Cambio - Excellence in Molecular Biology

In Vitro Toxicology

In Vitro Toxicology: Endocrine disruptors

XenoScreen YES/YAS Assay kit for the detection of estrogenic and androgenic endocrine disruptors:

Endocrine disruptors are synthetic chemicals in the environment that mimic the actions of sex hormones and are associated with adverse reproductive and developmental effects on animal physiology.

Of major concern are such chemicals that are found in waste and surface waters, but also in certain industrial products such as plastic food containers, chemical mixtures or cosmetic products. They may interfere with the endocrine system and produce adverse developmental, reproductive, neurological and immune effects in animals and humans.

XenoScreen YES/YAS and YES/YAS XL Assay kit

XenoScreen YES/YAS Assay kit for the detection of estrogenic and androgenic endocrine disruptors

Please note for convenience the XenoScreen YES/YAS Assay kit does NOT include the yeast strains expressing human oestrogen or androgen receptors- These are available to purchase separately

Xenometrix AG

Catalogue No.DescriptionPack SizePriceQty
XN04-233-YXenoScreen XL YES / YAS Assay kit (faster and more sensitive - with Lyticase - without strains)4 compounds + controls £840.00 Quantity Add to Order
XN05-230-AXenoScreen YAS Strain1 Vial £200.00 Quantity Add to Order
XN05-230-EXenoScreen YES Strain1 Vial £200.00 Quantity Add to Order
XN05-233-YXenoScreen YES/YAS Assay kit (standard kit without strains)5 compounds + controls £770.00 Quantity Add to Order
XN05-PMY-7XenoScreen YES / YAS Media SetKit £240.00 Quantity Add to Order
XN05-PPC-4XenoScreen YES / YAS Calibrator SetKit £240.00 Quantity Add to Order
XN32-233-YXenoScreen XL YES (Agonist only - No strains)4 or 32 compounds £300.00 Quantity Add to Order
XN32-234-YXenoScreen XL YAS (Agonist assay only)4/32 sample kit £300.00 Quantity Add to Order

XenoScreen YES/YAS and YES/YAS XL Assay kit

XenoScreen YES/YAS Assay kit for the detection of estrogenic and androgenic endocrine disruptors

Please note for convenience the XenoScreen YES/YAS Assay kit does NOT include the yeast strains expressing human oestrogen or androgen receptors- These are available to purchase separately

Xenometrix AG

XenoScreen YES/YAS Assay kit for the detection of estrogenic and androgenic endocrine disruptors:

Endocrine disruptors are synthetic chemicals in the environment that mimic the actions of sex hormones and are associated with adverse reproductive and developmental effects on animal physiology.

 

 

Of major concern are such chemicals that are found in waste and surface waters, but also in certain industrial products such as plastic food containers, chemical mixtures or cosmetic products. They may interfere with the endocrine system and produce adverse developmental, reproductive, neurological and immune effects in animals and humans.

Xenometrix now offers a bioassay kit (XenoScreen YES/YAS) for the detection of substances activating or inhibiting  the human estrogen and androgen receptors (agonistic and antagonistic action).  The receptors are stably integrated in the yeast (Saccharomyces cerevisiae) chromosome and can activate a reporter gene system upon binding of estrogenic or androgenic compounds.

YAS1-k  YAS2-kYES-principle

 

Principle of the endocrine distruptor assay

The common Baker’s or Brewer’s yeast (Saccharomyces cerevisiae) was genetically modified to identify compounds that can interact with the human estrogen and androgen receptors hERα and hAR. For this purpose the DNA sequences of hERα or hAR were stably integrated into the main chromosome of yeast cells. Additionally, the cells also contain an expression plasmid carrying the reporter gene lacZ encoding the enzyme β-galactosidase and estrogen (YES) or androgen (YAS) responsive elements (Routledge, E.J. and Sumpter, J.P. 1996. Environ. Toxicol. Chem. 13; 241-248; Sohoni, P. and Sumpter, J.P. 1998. J. Endocrinol. 158, 327-339).

Upon binding of a ligand, the hERα and hAR interact with the corresponding response elements on the expression plasmid and modulate the transcription of the lacZ reporter gene. The β-galactosidase is secreted into the medium and converts the yellow substrate chlorophenol red-β-D-galactopyranoside (CPRG) into a red product which can be quantified colorimetrically at 570 nm. The measured OD570 correlates directly with the amount of secreted β-galactosidase and thus with the activity of the test substance which binds to the corresponding receptor.

The XenoScreen YES/YAS assay system can identify both activating (agonistic) and inhibitory (antagonistic) activities of test compounds. For the determination of antagonist activities, the samples are incubated in the presence of a fixed concentration of a reference agonist (17-β estradiol for YES and 5α-dihydrotestosterone for YAS). Inhibition of the response relative to this fixed agonist concentration is a sign of antagonist activity. The assay also identifies cytotoxic effects which lead to growth arrest or lysis of the tester yeast cells. Cytotoxicity is measured as a reduction of light scatter at a wavelength of 690 nm.

Assay Description

Growing yeast cells stably transformed with either hERα (YES) or hAR (YAS) are exposed to serial dilutions of test compound, positive control chemicals (17-β estradiol for YES and 5α-dihydrotestosterone for YAS) and a combination of a fixed concentration of positive controlchemical and serial dilutions of the test compound. The cells are incubated for 48 hrs at 31°C in the presence of a substrate for β-galactosidase. The expression of β-galactosidase is directly linked to the presence of activating (agonistic) or inhibiting (antagonistic) compounds and leads to a conversion of the yellow substrate to the red cleavage product chlorophenol red. Color development and yeast growth are quantified in a spectrophotometer at 570 and 690 nm, respectively. The results are evaluated for estrogenic and androgenic agonistic and antagonistic activities as well as for yeast growth inhibition or cytotoxicity.

Please note for convenience the XenoScreen YES/YAS Assay kit does NOT include the Yeast strains- These are available to purchase separately.

 

XenoScreen XL YES YAS ( includes Lyticase for increased sensitivity)

Rapid, high-sensitivity, combined endocrine disruptor bioassay with YES (yeast estrogen screen) and YAS (yeast androgen screen) for the determination of hormonally active compounds (endocrine disruptors) in environmental, chemical, agrochemical, biocide, pesticide and cosmetic samples. XenoScreen YES YAS and XenoScreen XL YES YAS  are in vitro estrogen and androgen receptor transcriptional activation assays. The testkits are designed to identify both activating (agonistic) and inhibiting (antagonistic) properties of test samples but allow also to test for agonistic activity only. Fresh water, waste water, aqueous extracts and leachates, or chemical, agrochemical or cosmetic compounds,  and biocides, pesticides, plasticizers, detergents, fire retardants, UV filters or mixtures can be tested for endocrine disruption. The bioassay XenoScreen XL YES YAS includes additional lyticase for increased sensitivity.

Benefits:

  •     High sensitivity up to: 4 x 10-12 M (LoD; XenoScreen XL YES YAS)
  •     Standardized procedure with step-by-step instruction manual for sucessful result first-time
  •     Simultaneous analysis of activating (agonist) and inhibiting (antagonist) behaviour
  •     Results within 48 hours (XenoScreen YES YAS); 18 hours (XenoScreen XL YES YAS)
  •    1–2 hours hands-on time
  •    Assay for concentrated or diluted samples requiring 73 μl or 16 μl (XL) as little as sample volumes

   

4 x 96 measuring points: Suggested configuration for XenoScreen YES YAS (2 receptors) allows analysis of 5 samples and for XenoScreen XL YES YAS (2 receptors) of 4 samples each in duplicate, 8 dilution steps, detection of agonist and antagonist activities, with positive and solvent controls. Other assay configurations are also possible.

Excel calculation sheet for evaluation of results is provided with every kit. Xenometrix also offers the evaluation of results to customers free of charge - just send your raw data.

If you cannot find the answer to your problem below then please contact us or telephone 01954 210 200

XenoScreen YES/YAS and YES/YAS XL Assay kit

XenoScreen YES/YAS Assay kit for the detection of estrogenic and androgenic endocrine disruptors

Please note for convenience the XenoScreen YES/YAS Assay kit does NOT include the yeast strains expressing human oestrogen or androgen receptors- These are available to purchase separately

Xenometrix AG

Advantages of XenoScreen YES YAS kits: 

  • Sensitivities: YES: <1x10-10 M; YAS: <1x10-9 M

  • 4-parameter testing: simultaneous analysis of activating (agonistic) and inhibiting (antagonistic) estrogenic and androgenic activities
  • Fast and reliable service (48 h for standard kit and only 18h for the XL kits)
  • Assay data without capital investment or training
  • Detailed assay documentation and data reporting
  • Standard Operating Procedure protocols
  • A fully interactive process
  • Full confidentiality

 

Ordering details and components included in kits:

XenoScreen YES / YAS without Strains

5 Sample Kit without Strains - 384 Measuring Endpoints

Cat. No.  XN05-233-Y 

Details: Sufficient media and reagents to test 5 compounds at 7 concentrations in duplicate  ( calibration curve positive and negative controls) - 384 Total Measuring Endpoints.

Contains: Medium and Supplements, Buffers Substrate Solution CPRG, DMSO Positive Controls 5 x 96 Well Microplates 4 Plate Sealers, 2 Culture Flasks

48 hour incubation.

Strains need to be purchased separately. 

 

XenoScreen XL YES / YAS without Strains

4 Sample Kit without Strains controls for LoD, LoQ - 384 Measuring Endpoints

Cat. No.  XN04-233-Y 

Details: Sufficient media and reagents to test 4 compounds at 8 concentrations in duplicate calibration curve positive and negative controls - 384 Total Measuring Points.

Contains: Lyticase Media and Supplements, Buffers Substrate Solution CPRG, DMSO Positive Controls 9 x 96 Well Microplates 4 Plate Sealers, 4 Culture Flasks.

  • XenoScreen XL YES/YAS kit uses and includes lyticase and a detergent (=LYES and LYAS) to facilitate the secretion of the intracellularly synthesized β-galactosidase (Schultis T. and Metzger J.W., 2004. Chemosphere 57, 1649-1655).
  • Allows the incubation time to be reduced from 48 hrs in the standard YES/YAS assay to 18 hours in the XL assay.
  • The accelerated protocol also enables enhanced sensitivity for testing estrogenic and androgenic compounds.

Strains need to be purchased separately. 

 

XenoScreen XL YES (YES agonist assay only) without Strains

Cat. No.  XN32-233-Y

The “XenoScreen YES” bioassay employs yeast cells stably transfected human estrogen receptor and measures qualitatively or quantitatively compounds with agonistic hormonal activity on the estrogen receptor only. The kit includes all media, controls, plastic material (except pipette tips) for testing 32 environmental samples, e.g. drinking, surface or waste water, in one concentration. A detailed instruction manual as well as an excel calculation sheet for data evaluation are provided. Xenometrix also offer data evaluation of results free of charge to customers.

Details: Sufficient media and reagents to test 4 compounds at 8 concentrations in duplicate or 32 single-dose compounds in duplicate controls - 96 Total Measuring Points.

Contains: Lyticase Media and Supplements, Buffers Substrate Solution CPRG, DMSO Positive Controls 3 x 96 Well Microplates 1 Plate Sealer, 2 Culture Flasks All media and strains provided are sufficient to analyze 4 compounds, duplicates, 8 concentrations, OR 32 single-dose compounds in duplicates, calibration curves, negative and positive controls.

  • Allows the incubation time to be reduced from 48 hrs in the standard YES/YAS assay to 18 hours in the XL assay.
  • The accelerated protocol also enables enhanced sensitivity for testing estrogenic and androgenic compounds.

Strains need to be purchased separately. 

  

XenoScreen YES Strain, 1 vial

XenoScreen YES Strain only, 1 vial   

Cat. No. XN05-230-E

 

XenoScreen YAS Strain, 1 vial

XenoScreen YAS Strain only, 1 vial 

Cat. No. XN05-230-A 

  

XenoScreen YES / YAS Culture Maintenance Set

Includes all necessary reagents for grwoing the strains including basal Medium, Vitamin Solution, Amino Acid Solutions, Copper sulphate Solution 

Cat. No. XN05-PMY-7

 

What is the difference between the XenoScreen YES/YAS and the XenoScreen YES/YAS XL assay?

Both assays use the same transformed yeast cells and similar protocols. The XenoScreen XL YES/YAS uses a modification of the original Routledge and Sumpter protocol which results in a higher assay sensitivity and a shorter assay time (18 hrs of exposure). It includes a cell lysis step using lyticase (Schultis and Metzger, 2004) and avoids contact of the cells with the substrate CPRG during the induction phase. The main differences are listed in the table below:

 

 

 

If you cannot find the answer to your problem below then please contact us or telephone 01954 210 200