Bases moleculares da resistência ao mercúrio em bactérias Gram-negativas da Amazônia brasileira

Abstract

Mercury is one of the most toxic elements, for both human and animals. Its compounds in natural environments can arise from natural and anthropogenic sources. Microbial activities play a critical rule in bioremediation. Mercury resistance in bacteria is associated with a gene cluster present on mer operon. Considering that picture we carried on a study with Gram-negative bacteria isolates from freshwater sediment from two areas with distinct anthropogenic impact, Barreiras and Caxiuanã. Resistance to Hg was evaluated by in vitro growing in medium containing Hg. The presence of mer operon was evaluated by PCR targeting RTPCABD mer gene sequences. The in vitro assay revealed that only two strains, from 107 isolates, were resistant to Hg the bacteria Acinetobacter baumannii from Caxiuanã and a Pseudomonas stutzeri from Barreiras. A mer operon was identified in the Acinetobacter baumannii strain and its sequencing revealed a organization as merRTPCAD and a complete nucleotide identity with a mer operon identified in a Acinetobacter calcoaceticus from Russia.