Learn About Bioluminescence

In this episode of the I Can't Sleep Podcast, fall asleep learning about bioluminescence. I think it's pretty cool that animals and insects have the ability to glow different colors for different reasons. To find out what those are you'll have to stay awake through the whole episode. Good luck with that.

Happy sleeping!

Transcript

Welcome to the I Can't Sleep Podcast,

Where I read random articles from across the web to bore you to sleep with my soothing voice.

I'm your host,

Benjamin Boster.

Today's episode is from a Wikipedia article titled,

Bioluminescence.

Bioluminescence is the production and emission of light by living organisms.

It is a form of chemiluminescence.

Bioluminescence occurs widely in marine vertebrates and invertebrates,

As well as in some fungi,

Microorganisms,

Including some bioluminescent bacteria,

And terrestrial arthropods such as fireflies.

In some animals,

The light is bacteriogenic,

Produced by symbiotic bacteria such as those from the genus Vibrio.

In others,

It is autogenic,

Produced by the animals themselves.

In a general sense,

The principal chemical reaction in bioluminescence involves a light-emitting molecule and an enzyme,

Generally called luciferin and luciferase,

Respectively.

Because these are genetic names,

Luciferins and luciferases are often distinguished by the species or group,

E.

G.

Firefly luciferin.

In all characterized cases,

The enzyme catalyzes the oxidation of the luciferin.

In some species,

The luciferase requires other co-factors,

Such as calcium or magnesium ions,

And sometimes also the energy-carrying molecule adenosine triphosphate,

ATP.

In evolution,

Luciferins vary little.

One in particular,

Coelenterazine,

Is found in 11 different animal phyla,

Though in some of these the animals obtain it through their diet.

Conversely,

Luciferases vary widely between different species,

Which is evidence that bioluminescence has arisen over 40 times in evolutionary history.

Both Aristotle and Pliny the Elder mention that damp wood sometimes gives off a glow.

Many centuries later,

Robert Boyle showed that oxygen was involved in the process in both wood and glowworms.

It was not until the late 19th century that bioluminescence was properly investigated.

The phenomenon is widely distributed among animal groups,

Especially in marine environments.

On land,

It occurs in fungi,

Bacteria,

And some groups of invertebrates,

Including insects.

The use of bioluminescence by animals include counter-illumination camouflage,

Mimicry of other animals,

For example to lure prey,

And signaling to other individuals of the same species,

Such as to attract mates.

In the laboratory,

Luciferase-based systems are used in genetic engineering and biomedical research.

Researchers are also investigating the possibility of using bioluminescent systems for street and decorative lighting,

And a bioluminescent plant has been created.

Before the development of the safety lamp for use in coal mines,

Tried fish skins were used in Britain and Europe as a weak source of light.

This experimental form of illumination avoided the necessity of using candles,

Which risked sparking explosions of fire damp.

Another safe source of illumination in mines was bottles containing fireflies.

In 1920,

The American zoologist E.

Newton Harvey published a monograph,

The Nature of Animal Light,

Summarizing early work on bioluminescence.

Harvey notes that Aristotle mentions light produced by dead fish and flesh,

And that both Aristotle and Pliny the Elder,

In his Natural History,

Mention light from damp wood.

He records that Robert Boyle experimented on these light sources,

And showed that both they and the glowworm require air for light to be produced.

Harvey notes that in 1753,

J.

Baker identified the flagellate Noctiluca as a luminous animal,

Just visible to the naked eye,

And in 1854,

Johann Florian Heller identified strands of fungi as the source of light in dead wood.

Tuckey,

In his posthumous 1818 narrative of the expedition to the Zaire,

Described catching the animals responsible for luminescence.

He mentions pellucids,

Crustaceans,

To which he ascribes the milky whiteness of the water,

And cancers,

Shrimps,

And crabs.

Under the microscope,

He described the luminous property to be in the brain,

Resembling a most brilliant amethyst about the size of a large pin's head.

Charles Darwin noticed bioluminescence in the sea,

Describing it in his journal.

While sailing in these latitudes on one very dark night,

The sea presented a wonderful and most beautiful spectacle.

There was a fresh breeze,

And every part of the surface,

Which during the day is seen as foam,

Now glowed with a pale light.

The vessel drove before her bows two billows of liquid phosphorus,

And in her wake she was followed by a milky train.

As far as the eye reached,

The crest of every wave was bright,

And the sky above the horizon from the reflected glare of these livid flames was not so utterly obscure as over the rest of the heavens.

Darwin also observed a luminous jellyfish of the genus Dionea.

When the waves scintillate with bright green sparks,

I believe it is generally owing to minute crustacea.

But there can be no doubt that very many other pelagic animals,

When alive,

Are phosphorescent.

He guessed that a disturbed electrical condition of the atmosphere was probably responsible.

Daniel Pauley comments that Darwin was lucky with most of his guesses,

But not here,

Noting that biochemistry was too little known,

And that the complex evolution of the marine animals involved would have been too much for comfort.

Bioluminescence attracted the attention of the United States Navy in the Cold War,

Since submarines in some waters can create a bright enough wake to be detected.

A German submarine was sunk in the First World War,

Having been detected in this way.

The Navy was interested in predicting when such detection would be possible,

And hence guiding their own submarines to avoid detection.

Among the anecdotes of navigation by bioluminescence is one recounted by the Apollo 13 astronaut Jim Lovell,

Who as a Navy pilot had found his way back to his aircraft carrier USS Shangri-La when his navigation systems failed.

Turning off his cabin lights,

He saw the glowing wake of the ship,

And was able to fly to it and land safely.

The French pharmacologist Raphael Dubois carried out work on bioluminescence in the late 19th century.

He studied click beetles in the marine bivalve mollusk Phallostactylus.

He refuted the old idea that bioluminescence came from phosphorus,

And demonstrated that the process was related to the oxidation of a specific compound,

Which he named luciferin,

By an enzyme.

He sent Harvey siphons from the mollusk preserved in sugar.

Harvey had become interested in bioluminescence as a result of visiting the South Pacific and Japan,

And observing phosphorescent organisms there.

He studied the phenomenon for many years.

His research aimed to demonstrate that luciferin and the enzymes that act on it to produce light were interchangeable between species,

Showing that all bioluminescent organisms had a common ancestor.

However,

He found his hypothesis to be false,

With different organisms having major differences in the composition of their light-producing proteins.

He spent the next 30 years purifying and studying the components,

But it fell to the young Japanese chemist Osamu Shimomura to be the first to obtain crystalline luciferin.

He used the C.

Firefly vargula Hilgendorfii,

But it was another ten years before he discovered the chemical structure,

And published his 1957 paper,

Crystalline Cypridina Luciferin.

Martin Chalfie and Roger Weizian won the 2008 Nobel Prize in Chemistry for their 1961 discovery and development of green fluorescent protein as a tool for biological research.

Harvey wrote a detailed historical account on all forms of luminescence in 1957.

An updated book on bioluminescence covering also the 20th and early 21st century was published recently.

In 1932,

E.

N.

Harvey was among the first to propose how bioluminescence could have evolved.

In this early paper,

He suggested that protobioluminescence could have arisen from respiratory chain proteins that hold fluorescent groups.

This hypothesis had since been disproven,

But it did lead to considerable interest in the origins of the phenomenon.

Today,

The two prevailing hypotheses,

Both concerning marine bioluminescence,

Are those put forth by Howard Seliger in 1993 and Reese et al.

In 1998.

Seliger's theory identifies luciferase enzymes as the catalyst for the evolution of bioluminescent systems.

It suggests that the original purpose of luciferases was as mixed-function oxygenases.

As the early ancestors of many species moved into deeper and darker waters,

Natural selection favored the development of increased eye sensitivity and enhanced visual signals.

If selection were to favor a mutation in the oxygenase enzyme required for the breakdown of pigment molecules,

Molecules often associated with spots used to attract a mate or distract a predator.

It could have eventually resulted in external luminescence in tissues.

Reese et al.

Used evidence gathered from the marine luciferin coelenterazine to suggest that selection acting on luciferins may have arisen from pressures to protect oceanic organisms from potentially deleterious reactive oxygen species.

The functional shift from antioxidation to bioluminescence probably occurred when the strength of selection for antioxidation defense decreased as early species moved further down the water column.

At great depths,

Exposure to ROS is significantly lower,

As is the indigenous production of ROS through metabolism.

While popular at first,

Seliger's theory has been challenged,

Particularly on the biochemical and genetic evidence that Reese examines.

What remains clear,

However,

Is that bioluminescence has evolved independently at least 40 times.

Bioluminescence in fish began at least by the Cretaceous period.

About 1,

500 fish species are known to be bioluminescent,

The capability evolved independently at least 27 times.

Of these,

17 involve the taking up of bioluminescent bacteria from the surrounding water while,

In the others,

The intrinsic light evolved through chemical synthesis.

These fish have become surprisingly diverse in the deep ocean and control their light with the help of their nervous system,

Using it not just to lure prey or hide from predators,

But also for communication.

All bioluminescent organisms have in common that the reaction of a luciferin in oxygen is catalyzed by luciferase to produce light.

McElroy and Seliger proposed in 1962 that the bioluminescent reaction involved to detoxify oxygen in parallel with photosynthesis.

Thewson,

Davis,

Et al.

Showed in 2016 that bioluminescence has evolved independently 27 times within 14 fish clades across ray-finned fishes.

The oldest of these appears to be stomiiformes and myctophidae.

In sharks,

Bioluminescence has evolved only once.

Bioluminescence is a form of chemiluminescence where light energy is released by a chemical reaction.

This reaction involves a light-emitting pigment,

The luciferin,

And luciferase,

The enzyme component.

Because of the diversity of luciferin-luciferase combinations,

There are very few commonalities in the chemical mechanism.

From currently studied systems,

The only unifying mechanism is the role of molecular oxygen.

Often there is a concurrent release of carbon dioxide,

CO2.

For example,

The firefly-luciferin-luciferase reaction requires magnesium and ATP and produces CO2,

Adenosine monophosphate,

And pyrophosphate as waste products.

Other cofactors may be required,

Such as calcium for the photoprotein equorin or magnesium ions and ATP for the firefly-luciferase.

Instead of luciferase,

The jellyfish Equorea victoriae makes use of another type of protein called a photoprotein,

In this case specifically equorin.

When calcium ions are added,

Rapid catalysis creates a brief flash,

Quite unlike the prolonged glow produced by luciferase.

In a second,

Much slower step,

Luciferin is regenerated from the oxidized form,

Allowing it to recombine with equorin in preparation for a subsequent flash.

Photoproteins are thus enzymes,

But with unusual reaction kinetics.

Furthermore,

Some of the blue light released by equorin in contact with calcium ions is absorbed by a green fluorescent protein,

Which in turn releases green light in a process called resonant energy transfer.

Overall,

Bioluminescence has arisen over 40 times in evolutionary history.

In evolution,

Luciferans tend to vary little.

One in particular,

Coelenterazine,

Is the light-emitting pigment for 9 phyla,

Groups of very different organisms.

Including polycysteine radiolaria,

Cercazoa,

Protozoa,

Comb jellies,

Cnidaria,

Including jellyfish and corals,

Crustaceans,

Mollusks,

Arrowworms,

And vertebrates,

Rayfin fish.

Not all these organisms synthesize coelenterazine.

Some of them obtain it through their diet.

Conversely,

Luciferase enzymes vary widely and tend to be different in each species.

Bioluminescence occurs widely among animals,

Especially in the open sea,

Including fish,

Jellyfish,

Comb jellies,

Crustaceans,

And cephalopod mollusks,

In some fungi and bacteria,

And in various terrestrial invertebrates,

Including insects.

In marine coastal habitats,

About 2.

5% of organisms are estimated to be bioluminescent,

Whereas in pelagic habitats in the eastern Pacific,

About 76% of the main taxa of deep-sea animals have been found to be capable of producing light.

More than 700 animal genera have been recorded with light-producing species.

Most marine light emissions is in the blue and green light spectrum.

However,

Some loose-jawed fish emit red and infrared light,

And the genus Tomopterus emits yellow light.

The most frequently encountered bioluminescent organisms may be the dinoflagellates in the surface layers of the sea,

Which are responsible for the sparkling luminescence sometimes seen at night in disturbed water.

At least 18 genera exhibit luminosity.

Luminescent dinoflagellate ecosystems are present in warm water lagoons and bays,

With narrow openings to the ocean.

A different effect is the thousands of square miles of the ocean,

Which shine with the light produced by bioluminescent bacteria,

Known as Muriel or the Milky Seas effect.

Bioluminescence is abundant in the pelagic zone,

With the most concentration at depths devoid of light and surface waters at night.

These organisms participate in diurnal vertical migration from the dark depths to the surface at night,

Dispersing the population of bioluminescent organisms across the pelagic water column.

The dispersal of bioluminescence across different depths in the pelagic zone has been attributed to the selection pressures imposed by predation and the lack of places to hide in the open sea.

In depths where sunlight never penetrates,

Often below 200 meters,

The significance of bioluminescent is evidence in the retainment of functionalized organisms to detect bioluminescence.

Organisms often produce bioluminescence themselves.

Rarely do they generate it from outside phenomena.

However,

There are occasions where bioluminescence is produced by bacterial symbionts that have a symbiotic relationship with the host organism.

Although many luminous bacteria in the marine environment are free-living,

A majority are found in symbiotic relationships A majority are found in symbiotic relationships that involve fish,

Squids,

Crustaceans,

Etc.

As hosts.

Most luminous bacterial inhabit the marine sea with Photobacterium and Vibrio genera dominating the marine environment.

In the symbiotic relationship,

Bacterium benefit from having a source of nourishment and a refuge to grow.

Hosts obtain these bacterial symbionts either from the environment,

Spawning,

Or the luminous bacterium is evolving with their host.

Co-evolutory interactions are suggested as host organisms' anatomical adaptations have become specific to only certain luminous bacteria,

To suffice ecological dependence of bioluminescence.

Bioluminescence is widely studied amongst species located in the Mesopelagic zone,

But the Benthic zone at Mesopelagic depths has remained widely unknown.

Benthic habitats at depths beyond the Mesopelagic are also poorly understood due to the same constraints.

Unlike the Pelagic zone where the emission of light is undisturbed in the open sea,

The occurrence of bioluminescence in the Benthic zone is less common.

It has been attributed to the blockage of emitted light by a number of sources,

Such as the seafloor and inorganic and organic structures.

Visual signals and communication that is prevalent in the Pelagic zone,

Such as counter-illumination,

May not be functional or relevant in the Benthic realm.

Bioluminescence in Basiobenthic species still remains poorly studied due to difficulties of the collection of species at these depths.

Bioluminescence has several functions in different taxa.

Stephen Haddock et al.

2010 lists as more or less definite functions in marine organisms the following defensive functions of startle counter-illumination counter-illumination,

Camouflage,

Misdirection,

Smokescreen,

Distraction,

Distractive body parts,

Burglar alarm,

Making predators easier for higher predators to see,

And warning to deter settlers.

Offensive functions of lure,

Stun or confuse prey,

Illuminate prey,

And mate attraction recognition.

It is much easier for researchers to detect that a species is able to produce light and to analyze the chemical mechanisms,

Or to prove what function the light serves.

In some cases the function is unknown,

As with species in three families of earthworm,

Oligoceta,

Such as Diplocardia longa,

Where the salamic fluid produces light when the animal moves.

In many animals of the deep sea,

Including several squid species,

Bacterial bioluminescence is used for camouflage by counter-illumination,

In which the animal matches the overhead environmental light as seen from below.

In these animals,

Photoreceptors control the illumination to match the brightness of the background.

These light organs are usually separate from the tissue containing the bioluminescent bacteria.

However,

In one species,

Euprymnus scallops,

The bacteria are an integral component of the animal's light organ.

Bioluminescence is used in a variety of ways and for different purposes.

The serrate octopod Stauroteuthis certensis emits bioluminescence from its sucker-like structures.

These structures are believed to have evolved from what are more commonly known as octopus suckers.

They do not have the same function as the normal suckers because they no longer have any handling or grappling ability due to its evolution of photophores.

The placement of the photophores are within the animal's oral reach,

Which leads researchers to suggest that it uses its bioluminescence to capture and lure prey.

Fireflies use light to attract mates.

Two systems are involved according to species.

In one,

Females emit light from their abdomens to attract males.

In the other,

Flying males emit signals to which sometimes sedentary females respond.

Click beetles emit an orange light from the abdomen when flying and a green light from the thorax when they are disturbed or moving about on the ground.

The former is probably a sexual attractant,

But the latter may be defensive.

Larvae and the click beetle live in the surface layers of termite mounds in Brazil.

They light up the mounds by emitting a bright greenish glow,

Which attracts the flying insects on which they feed.

In the marine environment,

Use of luminescence for mate attraction is chiefly known among ostracods,

Small shrimp-like crustaceans,

Especially in the family Cyprididae.

Pheromones may be used for long-distance communication,

With bioluminescence used at close range to enable mates to home in.

A polychaete worm,

The Bermuda fireworm,

Creates a brief display a few nights after the full moon when the female lights up to attract males.

The defense mechanisms for bioluminescent organisms can come in multiple forms.

Startling prey,

Counter-illumination,

Smokescreen or misdirection,

Distractive body parts,

Burglar alarm,

Sacrificial tag or warning coloration.

The shrimp family Opliforidae use their bioluminescence as a way of startling the predator that is after them.

Echinthephora purpurea within the Opliforidae family uses photophores to emit light and can secrete a bioluminescent substance when in the presence of a predator.

This secretory mechanism is common among prey fish.

Many cephalopods,

Including at least seven egenera of squid,

Are bioluminescent.

Some squid and small crustaceans use bioluminescent chemical mixtures or bacterial slurries in the same way as many squid use ink.

A cloud of luminescent material is expelled,

Distracting or repelling a potential predator while the animal escapes to safety.

The deep sea squid may autotomize portions of its arms which are luminous and continue to twitch and flash,

Thus distracting a predator while the animal flees.

Dinoflagellates may use bioluminescence for defense against predators.

They shine when they detect a predator,

Possibly making the predator itself more vulnerable by attracting the attention of predators from higher trophic levels.

Grazing copepods release any phytoplankton cells that flash,

Unharmed.

If they were eaten,

They would make the copepods glow,

Attracting predators.

So the phytoplankton's bioluminescence is defensive.

The problem of shining stomach contents is solved and the explanation corroborated in predatory deep sea fishes.

Their stomachs have a black lining able to keep the light from any bioluminescent fish prey which they have swallowed from attracting larger predators.

The sea firefly is a small crustacean living in sediment.

At rest it emits a dull glow,

But when disturbed it darts away leaving a cloud of shimmering blue light to confuse the predator.

During World War II it was gathered and dried for use by the Japanese army as a source of light during clandestine operations.

The larvae of railroad worms have paraphotic organs on each body segment able to glow with green light.

These are thought to have a defensive purpose.

They also have organs on the head which produce red light.

They are the only terrestrial organisms to emit light of this color.

Reviews

Thank you as always! I wish it worked on my cat too. 😂😂😂