Yeast Estrogen and Androgen Screens

Yeast Estrogen and Androgen Screens

Test organism

  • Baker’s yeast (Saccharomyces cerevisiae)

Detectable effects (impact)

Activation or inhibition of the human estrogen receptor (YES, (anti-)estrogenic effect)
Activation or inhibition of the human androgen receptor (YAS, (anti-)androgenic effect)

Test principle, taking YES as an example

  • In the Yeast Estrogen Screen, genetically modified yeast cells (Saccharomyces cerevisiae), which contain the gene for the human estrogen receptor coupled with a so-called reporter gene (LacZ), indicate estrogenic effects.
  • If an estrogenically active substance binds to the estrogen receptor in the cell, the corresponding gene and then the reporter gene are read. The latter gene encodes for an enzyme (beta-galactosidase), which converts a dye (yellow to red) and thus induces a colour reaction, which is directly correlated to the existence of estrogenically active substances.
  • After 18-hour exposure to chemicals or environmental samples, the estrogeneity of the analysed samples can be measured based on colour induction.
  • By means of lyticase digestion of the yeast cells (L-YES) after exposure, the sensitivity can be increased by about one order of magnitude.
    The same assay principle applies to the detection of anti-estrogenic substances in YES, as well as androgenic and anti-androgenic substances in YAS.

Flow Chart

Video tutorial

Test duration

  • 3 days (exposure time: 18 hours)

Relevance

  • Suitable for detecting numerous natural and synthetic hormonally active substances such as environmental toxins from everyday products, e.g. birth control pill ingredients (17α-ethinylestradiol), synthetic materials (bisphenol A, phthalates), pesticides (methoxychlorine) and non-ionic surfactants (alkylphenoles).
  • Substances with an activating or inhibitory effect on the estrogen and/or androgen receptor of organisms may interfere with reproduction, affect the metabolism and immune system and induce the formation of tumours.

Guidelines and literature

  • ISO 19040-1:2018 Water quality — Determination of the estrogenic potential of water and waste water — Part 1: Yeast estrogen screen (Saccharomyces cerevisiae)
  • Routledge EJ and Sumpter JP (1996). Estrogenic activity of surfactants and some of their degradation products assessed using a recombinant yeast screen. Environ. Toxicol. Chem. 15(3): 241-248.