Validation of Arxula Yeast Estrogen Screen assay for detection of estrogenic activity in water samples: Results of an international interlaboratory study

Abstract

Endocrine-active substances can adversely impact the aquatic ecosystems. A special emphasis is laid, among others, on the effects of estrogens and estrogen mimicking compounds. Effect-based screening methods like in vitro bioassays are suitable tools to detect and quantify endocrine activities of known and unknown mixtures. This study describes the validation of the Arxula-Yeast Estrogen Screen (A-YES®) assay, an effect-based method for the detection of the estrogenic potential of water and waste water. This reporter gene assay, provided in ready to use format, is based on the activation of the human estrogen receptor alpha. The user-friendly A-YES® enables inexperienced operators to rapidly become competent with the assay. Fourteen laboratories from four countries with different training levels analyzed 17β-estradiol equivalent concentrations (EEQ) in spiked and unspiked waste water effluent and surface water samples, in waste water influent and spiked salt water samples and in a mixture of three bisphenols. The limit of detection (LOD) for untreated samples was 1.8ng/L 17β-estradiol (E2). Relative repeatability and reproducibility standard deviation for samples with EEQ above the LOD (mean EEQ values between 6.3 and 20.4ng/L) ranged from 7.5 to 21.4% and 16.6 to 28.0%, respectively. Precision results are comparable to other frequently used analytical methods for estrogens. The A-YES® has been demonstrated to be an accurate, precise and robust bioassay. The results have been included in the ISO draft standard. The assay was shown to be applicable for testing of typical waste water influent, effluent and saline water. Other studies have shown that the assay can be used with enriched samples, which lower the LOD to the pg/L range. The validation of the A-YES® and the development of a corresponding international standard constitute a step further towards harmonized and reliable bioassays for the effect-based analysis of estrogens and estrogen-like compounds in water samples.

Ecotoxicological evaluation of construction products: inter-laboratory test with DSLT and percolation test eluates in an aquatic biotest battery

“…A universally valid value for a minimum reproducibility is not considered reasonable for the different toxicity tests and therefore recommendations for reasonable variation of ring test results have not been specified [29]. Our results resemble those presented and discussed by other authors with the same type of questions for similar bioassays mostly in the reproducibility range from 15 to 40%, but also including occasionally higher figures [30][31][32][33][34][35][36]. Thus, reproducibility in this study can be judged as very good for bacteria, daphnia, and fish egg tests.…”

Estrogenic activity of biological samples as a biomarker

“…Recently, a gene reporter assay using stably transfected human cells has also been described in the ISO 19040-3 (ISO 2018) for the assessment of estrogenic activity in water and waste water. As for gene reported assays based on yeasts, two assays, based on Saccharomyces cerevisiae or Arxula adeninivorans, have been described in the ISO 19040-1 (2018) and in the ISO 19040-2 (2018) as methods for the assessment of estrogenic activity in water and waste water (Hettwer et al 2018).…”

Development of the yeastSaccharomycescerevisiae as a biosensor for the toxicity detection of toxic substances

“…Yeast is a single cell eukaryote with a size of 10-20 μm. Because of its advantages of easy culture and rapid proliferation, yeast cell is regarded as an ideal model biomaterial in modern biological research [15], such as the acute toxicity of endocrine disruptors, sewage sediments, heavy metals and other chemicals [16-18].…”