Bioluminescence from single bacterial cells exhibits no oscillation

Area of Science:

• Microbiology
• Biophysics
• Photochemistry

Background:

• Marine bacteria luminescence is typically measured in bulk, leaving individual cell emission patterns unclear.
• Previous studies have questioned whether single-cell bioluminescence is continuous or intermittent.

Purpose of the Study:

• To investigate the temporal pattern of light emission from individual marine bacterial cells.
• To determine if single-cell bioluminescence is continuous or exhibits flashes/bursts.

Main Methods:

• Development of a sensitive photo-counting system with computerized data acquisition.
• Analysis of single-cell luminescence in *Beneckea harveyi*, *Photobacterium belozerskii*, *P. fischeri*, and *P. leiognathi*.
• Application of photo time-correction and power spectral analysis on photon count data.

Main Results:

• Single luminous marine bacteria exhibited count rates 2-10 times background levels.
• No evidence of flashes, bursts, or oscillations was detected in 100 ms intervals.
• Photon emission patterns closely matched random emission from a reference light source.

Conclusions:

• Individual marine bacteria emit photons randomly and continuously.
• The study provides the first direct evidence of continuous single-cell bioluminescence in marine bacteria.
• The findings resolve long-standing questions about the nature of bacterial light emission.