Background

In the Amazon, mercury is considered one of the region main contaminants because is utilized in mines, being part of the gold amalgamation This operation consists of the connection of mercury with another metal, or the separation of gold and ganga's silver, through mercury. (Au-Hg) process. Where a quantity of metallic mercury (Hg0) is released upon rivers and soils by the handling in insecure situations , and through the outdoor burning process, where there is a release of the element's vapor to the atmosphere, practices that cause the aquatic ecosystem contamination.

In the Amazon effluents, around 3.000 tons of mercury are found available. This mercury can be bio-converted into forms that are more toxic to human beings, through de methylation - the addition of a CH3 radical - of mercury, acquiring bio-accumulative propertiesnot easily expelled through the living beings, increasing the concentration in the organisms as they are ingested or inhaled. , due to its affinity to animal tissues (Souza and Barbisa 2010). The mercury methylation is a crucial step to its entry in the aquatic organisms food chain, which are the biggest bio-concentrators of this metal, therefore they contaminate the riverside communities through the fish ingestion.

Taking in consideration that the riverside communitiesa traditional pupulation that resides in the rivers proximities and they have the artisanal fishing as main food supplying activity., during a long period, have as their major source of proteins, the consumption of fish, thus they became more vunerable to a high Hg concentration in their bodies, causing the following harmfull effects : abdominal pains, diarrhea, osteoporosis, brain and renal lesions, psychological and psychomotor alterations.

In the environment, the successive transformations suffered by Hg, represent risks not only for superior organisms, but also for microorganisms. However, is known that some bacterias own resistance to mercury, among them Serratia marcescens, Pseudomonas putida, Cupriavidus metallidurans, Entereobacter. The bacteria resistance occurs by the activity of proteins that are expressed through a gene set denominated operon mer . This operon has big bio-remediating capacity for presenting the proteins merA e merB which catalyze Hg2+ and CH3Hg, respectively, converting then into Hg0 (volatile in room temperature). In addition to the catalytic function, the operon presents proteins that hold carrier functions merP e merT , which carry Hg of the periplasm to the cytoplasm (Biondo 2008).

On the above, UFAM_Brazil Team aims to utilize the operon Mer mechanism to solve the adversities created by the inappropriate use of Hg through the synthetic biology technologies.