BACTERIA OF THE MONTH

BACTERIA OF THE MONTH: VIBRIO FISCHERI

By: Georgia Johnson-King, m UHM MOP Student This species of bioluminescent motile bacteria are found in both fresh water and sea water, in temperate and tropical waters. The organisms can live freely as “marine snow,” but are often found in symbiotic relationships with other marine creatures. These specific bacteria are able to bio-illuminate through the control of a small set of genes called the lux operon, which controls the enzyme reaction that makes the bacteria glow. When the light chemical luciferin is oxidized by the enzyme luciferase the result is the emission of a blue-green light. Vibrio fischeri are often involved in symbiotic relationships, particularly with one Hawaiian squid known as Euprymna scolopes, or, the bobtail squid. This reaction is mutually beneficial, as in exchange for shelter and nutrients, the Vibrio fischeri kickstart the squid’s light organ maturation. The light organ is used to help protect the bobtail squid from predators, as the bioluminescence provides countershading. Vibrio fischeri light on the underside of the nocturnal hunting squid disguises them against the moon. Once the bacterium is fully established within its host, the light producing symbiosis is carried on throughout its entire life.