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Community of thermoacidophilic and arsenic resistant microorganisms isolated from a deep profile of mine heaps.

Casas-Flores S, Gómez-Rodríguez EY, García-Meza JV - AMB Express (2015)

Bottom Line: We found that 0.5 g/L of As does not affect living biomass or biooxidative activity on Cu sulfides, but it dissolves Cu, while As precipitates as arsenic acid (H3AsO4·½H2O).The results indicated arsenic resistance in the microbial community, therefore specific primers were used to amplify ars (arsenic resistance system), aio (arsenite oxidase), or arr (arsenate respiratory reduction) genes from total sample DNA.Presence of arsB genes in S. thermosulfidooxidans in the Q63-66 cultures permits H3AsO4-As(V) detoxification and strengthens the community's response to As.

View Article: PubMed Central - PubMed

Affiliation: División de Biología Molecular, IPCYT, Camino a la Presa San José 2055, Lomas 4a, 78216, San Luis Potosí, SLP, México, scasas@ipicyt.edu.mx.

ABSTRACT
Soluble arsenic (As) in acidic feed solution may inhibit the copper (Cu) bioleaching process within mine heaps. To clarify the effect of soluble arsenic on the live biomass and bioxidative activity in heaps, toxicological assays were performed using a synthetic feed solution given by a mine company. The microorganisms had previously been isolated from two heap samples at up to 66 m depth, and cultured using specific media for chemolithotrophic acidophiles (pH 1-2) and moderate thermophiles (48°C), for arsenic tolerance assay. The four media with the highest biomass were selected to assay As-resistance; one culture (Q63h) was chosen to assay biooxidative activity, using a heap sample that contained chalcopyrite and covellite. We found that 0.5 g/L of As does not affect living biomass or biooxidative activity on Cu sulfides, but it dissolves Cu, while As precipitates as arsenic acid (H3AsO4·½H2O). The arsenic tolerant community, as identified by 16S rDNA gene sequence analysis, was composed of three main metabolic groups: chemolithotrophs (Leptospirillum, Sulfobacillus); chemolithoheterotrophs and organoheterotrophs as Acidovorax temperans, Pseudomonas alcaligenes, P. mendocina and Sphingomonas spp. Leptospirillum spp. and S. thermosulfidooxidans were the dominant taxa in the Q63-66 cultures from the deepest sample of the oldest, highest-temperature heap. The results indicated arsenic resistance in the microbial community, therefore specific primers were used to amplify ars (arsenic resistance system), aio (arsenite oxidase), or arr (arsenate respiratory reduction) genes from total sample DNA. Presence of arsB genes in S. thermosulfidooxidans in the Q63-66 cultures permits H3AsO4-As(V) detoxification and strengthens the community's response to As.

No MeSH data available.


Related in: MedlinePlus

Maximum parsimony tree of arsB Permease sequences. The optimal tree with the sum of branch lengths = 2.73 is shown. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The evolutionary distances are in the units of the number of base substitutions per site. All sequenced codon positions were included in the alignment, for introns and exons in arsB; however, every site containing gaps or missing data was then eliminated from the dataset. There were a total of 707 positions in the final dataset. arsB genes from different bacteria were used as indicated in the tree by their name, followed by the GenBank accession numbers. The consensus sequences of Q18 and Q63 samples were used to construct the tree.
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Fig5: Maximum parsimony tree of arsB Permease sequences. The optimal tree with the sum of branch lengths = 2.73 is shown. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The evolutionary distances are in the units of the number of base substitutions per site. All sequenced codon positions were included in the alignment, for introns and exons in arsB; however, every site containing gaps or missing data was then eliminated from the dataset. There were a total of 707 positions in the final dataset. arsB genes from different bacteria were used as indicated in the tree by their name, followed by the GenBank accession numbers. The consensus sequences of Q18 and Q63 samples were used to construct the tree.

Mentions: The arsB gene, an As efflux pump, was amplified from DNA samples from Q63h and Q18 communities, using primers darsBIF and darsBIR (Table 2). The sequences obtained were classified, using BLAST, as belonging to Sulfobacillus species, S. thermosulfidooxidans and S. acidophilus. Phylogenetic relationships of the arsB sequences (Fig. 5) are consistent with those in the 16S rDNA tree (Fig. 6).Fig. 5


Community of thermoacidophilic and arsenic resistant microorganisms isolated from a deep profile of mine heaps.

Casas-Flores S, Gómez-Rodríguez EY, García-Meza JV - AMB Express (2015)

Maximum parsimony tree of arsB Permease sequences. The optimal tree with the sum of branch lengths = 2.73 is shown. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The evolutionary distances are in the units of the number of base substitutions per site. All sequenced codon positions were included in the alignment, for introns and exons in arsB; however, every site containing gaps or missing data was then eliminated from the dataset. There were a total of 707 positions in the final dataset. arsB genes from different bacteria were used as indicated in the tree by their name, followed by the GenBank accession numbers. The consensus sequences of Q18 and Q63 samples were used to construct the tree.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4539307&req=5

Fig5: Maximum parsimony tree of arsB Permease sequences. The optimal tree with the sum of branch lengths = 2.73 is shown. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The evolutionary distances are in the units of the number of base substitutions per site. All sequenced codon positions were included in the alignment, for introns and exons in arsB; however, every site containing gaps or missing data was then eliminated from the dataset. There were a total of 707 positions in the final dataset. arsB genes from different bacteria were used as indicated in the tree by their name, followed by the GenBank accession numbers. The consensus sequences of Q18 and Q63 samples were used to construct the tree.
Mentions: The arsB gene, an As efflux pump, was amplified from DNA samples from Q63h and Q18 communities, using primers darsBIF and darsBIR (Table 2). The sequences obtained were classified, using BLAST, as belonging to Sulfobacillus species, S. thermosulfidooxidans and S. acidophilus. Phylogenetic relationships of the arsB sequences (Fig. 5) are consistent with those in the 16S rDNA tree (Fig. 6).Fig. 5

Bottom Line: We found that 0.5 g/L of As does not affect living biomass or biooxidative activity on Cu sulfides, but it dissolves Cu, while As precipitates as arsenic acid (H3AsO4·½H2O).The results indicated arsenic resistance in the microbial community, therefore specific primers were used to amplify ars (arsenic resistance system), aio (arsenite oxidase), or arr (arsenate respiratory reduction) genes from total sample DNA.Presence of arsB genes in S. thermosulfidooxidans in the Q63-66 cultures permits H3AsO4-As(V) detoxification and strengthens the community's response to As.

View Article: PubMed Central - PubMed

Affiliation: División de Biología Molecular, IPCYT, Camino a la Presa San José 2055, Lomas 4a, 78216, San Luis Potosí, SLP, México, scasas@ipicyt.edu.mx.

ABSTRACT
Soluble arsenic (As) in acidic feed solution may inhibit the copper (Cu) bioleaching process within mine heaps. To clarify the effect of soluble arsenic on the live biomass and bioxidative activity in heaps, toxicological assays were performed using a synthetic feed solution given by a mine company. The microorganisms had previously been isolated from two heap samples at up to 66 m depth, and cultured using specific media for chemolithotrophic acidophiles (pH 1-2) and moderate thermophiles (48°C), for arsenic tolerance assay. The four media with the highest biomass were selected to assay As-resistance; one culture (Q63h) was chosen to assay biooxidative activity, using a heap sample that contained chalcopyrite and covellite. We found that 0.5 g/L of As does not affect living biomass or biooxidative activity on Cu sulfides, but it dissolves Cu, while As precipitates as arsenic acid (H3AsO4·½H2O). The arsenic tolerant community, as identified by 16S rDNA gene sequence analysis, was composed of three main metabolic groups: chemolithotrophs (Leptospirillum, Sulfobacillus); chemolithoheterotrophs and organoheterotrophs as Acidovorax temperans, Pseudomonas alcaligenes, P. mendocina and Sphingomonas spp. Leptospirillum spp. and S. thermosulfidooxidans were the dominant taxa in the Q63-66 cultures from the deepest sample of the oldest, highest-temperature heap. The results indicated arsenic resistance in the microbial community, therefore specific primers were used to amplify ars (arsenic resistance system), aio (arsenite oxidase), or arr (arsenate respiratory reduction) genes from total sample DNA. Presence of arsB genes in S. thermosulfidooxidans in the Q63-66 cultures permits H3AsO4-As(V) detoxification and strengthens the community's response to As.

No MeSH data available.


Related in: MedlinePlus