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In broad daylight, Neonothopanus nambi is a rather common brown mushroom. But a surprise hides behind the dull facade: at night, the mushroom shines a ghostly green. Neonothopanus nambi is one of more than 100 species of mushrooms that emit light. Aristotle has already documented this phenomenon, called bioluminescence, when he described the tree bark as glowing and rotting. Today, scientists have for the first time identified the biochemical pathway that allows bioluminescent fungi to illuminate it. But they went even further: by putting the three genes necessary to generate luminescence in a non-glowing yeast, they created an artificially luminescent eukaryote. Fyodor Kondrashov, professor at the Institute of Science and Technology of Austria (IST Austria) was co-author of the study published today in PNASdirected by Ilia Yampolsky at the Institute of Bioorganic Chemistry of the Russian Academy of Sciences in Moscow.
Fireflies and shiny mushrooms on the forest floor are among the few things to see in a dark night deep in the Brazilian forest. Both behave like live night lights through the bioluminescence process, a natural phenomenon whereby a substance called luciferin is oxidized with the help of the luciferase enzyme to emit light. Bioluminescence is present in many species, worms glowing to deep-water fish. Until now, however, the biochemical pathway that manufactures luciferin has not been included in any organism, with the exception of bacteria. This lack of knowledge has hindered efforts to shine higher organisms, such as animals and plants. Now, an international collaboration between twelve different institutions and led by Ilia Yampolsky, with the participation of Fyodor Kondrashov, Louisa Gonzalez Somermeyer and her former group member, Karen Sarkisyan, helped determine how eukaryotic Neonothopanus nambi shines.
Scientists have discovered the key genes responsible for the bioluminescence of Neonothopanus nambi. With the help of library screening and genome badysis, the team identified the enzymes that contribute to luciferin synthesis. They showed that fungal luciferin, the substrate of the bioluminescence reaction, is only at two enzymatic stages of a well-known metabolite, caffeic acid, which it generates. By comparing fungi that shine with those that are not, Kondrashov's team also discovered how gene duplication allowed bioluminescence to evolve over a hundred million years ago. Why has Kondrashov not evolved yet, said Kondrashov: "Is bioluminescence beneficial or is it a by-product? We do not know yet. It is obvious that the glow attracts the insects that distribute the spores. But I do not think it's convincing. "
Knowing how bioluminescent fungi shine, researchers then illuminated non-bioluminescent eukaryotes. Insertion of the gene coding for luciferase in Neonothopanus nambi as well as three other genes whose products form the chain that converts the caffeic metabolic acid into a substrate for reaction, luciferin, yeast Pichia pastoris leads to glowing yeast colonies. "We do not provide a chemical that makes the yeast shine. Instead, we provide the enzymes needed to convert a metabolic product already present in yeast into light, "says Kondrashov.
This discovery could find many applications, tissues that signal changes in their physiology by illuminating the creation of animals and vibrant plants. "If we think of sci-fi scenarios in which bright plants replace street lights, that's it. This is the breakthrough that can lead to this, "concludes Kondrashov," However, it may be several years before the development of such a lamp post. "
Source:
Institute of Science and Technology of Austria. .
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