Construction of bioluminescent cyanobacterial reporter strains for detection of nickel, cobalt and zinc

Abstract

Two whole-cell bioluminescent reporters were constructed by fusing the reporter genes luxAB with the Co(2+) and Zn(2+) inducible coaT promoter or the Ni(2+)-inducible nrsBACD promoter, respectively, in the genome of Synechocystis sp. PCC 6803. The obtained reporters, designated coaLux and nrsLux, respectively, responded quantitatively to metal ions. After 3 h incubation at 40 micromol m(-2) s(-1) visible light, the detection range of coaLux was 0.3-6 microM for Co(2+) and 1-3 microM for Zn(2+). Incubation in darkness increased the detection range by about four times. The nrsLux reporter was specific to Ni(2+), with a detection range of 0.2-6 microM. However, its activity was inhibited by Zn(2+) with a half maximal inhibitory concentration c. 6 microM, and totally inhibited by darkness. This is the first whole-cell Ni(2+)-specific reporter with a clear dose-signal relationship. In a soil-like mixture of different chemical and oil industry wastes, the coaLux reporter strain detected about 90% of the zinc content of the sample. This study demonstrates the potential for development of a rapid, simple and economical field assay for nickel, cobalt and zinc detection using the coaLux and nrsLux reporters.

Ethylene Synthesis and Regulated Expression of Recombinant Protein in Synechocystis sp. PCC 6803

“…The few systems described up to date in the literature that are able to carry out finely tuned heterologous expression in cyanobacteria are native metal-inducible promoters, including promoters preceding genes encoding plastocyanin ( petE [36]), cytochrome c 6 ( petJ [37]), the nrsBACD operon [38], CoaT ( coaT [38]) and metallothionein ( smtA [39]). In order to compare the relative utility of these promoters with the E. coli promoters, we selected three of these systems (P petE , P coa , P smt – Figure 6), sub-cloned them into the self-replicating plasmid in place of the lacI q and P trc elements and evaluated all constructs in both E. coli and Synechocystis (Figure 7).…”

Evaluation of promoters and ribosome binding sites for biotechnological applications in the unicellular cyanobacterium Synechocystis sp. PCC 6803

“…An alternative set of regulated promoters are metal ion inducible promoters that have already been used for several applications8910111213. In Synechocystis , a set of genes responsible for Ni 2+ , Co 2+ , and Zn 2+ tolerance are all grouped together in a gene cluster14.…”

Whole-Cell Fluorescent Biosensors for Bioavailability and Biodegradation of Polychlorinated Biphenyls

“…Previous applications of whole-cell microbial biosensors for environmental studies mainly concentrated on their use as biomarkers to investigate survival and competition ability [7–11] and as biosensors to detect the bioavailability or toxicity of environmental pollutants [15,16,28–33]. Layton et al .…”