Interfacial extracellular electron uptake is linked to nitrate respiration in the marine heterotroph, Thalassospira xiamenensis SN3.
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| Title: | Interfacial extracellular electron uptake is linked to nitrate respiration in the marine heterotroph, Thalassospira xiamenensis SN3. |
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| Authors: | Sackett, Joshua D.1 (AUTHOR) Joshua.sackett@uc.edu, Tonucci, Gabriel P.1 (AUTHOR), Rowe, Annette R.1,2,3 (AUTHOR) |
| Source: | Bioelectrochemistry. Oct2025, Vol. 165, pN.PAG-N.PAG. 1p. |
| Subjects: | Nitrate reductase, Coastal sediments, Iron corrosion, Charge exchange, Marine sediments |
| Abstract: | Thalassospira species are ubiquitous marine bacteria with poorly understood ecology, and some have been implicated in iron corrosion. To better elucidate the mechanisms and ecological implications of extracellular electron transfer (EET) in oxidative processes, we conducted genomic and bioelectrochemical characterization of Thalassospira xiamenensis strain SN3, an obligate heterotroph isolated from coastal marine sediment cathode-oxidizing enrichments. Physiologic and genomic analyses indicate that SN3 lacks the capacity for lithoautotrophic growth and lacks homologs to genes canonically involved in EET. Bioelectrochemical characterization of SN3 cells shows that inward EET requires a terminal electron acceptor (respiration). Deletion of nitrate reductase catalytic subunit napA abolished current consumption and catalytic activity under nitrate-reducing conditions. Media exchange experiments demonstrate that inward EET in SN3 is facilitated by direct contact with the electrode, with a formal midpoint potential of −153 ± 16 mV vs. SHE. Through deletion of the formate dehydrogenase fdhABCD and electrochemical characterization of mutant cells, we show that inward EET is not a function of Fdh enzyme sorption to the electrode, as has been demonstrated for other organisms. This provides further evidence of a cell-mediated and contact-dependent EET mechanism. This work provides a foundation for investigating this metabolically versatile organism's yet uncharacterized mechanism of EET. • T. xiamenensis SN3 oxidizes a cathode poised at an electron-donating potential. • SN3 couples electrode oxidation with respiration (oxygen or nitrate). • Electrode oxidation is not facilitated by formate dehydrogenase. • Electrode oxidation requires direct cell-electrode contact. [ABSTRACT FROM AUTHOR] |
| Copyright of Bioelectrochemistry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 185746450 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Interfacial extracellular electron uptake is linked to nitrate respiration in the marine heterotroph, Thalassospira xiamenensis SN3. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Sackett%2C+Joshua+D%2E%22">Sackett, Joshua D.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> Joshua.sackett@uc.edu</i><br /><searchLink fieldCode="AR" term="%22Tonucci%2C+Gabriel+P%2E%22">Tonucci, Gabriel P.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Rowe%2C+Annette+R%2E%22">Rowe, Annette R.</searchLink><relatesTo>1,2,3</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Bioelectrochemistry%22">Bioelectrochemistry</searchLink>. Oct2025, Vol. 165, pN.PAG-N.PAG. 1p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Nitrate+reductase%22">Nitrate reductase</searchLink><br /><searchLink fieldCode="DE" term="%22Coastal+sediments%22">Coastal sediments</searchLink><br /><searchLink fieldCode="DE" term="%22Iron+corrosion%22">Iron corrosion</searchLink><br /><searchLink fieldCode="DE" term="%22Charge+exchange%22">Charge exchange</searchLink><br /><searchLink fieldCode="DE" term="%22Marine+sediments%22">Marine sediments</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Thalassospira species are ubiquitous marine bacteria with poorly understood ecology, and some have been implicated in iron corrosion. To better elucidate the mechanisms and ecological implications of extracellular electron transfer (EET) in oxidative processes, we conducted genomic and bioelectrochemical characterization of Thalassospira xiamenensis strain SN3, an obligate heterotroph isolated from coastal marine sediment cathode-oxidizing enrichments. Physiologic and genomic analyses indicate that SN3 lacks the capacity for lithoautotrophic growth and lacks homologs to genes canonically involved in EET. Bioelectrochemical characterization of SN3 cells shows that inward EET requires a terminal electron acceptor (respiration). Deletion of nitrate reductase catalytic subunit napA abolished current consumption and catalytic activity under nitrate-reducing conditions. Media exchange experiments demonstrate that inward EET in SN3 is facilitated by direct contact with the electrode, with a formal midpoint potential of −153 ± 16 mV vs. SHE. Through deletion of the formate dehydrogenase fdhABCD and electrochemical characterization of mutant cells, we show that inward EET is not a function of Fdh enzyme sorption to the electrode, as has been demonstrated for other organisms. This provides further evidence of a cell-mediated and contact-dependent EET mechanism. This work provides a foundation for investigating this metabolically versatile organism's yet uncharacterized mechanism of EET. • T. xiamenensis SN3 oxidizes a cathode poised at an electron-donating potential. • SN3 couples electrode oxidation with respiration (oxygen or nitrate). • Electrode oxidation is not facilitated by formate dehydrogenase. • Electrode oxidation requires direct cell-electrode contact. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Bioelectrochemistry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.bioelechem.2025.108976 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 1 StartPage: N.PAG Subjects: – SubjectFull: Nitrate reductase Type: general – SubjectFull: Coastal sediments Type: general – SubjectFull: Iron corrosion Type: general – SubjectFull: Charge exchange Type: general – SubjectFull: Marine sediments Type: general Titles: – TitleFull: Interfacial extracellular electron uptake is linked to nitrate respiration in the marine heterotroph, Thalassospira xiamenensis SN3. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Sackett, Joshua D. – PersonEntity: Name: NameFull: Tonucci, Gabriel P. – PersonEntity: Name: NameFull: Rowe, Annette R. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 10 Text: Oct2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 15675394 Numbering: – Type: volume Value: 165 Titles: – TitleFull: Bioelectrochemistry Type: main |
| ResultId | 1 |
