Arsenic Resistant Bacteria Isolated from Arsenic Contaminated River in the Atacama Desert (Chile)

Abstract

In this study, arsenic resistant bacteria were isolated from sediments of an arsenic contaminated river. Arsenic tolerance of bacteria isolated was carried out by serial dilution on agar plate. Redox abilities were investigated using KMnO4. arsC and aox genes were detected by PCR and RT-PCR, respectively. Bacterial populations were identified by RapID system. Forty nine bacterial strains were isolated, of these, 55 % corresponded to the reducing bacteria, 4% to oxidizing bacteria, 8% presented both activities and in 33% of the bacteria none activity was detected. arsC gene was detected in 11 strains and aox genes were not detected. The activity of arsenic transforming microorganisms in river sediment has significant implications for the behavior of the metalloid.

Genome comparison of two Exiguobacterium strains from high altitude andean lakes with different arsenic resistance: identification and 3D modeling of the Acr3 efflux pump

“…These ecosystems are unique not only for their geographical characteristics and broad range of extreme environments but also for their abundant biodiversity (Fernandez Zenoff et al, 2006;Dib et al, 2008;Seufferheld et al, 2008;Flores et al, 2009;Ordoñez et al, 2009;Albarracín et al, 2011;Farias et al, 2013). In these environments high concentrations of arsenic were described in the water due to a natural geochemical phenomenon (Mantelli et al, 2003;Romero et al, 2003;Escudero et al, 2007;Dib et al, 2008Dib et al, , 2009Escalante et al, 2009). The high concentration of arsenic present in HAAL is strongly limiting not only for human life but also for growth of many microorganisms (Valko et al, 2005) and selects development of arsenic tolerant bacteria (Dib et al, 2008;Ordoñez et al, 2009).…”

Unsuspected Diversity of Arsenite-Oxidizing Bacteria as Revealed by Widespread Distribution of theaoxBGene in Prokaryotes

“…The aerobic arsenite oxidases involved in such processes are heterodimers consisting of a large subunit with a molybdenum center and a [3Fe-4S] cluster (AroA, AsoA, and AoxB) and a small subunit containing a Rieske-type [2Fe-2S] cluster (AroB, AsoB, and AoxA) (1, 13). The large subunit in these enzymes is similar to that found in other members of the dimethyl sulfoxide (DMSO) reductase family of molybdenum enzymes but is clearly phylogenetically divergent from the respiratory arsenate reductases (ArrA) or other proteins of the DMSO reductase family of molybdenum oxidoreductases, such as the new arsenite reductase described recently for Alkalilimnicola ehrlichii (25,31,40).aox genes have been identified in 25 bacterial and archaeal genera isolated from various arsenic-rich environments, most of which belong to the Alpha-, Beta-, or Gammaproteobacteria phylum (7,10,12,14,23,25,29,32,37). Recent studies based on environmental DNA extracted from soils, sediments, and geothermal mats with different chemical characteristics and various levels of arsenic contamination have suggested that the distribution and the diversity of arsenite-oxidizing microorganisms may be greater than previously suggested (6, 10, 14-16, 18, 28, 29).…”

“…aox genes have been identified in 25 bacterial and archaeal genera isolated from various arsenic-rich environments, most of which belong to the Alpha-, Beta-, or Gammaproteobacteria phylum (7,10,12,14,23,25,29,32,37). Recent studies based on environmental DNA extracted from soils, sediments, and geothermal mats with different chemical characteristics and various levels of arsenic contamination have suggested that the distribution and the diversity of arsenite-oxidizing microorganisms may be greater than previously suggested (6, 10, 14-16, 18, 28, 29).…”

Arsenic interception by cell wall of bacteria observed with surface-enhanced Raman scattering

“…They were identified as belonging to four genera capable of tolerating high As concentrations (Chitpirom, et al, 2009;Escalante et al, 2009). Among the four genera, Pseudomonas is the most widely reported genus detected in As contaminated soils (Achour et al, 2007;Escalante, et al, 2009;Huang et al, 2010), As-free soils (Jackson et al, 2005), and natural groundwater (Liao et al, 2011).…”