Presentation on theme: "STEM workshop Illuminating Life: What's New and Noteworthy in Luminescence Spectroscopy and Imaging Pat O’Hara October 3, 2009."— Presentation transcript:
1STEM workshop Illuminating Life: What's New and Noteworthy in Luminescence Spectroscopy and Imaging Pat O’HaraOctober 3, 2009
2Emission of Light Incandescence Luminescence Triboluminescence YESAfter heating?NOIncandescenceLuminescenceAfter excitation with sound?After using mechanical forces?YESYESTriboluminescenceSonoluminescenceAfter excitation with light?YESNOImmediately?Inanimate?YESNOYESNOfluorescencephosphorescencechemiluminescencebioluminescence
3What is fluorescence? http://micro.magnet.fsu.edu/primer/ Fluorescence is the emission of a photon by an excited state molecule.
4What’s new in fluorescence? Fluorescence of gemstones used to detect fake diamondsFluorescence is key to spider sex in some speciesFireflies chemiluminescenceDeep Sea Bioluminescence-Bananas that glow: Fluorescence of ripening fruit is key to cellular processes
8Fluorescence of Plants Ultraviolet fluorescence of plants is detected by bees, who have photoreceptors in this region of the spectrum and can see what looks to us like landing patterns on the petals directed towards pollen
9Emission of Light Incandescence Luminescence Triboluminescence YESAfter heating?NOIncandescenceLuminescenceAfter excitation with sound?After using mechanical forces?YESYESTriboluminescenceSonoluminescenceAfter excitation with light?YESNOImmediately?Inanimate?YESNOYESNOfluorescencephosphorescencechemiluminescencebioluminescence
10What is chemiluminescence? Chemical reaction results in an intermediate that is in an excited state.Reaction goes to product after this intermediate releases a photonEnergy of the photon comes from chemical energy due to the difference in energy of reactants and products
11What is Chemiluminescence? Example 1: Chemistry of LightsticksPhenol + CO2 + Dye + Light
12What is Chemiluminescence? Example 2: Chemistry of the Luminol ReactionOxidants: Peroxide, bleach, hemoglobinlight3-aminophthalhyrazideCatalysts: sodium perborate, cupric chloride,
13Emission of Light Incandescence Luminescence Triboluminescence YESAfter heating?NOIncandescenceLuminescenceAfter excitation with sound?After using mechanical forces?YESYESTriboluminescenceSonoluminescenceAfter excitation with light?YESNOImmediately?Inanimate?YESNOYESNOfluorescencephosphorescencechemiluminescencebioluminescence
15What is Bioluminescence? Chemistry of the Luciferase ReactionIn the dark cycle (quiescent) oxygen is consumed by mitochondria (green) and ATP and luciferin are stored up in peroxisomes.In the flash cycle, (NO) is released, and prevents consumption of O2 by mitocondria. Instead, O2 diffuses to peroxisome and voila! A flash!!
16What is Bioluminescence? Chemistry of the Luciferase ReactionThe luciferase catalyzes the oxidation of luciferinResulting in light and an inactive "oxyluciferin"
18Bioluminescence from surface water Animal------Jellyfish near surfaceSmall algae called milky sea
19Bioluminescence from mid-water range Let’s see video clip……….Mid-water … ft deeplight intensity decreases exponentially250 ft 10% less than surface500 ft 1% less than surfacePlants can not photosynthesizeWhy do organisms emit this light?1. defense against predators2. camouflage3. see things and find food4. communicate
20Giant Squid- caught in action in 2007 There are 100 known genera of squid and cuttlefish, 63 of which produce bioluminescence. Cephalopods possess light-producing organs called photophores, which can be arranged in simple clusters or in complex organs containing lenses, reflectors and light filters. In some cephalopods, light is produced by symbiotic bacteria which are housed and cultured within pockets in the skin; other species produce the light themselves.Squid also use bioluminescence to avoid being detected by predators. In a process called countershading, they turn on downward- facing photophores when illuminated from above; when the intensity of the bioluminescence matches that of the overhead illumination, the squid becomes invisible.Bioluminescence is produced when pigment molecules called luciferins are oxidized (i.e. have electrons removed from them). This reaction is carried out by enzymes called luciferases, which are believed to have evolved from oxygenases. The function of luciferases and oxygenases is to transfer electrons from one molecule to another, and they are therefore involved in neutralizing free radicals (compounds which contain unpaired electrons, and which are damaging to tissues). In the deep sea environment there is little light, and organisms are therefore not exposed to free radicals produced by direct sunlight as are organisms which live nearer the surface. Neutralization of free radicals is therefore not crucial in deep waters, and this is where luciferases evolved their light-producing functions.The photophores found in T. danae measure up to 5 cm in diameter and are the largest found in the animal kingdom. They are equipped with black “eyelids” which can open and shut rapidly, so that the emitted light appears to flash on and off.
22Green Fluorescent Protein GFP GFP is a small very fluorescent protein isolated from the bioluminescent jellyfish, Aequorea victoria. This protein glows or fluoresces green when it absorbs blue light emitted from another protein in the jellyfish, aqueorin.
23Fluorescent Bomb Throwing Marine Worm “fast, agile swimmers with glistening, translucent bodies sprouting rows of bristles that work like paddles. When disturbed, they eject glowing, green blobs that probably serve as decoys to distract predators’”
24Pat’s Picks Bizarre deep ocean sea creatures: Deep sea luminescent animals:UCSB links:
25Milky Sea Captured on Satellite Image off coast of East Africa
26Glowing bananas: photo credit: Zina Deretsky, National Science Foundation
27Glowing bananas: photo credit: Zina Deretsky, National Science Foundation
28Your Banana ChallengeI’ve brought in two dozen bananas of various stages of ripeness, some common solvents, knives, jars, and a black light.I’d like us to explore this phenomenon and put together some discovery lab questions that –with a black light and a ripe banana, might be useful to you in your lab.