| Objectives: This study aims to investigate the physiological and biochemical effects of different levels ?-irradiation on three strains of Drosophila melanogaster,W1118,UAS-EGFP and Actin-Gal4,and to elucidate damages and oxidation caused by radiation,which might provide some theoretical basis for developing biological dosimeter that is used to monitor the leakage dose of nuclear accidents and studying the radiation protection via delivering radiation-resistant genes of Deinococcus radiodurans to Drosophila melanogaster.Methods: 1.W1118,UAS-EGFP and Actin-Gal4 female Drosophila melanogaster were treated with different doses of 137Cs-?-ray,and then the survival fraction and reproductive capacity and pupae movement index were determined.2.ELISA assay was utilized to measure intracellular reactive oxygen species content,total superoxide dismutase activity,catalase activity,malondialdehyde content and reduced glutathione content in Drosophila melanogaster.The radiation oxidative damage of adults Drosophila melanogaster was evaluated.3.After the irradiation,the Drosophila melanogaster genome was extracted and sequenced by PCR amplification and electrophoresis purification.The change of Gadd45 gene in three strains was analyzed.Results: 1.The 50% lethal doses of W1118,UAS-EGFP and Actin-Gal4 strains were 1513 Gy,1643Gy and 1809 Gy,respectively.The 95% lethal doses of W1118,UAS-EGFP and Actin-Gal4 were 1767 Gy,2152Gy,2320 Gy,respectively and the complete death doses were 2200 Gy,2200Gy,2600 Gy,respectively.The reproductive thresholds were 240 Gy,160 Gy and 200 Gy,respectively.The survival rate,climbing height fraction,fecundity,and deuteration height of the three-day-old female Drosophila adults were negatively correlated with the ?-irradiation dose.2.The activitiyactivity of SOD and CAT and the content of GSH in the 160 Gy irradiation group and the 1550 Gy irradiation group were decreased,while the contents of ROS and MDA were increased.3.The similarity of nucleotide sequence of Gadd45 gene in the half lethal dose radiation treatment group with that of unirradiated Drosophila melanogaster Gadd45 gene was 99% and the deletion rate in the sequence was 1%.The base of DNA sequence in the radiation group was changed from T to A/N at the 262 th and 337 th position.The deletion of A and T nucleotides occurred at the 276 th and 433 th position,which resulted in the changed reading frame.Conclusions: 1.137Cs-? radiation may reduce the capacities of the survival,movement and reproduction of three female Drosophila melanogaster strains,W1118,UAS-EGFP and Actin-Gal4,by generating the high-level free radical which causes oxidative damage.2.137Cs-? radiation can cause the nucleotide deletion of the Gadd45 associated with DNA damage repair in Drosophila melanogaster,ultimately yielding defective phenotypes. |
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