ESTROGENIC ACTIVITY OF SURFACTANTS AND SOME OF THEIR DEGRADATION PRODUCTS ASSESSED USING A RECOMBINANT YEAST SCREEN

An estrogen-inducible screen was developed in yeast (Saccharomyces cer evisiae) in order to assess whether surfactants and their major degrad ation products are estrogenic. The DNA sequence of the human estrogen receptor (hER) was integrated into the yeast genome, which also contai ned expression plasmids carrying estrogen-responsive sequences (ERE) c ontrolling the expression of the reporter gene lac-Z (encoding the enz yme beta-galactosidase), Thus, in the presence of estrogens, beta-gala ctosidase is synthesized and secreted into the medium, where it causes a color change from yellow to red. This recombinant strain was used t o determine whether representatives of major surfactant classes and so me of their principal degradation products possess estrogenic activity . The results were compared to the effects of the main natural estroge n 17 beta-estradiol. None of the parent surfactants tested possessed e strogenic activity. However, one class of surfactants, the alkylphenol polyethoxylates, degrade to persistent metabolites that were weakly e strogenic. Another group of degradation products, the sulfophenyl carb oxylates, which are derived from the biodegradation of linear alkylben zene sulfonates, do not appear to possess estrogenic activity.