The current study was aimed at isolating and identifying the halophilic and halotolerant bacteria which can produce mercuric reductase in Gavkhuni wetland in Iran. Moreover, tracking and sequencing merA gene and kinetic properties of mercuric reductase in the selected strain were performed in this study. Soil samples were taken from Gavkhuni wetland and cultured in nutrient agar medium...

introduction: the fate of xenobiotics that is present, increasing day by day. the increasing fates altered or inhibit the metabolic activities like detoxification and biotransformation. methods: the present study highlights this slow biotransformation and detoxification on the basis of specific enzymes which have a say in assessment of mercuric chloride toxicity and modulation by panax ginseng ...

Introduction: The fate of xenobiotics that is present, increasing day by day. The increasing fates altered or inhibit the metabolic activities like detoxification and biotransformation. Methods: The present study highlights this slow biotransformation and detoxification on the basis of specific enzymes which have a say in assessment of mercuric chloride toxicity and modulation by Panax ginse...

The most common bacterial mercury resistance mechanism is based on the reduction of Hg(II) to Hg(0), which is dependent of the mercuric reductase enzyme (MerA) activity. The use of a 431 bp fragment of a conservative region of the mercuric reductase (merA) gene was applied as a molecular marker of this mechanism, allowing the identification of mercury resistant bacterial strains.

A colorimetric assay for NADPH-dependent, mercuric ion-specific oxidoreductase activity was developed to facilitate the investigation of mercuric reductase gene expression in polluted aquatic ecosystems. Protein molecules extracted directly from unseeded freshwater and samples seeded with Pseudomonas aeruginosa PU21 (Rip64) were quantitatively assayed for mercuric reductase activity in microtit...

A Chesapeake Bay water isolate of Mycobacterium scrofulaceum containing a 115-megadalton plasmid (pVT1) grew in the presence of 100 microM HgCl2 and converted soluble 203Hg2+ to volatile mercury at a rate of 50 pmol/10(8) cells per min. Cell extracts contained a soluble mercuric reductase whose activity was not dependent on exogenously supplied thiol compounds. The enzyme displayed nearly ident...

The flavoprotein mercuric reductase catalyzes the two-electron reduction of mercuric ions to elemental mercury using NADPH as an electron donor. It has now been purified from Pseudomonas aeruginosa PAO9501 carrying the plasmid pVS1. In this plasmid system, where the mer operon is on the transposon Tn501, mercuric reductase comprises up to 6% of the soluble cellular protein upon induction with m...

Experiments involving mercury resistance mer operon-lacZ fusions, point mutations in the mercuric ion reductase merA gene, and transcomplementation have revealed that in Hg2+-resistant cells, the inducer Hg2+ concentration is rate determining for activation of transcription. mer operon expression is activated by the presence of nanomolar concentrations of Hg2+ in liquid media only when the merc...

Mercuric reductase, a cytosolic flavoprotein which catalyzes the NADPHdependent reduction of mercuric ion to metallic mercury, has been purified about 82-fold from Klebsiella pneumoniae cells and kinetic properties were investigated. The purification method consisted of rapid (two-step) and straightforward procedure involving dye matrix affinity chromatography. The freshly native protein exhibi...

After freezing and thawing, Pseudomonas aeruginosa harboring a drug resistance plasmid (Hg , Strep ), became acutely sensitive to mercuric ions but not to streptomycin in the plating medium. Its sensitivity to both agents in the plating medium became more pronounced, suggesting a synergistic effect of the mercuric ions with streptomycin. This freeze-thaw-induced sensitivity was transient and ca...