Improved bacterial SOS promoter∷ lux fusions for genotoxicity detection

• Published in: Mutation research Vol. 466; no. 1; pp. 97 - 107
• Main Authors: Davidov, Yaakov, Rozen, Rachel, Smulski, Dana R, Van Dyk, Tina K, Vollmer, Amy C, Elsemore, David A, LaRossa, Robert A, Belkin, Shimshon
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 03.03.2000; Elsevier
• Subjects: Alginates; Ames test; Bacteria - drug effects; Bacteria - genetics; Bacterial Outer Membrane Proteins - genetics; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological and medical sciences; Bioluminescence; Escherichia coli; Escherichia coli - genetics; Escherichia coli Proteins; General aspects. Methods; Genes, Reporter - genetics; Genotoxicity testing; Glucuronic Acid; Hexuronic Acids; Hydrogen Peroxide - toxicity; Industrial Waste; Kinetics; Luminescent Measurements; lux; Medical sciences; Membrane Transport Proteins; Mutagenicity Tests - methods; Mutation; Photorhabdus - genetics; Promoter Regions, Genetic - genetics; recA; Recombinant Fusion Proteins - drug effects; Recombinant Fusion Proteins - genetics; Replicon; Repressor Proteins - genetics; Salmonella typhimurium - genetics; Serine Endopeptidases - genetics; Serine Endopeptidases - metabolism; SOS response; SOS Response (Genetics) - drug effects; SOS Response (Genetics) - genetics; Species Specificity; Temperature; Time Factors; Toxicology; Trans-Activators - genetics; Vibrio - genetics; Water Pollutants - toxicity; Bioluminescence; Ames test; recA; Escherichia coli; Genotoxicity testing; SOS response; lux; Enzyme; Transcription promoter; Mutagenicity testing; Toxicity; Luciferase; Method; Salmonella typhimurium; Bacteria; Oxidoreductases; Hybrid gene; Enterobacteriaceae
• ISSN: 1383-5718; 0027-5107; 1879-3592
• DOI: 10.1016/S1383-5718(99)00233-8

Escherichia coli strains containing plasmid-borne fusions of Vibrio fischeri lux to the recA promoter–operator region were previously shown to be potentially useful for detecting genotoxicants. In an attempt to improve past performance, the present study examines several modifications and variations of this design, singly or in various combinations: (1) modifying the host cell's toxicant efflux capacity via a tolC mutation; (2) incorporating the lux fusion onto the bacterial chromosome, rather then on a plasmid; (3) changing the reporter element to a different lux system ( Photorhabdus luminescens), with a broader temperature range; (4) using Salmonella typhimurium instead of an E. coli host. A broad spectrum of responses to pure chemicals as well as to industrial wastewater samples was observed. Generally, fastest responses were exhibited by Sal94, a S. typhimurium strain harboring a plasmid-borne fusion of V. fischeri lux to the E. coli recA promoter. Highest sensitivity, however, was demonstrated by DPD3063, an E. coli strain in which the same fusion was integrated into the bacterial chromosome, and by DPD2797, a plasmid-bearing tolC mutant. Overall, the two latter strains appeared to perform better and seemed preferable over the others. The sensor strains retained their sensitivity following a 2-month incubation after alginate-embedding, but at the cost of a significantly delayed response.