Bioluminescence in Fungi

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Bioluminescence in Fungi

INTRODUCTION
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 1850s 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
1920s till 1950s (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 organisms. –
Substrate (Luciferin) – a specific molecule that undergoes a chemical charge
when affixed by an enzyme. – Oxygen – as a catalyst
A simplified formula of the bioluminescent reaction:
ATP(energy) + Luciferin (substrate)+ Luciferase(enzyme) + O2(oxidizer) ==
== light (protons)
The bioluminescent reaction occurs in two basic stages:
1) The reaction involves a substrate (D-Luciferin), combining with ATP, and
oxygen which is controlled by the enzyme(Luciferase). Luciferins and Luciferase
differ chemically in different organisms but they all require molecular energy
(ATP) for the reaction. 2) The chemical energy in stage one excites a specific
molecule (The Luminescent Molecule: the combining of Luciferase and Luciferin).

The excitement is caused by the increased energy level of the luminescent
molecule. The result of this excitement is decay which is manifested in the form
of photon emissions, which produces the light. The light given off does not
depend on light or other energy taken in by the organism and is just the
byproduct of the chemical reaction and is therefore cold light. The
bioluminescence in fungi occurs intracellularyand has been noted at the
spore level(Burr 1985, Newton 1952 and Herring 1978). This may at times be
mistaken for a extracellular source of light but this is due to the diffusion
of the light through the cells of the fungus. In examining the photograph in
figure 1, it appear that the cap of the fungus is glowing but after study, it
was observed that just the gill structures that emits the light and the cap
(which is thin) emits the light of the gills by diffusion(Herring 1978). The
energy in photons can vary with the frequency (color) of the light. Different
types of substrates(Luciferins) in organisms produce different colors. Marine
organisms emit blue light, jellyfish emit green, fireflies emit greenish yellow,
railroad worms emit red and fungi emit greeny bluish light (Patel 1997).


Fungal Families Exhibiting Bioluminescence
The phylum Fungi is composed of the following 5 divisions (Newton 1952):
– Myxomycetes (slime molds) – Schizomycestes (bacteria) – Phycomycetes (moulds)
– Ascomycetes ( yeasts, sac fungi and some molds) – Basidiomycetes (smuts, rusts,
and mushrooms)
Of the above divisions the majority of bioluminescence occurs in the
Basidiomycetes and only one observation has been made involving the Ascomycetes;
specifically in the Ascomycete genus Xylaria (Harvey 1952). At present there
are 42 confirmed bioluminescent Basidiomycetes that occur world wide and share
no resemblance to each other visually, other than the ability to be
bioluminescent. Of these 42 species that have been confirmed 24 of these have
been identified just in the past 20 years and as such many more species may
exhibit this trait but are yet to be found. The two main genus that display
bioluminescence are the genus Pleurotus which have at present 12 species which
occur in continental Europe and Asia. The genus Mycena have 19 species
identified to date with a world wide distribution range. In North America only
5 species of bioluminescent basiodiomycetes have been reported. These include
the Honey mushroom -Armillaria mellea (illustrated in figure 3), the common
Mycena -Mycena galericulata (illustrated in figure 1), the Jack OLatern –
Ophalalotus olearius (pictured in figure 4), Panus styticus and Clitocybe
illudens. The question of whether bioluminescent mushrooms were all poisonous
was raised in the discussions between my laboratory partner and myself. After
examining the literature and a mushroom field guide book it was evident that
there was no correlation between the edibility of the mushroom and its
bioluminescence. Some mushrooms such as Armillaria mellea the Honey mushroom
was listed as being excellent to eat. While the Jack OLatern – Omphalalotus
olearius was listed as poisonous and caused sever gastrointestinal cramps. The
edible merits of the common Mycea were unknown and while Panus stypticus was
listed as poisonous it was found to contain a clotting agent and useful in
stopping bleeding (Lincoff 1981, Newton 1952 and Herring 1978). As it only a
field guide to North American mushrooms was available, only the North American
varieties were examined. If all 42 species of bioluminescent basidiomycetes
were included in the search, a possible correlation may have been found.


Bioluminescence Research Applications
Luminescence has a unique advantages for scientific studies as it is the only
biochemical process that has a visible indicator than can be measured. The
light given off in the bioluminescent reaction is now able to be accurately
measured with the use of a luminometer. This ability to easily and accurately
detect small amounts of light has led to the use of the bioluminescent reaction
in scientific research involving biological process applications. The following
are just a few applications, some of which have been developed in only the last
few years (Johnson and Yata 1966, and Patel 1997). The following are two
examples of which have been recently developed.


The Tuberculosis Test
Testing for tuberculosis has long been a problem because of the long time it
takes for the species to grow to a size that is detectable by modern medicine.

Typically growing a culture of Mycobacterium tuberculosis large enough to
determine the strain that a particular patient has can take up to three months.

Of course, this poses a problem because the patient often can not wait for the
diagnosis and must be given drugs that his strain may be resistant to. This is
further complicated because there are 11 drugs used to combat TB, picking the
right one before determining the strain has a 1/11 chance of success. Recently
a way of incorporating bioluminescence into the TB tests has been found and can
sharply reduce the diagnosis time to as little as 2 days. The technique
involves inserting the gene that codes for luciferase into the genome of the TB
bacterial culture taken from the patient. The gene is introduced through a viral
vector and once incorporated, the bacteria produces the luciferase. When
luciferin is added to the culture, light is produced. Since less than 10,000
bacteria are needed to code for enough luciferase to produce a detectable amount
of light, the culture time is reduced to only 2-3 days. Since the luciferase-
luciferin reaction requires ATP, the resistance of the strain in the culture can
be tested by adding a drug and watching for light. This will indicate which of
the 11 drugs therapys will be effective in treating Tuberculosis. By reducing
the time needed to prescribe the correct drugs for treatment, this application
of bioluminescence will someday be ready to save some of the 3 million killed
each year by tuberculosis (Patel 1997).


Biosensors
Bioluminescence has also been used for several years as a biosensor of many
substances. As seen in the tuberculosis example, bioluminescence can be used a
sensor for the presence of ATP because ATP is needed in the light producing
reaction. Other techniques have been used for detecting ions of mercury and
aluminum, among others, by using bacteria with light genes fused to their ion-
resistant regulons. For example, if a bacteria that is resistant to Hg is in the
presence of Hg, the genes coding for its Hg resistance will be activated. The
activation of that gene will also activate the luciferase gene fused to it, so
the bacteria will produce luciferase whenever Hg is present. Adding luciferin
and testing for light production with a luminometer reveals the presence of the
metal ion in the solution. This technique is especially useful in testing for
pollutants in the water supply when concentrations are too low to detect by
conventional means(Herring 1978, and Patel 1997). Other areas that are currently
using bioluminescence in scientific research include evolution, ecology,
histology, physiology, biochemistry, biomedical applications, cytology and
taxonomy. Any area that involves a living organism can utilize bioluminescent
technology as a biosensor.


Conclusion
The glow light generated by bioluminescent Fungi has for centuries
generated interest from philosophers and scientists and has benefited science by
providing problems to solve -How does it work and does it have a practical
application? The answers to those basic problems that have been discovered
today and have resulted in benefiting mankind, by bettering our lives
especially in regard to its biomedical applications.Further research with
bioluminescent Fungi is being conducted on a world wide scale and include North
America, Japan, and Europe. Future research may lead to new discoveries and
uses from bioluminescent organisms such as the Fungi group.


References
Burr, G.J. 1985. Chemiluminescence and Bioluminescence. Marcel Dekker, Inc. New
York, U.S.A.


Johnson, F. H. and Yata, H. 1966. Bioluminescence in progress. Princton, New
Jersey, Princeton University Press.


Lincoff,G.H. 1981. The Audubon Society field guide to North American Mushrooms.

Knopf Inc. New York. U.S.A.


Newton, H.E. 1952. Bioluminescence. Academic Press. New York. U.S.A.


Herring, P.J. 1978. Bioluminescence in Action. Academic Press. New York. U.S.A.


Patel, P.Y. 1997. Bioluminescence in scientific research. Jan 10, 1997.

Http://www. emailprotected
Wood, M.F. and Stevens, F. 1997. The Myko web page -Fungi Photos. Jan 10, 1997.

. http://www.mycoweb.com/ba_index.html#A
WED. AM GROUP BIOLOGY 201 BIOLUMINESCENT FUNGI DUE MARCH 7, 1997
Category: Science