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Chemolithotrophic nitrate-dependent Fe(II)-oxidizing nature of actinobacterial subdivision lineage TM3

Chemolithotrophic nitrate-dependent Fe(II)-oxidizing nature of actinobacterial subdivision lineage TM3
Chemolithotrophic nitrate-dependent Fe(II)-oxidizing nature of actinobacterial subdivision lineage TM3
Anaerobic nitrate-dependent Fe(II) oxidation is widespread in various environments and is known to be performed by both heterotrophic and autotrophic microorganisms. Although Fe(II) oxidation is predominantly biological under acidic conditions, to date most of the studies on nitrate-dependent Fe(II) oxidation were from environments of circumneutral pH. The present study was conducted in Lake Grosse Fuchskuhle, a moderately acidic ecosystem receiving humic acids from an adjacent bog, with the objective of identifying, characterizing and enumerating the microorganisms responsible for this process. The incubations of sediment under chemolithotrophic nitrate-dependent Fe(II)-oxidizing conditions have shown the enrichment of TM3 group of uncultured Actinobacteria. A time-course experiment done on these Actinobacteria showed a consumption of Fe(II) and nitrate in accordance with the expected stoichiometry (1:0.2) required for nitrate-dependent Fe(II) oxidation. Quantifications done by most probable number showed the presence of 1 × 10(4) autotrophic and 1 × 10(7) heterotrophic nitrate-dependent Fe(II) oxidizers per gram fresh weight of sediment. The analysis of microbial community by 16S rRNA gene amplicon pyrosequencing showed that these actinobacterial sequences correspond to ~0.6% of bacterial 16S rRNA gene sequences. Stable isotope probing using (13)CO2 was performed with the lake sediment and showed labeling of these Actinobacteria. This indicated that they might be important autotrophs in this environment. Although these Actinobacteria are not dominant members of the sediment microbial community, they could be of functional significance due to their contribution to the regeneration of Fe(III), which has a critical role as an electron acceptor for anaerobic microorganisms mineralizing sediment organic matter. To the best of our knowledge this is the first study to show the autotrophic nitrate-dependent Fe(II)-oxidizing nature of TM3 group of uncultured Actinobacteria
1751-7362
1582-1594
Kanaparthi, Dheeraj
be78d674-71e6-40d6-b92e-50646258c757
Pommerenke, Bianca
b88ad6f7-3df5-46b2-ad72-395ecef447f3
Casper, Peter
90dac29d-fee3-4d8c-8b50-db661e71c80a
Dumont, Marc
afd9f08f-bdbb-4cee-b792-1a7f000ee511
Kanaparthi, Dheeraj
be78d674-71e6-40d6-b92e-50646258c757
Pommerenke, Bianca
b88ad6f7-3df5-46b2-ad72-395ecef447f3
Casper, Peter
90dac29d-fee3-4d8c-8b50-db661e71c80a
Dumont, Marc
afd9f08f-bdbb-4cee-b792-1a7f000ee511

Kanaparthi, Dheeraj, Pommerenke, Bianca, Casper, Peter and Dumont, Marc (2013) Chemolithotrophic nitrate-dependent Fe(II)-oxidizing nature of actinobacterial subdivision lineage TM3. The ISME Journal, 7 (8), 1582-1594. (doi:10.1038/ismej.2013.38). (PMID:23514778)

Record type: Article

Abstract

Anaerobic nitrate-dependent Fe(II) oxidation is widespread in various environments and is known to be performed by both heterotrophic and autotrophic microorganisms. Although Fe(II) oxidation is predominantly biological under acidic conditions, to date most of the studies on nitrate-dependent Fe(II) oxidation were from environments of circumneutral pH. The present study was conducted in Lake Grosse Fuchskuhle, a moderately acidic ecosystem receiving humic acids from an adjacent bog, with the objective of identifying, characterizing and enumerating the microorganisms responsible for this process. The incubations of sediment under chemolithotrophic nitrate-dependent Fe(II)-oxidizing conditions have shown the enrichment of TM3 group of uncultured Actinobacteria. A time-course experiment done on these Actinobacteria showed a consumption of Fe(II) and nitrate in accordance with the expected stoichiometry (1:0.2) required for nitrate-dependent Fe(II) oxidation. Quantifications done by most probable number showed the presence of 1 × 10(4) autotrophic and 1 × 10(7) heterotrophic nitrate-dependent Fe(II) oxidizers per gram fresh weight of sediment. The analysis of microbial community by 16S rRNA gene amplicon pyrosequencing showed that these actinobacterial sequences correspond to ~0.6% of bacterial 16S rRNA gene sequences. Stable isotope probing using (13)CO2 was performed with the lake sediment and showed labeling of these Actinobacteria. This indicated that they might be important autotrophs in this environment. Although these Actinobacteria are not dominant members of the sediment microbial community, they could be of functional significance due to their contribution to the regeneration of Fe(III), which has a critical role as an electron acceptor for anaerobic microorganisms mineralizing sediment organic matter. To the best of our knowledge this is the first study to show the autotrophic nitrate-dependent Fe(II)-oxidizing nature of TM3 group of uncultured Actinobacteria

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Accepted/In Press date: 3 February 2013
Published date: 21 March 2013
Organisations: Centre for Biological Sciences

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Local EPrints ID: 387933
URI: http://eprints.soton.ac.uk/id/eprint/387933
ISSN: 1751-7362
PURE UUID: ed3320d5-7dbf-40fd-a711-087a5d33b6f3
ORCID for Marc Dumont: ORCID iD orcid.org/0000-0002-7347-8668

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Date deposited: 08 Jul 2016 13:57
Last modified: 15 Mar 2024 03:53

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Contributors

Author: Dheeraj Kanaparthi
Author: Bianca Pommerenke
Author: Peter Casper
Author: Marc Dumont ORCID iD

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