The LUX-FLUORO Test as a Rapid Bioassay for Environmental Pollutants

Abstract

The bioassay LUX-FLUORO test was developed for the rapid detection and quantification of environmental pollutants with genotoxic and/or cytotoxic effects. This bacterial test system uses two different reporter genes whose gene products and their reactions, respectively, can be measured easily and simultaneously by optical methods. Genotoxicity is measured by the increase of bioluminescence in genetically modified bacteria which carry a plasmid with a complete lux operon for the enzyme luciferase from the marine photobacterium P. leiognathi under the control of a DNA-damage dependent so-called SOS promoter. If the desoxyribonucleic acid (DNA) in these bacteria is damaged by a genotoxic chemical, the SOS promoter is turned on and the lux operon is expressed. The newly synthesized luciferase reacts with its substrate thereby producing bioluminescence in a damage-proportional manner. In the second part of the system, genetically modified bacteria carry the gfp gene for the green fluorescent protein from the jellyfish A. victoria downstream from a constitutively expressed promoter. These bacteria are fluorescent under normal conditions. If their cellular metabolism is disturbed by the action of cytotoxic chemicals the fluorescence decreases in a dose-proportional manner. The combined LUX-FLUORO test can be used for the biological assessment of the geno- and cytotoxicity of a wide variety of organic and inorganic chemicals including complex mixtures in different matrices.