HALOARCHAEA FROM THE ANDEAN PUNA: BIOLOGICAL ROLE IN THE ENERGY METABOLISM OF ARSENIC

RASUK MARIA CECILIA; FARIAS MARIA EUGENIA; SORIA MARIANA N.; ORDOÑEZ OMAR F.; CONTRERAS MANUEL

MICROBIAL ECOLOGY

SPRINGER

Lugar: Berlin; Año: 2017

0095-3628

Biofilm, microbial mats and microbialites dwell under highle limiting conditions (high salinity, extreme aridity, pH and elevated arsenic concentration) in the Andean Puna. Even so, not only recent pioneering studies have described the microbial diversity of different Altiplano lakes, but also revealed unexpectedly diverse microbial communities. Arsenic metabolism is proposed to be an ancient mechanism in microbial life. In fact, some Bacteria and Archaea are able to exploit arsenic as a bioenergetic substrate in either anaerobic arsenate respiration or chemolithotrophic growth on arsenite. Only six aioAB sequences coding for arsenite oxidase and three arrA sequences coding for arsenate reductase from haloarchaea were previously deposited in the NCBI Database. However, no experimental data on their expression and function has been reported. Recently our working group reported in a High-Altitude Andean Lake (HAAL) in Argentinean Puna a prevalence of haloarchaea in a biofilm. Besides, it had a surprisingly high abundance of genes used for anaerobic arsenate respiration (arr) and arsenite oxidation (aio). Herein, were investigated the presence and expression of both genes involved in obtaining energy from arsenic compounds in the communities harboring microbial mats and microbialites, and isolated strains. Their presence was confirmed in metagenomic DNA of samples from Diamante and Tebenquiche Lakes, and the expression of these genes was confirmed by metatranscriptomic RNA samples. Using selective isolation techniques, eighteen microorganisms belonging to the Halorubrum genera (phylum Euryarchaeota)