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Cable Bacteria in Freshwater Sediments.
Appl Environ Microbiol. 2015 Sep 01; 81(17):6003-11.AE

Abstract

In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage.

Authors+Show Affiliations

Center for Geomicrobiology, Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark nils.risgaard-petersen@bios.au.dk.Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.Center for Geomicrobiology, Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.Center for Geomicrobiology, Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.Center for Geomicrobiology, Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.Center for Geomicrobiology, Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.Center for Geomicrobiology, Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26116678

Citation

Risgaard-Petersen, Nils, et al. "Cable Bacteria in Freshwater Sediments." Applied and Environmental Microbiology, vol. 81, no. 17, 2015, pp. 6003-11.
Risgaard-Petersen N, Kristiansen M, Frederiksen RB, et al. Cable Bacteria in Freshwater Sediments. Appl Environ Microbiol. 2015;81(17):6003-11.
Risgaard-Petersen, N., Kristiansen, M., Frederiksen, R. B., Dittmer, A. L., Bjerg, J. T., Trojan, D., Schreiber, L., Damgaard, L. R., Schramm, A., & Nielsen, L. P. (2015). Cable Bacteria in Freshwater Sediments. Applied and Environmental Microbiology, 81(17), 6003-11. https://doi.org/10.1128/AEM.01064-15
Risgaard-Petersen N, et al. Cable Bacteria in Freshwater Sediments. Appl Environ Microbiol. 2015 Sep 1;81(17):6003-11. PubMed PMID: 26116678.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cable Bacteria in Freshwater Sediments. AU - Risgaard-Petersen,Nils, AU - Kristiansen,Michael, AU - Frederiksen,Rasmus B, AU - Dittmer,Anders Lindequist, AU - Bjerg,Jesper Tataru, AU - Trojan,Daniela, AU - Schreiber,Lars, AU - Damgaard,Lars Riis, AU - Schramm,Andreas, AU - Nielsen,Lars Peter, Y1 - 2015/06/26/ PY - 2015/04/01/received PY - 2015/06/19/accepted PY - 2015/6/28/entrez PY - 2015/6/28/pubmed PY - 2016/2/9/medline SP - 6003 EP - 11 JF - Applied and environmental microbiology JO - Appl Environ Microbiol VL - 81 IS - 17 N2 - In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage. SN - 1098-5336 UR - https://www.unboundmedicine.com/medline/citation/26116678/Cable_Bacteria_in_Freshwater_Sediments_ L2 - http://aem.asm.org/lookup/pmidlookup?view=long&pmid=26116678 DB - PRIME DP - Unbound Medicine ER -