Scientists unravel secrets of glowing cat sharks

Scientists have unraveled the mysteries of the glow of cat sharks and uncovered the molecular mechanism responsible for that vital light, according to a study published Thursday in the journal Science.

Cat sharks are one of the largest species of sharks, have cat-like eyes, settle in temperate and tropical seas, live in the depths near the seabed, and feed on fish and invertebrates.

Mysterious novel
Many animals shine dynamically - including frogs, scorpions, turtles and a host of marine organisms - but the vast majority of them have developed similar mechanisms through the production of GFP, or proteins that are very similar to them, or about The pathway of proteins associated with fatty acid (FABP).

But according to the study, glowing cat sharks have a glow mechanism not seen before in any other organism, and their skin is characterized by a unique structure that absorbs blue light on the seabed and then reissues it in the form of glowing green light.

"The study of bio-fluorescence in the ocean is like a mysterious novel that is constantly evolving," said biologist David Gruber of the study.

Secret visual language
There are two types of cat sharks, the cat shark, and the puffy shark, both dotted with light and dark leather motifs, and a dynamic fluorescent glow is produced by a chemical path never seen in any other animal.

Instead of any of the mechanisms described above, shark glow occurs by metabolites of the small bromine quinorenin tryptophan molecule, present only in the light parts of its decorative skin.

In other vertebrates, these small molecular metabolites participate in the immune system and the central nervous system.

But these metabolites found in shark skin help produce a vital glow in low-light conditions on the seabed.

This glow is invisible to the naked human eye, but shark eyes can see it.

The sharks direct this glow through their scales, or small teeth, which appear to be specifically designed for this task, shimmering with green light.

Because it is a different chemical pathway than those used by other marine animals, the researchers believe it may form a secret visual language for sharks only, which they can understand to help them catch and mate.

"It's a completely different system for them to see each other, and other animals can't necessarily benefit from it," said biologist Jason Crawford of Yale University, who is involved in the study.

Anti - fouling
The sharks appear to be unusually clean, with no biological contamination or growth on their skin, although the sharks involved in the study spend a lot of time in sediments that contain more bacteria than the water column, the researchers note.

So researchers have begun to determine the role metabolites play in keeping sharks clean. When they isolated and tested some metabolites against bacterial pathogens, metabolites showed some ability to inhibit the growth of these bacteria.

This may indicate that fluorescent molecules have some antimicrobial properties, and of course more research will help prove this.

"This study highlights another mystery of sharks, and I hope this will inspire us to learn more about its secrets and better protect them," Gruber said.