extracted RNA and DNA of whole fish,counted RNA/DNA in marine madaka,and the circulating threshold of Shh gene were determined using reverse transcription PCR(RT-PCR)and real-time quantitative PCR(RTQ-PCR).The relative expression levels of Shh gene were evaluated using 2-△△Ct and the results as follows:1.In our experimental conditions,Cd-PCB153(0-250 μg/L)can significantly reduce the ratio of RNA/DNA,and the relative expression levels of Shh gene were suppressed,and the content of Cd and PCB153 in fish body increased with initial dose of Cd and PCB153 in water.The ratio of RNA/DNA of control group GO was 1.30±0.01,the expression level Shh gene of the 2-△△Ct value was 1.82±0.03,the content of Cd,PCB153 in fish samples are not detected,while for G5,the max Cd-PCB153 concentrations of 250-250 μg/L,resulting in the ratio of RNA/DNA of 1.00±0.04,the expression level Shh gene of the 2-△△ct value of 1.33±0.04,the content of Cd,PCB153 in fish samples are(70.20± 1.93),(73.64±1.82)μg/g.And there was a negative correlation between the concentration of Cd-PCB153 and the growth,when the concentration of Cd-PCB153 less than 200-200 μg/L.And when the concentration more than 200-200 μg/L,every index was steady,that is to say,Cd-PCB(200-200 μg/L)was the concentration of largest toxicity on marine medaka larva.2.Under our experimental conditions,FA could significantly reduce the influence of Cd-PCB 153 on the ratio of RNA/DNA,and the relative transcript level of Shh gene of marine medaka prelarva,and the content of Cd and PCB153 in fish body decreased with initial dose of FA in water.The ratio of RNA/DNA and the expression level Shh gene of 2-△△Ct value of control group was 0.931±0.04,(0.98±0.03,the content of Cd,PCB153 in fish samples are(69.04±1.21),(73.91±2.37)μg/g,60 mg C/L FA group was 1.28±0.00,1.91±0.05,the content of Cd,PCB 153 in fish samples are(8.33± 0.57),(8.97±0.48)μg/g.And there was a positive correlation between the concentration of FA and the growth,the expression level Shh gene when the concentration of FA less than 60 mg C/L.And when the concentration more than 60 mg C/L,the indexes were steady,that is to say,under this FA concentration,it was the Cd-PCB(200-200μg/L)best suitable detoxification dose.