A GFP-based bacterial biosensor with chromosomally integrated sensing cassette for quantitative detection of Hg(II) in environment

Priyadarshi, Himanshu; Alam, Absar; Gireesh‐Babu, P.; Das, Rekha; Kishore, Pankaj; Kumar, Shivendra; Chaudhari, Aparna

doi:10.1016/s1001-0742(11)60820-6

Cited by 25 publications

(16 citation statements)

References 27 publications

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“…Several biosensors have been developed for the detection and quantification of inorganic mercury (Hg(II)) in bacterial cells [ 1 – 6 ]. These tools have been used to assess the bioavailability and uptake pathways of Hg(II) complexes to microorganisms as they have the advantage that they only respond to Hg that has entered the cell [ 2 – 6 ]. These bioassays may therefore be applicable to the evaluation of effects of ligand complexation on Hg(II) bioavailability, the deciphering of mechanisms of Hg(II) uptake, and the involvement of various transport pathways in the uptake of Hg(II).…”

Section: Introductionmentioning

confidence: 99%

The Use of a Mercury Biosensor to Evaluate the Bioavailability of Mercury-Thiol Complexes and Mechanisms of Mercury Uptake in Bacteria

Ndu

Barkay

Schartup³

et al. 2015

PLoS ONE

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As mercury (Hg) biosensors are sensitive to only intracellular Hg, they are useful in the investigation of Hg uptake mechanisms and the effects of speciation on Hg bioavailability to microbes. In this study, bacterial biosensors were used to evaluate the roles that several transporters such as the glutathione, cystine/cysteine, and Mer transporters play in the uptake of Hg from Hg-thiol complexes by comparing uptake rates in strains with functioning transport systems to strains where these transporters had been knocked out by deletion of key genes. The Hg uptake into the biosensors was quantified based on the intracellular conversion of inorganic mercury (Hg(II)) to elemental mercury (Hg(0)) by the enzyme MerA. It was found that uptake of Hg from Hg-cysteine (Hg(CYS)2) and Hg-glutathione (Hg(GSH)2) complexes occurred at the same rate as that of inorganic complexes of Hg(II) into Escherichia coli strains with and without intact Mer transport systems. However, higher rates of Hg uptake were observed in the strain with a functioning Mer transport system. These results demonstrate that thiol-bound Hg is bioavailable to E. coli and that this bioavailability is higher in Hg-resistant bacteria with a complete Mer system than in non-resistant strains. No difference in the uptake rate of Hg from Hg(GSH)2 was observed in E. coli strains with or without functioning glutathione transport systems. There was also no difference in uptake rates between a wildtype Bacillus subtilis strain with a functioning cystine/cysteine transport system, and a mutant strain where this transport system had been knocked out. These results cast doubt on the viability of the hypothesis that the entire Hg-thiol complex is taken up into the cell by a thiol transporter. It is more likely that the Hg in the Hg-thiol complex is transferred to a transport protein on the cell membrane and is subsequently internalized.

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Section: Introductionmentioning

confidence: 99%

The Use of a Mercury Biosensor to Evaluate the Bioavailability of Mercury-Thiol Complexes and Mechanisms of Mercury Uptake in Bacteria

Ndu

Barkay

Schartup³

et al. 2015

PLoS ONE

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“…Toxicity is the main reason behind the development of metal biosensors. WCBs were successfully constructed to detect Hg(II) in environmental samples ( Bontidean et al, 2004 ; Priyadarshi et al, 2012 ). Cadmium is detected using WCBs containing GFP-metallothionein ( Amaro et al, 2014 ) and WCBs with an engineered modular genetic AND logic gate are able to detect As(III), Hg(II), Cu(II), and Zn(II) and distinguish between them ( Wang et al, 2013 ).…”

Section: Detection Of Metal Ionsmentioning

confidence: 99%

Transcription factor-based biosensors enlightened by the analyte

et al. 2015

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Whole cell biosensors (WCBs) have multiple applications for environmental monitoring, detecting a wide range of pollutants. WCBs depend critically on the sensitivity and specificity of the transcription factor (TF) used to detect the analyte. We describe the mechanism of regulation and the structural and biochemical properties of TF families that are used, or could be used, for the development of environmental WCBs. Focusing on the chemical nature of the analyte, we review TFs that respond to aromatic compounds (XylS-AraC, XylR-NtrC, and LysR), metal ions (MerR, ArsR, DtxR, Fur, and NikR) or antibiotics (TetR and MarR). Analyzing the structural domains involved in DNA recognition, we highlight the similitudes in the DNA binding domains (DBDs) of these TF families. Opposite to DBDs, the wide range of analytes detected by TFs results in a diversity of structures at the effector binding domain. The modular architecture of TFs opens the possibility of engineering TFs with hybrid DNA and effector specificities. Yet, the lack of a crisp correlation between structural domains and specific functions makes this a challenging task.

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“…A recombinant E. coli (Hakkila et al, 2002) containing merR and luxCDABE from Photorhabdus luminescence could detect Hg from 0.001 mg/L to 0.03mg/L (Ivask et al, 2007). A number of green fluorescent protein (gfp) based Hg biosensors have been reported (Hakkila et al, 2002;Priyadarshi et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…A E.coli construct DH5α was made with the merR gene derived from the Pdu1358 plasmid of Serratia marcescens and the gfp gene from plasmid Pdb402 which responded to 100-1700 nM (0.02 -0.36 mg/L) concentration of Hg 2+ in 5 h, and was stable at very high concentrations of Hg (Priyadarshi et al, 2012). Another GFP based whole cell E. coli sensor could detect 0.001 -0.12 mg/L Hg in 16 h which could simultaneously respond to Zn and Cd (Gireesh-Babu and Chaudhari, 2012).…”

Section: Introductionmentioning

confidence: 99%

Development of a whole cell biosensor for the detection of inorganic mercury

Mahbub

Krishnan

Naidu

et al. 2017

Environmental Technology & Innovation

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A whole cell bacterial biosensor was developed by modification of chromosomal DNA of an environmental bacterial isolate Sphingobium SA2. The sensing element contained green fluorescence protein gene gfp fused to short segment of merA gene of Sphingobium SA2. The sensing element was introduced into electro-competent cells of Sphingobium SA2, where it integrated into the bacterial chromosomal DNA due to homologous recombination. The transformed cells were able to produce green fluorescence in 5 h in the presence of nanomolar concentrations of mercury. A linear positive correlation was observed between 0-40 nm Hg and fluorescence intensity.

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A GFP-based bacterial biosensor with chromosomally integrated sensing cassette for quantitative detection of Hg(II) in environment

Cited by 25 publications

References 27 publications

The Use of a Mercury Biosensor to Evaluate the Bioavailability of Mercury-Thiol Complexes and Mechanisms of Mercury Uptake in Bacteria

The Use of a Mercury Biosensor to Evaluate the Bioavailability of Mercury-Thiol Complexes and Mechanisms of Mercury Uptake in Bacteria

Transcription factor-based biosensors enlightened by the analyte

Development of a whole cell biosensor for the detection of inorganic mercury

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