Detection of Lead and Cadmium using Biosensor Expressing Luciferase Reporting Gene in Aquatic Environment

Background and Objective: Bacterial biosensors refer to bacterial cells that have been genetically engineered to produce a measurable signal in response to a specific chemical or physical agent in their environment. Bacterial biosensors for detection of heavy metals typically composed of a promoter (responsible for sensing or interacting with the target analyte) fused to a reporter gene (responsible for generation of the detectable biological signal). Biosensor has great potential for detection of environmental contaminants. Method and material: Two biosensor gene constructs were engineered by using lead responsive elements from plasmid pMOL30 of Ralstonia metallidurans CH34 strain (pbr promoter and pbrR as a regulatory gene) and lead and cadmium responsive elements from pI258 plasmid of Staphylococcus aureus (cadA promoter and cadC as a regulatory gene) to control the expression of the firfly luciferase gene, which functioned as the reporter. They were called pGL3-luc/pbr-Biosensor and pGL3-luc/Cad-Biosensor respectively. Escherichia coli DH5α is the host organism. Results: pGL3-luc/pbr-Biosensor is reported to be able to detect Pb+2 in the range of 1–100 μM by expressing firefly luciferase and not expressing reporter in present of other metals such as Sn+2, Ni+2, Cd+2. Moreover, this biosensor is 50 times more sensitive compared to the previous biosensors constructed by Chakraborty. Conclusion: Use of these bacterial biosensors has many benefits such as measuring the available concentrations of heavy metals, saving time and cost and ease of use.

کلیدواژه ها:

bacterial biosensor ، pbr promoter ، cadA promoter ، heavy metals ، contamination ، detection ، lucifer