title: Dose-response relationships and statistical performance of a battery of bacterial gene profiling assays.
abstract: Because of increasing awareness and legislative demands, there is a demand for the development and use of biological assays for the assessment of the toxicity of chemicals, environmental samples. Recently, a growing number of bacterial reporter assays have been developed and implemented. Nevertheless, little data is published on the performance of these assays in terms of analytical parameters. We present results on a battery of 14 transgenic Escherichia coli strains carrying different promoter::reporter fusions. Growth characteristics and basal expression levels were modeled and fitted, data show that growth curves should be taken into account during test development. Our study shows that the induction profiles reflect the mode of action, e.g., paraquat clearly induces the soxRS operon. The sensitivity of the assay compares well to that of whole organism tests, e.g., fish and Daphnia for polar organics. Metal toxicity is detected less efficiently, e.g., cadmium is detected near the LC50 of carp, considered a relatively insensitive species towards cadmium. The assay variability ranges from 10 to 40% depending on the strain, comparable to that of other bioassays. The variability was shown to be determined by the intrinsic traits of the promoter-strain combination, not by operating conditions.
authors.affiliation: Department of Biology, Ecophysiology, Biochemistry and Toxicology Group, University of Antwerp, Groenenborgerlaan 171/U7, Antwerp, Belgium. freddy.dardenne@ua.ac.be
authors.forename: F
authors.initials: F
authors.lastname: Dardenne
authors.forename: I
authors.initials: I
authors.lastname: Nobels
authors.forename: W
authors.initials: W
authors.lastname: De Coen
authors.forename: R
authors.initials: R
authors.lastname: Blust
mesh_terms: D019256:Cadmium Chloride / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering / Q000379:methods; D015386:Hazardous Substances / Q000145:classification / Q000494:pharmacology / Q000633:toxicity*; D018869:Heat-Shock Response; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007763:Lac Operon; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D010269:Paraquat / Q000494:pharmacology; D010416:Pentachlorophenol / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018675:Toxicity Tests
chemical_list: D015386:Hazardous Substances; D011993:Recombinant Fusion Proteins; D008741:Methyl Methanesulfonate; D006861:Hydrogen Peroxide; D010416:Pentachlorophenol; D019256:Cadmium Chloride; D010269:Paraquat