title: Monitoring of endocrine disruptors in surface waters by the yeast recombinant assay.
abstract: Endocrine disruptors exert physiological effects at very low concentrations. Surface waters present often a mixture of high concentrations of low-potency disruptors and low amounts of very powerful ones, making their chemical analysis complicated and expensive. We developed a recombinant yeast assay (RYA) for estrogenic compounds using 96-well microtiter plates. This assay is based on three yeast strains, transformed with self-propagating plasmids. One strain contains an expression plasmid for the human estrogen hormone receptor and an appropriate reporter; it detects estrogenic and antiestrogenic activities. The two other yeast strains, one expressing the human progesterone receptor and a second based on the yeast activator Gal4p, served to analyze the nature of antiestrogenic activities. We applied this technique to water samples from two tributaries on the Llobregat river (NE Spain) as well as from four sewage treatment plants discharging on them. Our results indicate that the efficiency of sewage treatment plants for eliminating estrogenic compounds varied notably, being in at least one case completely inefficient. We also observed a prevalence of an inhibitory activity all through the two rivers; this inhibition was hormone specific. These results were consistent to previously obtained chemical analyses of the same samples, although chemical and in vivo analyses showed rather different levels of sensitivity for some compounds. Our findings demonstrate the utility of the yeast recombinant assay for analyzing complex natural samples; at the same time, they stress the necessity of a panel of different yeast systems to adequately describe endocrine-disruptor activities.
authors.affiliation: Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona 08034, Spain.
authors.forename: N
authors.initials: N
authors.lastname: García-Reyero
authors.forename: E
authors.initials: E
authors.lastname: Grau
authors.forename: M
authors.initials: M
authors.lastname: Castillo
authors.forename: M J
authors.initials: MJ
authors.lastname: López de Alda
authors.forename: D
authors.initials: D
authors.lastname: Barceló
authors.forename: B
authors.initials: B
authors.lastname: Piña
mesh_terms: D000465:Algorithms; D004268:DNA-Binding Proteins; D004702:Endocrine Glands / Q000187:drug effects*; D004784:Environmental Monitoring / Q000379:methods*; D045166:Estradiol Congeners / Q000633:toxicity*; D005656:Fungal Proteins / Q000235:genetics; D017930:Genes, Reporter / Q000187:drug effects; D006801:Humans; D010957:Plasmids / Q000235:genetics; D011960:Receptors, Estrogen / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins; D012441:Saccharomyces cerevisiae / Q000187:drug effects*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D001616:beta-Galactosidase / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D045166:Estradiol Congeners; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D011960:Receptors, Estrogen; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D014874:Water Pollutants, Chemical; D001616:beta-Galactosidase