A Rapid Electrochemical Procedure for the Detection of Hg(0) Produced by Mercuric-Reductase: Application for Monitoring Hg-resistant Bacteria Activity.

Abstract

In this work, gold microelectrodes are employed as traps for the detection of volatilized metallic mercury produced by mercuric reductase (MerA) extracted from an Hg-resistant Pseudomonas putida strain FB1. The enzymatic reduction of Hg (II) to Hg (0) was induced by NADPH cofactor added to the samples. The amount of Hg(0) accumulated on the gold microelectrode surface was determined by anodic stripping voltammetry (ASV) after transferring the gold microelectrode in an aqueous solution containing 0.1 M HNO(3) + 1 M KNO(3). Electrochemical measurements were combined with spectrofluorometric assays of NADPH consumption to derive an analytical expression for the detection of a relative MerA activity of different samples with respect to that of P. putida. The method developed here was employed for the rapid determination of MerA produced by bacteria harbored in soft tissues of clams (Ruditapes philippinarum), collected in high Hg polluted sediments of Northern Adriatic Sea in Italy.

Microorganism remediation strategies towards heavy metals

“…For instance, Pseudomonas putida FB1 and Pseudomonas sp. B50A can reduce Hg(II) to Hg 0 with the help of merA reductase [126,127]. The engineered strains containing merA can increase mercury resistance and remediate mercury pollution to Hg 0 [128].…”

Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

“…at 14,100 g ). The supernatant was recovered, filtered (0.02 mm pore size) and stored at − 20 °C until phosphatase assay was performed [ 39 ]. The supernatant (cytosol) and the pellet (cell membranes) were characterized for total protein concentration by Coomassie Blue dye (Biorad, Italy) assay protocol [ 28 ].…”

Highly Sensitive Electrochemiluminescence Detection of Mercury(II) Ions Based on DNA‐Linked Luminol‐Au NPs Superstructure

“…Thus, various assays for the detection of Hg 2+ ions based on of the unique THg 2+ T coordination chemistry have been developed 6,7. In recent years, much effort has been devoted towards the design of sensing systems for Hg 2+ ions based on various materials, such as organic chromophores 7 or fluorophores 8, conjugated polymers 9, DNAzymes 10, gold nanoparticles 11, semiconductor quantum dots 12, proteins 13, and mercuric‐reductase 14. However, most of these sensors have certain limitations such as poor selectivity with interference from closely related metals, and insufficient sensitivity (limit of detection (LOD)>100 nM).…”