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Physiological and genomic characterization of Arcobacter anaerophilus IR-1 reveals new metabolic features in Epsilonproteobacteria.

Roalkvam I, Drønen K, Stokke R, Daae FL, Dahle H, Steen IH - Front Microbiol (2015)

Bottom Line: Electron acceptors utilized by most Epsilonproteobacteria, such as oxygen, nitrate, and sulfur, were also used by A. anaerophilus IR-1.The presence of genes for NAD(+)-reducing hydrogenase (hox) and dissimilatory iron reduction (fre) were unique for A. anaerophilus IR-1 among Epsilonproteobacteria.Altogether, our study shows that traditional characterization in combination with a modern genomics approach can expand our knowledge on free-living Arcobacter, and that this complementary approach could also provide invaluable knowledge about the physiology and metabolic pathways in other Epsilonproteobacteria from various environments.

View Article: PubMed Central - PubMed

Affiliation: Centre for Geobiology, University of Bergen Bergen, Norway ; Department of Biology, University of Bergen Bergen, Norway.

ABSTRACT
In this study we characterized and sequenced the genome of Arcobacter anaerophilus strain IR-1 isolated from enrichment cultures used in nitrate-amended corrosion experiments. A. anaerophilus IR-1 could grow lithoautotrophically on hydrogen and hydrogen sulfide and lithoheterothrophically on thiosulfate and elemental sulfur. In addition, the strain grew organoheterotrophically on yeast extract, peptone, and various organic acids. We show for the first time that Arcobacter could grow on the complex organic substrate tryptone and oxidize acetate with elemental sulfur as electron acceptor. Electron acceptors utilized by most Epsilonproteobacteria, such as oxygen, nitrate, and sulfur, were also used by A. anaerophilus IR-1. Strain IR-1 was also uniquely able to use iron citrate as electron acceptor. Comparative genomics of the Arcobacter strains A. butzleri RM4018, A. nitrofigilis CI and A. anaerophilus IR-1 revealed that the free-living strains had a wider metabolic range and more genes in common compared to the pathogen strain. The presence of genes for NAD(+)-reducing hydrogenase (hox) and dissimilatory iron reduction (fre) were unique for A. anaerophilus IR-1 among Epsilonproteobacteria. Finally, the new strain had an incomplete denitrification pathway where the end product was nitrite, which is different from other Arcobacter strains where the end product is ammonia. Altogether, our study shows that traditional characterization in combination with a modern genomics approach can expand our knowledge on free-living Arcobacter, and that this complementary approach could also provide invaluable knowledge about the physiology and metabolic pathways in other Epsilonproteobacteria from various environments.

No MeSH data available.


Related in: MedlinePlus

Scanning electron micrographs of Arcobacter anaerophilus IR-1. Cells are curved rods with a single polar flagellum.
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Figure 1: Scanning electron micrographs of Arcobacter anaerophilus IR-1. Cells are curved rods with a single polar flagellum.

Mentions: The cells of the new strain were gram negative, curved rods, 1.5–2 μm long and 0.4–0.5 μm wide (Figure 1), and were observed as single cells or in chains of 2–6 cells during active growth. Cells were motile by a single polar flagellum (Figure 1), and were particularly active at early stages of growth. Cells were non-spore forming. The physiological characteristics of strain IR-1 were compared to published descriptions of other Arcobacter species (Table 1) using a selection of parameters devised to distinguish members of the family Campylobacteraceae, as resolved by the International Committee on Systematic Bacteriology (Ursing et al., 1994). Strain IR-1 grew under microaerophilic conditions at 37°C, but not at 42°C or under aerobic conditions. Growth was observed at both 0.5 and 4% NaCl. The strain did not utilize 1% glycine, and no hemolysis was observed. The strain was oxidase and urease positive, but did not have enzyme activity for catalase or indoxyl acetate hydrolysis. The new isolate showed a unique profile of characteristics among the chosen representatives of Arcobacter, and could be distinguished from other Arcobacter species based on three or more parameters (Table 1).


Physiological and genomic characterization of Arcobacter anaerophilus IR-1 reveals new metabolic features in Epsilonproteobacteria.

Roalkvam I, Drønen K, Stokke R, Daae FL, Dahle H, Steen IH - Front Microbiol (2015)

Scanning electron micrographs of Arcobacter anaerophilus IR-1. Cells are curved rods with a single polar flagellum.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4584990&req=5

Figure 1: Scanning electron micrographs of Arcobacter anaerophilus IR-1. Cells are curved rods with a single polar flagellum.
Mentions: The cells of the new strain were gram negative, curved rods, 1.5–2 μm long and 0.4–0.5 μm wide (Figure 1), and were observed as single cells or in chains of 2–6 cells during active growth. Cells were motile by a single polar flagellum (Figure 1), and were particularly active at early stages of growth. Cells were non-spore forming. The physiological characteristics of strain IR-1 were compared to published descriptions of other Arcobacter species (Table 1) using a selection of parameters devised to distinguish members of the family Campylobacteraceae, as resolved by the International Committee on Systematic Bacteriology (Ursing et al., 1994). Strain IR-1 grew under microaerophilic conditions at 37°C, but not at 42°C or under aerobic conditions. Growth was observed at both 0.5 and 4% NaCl. The strain did not utilize 1% glycine, and no hemolysis was observed. The strain was oxidase and urease positive, but did not have enzyme activity for catalase or indoxyl acetate hydrolysis. The new isolate showed a unique profile of characteristics among the chosen representatives of Arcobacter, and could be distinguished from other Arcobacter species based on three or more parameters (Table 1).

Bottom Line: Electron acceptors utilized by most Epsilonproteobacteria, such as oxygen, nitrate, and sulfur, were also used by A. anaerophilus IR-1.The presence of genes for NAD(+)-reducing hydrogenase (hox) and dissimilatory iron reduction (fre) were unique for A. anaerophilus IR-1 among Epsilonproteobacteria.Altogether, our study shows that traditional characterization in combination with a modern genomics approach can expand our knowledge on free-living Arcobacter, and that this complementary approach could also provide invaluable knowledge about the physiology and metabolic pathways in other Epsilonproteobacteria from various environments.

View Article: PubMed Central - PubMed

Affiliation: Centre for Geobiology, University of Bergen Bergen, Norway ; Department of Biology, University of Bergen Bergen, Norway.

ABSTRACT
In this study we characterized and sequenced the genome of Arcobacter anaerophilus strain IR-1 isolated from enrichment cultures used in nitrate-amended corrosion experiments. A. anaerophilus IR-1 could grow lithoautotrophically on hydrogen and hydrogen sulfide and lithoheterothrophically on thiosulfate and elemental sulfur. In addition, the strain grew organoheterotrophically on yeast extract, peptone, and various organic acids. We show for the first time that Arcobacter could grow on the complex organic substrate tryptone and oxidize acetate with elemental sulfur as electron acceptor. Electron acceptors utilized by most Epsilonproteobacteria, such as oxygen, nitrate, and sulfur, were also used by A. anaerophilus IR-1. Strain IR-1 was also uniquely able to use iron citrate as electron acceptor. Comparative genomics of the Arcobacter strains A. butzleri RM4018, A. nitrofigilis CI and A. anaerophilus IR-1 revealed that the free-living strains had a wider metabolic range and more genes in common compared to the pathogen strain. The presence of genes for NAD(+)-reducing hydrogenase (hox) and dissimilatory iron reduction (fre) were unique for A. anaerophilus IR-1 among Epsilonproteobacteria. Finally, the new strain had an incomplete denitrification pathway where the end product was nitrite, which is different from other Arcobacter strains where the end product is ammonia. Altogether, our study shows that traditional characterization in combination with a modern genomics approach can expand our knowledge on free-living Arcobacter, and that this complementary approach could also provide invaluable knowledge about the physiology and metabolic pathways in other Epsilonproteobacteria from various environments.

No MeSH data available.


Related in: MedlinePlus