6 research outputs found
Coupling High-Performance Thin-Layer Chromatography with Bacterial Genotoxicity Bioreporters
We present an innovative technological
platform for monitoring
the direct genotoxicity of individual components in complex environmental
samples, based on bioluminescent <i>Escherichia coli</i> genotoxicity bioreporters, sprayed onto the surface of a high-performance
thin-layer chromatography (HPTLC) plate. These sensor strains harbor
plasmid-borne fusions of selected gene promoters of the <i>E.
coli</i> SOS DNA repair system to the <i>Photorhabdus luminescens
luxABCDE</i> gene cassette, and mark by increased luminescence
the presence of potentially DNA-damaging sample components separated
on the plate. We demonstrate an “on plate” quantifiable
dose-dependent response to several model genotoxicants (without metabolic
activation). We further demonstrate the applicability of the system
by identifying as genotoxic specific components of HPTLC-separated
influent and effluent samples of wastewater treatment plants, thereby
alleviating the need for a comprehensive chemical analysis of the
sample
Estrogenicity of chemical mixtures revealed by a panel of bioassays
International audienceEstrogenic compounds are widely released to surface waters and may cause adverse effects to sensitive aquatic species. Three hormones, estrone, 17β-estradiol and 17α-ethinylestradiol, are of particular concern as they are bioactive at very low concentrations. Current analytical methods are not all sensitive enough for monitoring these substances in water and do not cover mixture effects. Bioassays could complement chemical analysis since they detect the overall effect of complex mixtures. Here, four chemical mixtures and two hormone mixtures were prepared and tested as reference materials together with two environmental water samples by eight laboratories employing nine in vitro and in vivo bioassays covering different steps involved in the estrogenic response. The reference materials included priority substances under the European Water Framework Directive, hormones and other emerging pollutants. Each substance in the mixture was present at its proposed safety limit concentration (EQS) in the European legislation. The in vitro bioassays detected the estrogenic effect of chemical mixtures even when 17β-estradiol was not present but differences in responsiveness were observed. LiBERA was the most responsive, followed by LYES. The additive effect of the hormones was captured by ERα-CALUX, MELN, LYES and LiBERA. Particularly, all in vitro bioassays detected the estrogenic effects in environmental water samples (EEQ values in the range of 0.75–304 × EQS), although the concentrations of hormones were below the limit of quantification in analytical measurements. The present study confirms the applicability of reference materials for estrogenic effects' detection through bioassays and indicates possible methodological drawbacks of some of them that may lead to false negative/positive outcomes. The observed difference in responsiveness among bioassays – based on mixture composition - is probably due to biological differences between them, suggesting that panels of bioassays with different characteristics should be applied according to specific environmental pollution conditions