Long-distance electron transport in multicellular freshwater cable bacteria.

Autor:	Yang T; Department of Physics and Astronomy, University of Southern California, Los Angeles, United States., Chavez MS; Department of Physics and Astronomy, University of Southern California, Los Angeles, United States., Niman CM; Department of Physics and Astronomy, University of Southern California, Los Angeles, United States., Xu S; Department of Physics and Astronomy, University of Southern California, Los Angeles, United States., El-Naggar MY; Department of Physics and Astronomy, University of Southern California, Los Angeles, United States.; Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, United States.; Department of Chemistry, University of Southern California, Los Angeles, United States.
Jazyk:	angličtina
Zdroj:	ELife [Elife] 2024 Aug 29; Vol. 12. Date of Electronic Publication: 2024 Aug 29.
DOI:	10.7554/eLife.91097
Abstrakt:	Filamentous multicellular cable bacteria perform centimeter-scale electron transport in a process that couples oxidation of an electron donor (sulfide) in deeper sediment to the reduction of an electron acceptor (oxygen or nitrate) near the surface. While this electric metabolism is prevalent in both marine and freshwater sediments, detailed electronic measurements of the conductivity previously focused on the marine cable bacteria ( Candidatus Electrothrix), rather than freshwater cable bacteria, which form a separate genus ( Candidatus Electronema) and contribute essential geochemical roles in freshwater sediments. Here, we characterize the electron transport characteristics of Ca . Electronema cable bacteria from Southern California freshwater sediments. Current-voltage measurements of intact cable filaments bridging interdigitated electrodes confirmed their persistent conductivity under a controlled atmosphere and the variable sensitivity of this conduction to air exposure. Electrostatic and conductive atomic force microscopies mapped out the characteristics of the cell envelope's nanofiber network, implicating it as the conductive pathway in a manner consistent with previous findings in marine cable bacteria. Four-probe measurements of microelectrodes addressing intact cables demonstrated nanoampere currents up to 200 μm lengths at modest driving voltages, allowing us to quantify the nanofiber conductivity at 0.1 S/cm for freshwater cable bacteria filaments under our measurement conditions. Such a high conductivity can support the remarkable sulfide-to-oxygen electrical currents mediated by cable bacteria in sediments. These measurements expand the knowledgebase of long-distance electron transport to the freshwater niche while shedding light on the underlying conductive network of cable bacteria. Competing Interests: TY, MC, CN, SX, ME No competing interests declared (© 2023, Yang, Chavez et al.)
Databáze:	MEDLINE
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