Transcript Bioluminescence

Outline
• Introduction
• Bioluminescence Mechanism
• Typical Luciferin Molecules
Many naturally occurring organisms are bioluminescent,
including insects, fungi, bacteria, jellyfish and dinoflagellates.
Bioluminescence has various useful functions:
Finding or attracting prey, example: anglerfish
Defense against predators, example: squid, shrimp
scaleworms and brittlestars.
Communication, example: fireflies.
http://siobiolum.ucsd.edu/Biolum_q&a.html#question7
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Mechanism
• Bioluminescence is light produced by a chemical
reaction within an organism.
• Two chemicals are required for luminescence
The light-producing compound (luciferin)
The catalyst (luciferase)
http://www.bioart.co.uk/lux/intro.html
• The mechanism of luminescence is regulated
by activity of enzymes (luciferases) upon
luminescent proteins (luciferins), and requires
oxygen.
http://www.bioart.co.uk/lux/dino.html
Luciferin and dehydroluciferin
are exactly alike except for
one pair of hydrogen atoms
http://philmintz.tripod.com/Chemistry/
page7.html
The luciferinase attracts an oxygen
molecule and gets the oxygen into the
best position to attract both hydrogen
atoms of the luciferin.
During the departure of the hydrogen
atom from the carbon atom next to the
nitrogen atom, the second electron of
that bond starts to follow the hydrogen
atom.
While the shifting of the hydrogen
atom is taking place, the point of zero
force for the second electron is
unusually far from the center of the
carbon atom.
http://philmintz.tripod.com/Chemistry/page7.html
The two hydrogen atoms move off with the oxygen molecule
as hydrogen peroxide
With the hydrogen atoms gone, the point of zero
force, which was far from the carbon, returns to a
location between the two carbon atoms. This gives
the electron a long trip back, driven by potential
energy with the distance, and a corresponding store
of neg-pos. The electron oscillates with sufficient
amplitude to produce a photon with the right
resonance frequency. The photon is emitted in the
visible range.
http://philmintz.tripod.com/Chemistry/page7.html
Typical Luciferin Molecules
• Bacterial Luciferin
bacteria, some fish, some squid.
• Vargulin
some fish, firefleas.
• Dinoflagellate (a structure similar to chlorophyll)
euphausiid shrimp, etc.
• Coelenterazine (most common marine luciferins)
squid, shrimp, fish, jellyfish, etc.
• Insect
firefly.
• Marine Groups with No Known Luminous Members
sponges, heteropods, pteropods, etc.
http://www.lifesci.ucsb.edu/~biolum/chem/detail1.html
bioluminescent bacteria
a reduced riboflavin phosphate is oxidized in association with a long-chain
aldehyde,oxygen, and a luciferase
Vibrio fischeri grown for 24 hours on Photobacterium sea water agar
http://www.lifesci.ucsb.edu/~b
iolum/chem/detail2.html
Vargulin
There is a clear dietary link, with fish losing their
ability toluminescent until they are fed with
luciferin-bearing food.
http://www.lifesci.ucsb.edu/~biolum/organism/photo.
html
• Some lanternfish (myctophids) have very bright light organs near
their tail (the white spots above and below the body at the left).
These "sternchasers" produce a blinding flash at the instant that
the animal darts away, leaving a confused predator in its wake.
• http://www.lifesci.ucsb.edu /~biolum/organism/photo.html
Dinoflagellate luciferin
Is thought to be derived
from chlorophyll, and
has a very similar
structure.
http://www.lifesci.ucsb.edu/~
biolum/chem/detail2.html
Euphausia pacifica is a small vertically migrating
species of krill. It is not clear whether the
luminescence, concentrated in photophores along the
bottom of the body, is used for counterillumination.
(Length approx. 2 cm)
Coelenterazine
Coelenterazine is the most "popular" of the marine luciferins, found
in a variety of phyla
http://www.lifesci.ucsb.edu/~biolum/chem/detail2.html
This small squid in the genus
Abraliopsis has several
different types of light organs.
In addition to the bean-shaped
ones at the tips of two central
arms, it has small
photophores covering the
underside of its body.
http://www.lifesci.ucsb.edu/~biol
um/organism/photo.html
This
ctenophore
Beroe
forskalii illustrates one of the
reasons
that
many
transparent organisms have
pigmented guts. It has just
ingested a lobate ctenophore
Leucothea, and if the lights
were off, the glow of the
luminescing prey would be
visible to passing creatures.
The Beroe is swimming from
right to left in this picture, and
its mouth is at the left.
http://www.lifesci.ucsb.edu/~bio
lum/organism/photo.html
Aequorea victoria (jellyfish) is
probably the most famous
bioluminescent
marine
organism. Calcium-activated
photoprotein
and
greenfluorescent protein
http://www.lifesci.ucsb.edu/~biol
um/organism/photo.html
• This ctenophore Ocyropsis is heavily parasitized by amphipods,
(Length approx. 5 cm)
•
http://www.lifesci.ucsb.edu/~biolum/organism/photo.html
Firefly
• the most generally accepted
hypothesis is firefly larvae use
their luminescence as a
warning signal (aposematism)
that communicates to potential
predators that they taste bad
because they have defensive
chemicals in their bodies.
These larvae also increase
both the intensity and
frequency of their glow when
disturbed
• http://iris.biosci.ohiostate.edu/projects/FFiles/frfact.html
Marine Groups with No Known Luminous Members
• Heteropods like this
Carinaria are some of the
very few planktonic
organisms which are not
bioluminescent. However
they still must deal with
luminescence.
• http://www.lifesci.ucsb.edu/~biolum
/organism/photo.html
Pteropods, like this Clione, are one of the few kinds of planktonic
invertebrates which do not have bioluminescent members
.
Work sites
• http://www.lifesci.ucsb.edu/~biolum/
• http://philmintz.tripod.com/Chemistry/page7.html
• http://www.bioart.co.uk/lux/intro.html