Why do animals self-emit?

Green fluorescent proteins help some animals glow, which can prevent oxidation, protect them when they are sick or stressed.

Fluorescent protein on the lancelet body glows differently.The arrow points at the animal's head.Photo: Scripps.

Scientists at Scripps Institution of Oceanography (USA) studied the lancelet - an amphibious animal that breeds glowing fish - to explore the role of fluorescent proteins. They found that in addition to luminescent effects, those proteins had additional biological functions.

'Although scientists know quite a bit about the biochemical properties of fluorescent proteins, they understand very little about their biological functions , ' said Dimitri Deheyn, a member of the research team. . He and colleagues found that the lancelet's fluorescent proteins emitted light at different brightness. For example, the fluorescent proteins at the top are always the most luminous.

According to scientists, the fluorescent proteins have the ability to destroy oxidative radicals - highly reactive molecules often cause harmful chemical reactions to the body. Thus, they have the same effect on antioxidants in the human body. The team thinks their findings will help scientists better understand the evolution of fluorescent proteins in the animal world.

Lancelet is the most invertebrate animal that has the closest kinship to vertebrates. They possess a fairly flattened, transparent body and taper on both head and tail. The maximum lancelet body length is 2.5 cm. They bury themselves in the sand and just stick their heads up to make contact with the current flowing through it. Before the lancelet was discovered, it was thought that only jellyfish and corals had luminescence. Fluorescent glowing proteins helped three chemists win the Nobel Prize in chemistry last year.