BioluminescenceSample Presentation – General PowerPoint Formatting Example

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.

Types of Organisms That Utilize Bioluminescence

• Insects - ex. fireflies, glow worms, certain 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 • to illuminate for visual purposes

• to warn and intimidate other organisms • to communicate and for mating rituals

* A deep sea shrimp emits a bioluminescentfluid to distract a predator to escape

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 tofocus the light, control the intensity, andchange 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.

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05/02/10)

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References