Interferences in the yeast estrogen screen (YES) assay for evaluation of estrogenicity in environmental samples, chemical mixtures, and individual substances

Estrogenic activity and acute toxicity assessments of sediments from a chronically polluted estuarine area in southeastern Brazil

“…The methodology developed by Routledge and Sumpter (1996) was used with the modifications suggested by Gomes et al. (2023), which consists of genetically modified Saccharomyces cerevisiae yeast containing a DNA sequence of the human estrogen receptor (ERh). An interaction with the human receptor occurs in the presence of estrogenic compounds, leading to the expression of the Lac‐Z receptor gene that produces the enzyme β‐galactosidase, which is excreted in the medium, metabolizing the chromogenic substrate CPRG.…”

“…The microplates were then sealed with adhesive tape and, shaken vigorously on a plate shaker (IKA® MS3) for 72 h at 30°C in an incubator (New Ethics, 410). Absorption determinations were carried out at 575 nm (for color) and 620 nm (for yeast growth), (Gomes et al., 2023) employing a Spectramax M3 plate reader (Molecular Devices).Cytotoxicity calculations were performed and absorbance control was performed at 620 nm according to Equation (1), (Frische et al., 2009). $$$$\begin{equation}{\text{Cytotoxicity}} = 1 - \left( {\frac{{{\text{ABS}}620{\text{ sample}}}}{{{\text{ABS}}620{\text{ negative control}}}}} \right)\end{equation}$$$$…”

“…The microplates were then sealed with adhesive tape and, shaken vigorously on a plate shaker (IKA® MS3) for 72 h at 30 • C in an incubator (New Ethics, 410). Absorption determinations were carried out at 575 nm (for color) and 620 nm (for yeast growth), (Gomes et al, 2023) employing a Spectramax M3 plate reader (Molecular Devices).Cytotoxicity calculations were performed and absorbance control was performed at 620 nm according to Equation (1), (Frische et al, 2009).…”

“…In this regard, our findings are of significant concern for the Guanabara Bay estuary, as this area displays exorbitant species richness, productivity and biodiversity, also playing a critical role in the maintenance of surrounding ecosystems (Soares- Gomes et al, 2016;Baptista Neto et al, 2006; ) and high socio-economical importance regarding fishing, leisure, and tourism activities (Carvalho et al, 2016). For example, a considerable richness of important ecosystem resources, such as elasmobranchs, is observed in this area, related to the influence of an annual system of low intensity up welling in the adjacent ocean, directly affecting the temperature and nutrients of the region and resulting in the enrichment of the marine biota (Gonçalves-Silva & Vianna, 2018a;Valentin, 2001), and several threatened elasmobranch species, such as the spiny butterfly ray Gymnuraaltavela probably use this estuary as nursery ground (Gonçalves-Silva & Vianna, 2018b). Several bony fish species are also noted in high diversity at Guanabara Bay compared to other areas (Bonecker, 1997) and use the area as nurseries, some even completing their entire life cycles with in the bay (Mazzetti & Hubold, 1982).…”

“…The sediment endocrine disruptors assessments in estuarine areas; however, are still scarce, with most studies carried out in the marine environments (Cotrim et al., 2016). In this context, endocrine disrupting compounds are often detected through the yeast estrogen assay (YES assay), while the Vibrio fischeri bioassay is used to detect sediment toxicity (Cunha et al., 2021; Gomes et al., 2023). In the present study, these assays were used to evaluate the estrogenic activity and sediment toxicity of sediments from a hypereutrophic bay located in southeastern Brazil, named Guanabara Bay, the most important, although chronically polluted, estuary in southeastern Brazil.…”