Are effects of common ragwort in the Ames test caused by pyrrolizidine alkaloids?

It has previously been demonstrated by others that acetone extracts of Senecio jacobaea (syn. Jacobaea vulgaris, common or tansy ragwort) test positive in the Salmonella/microsome mutagenicity test (Ames test). Pyrrolizidine alkaloids (PAs) are thought to be responsible for these mutagenic effects.

Validation of a recombinant cell bioassay for the detection of (gluco)corticosteroids in feed.

Use of hormones for fattening purposes is forbidden in the animal production in Europe (European Commission. 1996. Council Directive EC/96/22 (replacement of 88/146/EC).

Some OH-PCBs are more potent inhibitors of aromatase activity and (anti-) glucocorticoids than non-dioxin like (NDL)-PCBs and MeSO₂-PCBs.

Traditional risk assessment of potential endocrine-disruptive pollutants, including PCBs, focus mainly on the effects of parent compounds. Still, biotransformation results in systemic exposure to PCBs and their bioactive metabolites. In the present paper, the effects of twenty ultra-pure non-dioxin-like (NDL) PCBs and their environmentally relevant hydroxy- (OH-) and methylsulfonyl- (MeSO(2)-) metabolites on aromatase activity and their glucocorticoid properties were investigated.

Recombinant cell bioassays for the detection of (gluco)corticosteroids and endocrine-disrupting potencies of several environmental PCB contaminants.

Sensitive and robust bioassays for glucocorticoids are very useful for the pharmaceutical industry, environmental scientists and veterinary control. Here, a recombinant yeast cell was constructed that expresses the human glucocorticoid receptor alpha and a green fluorescent reporter protein in response to glucocorticoids. Both the receptor construct and the reporter construct were stably integrated into the yeast genome.

A new highly specific and robust yeast androgen bioassay for the detection of agonists and antagonists.

Public concern about the presence of natural and anthropogenic compounds which affect human health by modulating normal endocrine functions is continuously growing. Fast and simple high-throughput screening methods for the detection of hormone activities are thus indispensable. During the last two decades, a panel of different in vitro assays has been developed, mainly for compounds with an estrogenic mode of action.

Rapid yeast estrogen bioassays stably expressing human estrogen receptors alpha and beta, and green fluorescent protein: a comparison of different compounds with both receptor types.

Previously, we described the construction of a rapid yeast bioassay stably expressing human estrogen receptor (hERalpha) and yeast enhanced green fluorescent protein (yEGFP) in response to estrogens. In the present study, the properties of this assay were further studied by testing a series of estrogenic compounds. Furthermore, a similar assay was developed based on the stable expression of human estrogen receptor beta (hERbeta).

Development of a rapid yeast estrogen bioassay, based on the expression of green fluorescent protein.

The aim of this study was to develop an estrogen transcription activation assay that is sensitive, fast and easy to use in the routine screening of estrogen activity in complex matrices such as agricultural products. Recombinant yeast cells were constructed that express the human estrogen receptor alpha (ER alpha) and beta-Galactosidase (beta Gal), Luciferase (Luc) or yeast Enhanced Green Fluorescence Protein (yEGFP) as a reporter protein. Compared to other yeast assays, these new cells contain both the receptor construct as well as the reporter construct stably integrated in the genome with only one copy of the reporter construct.