What is Bioluminescence?
The current paper main focus is on bioluminescent Fungi but the basic features of bioluminescence discussed are common to all bioluminescent organisms. Bioluminescence is simply light created by living organisms. Probably the most commonly known example of bioluminescence by North Americans is the firefly, which lights its abdomen during its mating season to communicate with potential mates. This bioluminescent ability occurs in 25 different phyla many of which are totally unrelated and diverse with the phylum Fungi included in this list (an illustration of a bioluminescent fungi is displayed in figure 1). One of the features of biological light that distinguishes it from other forms of light is that it is cold light. Unlike the light of a candle, a lightbulb, bioluminescent light is produced with very little heat radiation. This aspect of bioluminescence especially interested early scientists who explored it. The light is the result of a biochemical reaction in which the oxidation of a compound called "Luciferin" and the reaction was catalyzed by an enzyme called "Luciferase". The light generated by this biochemical reaction has been utilized by scientists as a bioindicator for Tuberculosis as well as heavy metals. On going research involving bioluminescence is currently underway in the areas of evolution, ecology, histology, physiology, biochemistry, and biomedical applications.
History of Bioluminescent Fungi
The light of luminous wood was first noted in the early writings of Aristotle which occurred in 382 B.C.(Johnson and Yata 1966 and Newton 1952) The next mention of luminous wood in the literature occurred in 1667 by Robert Boyle who noticed glowing earth and noted that heat was absent from the light. Many early scientists such as Conrad Gesner, Francis Bacon, and Thomas Bartolin all observed and made notation of luminous earth(Johnson and Yata 1966 and Newton 1952 ). These early observers thought that the light was due to small insects or animal interactions. The first mention that the light of luminous wood was due to fungi occurred from a study of luminous timbers used as supports in mines by Bishoff in 1823. This opened the way for further study by many other scientists and by 1855 modern experimental work began by Fabre ( Newton 1952). Fabre established the basic parameters of bioluminescent fungi, those being:
- The light without heat - The light ceased in a vacuum, in hydrogen, and carbon dioxide - The light was independent of humidity, temperature, light, and did not burn any
brighter in pure oxygen
The work by Herring (1978) found that the luminescent parts of the included pileus(cap), hymenium(gills) and the mycelial threads in combination or separately(figure 2) also the individual spores were also seen to be luminescent. Herring also stated that if the fruiting body (mushroom) was bioluminescent then the mycelial threads were always luminescent as well but not vice versa. From the 1850's to the early part of the 20th century the
identification of the majority of fungal species exhibiting bioluminescent traits was completed. The research of bioluminescent fungi stagnated from the 1920's till 1950's (Newton 1952 and Herring 1978 ). After which extensive research began involving the mechanisms of bioluminescence and is still carried out to the present.
The Process of Bioluminescence
Bioluminescence results because of a certain Biochemical reaction. This can be described as a chemiluminescent reaction which involves a direct conversion of chemical energy transformed to light energy( Burr 1985, Patel 1997 and Herring1978). The reaction involves the following elements:
- Enzymes (Luciferase) - biological catalysts that accelerate and control the rate of chemical reactions in cells. - Photons - packs of light energy. - ATP - adenosine triphosphate, the energy storing molecule of all living...