Transcript Sample Presentation

Bioluminescence
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Biology 210A
Objectives
• Define bioluminescence
• Identify the types of organisms that utilize bioluminescence
• Determine the different advantages of bioluminescence
• Examine the chemical process that occurs
• Illustrate modern day applications for bioluminescence
What is Bioluminescence?
• Bioluminescence is the production and emission of light from a
living organism.
• The term bioluminescence originated from the Greek bios
meaning “living” and the Latin lumen meaning “light”.
• The emission of light is produced by chemical reactions within
the organism. These reactions can occur internal and external to
the cell.
• Bioluminescence is not the same as fluorescence as it is the
direct production of light where fluorescence is light absorbed,
then re-emitted.
• Insects
ex. fireflies, glow
worms,
certainBioluminescence
Types
of- Organisms
That
Utilize
centipedes and millipedes
• Fish & other marine vertebrates
- ex. anglerfish, hatchetfish, cookie cutter shark,
gulper eel
• Marine invertebrates – ex. many corals and
jellyfish, certain squid and mollusks
• Fungi – ex. Jack O’Lantern mushroom, ghost
fungus, over 70 other species
• Other microorganisms – ex. dinoflagellates, and
many other bacteria
Advantages of Bioluminescence
• to startle or distract another
organism to escape from harm
• to lure prey
• to camouflage/counter shade
* A deep sea shrimp emits a bioluminescent
fluid to distract a predator to escape
• to illuminate for visual purposes
• to warn and intimidate other organisms
• to communicate and for mating rituals
Chemiluminescence: The Chemical Process
• Bioluminescence produces cool light, meaning nearly all energy
produced in the reaction is converted to light without heat.
• In light bulbs only 3% light is produced, while the remaining 97% of
the energy produced is wasted as heat.
• The three main requirements for the chemical reaction to occur are:
oxygen, luciferin (a molecular substrate) and luciferase (an enzyme)
resulting in light and oxyluciferin
O2 + luciferin + luciferase = oxyluciferin + LIGHT
• Sometimes luciferin and additional catalyzing proteins, along with a
co-factor such as oxygen, form a complex called a photoprotein.
• This molecule is then triggered by a secondary signal molecule,
usually calcium ions to activate the complex.
Photophores: The Light House
• Many organisms, mostly marine vertebrates and invertebrates,
produce bioluminescence in organs called photophores.
• These organisms collect light producing bacteria by allowing a small
opening to the organ that is exterior to the organism in which the
bacteria can enter.
• Photophores can be very complex, similar
to an eye, in that they can contain a lens,
reflectors, and filters.
• These features allow the organism to
focus the light, control the intensity, and
change the color of the light being emitted.
Lux Operon: Expression in Bacteria
• The lux operon consists of the gene that codes for luciferase.
• The lux system is an inducible operon.
• It is active when the concentration of homoserine lactose is high; when a high concentration
of bacteria is present.
• The lux operon has the sequence luxCDAB(F)E.
• luxA and luxB code for the subunits of the enzyme luciferase.
• LuxCDE code for enzymes that convert fatty acids into aldehydes which are needed
for the reaction to proceed.
• LuxI is responsible for the production of the autoinducer protein, homoserine lactose.
• When the concentration of homoserine lactose is high, it reacts with the protein
produced from the second operon, the regulator, luxR.
• This results in increasing the association of RNA polymerase to the promoter region of
the first operon and eventually producing luminescence.
Modern Applications of Bioluminescence
• Through gene splicing,
non-bioluminescent organisms have
been able to express the proteins
necessary for bioluminescence.
Some organisms include: bacteria, silk,
potatoes, orchids, and mice.
• The biomedical industry uses
bioluminescence as a “highlighter”
for monitoring the expression of other genes being studied. It
has also been used to study infections, the progression of cancer
and reconstitution kinetics using bioluminescent stem cells.
• Future uses include bioluminescent plants along streets for
illumination, advancements in gene therapy and simply for
entertainment.
References
Bosveld, J.. (2009, July). Aliens of the Sea. Discover, 30(7), 76. Retrieved May 4, 2010, from
Research Library Core.
Haddock, S.H.D., McDougall, C.M., & Case, J.F. "The Bioluminescence Web Page",
http://lifesci.ucsb.edu/~biolum/ (created 1997; updated 2010; accessed 05/02/10)
Latz, M. “Latz Laboratrory of Scripps Institute of Oceanography”
http://siobiolum.ucsd.edu/biolum_intro.html (created 1995; accessed 05/02/10).
Rowe, L., Dikici, E., & Daunert, S. (Nov 1, 2009). Engineering bioluminescent proteins: expanding
their analytical potential. Analytical Chemistry, 81, 21. p.8662(7).
“San Diego Natural History Museum: Lights Alive” http://www.sdnhm.org/kids/lightsalive/
(accessed 05/02/10).