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Distribution of microbial arsenic reduction, oxidation and extrusion genes along a wide range of environmental arsenic concentrations.

Escudero LV, Casamayor EO, Chong G, Pedrós-Alió C, Demergasso C - PLoS ONE (2013)

Bottom Line: A combination of primers from the literature and newly designed primers were used to explore the presence of the arsC gene, coding for the reduction of As (V) to As (III) in one of the most common detoxification mechanisms.The arrA gene, involved in anaerobic respiration using As (V) as electron acceptor, was found in all the systems studied.The As (III) oxidation gene aioA and the As (III) transport gene acr3 were tracked with two primer sets each and they were also found to be spread through the As concentration gradient.

View Article: PubMed Central - PubMed

Affiliation: Centro de Investigación Científico Tecnológico para la Minería-CICITEM, Universidad Católica del Norte, Antofagasta, Chile ; Centro de Biotecnología, Universidad Católica del Norte, Antofagasta, Chile.

ABSTRACT
The presence of the arsenic oxidation, reduction, and extrusion genes arsC, arrA, aioA, and acr3 was explored in a range of natural environments in northern Chile, with arsenic concentrations spanning six orders of magnitude. A combination of primers from the literature and newly designed primers were used to explore the presence of the arsC gene, coding for the reduction of As (V) to As (III) in one of the most common detoxification mechanisms. Enterobacterial related arsC genes appeared only in the environments with the lowest As concentration, while Firmicutes-like genes were present throughout the range of As concentrations. The arrA gene, involved in anaerobic respiration using As (V) as electron acceptor, was found in all the systems studied. The As (III) oxidation gene aioA and the As (III) transport gene acr3 were tracked with two primer sets each and they were also found to be spread through the As concentration gradient. Sediment samples had a higher number of arsenic related genes than water samples. Considering the results of the bacterial community composition available for these samples, the higher microbial phylogenetic diversity of microbes inhabiting the sediments may explain the increased number of genetic resources found to cope with arsenic. Overall, the environmental distribution of arsenic related genes suggests that the occurrence of different ArsC families provides different degrees of protection against arsenic as previously described in laboratory strains, and that the glutaredoxin (Grx)-linked arsenate reductases related to Enterobacteria do not confer enough arsenic resistance to live above certain levels of As concentrations.

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Related in: MedlinePlus

Total [As] in the natural environments analyzed (black triangles for water samples [mg/L] and yellow triangles for sediment samples [mg/Kg]), and range of concentrations where the arsenic related genes could be found with different primer sets (Table 2).The presence of the different genes is indicated by shades of gray; absence by white.
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pone-0078890-g005: Total [As] in the natural environments analyzed (black triangles for water samples [mg/L] and yellow triangles for sediment samples [mg/Kg]), and range of concentrations where the arsenic related genes could be found with different primer sets (Table 2).The presence of the different genes is indicated by shades of gray; absence by white.

Mentions: Primers for the arrA gene retrieved amplicons from all samples (Fig. 5). In most cases, the three primer pairs tested produced amplicons. In the water samples, primers arrA1 and arrA2 always produced the same result (17 positives and two negatives). In the sediment samples, however, primer arrA1 was always positive while arrA2 had three negative results. Primer pair arrA3 was the one with the largest number of negatives (three water and four sediment samples) but in two water samples it was the only one with positive results. In summary, all samples were positive with at least one of the primer sets.


Distribution of microbial arsenic reduction, oxidation and extrusion genes along a wide range of environmental arsenic concentrations.

Escudero LV, Casamayor EO, Chong G, Pedrós-Alió C, Demergasso C - PLoS ONE (2013)

Total [As] in the natural environments analyzed (black triangles for water samples [mg/L] and yellow triangles for sediment samples [mg/Kg]), and range of concentrations where the arsenic related genes could be found with different primer sets (Table 2).The presence of the different genes is indicated by shades of gray; absence by white.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815024&req=5

pone-0078890-g005: Total [As] in the natural environments analyzed (black triangles for water samples [mg/L] and yellow triangles for sediment samples [mg/Kg]), and range of concentrations where the arsenic related genes could be found with different primer sets (Table 2).The presence of the different genes is indicated by shades of gray; absence by white.
Mentions: Primers for the arrA gene retrieved amplicons from all samples (Fig. 5). In most cases, the three primer pairs tested produced amplicons. In the water samples, primers arrA1 and arrA2 always produced the same result (17 positives and two negatives). In the sediment samples, however, primer arrA1 was always positive while arrA2 had three negative results. Primer pair arrA3 was the one with the largest number of negatives (three water and four sediment samples) but in two water samples it was the only one with positive results. In summary, all samples were positive with at least one of the primer sets.

Bottom Line: A combination of primers from the literature and newly designed primers were used to explore the presence of the arsC gene, coding for the reduction of As (V) to As (III) in one of the most common detoxification mechanisms.The arrA gene, involved in anaerobic respiration using As (V) as electron acceptor, was found in all the systems studied.The As (III) oxidation gene aioA and the As (III) transport gene acr3 were tracked with two primer sets each and they were also found to be spread through the As concentration gradient.

View Article: PubMed Central - PubMed

Affiliation: Centro de Investigación Científico Tecnológico para la Minería-CICITEM, Universidad Católica del Norte, Antofagasta, Chile ; Centro de Biotecnología, Universidad Católica del Norte, Antofagasta, Chile.

ABSTRACT
The presence of the arsenic oxidation, reduction, and extrusion genes arsC, arrA, aioA, and acr3 was explored in a range of natural environments in northern Chile, with arsenic concentrations spanning six orders of magnitude. A combination of primers from the literature and newly designed primers were used to explore the presence of the arsC gene, coding for the reduction of As (V) to As (III) in one of the most common detoxification mechanisms. Enterobacterial related arsC genes appeared only in the environments with the lowest As concentration, while Firmicutes-like genes were present throughout the range of As concentrations. The arrA gene, involved in anaerobic respiration using As (V) as electron acceptor, was found in all the systems studied. The As (III) oxidation gene aioA and the As (III) transport gene acr3 were tracked with two primer sets each and they were also found to be spread through the As concentration gradient. Sediment samples had a higher number of arsenic related genes than water samples. Considering the results of the bacterial community composition available for these samples, the higher microbial phylogenetic diversity of microbes inhabiting the sediments may explain the increased number of genetic resources found to cope with arsenic. Overall, the environmental distribution of arsenic related genes suggests that the occurrence of different ArsC families provides different degrees of protection against arsenic as previously described in laboratory strains, and that the glutaredoxin (Grx)-linked arsenate reductases related to Enterobacteria do not confer enough arsenic resistance to live above certain levels of As concentrations.

Show MeSH
Related in: MedlinePlus