Luciferase-dependent oxygen consumption by bioluminescent vibrios

Area of Science:

• Microbiology
• Biochemistry
• Bioluminescence

Background:

• Marine luminous bacteria, such as Vibrio species, utilize the luciferase enzyme for light production.
• Understanding the energetic cost of bioluminescence is crucial for comprehending bacterial physiology and ecological roles.

Purpose of the Study:

• To quantify the in vivo oxygen consumption attributed to the luciferase enzyme in luminous Vibrio species.
• To estimate the bioluminescent quantum yields in these bacteria.

Main Methods:

• Employing specific inhibitors: decanol for luciferase and cyanide for cytochromes.
• Conducting cyanide titration experiments to differentiate oxygen uptake components.
• Measuring oxygen consumption in Vibrio harveyi and Vibrio fischeri.

Main Results:

• A distinct oxygen uptake component, insensitive to cyanide but inhibitable by decanol, was identified.
• Luciferase was estimated to account for <12% of total respiration in Vibrio harveyi.
• Luciferase was estimated to account for <20% of total respiration in Vibrio fischeri.

Conclusions:

• In vivo bioluminescence represents a relatively small fraction of the overall metabolic oxygen demand in these Vibrio species.
• Estimated in vivo bioluminescent quantum yields are at least 1.7% for Vibrio harveyi and 2.6% for Vibrio fischeri.