Characterization of bacterial community of a copper processing area and study of the mechanism of resistance to this metal.

Author(s)

Louise Hase Gracioso

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2017-06-28

Examining board members

Elen Aquino Perpetuo; Paula Christine Jimenez; Cláudio Augusto Oller do Nascimento; Vivian Helena Pellizari; Maria Filomena de Andrade Rodrigues

• Advisor: Elen Aquino Perpetuo

Abstract

This work aimed to characterize the bacterial diversity present in a mining area. Results showed the most abundant phylum of the classified bacteria are proteobacteria and 66% of this phylum are class betaproteobacteria. The diversity of bacteria found in the soil outside the mine differed from those found within the mine, showing that the mining action may have modified the local microbial community. In an attempt to elucidate the mechanism of resistance to copper present in the isolates, two strains resistant to high concentrations of copper were chosen: Acinetobacter sp. and Enterobacter sp. Proteomics results showed these two strains have different mechanisms of resistance. Acinetobacter had the expression of two CopA and CopB proteins under different cultivation conditions (200 ppm of copper 6h of culture and 24h and also in 450 ppm of copper and 72h of culture). With these results it was possible to elucidate, this strain has the same mechanism of resistance found in Enterococcus hirae, which the CopA protein functions as the copper influx and the CopB protein the efflux of excess intracellular copper. On the other hand, Enterobacter bacterium had only membrane proteins, and no proteins known as copper resistance. This result was corroborated with PCR, where there was no expression for this gene. Possibly the outer membrane proteins are responsible for the copper homeostasis performed by this strain. (AU)

• FAPESP's process: 13/11020-2 - Characterization of the bacterial community of a copper processing and identification of heavy metals resistance mechanism
• Grantee: Louise Hase Gracioso
• Support Opportunities: Scholarships in Brazil - Doctorate