2. BIOLUMINESCENCE
• Bioluminescence is light produced by a chemical reaction within a
living organism.
• Bioluminescence is chemiluminescence that takes place inside a living organism
• Bioluminescence is a “cold light.”
4. CHEMISTRY OF BIOLUMINESCENCE
• The chemical reaction that results in bioluminescence requires two
unique chemicals: luciferin and either luciferase or photoprotein.
• Luciferin is the compound that actually produces light.
• In a chemical reaction, luciferin is called the substrate.
• Some bioluminescent organisms produce (synthesize) luciferin on
their own.
• Some bioluminescent organisms do not synthesize luciferin. Instead,
they absorb it through other organisms, either as food or in a
symbiotic relationship.
5. • The chemical reaction catalyzed by firefly luciferase takes place in two
steps:
• luciferin + ATP → luciferyl adenylate + Ppi
• luciferyl adenylate + O2 → oxyluciferin + AMP + light
• Fireflies produce a chemical reaction inside their bodies that allows
them to light up.
• When oxygen combines with calcium, adenosine triphosphate (ATP)
and the chemical luciferin in the presence of luciferase, a
bioluminescent enzyme, light is produced.
6. OXYGEN IN BIOLUMINESCENCE
• A firefly controls the beginning and end of the chemical reaction, and
thus the start and stop of its light emission, by adding oxygen to the
other chemicals needed to produce light.
• This happens in the insect’s light organ.
• When oxygen is available, the light organ lights up, and when it is not
available, the light goes out.
7. WHY DO FIREFLIES LIGHT UP?
• Mating
• Sexual selection
• Display indications of mate:
• Quality
• Sex
• Species
• Exact location
• Critically timed signals
8. Male to female signalling
• Both males and females Use bioluminescense (Hotaria parvula)
• Secondary female produces light to attract male ( Microphitus)
• Sedentary females use pheromones to attract males and when in close
proximity,glow ( Pleotomus pellens )
• Only larvae emit light,rely solely on pheromones ( Lucidota atra)
9. Larvae bioluminescense
• Spend most of their lives in this
stage (2-3 years vs. 10 days as an
adult)
• Same reactions
• Difference: Isoenzymes, Difference
in location, Morphology and
physiology of insects
• Results : Different colours and
behavioural displays
10. How do fireflies produce light?
• Neural activity stimulates release of NT octopamine.
• Triggers the lantern organ in abdomen.
• Inside peroxisomes : Luciferin- luciferase reaction .
13. SYNCHRONY
• Certain firefly exhibit Synchrony.
• Anticipatory mechanisms.
• Rate of one dictates the rate of another.
14. DIFFERENT COLOURS IN LIGHT
• Different species of fireflies emit different wavelengths of light and
therefore different colours.
• Reaction route universal.
• Light emissions span wide range of wavelength from green (545 nm)
to red (620 nm).
15. HOW CAN LIGHT EMISSION VARY IN COLOR?
• Oxyluciferin: keto form= Red ; enol form = yellow.
• 5,5 – dimethyloxyluciferin can emit multi colour light despite being
constrained to keto form.
• Twisted structure of the keto form can rotate to change colour.
• OR polarization of oxyluciferin in microenvironment and the changes
in polarity of the luciferase binding sites.
16. FIREFLY LIGHT RECEPTORS
• 3 visual receptors
1) Near UV
2) Blue
3) Green Yellow
Species specific bioluminescence matches visual receptors.
Achromatic : Transmitting Light without separating it into its
constituent colours
17. APPLICATIONS
• The functions of Bioluminescence are for :
1)Defense
2) Feeding
3) Communication
4) Mating
• Bioluminescence plays an important role in the ecology of the ocean
18. Role of communication
• Larvae use their glows as warning displays to communicate
their distastefulness.
• As adults, many fireflies have flash patterns unique to their
species and use them to identify other members of their species
as well as to discriminate between members of the opposite
sex.
• Several studies have shown that female fireflies choose mates
depending upon specific male flash pattern characteristics.
• Higher male flash rates, as well as increased flash intensity,
have been shown to be more attractive to females in two
different firefly species.
19. REFERENCES
• The anatomy and the physiology of the light organ in the fireflies –
John B Buck . Annals of the Newyork academy of sciences 49(3), 397-
485-1948
• Chemistry of firefly bioluminescence– Bruce R. Branchini
• Flash communication in fireflies – AD Carlson
• https://www.frontiersin.org
• https://www.scientificamerican.org
• https://www.researchgate.net
