ABSTRACT
The most common bacterial mercury resistance mechanism is based on the reduction of Hg(II) to Hg0, 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.
O mecanismo de resistência bacteriana ao mercúrio mais comum é baseada na redução do Hg(II) a Hg0, através da atividade da enzima mercúrio redutase (MerA). O uso do fragmento de 431 pb amplificado de uma região conservada do gene merA, que codifica a enzima MerA,foi utilizado como marcador molecular deste mecanismo, permitindo a identificação de bactérias resistentes ao mercúrio.
Subject(s)
DNA Repair Enzymes , Environmental Microbiology , In Vitro Techniques , Mercury/analysis , Oxidoreductases/analysis , Genetic Markers , MethodsABSTRACT
Bacillus pasteurii DR2, a broad-spectrum Hg-resistant bacterial strain, exhibited delayed sporulation and less mercury volatilization in the presence of mercury compounds. However, Hg-sensitive Bacillus subtilis sporulated quickly in the presence of HgCl2 and volatilized no mercury. Levels of Hg2+-reductase and organomercurial lyase in the endospores of Bacillus pasteurii DR2 were lower than those in vegetative cells.
ABSTRACT
There exist a number of mercury-resistant bacterial in environment, Mer operon is involved in the resistant mechanism, MerRTPA of Mer operon encodes the proteins related to the regulation, transport and reduction of mercury ion, respectively. The toxic mercury ion is transported by MerTP from medium to cytoplasmic mercuric reductase, MerA, and deoxidized to non-toxic and volatile element mercury, Hg(0). Bacterial mercury-resistant system originated from ancient times, and evolved into the Mer operon with diversity by gene integration and insertion. Mercury-resistant bacteria highly specifically absorb mercury ion, and can be used in recovering the mercury-polluted environment as well as the genetic selective marker.