Bioluminescence in aquatic and terrestrial organisms elicited through various kinds of stimulation

The term bioluminescence refers to a conspicuous light emission displayed by numerous aquatic and terrestrial organisms. This phenomenon has so far not been observed in several taxonomic groups like archaea, protista, platyhelminthes, chelicerata, cephalochordata, amphibians, reptiles, birds, plants, and mammals. However, some luminescent bacteria, fungi and microalgae like dinoflagellates are known. Bioluminescence has become a powerful biological tool and revolutionized several medical, physiological and biotechnological approaches, such as, for example, the study of metabolic pathways of bacteria to mammals. In 2008 O. Shimomura, M. Chalfie and R. Tsien were awarded the Chemistry Nobel prize for their discovery of the protein GFP, which is co-expressed with aequorin, the calcium-activated photoprotein involved in the bioluminescence reaction of the jellyfish Aequorea victoria. Some organisms are known to display bioluminescence only under certain kinds of stimulation and stress conditions; others appear to produce their light without prior stimulation either continuously or intermittently. Despite the discovery of more than 700 genera of bioluminescent organisms from marine, terrestrial, and freshwater environments, there is often still insufficient knowledge about their bioluminescence emission patterns under natural and stress conditions. Furthermore, there are no detailed reviews on stimulation techniques that can be used to test whether organisms previously not having been recognized to be luminescent are luminescent or not. This paper reviews various stimulants, such as chemical, mechanical, photic, thermal, magnetic and electrical ones, used in tests to elicit the emission of light in known bioluminescent organisms. This account should help researchers to extend their investigations to identify organisms hitherto not deemed to be luminescent.