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Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum

Cable bacteria are centimeters-long filamentous bacteria that oxidize sulfide in anoxic sediment layers and reduce oxygen at the oxic-anoxic interface, connecting these reactions via electron transport. The ubiquitous cable bacteria have a major impact on sediment geochemistry and microbial communit...

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Autores principales: Lustermans, Jamie J. M., Bjerg, Jesper J., Burdorf, Laurine D. W., Nielsen, Lars Peter, Schramm, Andreas, Marshall, Ian P. G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9998039/
https://www.ncbi.nlm.nih.gov/pubmed/36910179
http://dx.doi.org/10.3389/fmicb.2023.1008293
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author Lustermans, Jamie J. M.
Bjerg, Jesper J.
Burdorf, Laurine D. W.
Nielsen, Lars Peter
Schramm, Andreas
Marshall, Ian P. G.
author_facet Lustermans, Jamie J. M.
Bjerg, Jesper J.
Burdorf, Laurine D. W.
Nielsen, Lars Peter
Schramm, Andreas
Marshall, Ian P. G.
author_sort Lustermans, Jamie J. M.
collection PubMed
description Cable bacteria are centimeters-long filamentous bacteria that oxidize sulfide in anoxic sediment layers and reduce oxygen at the oxic-anoxic interface, connecting these reactions via electron transport. The ubiquitous cable bacteria have a major impact on sediment geochemistry and microbial communities. This includes diverse bacteria swimming around cable bacteria as dense flocks in the anoxic zone, where the cable bacteria act as chemotactic attractant. We hypothesized that flocking only appears when cable bacteria are highly abundant and active. We set out to discern the timing and drivers of flocking over 81 days in an enrichment culture of the freshwater cable bacterium Candidatus Electronema aureum GS by measuring sediment microprofiles of pH, oxygen, and electric potential as a proxy of cable bacteria activity. Cable bacterial relative abundance was quantified by 16S rRNA amplicon sequencing, and microscopy observations to determine presence of flocking. Flocking was always observed at some cable bacteria, irrespective of overall cable bacteria rRNA abundance, activity, or sediment pH. Diverse cell morphologies of flockers were observed, suggesting that flocking is not restricted to a specific, single bacterial associate. This, coupled with their consistent presence supports a common mechanism of interaction, likely interspecies electron transfer via electron shuttles. Flocking appears exclusively linked to the electron conducting activity of the individual cable bacteria.
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spelling pubmed-99980392023-03-10 Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum Lustermans, Jamie J. M. Bjerg, Jesper J. Burdorf, Laurine D. W. Nielsen, Lars Peter Schramm, Andreas Marshall, Ian P. G. Front Microbiol Microbiology Cable bacteria are centimeters-long filamentous bacteria that oxidize sulfide in anoxic sediment layers and reduce oxygen at the oxic-anoxic interface, connecting these reactions via electron transport. The ubiquitous cable bacteria have a major impact on sediment geochemistry and microbial communities. This includes diverse bacteria swimming around cable bacteria as dense flocks in the anoxic zone, where the cable bacteria act as chemotactic attractant. We hypothesized that flocking only appears when cable bacteria are highly abundant and active. We set out to discern the timing and drivers of flocking over 81 days in an enrichment culture of the freshwater cable bacterium Candidatus Electronema aureum GS by measuring sediment microprofiles of pH, oxygen, and electric potential as a proxy of cable bacteria activity. Cable bacterial relative abundance was quantified by 16S rRNA amplicon sequencing, and microscopy observations to determine presence of flocking. Flocking was always observed at some cable bacteria, irrespective of overall cable bacteria rRNA abundance, activity, or sediment pH. Diverse cell morphologies of flockers were observed, suggesting that flocking is not restricted to a specific, single bacterial associate. This, coupled with their consistent presence supports a common mechanism of interaction, likely interspecies electron transfer via electron shuttles. Flocking appears exclusively linked to the electron conducting activity of the individual cable bacteria. Frontiers Media S.A. 2023-02-23 /pmc/articles/PMC9998039/ /pubmed/36910179 http://dx.doi.org/10.3389/fmicb.2023.1008293 Text en Copyright © 2023 Lustermans, Bjerg, Burdorf, Nielsen, Schramm and Marshall. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Lustermans, Jamie J. M.
Bjerg, Jesper J.
Burdorf, Laurine D. W.
Nielsen, Lars Peter
Schramm, Andreas
Marshall, Ian P. G.
Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum
title Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum
title_full Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum
title_fullStr Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum
title_full_unstemmed Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum
title_short Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum
title_sort persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, candidatus electronema aureum
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9998039/
https://www.ncbi.nlm.nih.gov/pubmed/36910179
http://dx.doi.org/10.3389/fmicb.2023.1008293
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