基因重组酵母细胞检测养殖场污水中环境雌激素

The Bioassay of Environmental Estrogens in the Livestock Wastewater Using Recombinant Yeast Cell

用细胞生物学分析方法,对某养殖场污水处理厂水样中的类雌激素活性进行了分析,其中处理前水样6份,处理后水样9份。水样中的雌激素类化合物分别用大孔树脂富集,依次用丙酮、甲醇、乙醚洗脱,洗脱液经水浴蒸发挥干并用二甲亚砜定容。用重组人雌激素受体酵母细胞测其类雌激素活性,报告基因为编码β-半乳糖苷酶的LacZ基因。结果发现,处理前水样雌激素活性较高,而处理后水样对β-半乳糖苷酶的诱导水平较低。经17β雌二醇(E2)标准曲线换算成雌二醇当量,发现处理前水样雌激素活性在0.0001至0.15nmol·L-1E2当量,而处理后水样雌激素活性明显下降,有17个水样雌激素活性低于检出限,这说明畜牧厂污水中的雌激素类化合物通过污水处理厂处理后可下降。

The extracts prepared from 15 selected water samples taken from the farm wastewater treatment plant, among them 6 samples from pre-treatment and 9 from post-treatment, were analyzed for estrogen-like activity with a cellular bioassay. After enriched by macroporous resin, the estrogen-like compounds in the water sample were eluted by acetone, methanol and diethyl ether respectively. The elution was evaporated in water bath and the extracts were metered to a volume using dimethyl sulfoxide （DMSO）. Yeast cell, which was transfected with the expression plasmid of human estrogen receptor and the Lac Z reporter plasmid encoding β-galactosidase, was used to measure the estrogen-like compounds in the extracts. The polluted water samples from pre-treatment showed the higher estrogenic potency compared to the effluent samples from post-treatment which showed low induction of β-galactosidase relative to solvent control conditions. By comparison with a standard curve for 17β-estradiol （E2）, estrogenic potency in the water samples from the pre-treatment was calculated as E2-equivalents and ranged from 0.000 1 to 0.15 nmol·L^-1 E2-equivalents. The estrogenic potency in water samples from the post-treatment was significantly lower compared with that of the pre-treatment, 17 water samples were less than the detection limit, illustrating that the estrogen-like compounds can decline after treatment in the plant.