Identification of a copper-responsive promoter and development of a copper biosensor in the soil bacterium Achromobacter sp. AO22

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Title: Identification of a copper-responsive promoter and development of a copper biosensor in the soil bacterium Achromobacter sp. AO22
Author(s): Ng, Shee Ping; Palombo, Enzo A.; Bhave, Mrinal
Abstract: A number of human activities result in environmental contamination with copper compounds that can cause severe detrimental effects on the ecosystem as well as human health. The physico-chemical methods of metal detection have limitations such as inability to distinguish between total versus bio-available metals and differences in metal uptake in different organisms. The heavy metal resistance-encoding genetic systems of certain bacteria provide critical tools for development of biosensors for these purposes. This study reports a copper biosensor utilizing the cop operon of the heavy metal resistant bacterial isolate, Achromobacter sp. AO22, isolated from a contaminated site in Australia. A section located between the divergently transcribed putative response regulator gene copR and multicopper oxidase gene copA that included a palindromic cop box was identified as a copper-responsive promoter using a lacZ reporter construct, pCOPRP, in E. coli. The expression was found to be enhanced by inclusion of copR. Another engineered strain, AO22(pCOPRP), showed stronger induction, and the lacZ expression in both backgrounds was enhanced significantly (250-400 fold) by copper but minimally by other metals. The construct in Achromobacter sp. AO22 thus has a high potential as biosensor for detecting copper bioavailability (hence potential toxicity) in a soil bacterial background, while the construct in E. coli is ideal for laboratory-based testing.
Publication type: Journal article
Research centre: Swinburne University of Technology. Faculty of Life and Social Sciences. Environment and Biotechnology Centre
Source: World Journal of Microbiology and Biotechnology, Vol. 28, no. 5 (May 2012), pp. 2221-2228
Publication year: 2012
FOR Code(s): 06 Biological Sciences; 10 Technology
Keyword(s): Biosensors; Cop box; Cop operon; Copper; Heavy metals; Signal transduction
Publisher: Springer
ISSN: 0959-3993
Publisher URL: http://dx.doi.org/10.1007/s11274-012-1029-y
Peer reviewed