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Thiomonas sp. CB2 is able to degrade urea and promote toxic metal precipitation in acid mine drainage waters supplemented with urea.

Farasin J, Andres J, Casiot C, Barbe V, Faerber J, Halter D, Heintz D, Koechler S, Lièvremont D, Lugan R, Marchal M, Plewniak F, Seby F, Bertin PN, Arsène-Ploetze F - Front Microbiol (2015)

Bottom Line: The urease activity of Thiomonas sp.In AMD water supplemented with urea, the degradation of urea promotes iron, aluminum and arsenic precipitation.Our data show that ureC was expressed in situ, which suggests that the ability to degrade urea may be expressed in some Thiomonas strains in AMD, and that this urease activity may contribute to their survival in contaminated environments.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Génétique Moléculaire, Génomique et Microbiologie, UMR7156, Université de Strasbourg - Centre National de la Recherche Scientifique, Institut de Botanique Strasbourg, France.

ABSTRACT
The acid mine drainage (AMD) in Carnoulès (France) is characterized by the presence of toxic metals such as arsenic. Several bacterial strains belonging to the Thiomonas genus, which were isolated from this AMD, are able to withstand these conditions. Their genomes carry several genomic islands (GEIs), which are known to be potentially advantageous in some particular ecological niches. This study focused on the role of the "urea island" present in the Thiomonas CB2 strain, which carry the genes involved in urea degradation processes. First, genomic comparisons showed that the genome of Thiomonas sp. CB2, which is able to degrade urea, contains a urea genomic island which is incomplete in the genome of other strains showing no urease activity. The urease activity of Thiomonas sp. CB2 enabled this bacterium to maintain a neutral pH in cell cultures in vitro and prevented the occurrence of cell death during the growth of the bacterium in a chemically defined medium. In AMD water supplemented with urea, the degradation of urea promotes iron, aluminum and arsenic precipitation. Our data show that ureC was expressed in situ, which suggests that the ability to degrade urea may be expressed in some Thiomonas strains in AMD, and that this urease activity may contribute to their survival in contaminated environments.

No MeSH data available.


Related in: MedlinePlus

Comparison between the genes involved in urea degradation and urease activity in the Thiomonas strains investigated. Only part of the urea island carrying the ure and urt genes involved in urea degradation is shown. The figure shows the synteny between CB1, CB2, CB3, and 3As. The percentage of nucleotide identity is expressed in shades of gray (see the gray scale). Figures were generated with Easyfig (Sullivan et al., 2011). The urea degradation activity is shown on the right: cells were grown in the absence (−U) and presence (+U) of urea. After growth, cells were incubated in the presence of urea and Bromo-cresol purple for 30 min, as described in Materials and methods (as indicated by “test + urea”). As a negative control, the test was performed in the absence of urea in the reaction mixture (as indicated by “test − urea”). In the case of the test performed in the presence of urea, the purple color indicates urea degradation.
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Figure 4: Comparison between the genes involved in urea degradation and urease activity in the Thiomonas strains investigated. Only part of the urea island carrying the ure and urt genes involved in urea degradation is shown. The figure shows the synteny between CB1, CB2, CB3, and 3As. The percentage of nucleotide identity is expressed in shades of gray (see the gray scale). Figures were generated with Easyfig (Sullivan et al., 2011). The urea degradation activity is shown on the right: cells were grown in the absence (−U) and presence (+U) of urea. After growth, cells were incubated in the presence of urea and Bromo-cresol purple for 30 min, as described in Materials and methods (as indicated by “test + urea”). As a negative control, the test was performed in the absence of urea in the reaction mixture (as indicated by “test − urea”). In the case of the test performed in the presence of urea, the purple color indicates urea degradation.

Mentions: The synteny of the genes detected in and around the urea island in CB2 was compared with that of the corresponding genes in CB1, 3As, CB3, CB6, and K12 (Figures 2, 3), and these analyses showed that some blocks of genes were highly conserved, although possibly translocated or inverted, whereas others were lacking in some Thiomonas strains. In particular, genes involved in urea degradation and transport processes were found to be present in 4 genomes from Thiomonas strains (CB2, CB1, CB6, and 3As) but not in CB3 or K12 (Figure 4), while the genes detected in the vicinity of the ure genes in CB2 are present in both of these strains (Figure 2). These results suggest that these urea islands have evolved differentially in these closely related Thiomonas strains. GEIs may endow bacterial strains with particular abilities (Juhas et al., 2009). Since urea degradation is thought to be involved in acid tolerance in some bacteria such as H. pylori (Stingl et al., 2002), and since Thiomonas strains were isolated from acidic AMDs, the contribution of these genes to acid tolerance was further investigated.


Thiomonas sp. CB2 is able to degrade urea and promote toxic metal precipitation in acid mine drainage waters supplemented with urea.

Farasin J, Andres J, Casiot C, Barbe V, Faerber J, Halter D, Heintz D, Koechler S, Lièvremont D, Lugan R, Marchal M, Plewniak F, Seby F, Bertin PN, Arsène-Ploetze F - Front Microbiol (2015)

Comparison between the genes involved in urea degradation and urease activity in the Thiomonas strains investigated. Only part of the urea island carrying the ure and urt genes involved in urea degradation is shown. The figure shows the synteny between CB1, CB2, CB3, and 3As. The percentage of nucleotide identity is expressed in shades of gray (see the gray scale). Figures were generated with Easyfig (Sullivan et al., 2011). The urea degradation activity is shown on the right: cells were grown in the absence (−U) and presence (+U) of urea. After growth, cells were incubated in the presence of urea and Bromo-cresol purple for 30 min, as described in Materials and methods (as indicated by “test + urea”). As a negative control, the test was performed in the absence of urea in the reaction mixture (as indicated by “test − urea”). In the case of the test performed in the presence of urea, the purple color indicates urea degradation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585258&req=5

Figure 4: Comparison between the genes involved in urea degradation and urease activity in the Thiomonas strains investigated. Only part of the urea island carrying the ure and urt genes involved in urea degradation is shown. The figure shows the synteny between CB1, CB2, CB3, and 3As. The percentage of nucleotide identity is expressed in shades of gray (see the gray scale). Figures were generated with Easyfig (Sullivan et al., 2011). The urea degradation activity is shown on the right: cells were grown in the absence (−U) and presence (+U) of urea. After growth, cells were incubated in the presence of urea and Bromo-cresol purple for 30 min, as described in Materials and methods (as indicated by “test + urea”). As a negative control, the test was performed in the absence of urea in the reaction mixture (as indicated by “test − urea”). In the case of the test performed in the presence of urea, the purple color indicates urea degradation.
Mentions: The synteny of the genes detected in and around the urea island in CB2 was compared with that of the corresponding genes in CB1, 3As, CB3, CB6, and K12 (Figures 2, 3), and these analyses showed that some blocks of genes were highly conserved, although possibly translocated or inverted, whereas others were lacking in some Thiomonas strains. In particular, genes involved in urea degradation and transport processes were found to be present in 4 genomes from Thiomonas strains (CB2, CB1, CB6, and 3As) but not in CB3 or K12 (Figure 4), while the genes detected in the vicinity of the ure genes in CB2 are present in both of these strains (Figure 2). These results suggest that these urea islands have evolved differentially in these closely related Thiomonas strains. GEIs may endow bacterial strains with particular abilities (Juhas et al., 2009). Since urea degradation is thought to be involved in acid tolerance in some bacteria such as H. pylori (Stingl et al., 2002), and since Thiomonas strains were isolated from acidic AMDs, the contribution of these genes to acid tolerance was further investigated.

Bottom Line: The urease activity of Thiomonas sp.In AMD water supplemented with urea, the degradation of urea promotes iron, aluminum and arsenic precipitation.Our data show that ureC was expressed in situ, which suggests that the ability to degrade urea may be expressed in some Thiomonas strains in AMD, and that this urease activity may contribute to their survival in contaminated environments.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Génétique Moléculaire, Génomique et Microbiologie, UMR7156, Université de Strasbourg - Centre National de la Recherche Scientifique, Institut de Botanique Strasbourg, France.

ABSTRACT
The acid mine drainage (AMD) in Carnoulès (France) is characterized by the presence of toxic metals such as arsenic. Several bacterial strains belonging to the Thiomonas genus, which were isolated from this AMD, are able to withstand these conditions. Their genomes carry several genomic islands (GEIs), which are known to be potentially advantageous in some particular ecological niches. This study focused on the role of the "urea island" present in the Thiomonas CB2 strain, which carry the genes involved in urea degradation processes. First, genomic comparisons showed that the genome of Thiomonas sp. CB2, which is able to degrade urea, contains a urea genomic island which is incomplete in the genome of other strains showing no urease activity. The urease activity of Thiomonas sp. CB2 enabled this bacterium to maintain a neutral pH in cell cultures in vitro and prevented the occurrence of cell death during the growth of the bacterium in a chemically defined medium. In AMD water supplemented with urea, the degradation of urea promotes iron, aluminum and arsenic precipitation. Our data show that ureC was expressed in situ, which suggests that the ability to degrade urea may be expressed in some Thiomonas strains in AMD, and that this urease activity may contribute to their survival in contaminated environments.

No MeSH data available.


Related in: MedlinePlus