BIOLUMINESCENCEBIOLUMINESCENCE

Submitted by,Submitted by,

SELMA ABDUL SAMADSELMA ABDUL SAMAD

BCH- 10 – 05 – 02BCH- 10 – 05 – 02

S2 MSc BIOCHEMISTRYS2 MSc BIOCHEMISTRY

Phenomenon of production and emission of light Phenomenon of production and emission of light by a living organism.by a living organism.

Creatures ( unicellular bacteria to vertebrates )Creatures ( unicellular bacteria to vertebrates )

chemical energy Light energychemical energy Light energy ((Wilson and Hastings, 1998)Wilson and Hastings, 1998)

Bioluminescent animalsBioluminescent animals

Are mostly - marineAre mostly - marine

Very few - terrestrialVery few - terrestrial

Process is 100 % efficientProcess is 100 % efficient

It is different from fluorescenceIt is different from fluorescence

Fluorescence – Needs high energy radiationFluorescence – Needs high energy radiation The molecule absorbs a photon and excites an electron The molecule absorbs a photon and excites an electron

It comes back to low energy state releasing energy in the It comes back to low energy state releasing energy in the form of light.form of light. (Williamson & Cummins,1983)(Williamson & Cummins,1983)

The original molecule is restored following fluorescent The original molecule is restored following fluorescent emission.emission.

Bioluminescence – A characteristic chemical reaction takes Bioluminescence – A characteristic chemical reaction takes place in the organism which releases enough energy place in the organism which releases enough energy producing a visible photon of light.producing a visible photon of light.

The expended molecule must be replaced by synthesis or The expended molecule must be replaced by synthesis or diet, it is not regenerated.diet, it is not regenerated.

Chart from lap as on page 1Chart from lap as on page 1

Next chart as on page 2Next chart as on page 2

LuciferinsLuciferins From different biological sources - chemically unrelatedFrom different biological sources - chemically unrelated They are polycyclic aromatic compounds that are They are polycyclic aromatic compounds that are

inherently fluorescent since their orbitals have multiple inherently fluorescent since their orbitals have multiple energy levels.energy levels.

1.1. Bacterial luciferinBacterial luciferin – a derivative of riboflavin – a derivative of riboflavin

2.2. Dinoflagellate luciferinDinoflagellate luciferin – related to the chlorophyll – related to the chlorophyll structure structure

3.3. Firefly luciferinFirefly luciferin – Requires ATP for bioluminescence – Requires ATP for bioluminescence

4.4. CoelenterazineCoelenterazine – extremely common,found in several – extremely common,found in several speciesspecies

5.5. VargulinVargulin – found in some shrimp species – found in some shrimp species (Vargula & Cypridina)(Vargula & Cypridina)

Structures of luciferins as on page Structures of luciferins as on page 22

The spectrum of radiation observed in The spectrum of radiation observed in bioluminescence is very broad bioluminescence is very broad

– ranges from violet to redranges from violet to red

– most common are blue or blue green (~470 nm)most common are blue or blue green (~470 nm)

– This may be because the phenomenon is largely This may be because the phenomenon is largely prevalent in oceans ; and seawater is especially prevalent in oceans ; and seawater is especially transparent to blue light ; Since other light do not travel transparent to blue light ; Since other light do not travel far in water , evolution might have selected blue color in far in water , evolution might have selected blue color in bioluminescence.bioluminescence.

TheThe color of bioluminescence depends oncolor of bioluminescence depends on

– mainly the structure of luciferin mainly the structure of luciferin (Wilson & Hastings,1998)(Wilson & Hastings,1998)

– 3D structure and amino acid sequence of luciferase 3D structure and amino acid sequence of luciferase proteinprotein

– The presence of accessory proteins or other The presence of accessory proteins or other chromophores also affect the spectrum of radiated lightchromophores also affect the spectrum of radiated light

(Wilson & Hastings,1998)(Wilson & Hastings,1998)

Physiological control of Physiological control of bioluminescencebioluminescence

ComplicatedComplicated– Involves wide variety of mechanisms for subcellular Involves wide variety of mechanisms for subcellular

localisation, signal induction & chemical regeneration.localisation, signal induction & chemical regeneration.– Eg. Bioluminescent bacteria – the photochemicals are present Eg. Bioluminescent bacteria – the photochemicals are present

throughout the cytoplasm and glow continuosly without throughout the cytoplasm and glow continuosly without flashing.flashing.

– Eg. Fireflies – highly structured specialised light producing Eg. Fireflies – highly structured specialised light producing organs( the lantern) that is regulated by flow of oxygen to it.organs( the lantern) that is regulated by flow of oxygen to it.

– Eg. Dinoflagellates – special light producing organelles Eg. Dinoflagellates – special light producing organelles (scintillons) regulated by shifts in pH.(scintillons) regulated by shifts in pH.

– Eg. Some worms – flashes controlled by CaEg. Some worms – flashes controlled by Ca2+ 2+ entry into cellsentry into cells

(William & Hastings,1998)(William & Hastings,1998)

Basic principle of bioluminescence is preserved across Basic principle of bioluminescence is preserved across diverse species.diverse species.

But its physiological implementation is extremely But its physiological implementation is extremely variegated.variegated.

UUses of Bioluminescenceses of Bioluminescence1.1. As a defense mechanism – night timeAs a defense mechanism – night time

– Two logics a) distract primary predatorTwo logics a) distract primary predator b) make primary predator visible to larger b) make primary predator visible to larger secondary predatorsecondary predator– Eg. Dinoflagellates – have a circadian rhythm of Eg. Dinoflagellates – have a circadian rhythm of

bioluminescence ; trigger light flash when they are bioluminescence ; trigger light flash when they are mechanically disturbed mechanically disturbed (wave, motion of fish nearby etc)(wave, motion of fish nearby etc)

They bioluminesce and produce beautiful displays during red tide They bioluminesce and produce beautiful displays during red tide blooms.blooms.

2.2. Camouflage at mid-ocean depths Camouflage at mid-ocean depths Where light is still availableWhere light is still available ~90% of animals in mesopelagic zone (200-1000 m depth)~90% of animals in mesopelagic zone (200-1000 m depth) are bioluminescentare bioluminescent - Some squids – symbiotic association of biolum.bacteria – uses - Some squids – symbiotic association of biolum.bacteria – uses

their bioluminescence to match envir. light their bioluminescence to match envir. light

3.3. Defense mechanism – DaytimeDefense mechanism – Daytime Some animals bioluminesce blue on their underbellies Some animals bioluminesce blue on their underbellies – the color – the color

blends with blue color of the surface water – thus masks them from the predators blends with blue color of the surface water – thus masks them from the predators lurking below.lurking below.

Repulsion of predators – Repulsion of predators – certain squids and shrimps give out biolum. certain squids and shrimps give out biolum. bacterial slurry,like smoke that repels predators.bacterial slurry,like smoke that repels predators.

4.4. Defense mechanism – Terrestrial Defense mechanism – Terrestrial Eg. Fireflies , centipedes , millipedes , wormsEg. Fireflies , centipedes , millipedes , worms Warning potential predators that they do not taste pleasantWarning potential predators that they do not taste pleasant (They also bioluminesce to procure food)(They also bioluminesce to procure food)

5.5. Procure foodProcure food Eg. Isistius brasiliensis (cookie-cutter shark)Eg. Isistius brasiliensis (cookie-cutter shark) Underbelly bioluminesce except a patch of skin near the throatUnderbelly bioluminesce except a patch of skin near the throat - appears like a small fish & attracts large predators- appears like a small fish & attracts large predators - suctions to large fish , clamps with teeth into their flesh and cuts and bites off - suctions to large fish , clamps with teeth into their flesh and cuts and bites off

cookie shaped chunk of fleshcookie shaped chunk of flesh

Some predators lure prey by mimicking their signals.Some predators lure prey by mimicking their signals.

Another eg. : Malacosteus (Black dragon fish)Another eg. : Malacosteus (Black dragon fish)

- Has 2 different bioluminescent organs- Has 2 different bioluminescent organs

- one produces blue-green light- one produces blue-green light

- the other (under the eye) produces long IR (red) light- the other (under the eye) produces long IR (red) light

- IR light or red light are invisible to most deep sea animals - IR light or red light are invisible to most deep sea animals

(other than malacosteus) (other than malacosteus)

- Thus it can see its prey without alerting them- Thus it can see its prey without alerting them

6.6. Attracting & Signaling Potential Mates Attracting & Signaling Potential Mates - By varying their light output- By varying their light output

- eg. Fireflies and Deep Sea Angler fish- eg. Fireflies and Deep Sea Angler fish

- Signaling by light help choose a compatible mate- Signaling by light help choose a compatible mate

- Intensity or Frequency of signals help discern the health- Intensity or Frequency of signals help discern the health

of the mate. (so stronger evolutionary advantage)of the mate. (so stronger evolutionary advantage)

eg. Fireflies – light production maybe a continuous glow, a eg. Fireflies – light production maybe a continuous glow, a certain frequency of flashes or a sequence of repeated flashes certain frequency of flashes or a sequence of repeated flashes that can alternate in frequency.that can alternate in frequency.

7.7. CommunicationCommunication BetweenBetween bacteriabacteria

- Bacterial lux operon controls bioluminescence- Bacterial lux operon controls bioluminescence

- In many bioluminescent bacteria, it is turned on only when- In many bioluminescent bacteria, it is turned on only when

the bacteria are in high cell densitiesthe bacteria are in high cell densities

(Quorum sensing – (Quorum sensing – The ability of bacteria to regulate gene The ability of bacteria to regulate gene

expression in response to cell density expression in response to cell density ))

- eg. Vibrio, Photomicrobium etc.- eg. Vibrio, Photomicrobium etc.

(mainly found in seawater and in symbiotic association (mainly found in seawater and in symbiotic association

with fishes like angler fish, flashlight fish,with fishes like angler fish, flashlight fish,

bobtail squid etc)bobtail squid etc)

PicturesPictures

PicturesPictures

PicturesPictures

ThusThus Bioluminescence Bioluminescence is an example of is an example of convergent evolution – different organisms convergent evolution – different organisms develop the same physical or functional feature develop the same physical or functional feature through separate evolutionary routes.through separate evolutionary routes.

Of greater need to marine dwellers – especially in dark Of greater need to marine dwellers – especially in dark faces of water – they produce light for survival , faces of water – they produce light for survival , reproduction , species recognition etc.reproduction , species recognition etc.

Not much terrestrial animals – light is abundant and life is Not much terrestrial animals – light is abundant and life is restricted to the surface of earthrestricted to the surface of earth.(.(fireflies, glow-worms, some larvae, fireflies, glow-worms, some larvae, insects, arachnids, annelids , fungi etc)insects, arachnids, annelids , fungi etc)

Also known as cold light emissionAlso known as cold light emission

FirefliesFireflies Photinus pyralis, Lampyris noctiluca etc.Photinus pyralis, Lampyris noctiluca etc.

Family – LampyridaeFamily – Lampyridae

About 2000 speciesAbout 2000 species

Found in temperate & tropical environmentsFound in temperate & tropical environments

Their larvae (glow worms) need wet areas.Their larvae (glow worms) need wet areas. Luminescent organs – LanternsLuminescent organs – Lanterns The luminescent cells of lanterns are close to the cells at The luminescent cells of lanterns are close to the cells at

the end of tracheolesthe end of tracheoles (that bring O(that bring O22 and take away CO and take away CO22 from tissues) from tissues)

These cells have NO synthase (NOS)These cells have NO synthase (NOS) activated by a nerve activated by a nerve impulseimpulse

Arginine Nitric oxideArginine Nitric oxide The NO diffuses to lantern cells and blocks cyt.c oxidase The NO diffuses to lantern cells and blocks cyt.c oxidase

and thus inhibits cellular respiration in mitochondria.and thus inhibits cellular respiration in mitochondria.

As such, the OAs such, the O22 content in the cells increase and this turns content in the cells increase and this turns on light production in peroxisomes.on light production in peroxisomes.

Peroxisomes contain luciferase and luciferin-ATP (ATP is Peroxisomes contain luciferase and luciferin-ATP (ATP is generated when lanterns are dark)generated when lanterns are dark)

Luciferin + ATP Luciferin + ATP luciferase luciferase Luciferyl adenylate + PPiLuciferyl adenylate + PPi

Luciferyl adenylate + OLuciferyl adenylate + O22 Oxyluciferin + AMP + Light Oxyluciferin + AMP + Light

(Light ~560 nm and 100% efficient)(Light ~560 nm and 100% efficient)

When oxyluciferin is of - ketoform -- red / green to red lightWhen oxyluciferin is of - ketoform -- red / green to red light

- enolate from -- yellow-green light- enolate from -- yellow-green light

The quick decay of NO probably contributes to the short The quick decay of NO probably contributes to the short duration of the flash.duration of the flash.

Fireflies produce light from their lower abdomenFireflies produce light from their lower abdomen

Green, Yellow or pale-red 510 – 670 nmGreen, Yellow or pale-red 510 – 670 nm Fireflies usually use bioluminescence for sexual selectionFireflies usually use bioluminescence for sexual selection