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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

Effects of incubating Thiomonas strains in AMD-impacted water. (A) OD600nm, (B) Viability expressed in CFU/mL, and (C) pH was measured in AMD-impacted water incubated with Thiomonas strains in the presence and absence of 1 g.L−1 urea. This experiment was representative of three independent experiments.
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Figure 6: Effects of incubating Thiomonas strains in AMD-impacted water. (A) OD600nm, (B) Viability expressed in CFU/mL, and (C) pH was measured in AMD-impacted water incubated with Thiomonas strains in the presence and absence of 1 g.L−1 urea. This experiment was representative of three independent experiments.

Mentions: The effects of the CB2 urea degradation activity were therefore tested in contaminated water from the AMD-impacted Carnoulès creek under laboratory conditions (Table 1). No urea was detected in the AMD-impacted water used in these experiments (data not shown). CB2, 3As, and K12 could therefore be incubated in this AMD-impacted water, whether or not it was supplemented with urea. When no urea was added to the AMD-impacted water, the growth of all three strains, as shown by an increase in the OD600nm, resulted in a decrease in the pH (Figures 6A,C). However, when CB2 was incubated in the AMD-impacted water with urea, the pH increased within 48 h (Figure 6C), reflecting the occurrence of urea degradation activity. The number of CFU.mL−1 decreased with time, which suggests that the Thiomonas cell survival ability decreases under these conditions (Figure 6B). Contrary to what was observed in m126 medium, the viability of the CB2 cells did not increase in the AMD water in the presence of urea, and was even slightly impaired. The urea degradation process therefore did not improve the rate of CB2 survival under these conditions tested. The acid resistance mechanism involving urea degradation activity may not have been sufficiently strong to improve the viability of Thiomonas sp. CB2 in the AMD-impacted water, the pH of which was lower than that of the synthetic medium.


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)

Effects of incubating Thiomonas strains in AMD-impacted water. (A) OD600nm, (B) Viability expressed in CFU/mL, and (C) pH was measured in AMD-impacted water incubated with Thiomonas strains in the presence and absence of 1 g.L−1 urea. This experiment was representative of three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 6: Effects of incubating Thiomonas strains in AMD-impacted water. (A) OD600nm, (B) Viability expressed in CFU/mL, and (C) pH was measured in AMD-impacted water incubated with Thiomonas strains in the presence and absence of 1 g.L−1 urea. This experiment was representative of three independent experiments.
Mentions: The effects of the CB2 urea degradation activity were therefore tested in contaminated water from the AMD-impacted Carnoulès creek under laboratory conditions (Table 1). No urea was detected in the AMD-impacted water used in these experiments (data not shown). CB2, 3As, and K12 could therefore be incubated in this AMD-impacted water, whether or not it was supplemented with urea. When no urea was added to the AMD-impacted water, the growth of all three strains, as shown by an increase in the OD600nm, resulted in a decrease in the pH (Figures 6A,C). However, when CB2 was incubated in the AMD-impacted water with urea, the pH increased within 48 h (Figure 6C), reflecting the occurrence of urea degradation activity. The number of CFU.mL−1 decreased with time, which suggests that the Thiomonas cell survival ability decreases under these conditions (Figure 6B). Contrary to what was observed in m126 medium, the viability of the CB2 cells did not increase in the AMD water in the presence of urea, and was even slightly impaired. The urea degradation process therefore did not improve the rate of CB2 survival under these conditions tested. The acid resistance mechanism involving urea degradation activity may not have been sufficiently strong to improve the viability of Thiomonas sp. CB2 in the AMD-impacted water, the pH of which was lower than that of the synthetic medium.

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