title: Novel bacterial bioassay for a high-throughput screening of 4-hydroxyphenylpyruvate dioxygenase inhibitors.
abstract: Plant 4-hydroxyphenylpyruvate dioxygenase (HPPD) is the molecular target of a range of synthetic β-triketone herbicides that are currently used commercially. Their mode of action is based on an irreversible inhibition of HPPD. Therefore, this inhibitory capacity was used to develop a whole-cell colorimetric bioassay with a recombinant Escherichia coli expressing a plant HPPD for the herbicide analysis of β-triketones. The principle of the bioassay is based on the ability of the recombinant E. coli clone to produce a soluble melanin-like pigment, from tyrosine catabolism through p-hydroxyphenylpyruvate and homogentisate. The addition of sulcotrione, a HPPD inhibitor, decreased the pigment production. With the aim to optimize the assay, the E. coli recombinant clone was immobilized in sol-gel or agarose matrix in a 96-well microplate format. The limit of detection for mesotrione, tembotrione, sulcotrione, and leptospermone was 0.069, 0.051, 0.038, and 20 μM, respectively, allowing to validate the whole-cell colorimetric bioassay as a simple and cost-effective alternative tool for laboratory use. The bioassay results from sulcotrione-spiked soil samples were confirmed with high-performance liquid chromatography.
authors.affiliation: Institut de Modélisation et d'Analyse en Géo-Environnement et Santé, Université Perpignan Via Domitia, EA 4218, 66860, Perpignan, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Rocaboy-Faquet
authors.forename: Thierry
authors.initials: T
authors.lastname: Noguer
authors.forename: Sana
authors.initials: S
authors.lastname: Romdhane
authors.forename: Cédric
authors.initials: C
authors.lastname: Bertrand
authors.forename: Franck Emmanuel
authors.initials: FE
authors.lastname: Dayan
authors.forename: Lise
authors.initials: L
authors.lastname: Barthelmebs
mesh_terms: D015111:4-Hydroxyphenylpyruvate Dioxygenase / Q000037:antagonists & inhibitors* / Q000235:genetics; D001681:Biological Assay / Q000379:methods*; D018914:Cells, Immobilized / Q000187:drug effects; D003124:Colorimetry / Q000379:methods; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004791:Enzyme Inhibitors / Q000302:isolation & purification*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D006540:Herbicides / Q000302:isolation & purification*; D010860:Pigments, Biological / Q000032:analysis; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D006540:Herbicides; D010860:Pigments, Biological; D011994:Recombinant Proteins; D015111:4-Hydroxyphenylpyruvate Dioxygenase