Abstract
The objective of this study was to optimize the yeast two-hybrid system for quantitative detection of the estrogenic activity of organics in sewage water. Most of the estrogenic activity of sewage water concentrates prepared by Amberlite XAD-2 resin column concentration method was due to that of 17β-estradiol (E2). As well as E2, sewage water concentrates showed higher estrogenic activity with the rise of assay pH than with the conventional pH (pH 4). When assay was performed at pH 7.6. the estrogenic activity of sewage water concentrates increased approximately 25 times as high as that in the case of the conventional pH. This increase was thought to be caused by the following reason: organic constituents of sewage water concentrates disturbed the detection of the activity of E2 at the conventional pH. but humic acid as an organic constituent did not interfere with the detection of the activity of E2 at pH 7.6. The estrogenic activity of sewage water concentrate assayed at pH 7.6 was almost the same as activity corresponding to E2 concentration that was measured by the ELISA method. This pH-optimized yeast two-hybrid system is useful for comprehensive evaluation of estrogenic substances in sewage water and environmental water.
