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Updated: Jun 14, 2025
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Fluorescently Labeled Bacteria as a Tracer to Reveal Novel Pathways of Organic Carbon Flow in Aquatic Ecosystems
Published on: September 13, 2019
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Long-distance electron transport in multicellular freshwater cable bacteria
Tingting Yang1, Marko S Chavez1, Christina M Niman1
1Department of Physics and Astronomy, University of Southern California, Los Angeles, United States.
Elife
|August 29, 2024
Summary
Freshwater cable bacteria (Candidatus Electronema) exhibit high electrical conductivity, enabling centimeter-scale electron transport in sediments. This study quantifies their nanofiber conductivity, crucial for their ecological roles.
Area of Science:
- Microbiology
- Geochemistry
- Biophysics
Background:
- Filamentous multicellular cable bacteria mediate centimeter-scale electron transport in sediments.
- This electric metabolism couples sulfide oxidation to oxygen/nitrate reduction.
- Previous conductivity studies focused on marine cable bacteria (Candidatus Electrothrix), not freshwater counterparts (Candidatus Electronema).
Purpose of the Study:
- To characterize the electron transport properties of freshwater cable bacteria (Candidatus Electronema).
- To investigate the conductive pathway within the cell envelope's nanofiber network.
- To quantify the electrical conductivity of freshwater cable bacteria filaments.
Main Methods:
- Current-voltage measurements using interdigitated electrodes.
- Electrostatic and conductive atomic force microscopy.
- Four-probe measurements on intact cable filaments.
Main Results:
- Confirmed persistent conductivity in freshwater cable bacteria under controlled atmospheres.
- Identified the cell envelope's nanofiber network as the conductive pathway.
- Quantified nanofiber conductivity at 0.1 S/cm for freshwater cable bacteria filaments.
Conclusions:
- Freshwater cable bacteria possess high conductivity supporting long-distance electron transport.
- This research expands knowledge of electron transport in freshwater sediments.
- The findings illuminate the conductive network enabling cable bacteria's geochemical functions.
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