Oxygen consumption of individual cable bacteria

Area of Science:

• Microbiology
• Biogeochemistry
• Environmental Science

Background:

• Cable bacteria are filamentous microorganisms found in aquatic sediments.
• They possess unique electric wire-like structures for electron transport.
• These bacteria inhabit oxic-anoxic interfaces, bridging oxygenated and oxygen-depleted zones.

Purpose of the Study:

• To investigate the respiration mode of cable bacteria.
• To quantify oxygen consumption rates of individual cable bacteria.
• To understand the spatial distribution of cellular activity within cable bacteria filaments.

Main Methods:

• Observing distortions of the oxic-anoxic interface caused by cable bacteria.
• Calculating biomass-specific oxygen consumption rates.
• Analyzing the spatial organization of cable bacteria filaments relative to oxygen gradients.

Main Results:

• Cable bacteria exhibit extremely high biomass-specific oxygen consumption rates.
• Less than 10% of individual cable bacteria filaments are exposed to oxygen at any given time.
• Electron transport and oxygen reduction are localized to a small fraction of cells.

Conclusions:

• Cable bacteria employ a unique respiration strategy, separating electron oxidation from oxygen reduction.
• This allows the majority of cells to metabolize in anoxic conditions, avoiding oxidative stress.
• The findings support a model of intercellular electrical signaling for coordinated respiration.