title: A transcriptional luxAB reporter fusion responding to fluorene in Sphingomonas sp. LB126 and its initial characterisation for whole-cell bioreporter purposes.
abstract: The promoter probe mini-Tn5-luxAB-tet was used to create a luxAB transcriptional fusion responding to fluorene in the fluorene utilising bacterium Sphingomonas sp. LB126. The mutant strain, named L-132, was impaired in fluorene utilisation and strongly emitted light upon addition of fluorene to the growth medium. L-132 was initially characterised and examined for its potential use as a whole-cell biosensor in the perspective of quantifying fluorene in environmental samples. Activity of the reporter gene as a response to fluorene was detectable after 30 min and was optimal after 4 h. A linear response to fluorene concentrations within the water solubility range was achieved, with a detection limit of 200 microg per litre. Besides fluorene, L-132 weakly responded to the polycyclic aromatic hydrocarbons phenanthrene and dibenzothiophene, whereas strong responses were obtained with 9-fluorenone, 9-hydroxyfluorene, phthalic acid and protocatechuic acid. The latter four compounds are metabolites formed in course of fluorene degradation, which suggested that a fluorene metabolite rather than fluorene itself was the true inducer of the luxAB fusion in L-132.
authors.affiliation: Environmental Technology, Flemish Institute for Technological Research (Vito), Mol, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Bastiaens
authors.forename: D
authors.initials: D
authors.lastname: Springael
authors.forename: W
authors.initials: W
authors.lastname: Dejonghe
authors.forename: P
authors.initials: P
authors.lastname: Wattiau
authors.forename: H
authors.initials: H
authors.lastname: Verachtert
authors.forename: L
authors.initials: L
authors.lastname: Diels
mesh_terms: D019677:Artificial Gene Fusion; D015374:Biosensing Techniques; D005449:Fluorenes / Q000032:analysis / Q000378:metabolism*; D005798:Genes, Bacterial; D017930:Genes, Reporter; D062385:Hydroxybenzoates / Q000032:analysis; D008027:Light; D008156:Luciferases / Q000235:genetics; D009154:Mutation; D010795:Phthalic Acids / Q000032:analysis; D011401:Promoter Regions, Genetic; D020578:Sphingomonas / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D005449:Fluorenes; D062385:Hydroxybenzoates; D010795:Phthalic Acids; C009091:protocatechuic acid; C041509:fluorene; C032279:phthalic acid; C028401:9-fluorenone; C042788:fluoren-9-ol; D008156:Luciferases