Mercury Microbiology: Resistance Systems, Environmental Aspects, Methylation, and Human Health

Mercury (II) removal by resistant bacterial isolates and mercuric (II) reductase activity in a new strain of Pseudomonas sp. B50A

“…The gene merA is part of an operon which comprises regulatory genes encoding transport proteins [7,8]. In general, many mercury resistant isolates possess the merR, merP and merA genes encoding proteins for regulatory function, transport and extracellular binding, and mercuric (II) reductase, respectively [9].…”

Isolation, screening and identification of mercury resistant bacteria from mercury contaminated soil

“…1A-D). It is reported several mercury resistance mechanisms such as methylation of mercury [16][17][18], involving methylation proceeded by bacteria excreting methylcobalamin [17], Hg 2 + to Hg 0 reduction by reductase encoded by mer operon possessed by numerous bacterial strains [19][20][21][22][23][24], presence of plasmids providing resistance to another heavy metals, correlated with antibiot ics resistance [17], precipitation in form of HgS [25] and the synthesis of thiols or another chelates binding the Hg compounds [17,26]. All of these mechanisms work efficiently and decrease mercury toxicity to the cells.…”

Metal Response in Cupriavidus metallidurans

“…Analysis of MerD showed that although it co-regulates expression of the mer operon and shows a high N-terminal sequence similarity to the transcriptional regulator MerR, it does not directly bind the mer operator (Champier et al 2004). Instead, MerD dissociates the Hg-MerR-mer operator complex allowing for the synthesis of new apo-MerR that can then bind to the mer operator (Silver and Hobman 2007;Champier et al 2004). For MerP and the MerP-like N-terminal extension of MerA, it was shown that the metal-binding site consists of the highly conserved GMTCXXC sequence found in 60 P. Monsieurs et al metallochaperones and metal-transporting ATPases (Serre et al 2004;Rossy et al 2004a).…”