Detection and quantification of tetracyclines by whole cell biosensors.
Three different mini-Tn5 plasmids, containing a tetracycline-inducible promoter, Ptet and a regulatory gene, tetR, in operon fusions with a reporter gene system (lacZYA, luxCDABE or gfp), were constructed. These biosensor constructs responded to low levels of tetracyclines by producing beta-galactosidase, light or green fluorescent protein. They did so in a quantitative manner, thus enabling the quantification of tetracyclines in the immediate surroundings of the biosensor organism. All three constructs were transferred successfully to different gram-negative bacteria by conjugation. An Escherichia coli strain containing the Ptet-lac construct was used to determine oxytetracycline in milk as a demonstration of the application of these biosensors.
Hansen
L H
LH
Department of General Microbiology, University of Copenhagen, Denmark.
Sørensen
S J
SJ
D000818:Animals; D001426:Bacterial Proteins; D001681:Biological Assay; D015374:Biosensing Techniques; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D006090:Gram-Negative Bacteria / Q000235:genetics*; D049452:Green Fluorescent Proteins; D007763:Lac Operon; D008164:Luminescent Proteins / Q000096:biosynthesis; D008892:Milk / Q000737:chemistry; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D013050:Spectrometry, Fluorescence; D013754:Tetracyclines / Q000032:analysis* / Q000494:pharmacology; D015534:Trans-Activators; D001616:beta-Galactosidase / Q000096:biosynthesis
D001426:Bacterial Proteins; D008164:Luminescent Proteins; C116102:TetR protein, Clostridium tetani; D013754:Tetracyclines; D015534:Trans-Activators; D049452:Green Fluorescent Proteins; D001616:beta-Galactosidase