Figure 1. The range of colour of bioluminescent systems is represented by these two terrestrial species, exposed by their own bioluminescence. (a) The Australasian glowworm, Arachnocampa (Dipteran), about 5 mm in length. (b) The South American railroad worm, Phrixothrix (Coleopteran), about 20 mm in length. By permission of Vivian VR and Bechara EJH, Annals of the Entomological Society of America 90: 389 (1997), p. 394, fig. 2D.

Figure 2. Overall chemical steps in firefly bioluminescence. These reactions occur on firefly luciferase. The asterisk indicates that the molecule is in its first electronic (fluorescent) state.

Figure 3. Many marine bioluminescence systems proceed by this overall chemistry, including the crustacean Vargula and the jellyfish Aequorea. For coelenterazine the R substituents are phenyl or benzyl groups.

Figure 4. The light organs of the jellyfish, Aequorea, are distributed in a circle around the edge of the umbrella. (a) With external illumination. The specimen is about 20 cm in diameter. (b) Exposed by its own bioluminescence. Photograph by permission of Dr. John Blinks, Friday Harbor Laboratories, University of Washington.

Figure 5. Reduced FMN reacts with oxygen on bacterial luciferase to produce a metastable peroxyflavin on the luciferase. Reaction with an aliphatic aldehyde generates the bioluminescence.

Figure 6. Certain antenna proteins are responsible for the different colours of bioluminescence from two species of marine bioluminescent bacteria. Left: Photobacterium phosphoreum. Right: Vibrio fischeri, strain Y1. Reproduced with permission from Daubner SC, Astorga AD, Leisman GB and Baldwin TO (1987) Proceedings of the National Academy of Sciences of the USA 84: 8912–8916.