Bacterial tests for toxicity determination

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The bacterial Lux-Fluoro test measures the genotoxic (SOS-Lux-Test) and cytotoxic (Lac-Fluoro-Test) potency of agents. The SOS-Lux test is based on the bacterial SOS-response which is induced in presence of DNA-damaging agents. It uses the strong SOS-dependent ColD-promoter as receptor component and the promoterless luxCDABFE genes of Photobacterium leiognathi as reporter component. With this system dose-dependent light yields can be recorded in Salmonella typhimurium treated with genotoxic agents.

The Lac-Fluoro-Test uses constitutive green fluorescent protein (GFP from Aequoria victoria) expression mediated by a bacterial protein expression vector to accentuate cellular response to cytotoxins by dose-dependent reduction of GFP-expression.

Recombinant Salmonella typhimurium strains carrying the SOS-LUX-plasmid (TA1535-pPLS-1) or the LAC-GFPuv plasmid (TA1535-pGFPuv) were treated with control substances of different genotoxic and cytotoxic potencies as well as with agents known to induce a broad range of irritation to the rabbit eye. Simultaneously determined cytotoxicity and genotoxicity data were related to publicly available Draize rabbit eye irritation scores (ECETOC database). Further applications contribute to the fields of water research and travel medicine. The SOS-Lux test is part of the space experiment Triple-Lux, to be flown at the ISS.