title: Optimization of a whole-cell cadmium sensor with a toggle gene circuit.
abstract: This work demonstrates improvement of a whole-cell cadmium detection sensor through construction of a gene circuit. A cadmium (II) specific regulatory promoter, P(cadR,) from Psuedomonas putida 06909, is used in the assembly of a toggle circuit. The circuit contains the cadR promoter fused to lacIq and gfp, and a divergently transcribed tac promoter and cadR. The toggle sensor exhibits lower background fluorescence, and a 20-fold lower detection limit in comparison to a nontoggle gene circuit. The detection limit of the toggle sensor is 0.01 microM (1.12 ppb) cadmium chloride, and tunable with the addition of isopropyl-b-D-thiogalactopyranoside (IPTG). The toggle sensor is highly specific to cadmium (II), and no response is elicited from zinc, lead, manganese, nickel, copper, and mercury.
authors.affiliation: Dept. of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA.
authors.forename: Cindy H
authors.initials: CH
authors.lastname: Wu
authors.forename: David
authors.initials: D
authors.lastname: Le
authors.forename: Ashok
authors.initials: A
authors.lastname: Mulchandani
authors.forename: Wilfred
authors.initials: W
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002104:Cadmium / Q000032:analysis*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods*; D011401:Promoter Regions, Genetic; D016958:Pseudomonas putida / Q000235:genetics / Q000378:metabolism
chemical_list: D002104:Cadmium; D049452:Green Fluorescent Proteins