(Phys.org)—A team of researchers from Russia, Brazil and Japan has uncovered the means by which two kinds of mushrooms glow in the dark. In their paper published on the open-access site Science Advances, the group describes their study of Neonothopanus gardneri and Neonothopanus nambi—mushrooms that grow and glow in Brazil and Vietnam respectively.
Scientists have long been fascinated by organisms that produce their own light (bioluminescence) and research has led to an understanding of how the process works in many insects and seafaring organisms (and recently in a frog). But how it works in fungi has remained a mystery. In this new effort, the researchers have finally solved that mystery.
Prior research has found just 80 species of fungi that are bioluminescent out of approximately 100,000 around the globe. It is believed that such fungi glow in the dark to attract wasps, beetles, flies, ants and other creatures—spores adhere to their bodies and are carried to other places, colonizing new territory.
The new research showed that bioluminescence occurred in the mushrooms when luciferin molecules interacted with a luciferase enzyme in the presence of oxygen—the reaction resulted in the production of a light-emitting substance called oxyluciferin. Over time, the oxyluciferin released its oxygen bringing the luciferin back to its ground state. The process repeated, allowing the mushrooms to emit light in the presence of oxygen. The team also found that luciferase in fungi appeared to be what they describe as "promiscuous," because it interacts with a multitude of luciferin molecule derivatives. They also found that they could change the colors emitted by a slurry of ground-up mushroom parts by changing the amount of luciferin in the mix, which suggests they may be useful in synthetic form in human applications such as imaging research—luciferase could potentially be used as a reporter gene in genetic research, for example.
Learning more about how nature produces bioluminescence has already led to applications in human endeavors—bio-researchers, for example, use them to aid in tracking cells to learn more about biological processes.
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More information: Zinaida M. Kaskova et al. Mechanism and color modulation of fungal bioluminescence, Science Advances (2017). DOI: 10.1126/sciadv.1602847
Bioluminescent fungi are spread throughout the globe, but details on their mechanism of light emission are still scarce. Usually, the process involves three key components: an oxidizable luciferin substrate, a luciferase enzyme, and a light emitter, typically oxidized luciferin, and called oxyluciferin. We report the structure of fungal oxyluciferin, investigate the mechanism of fungal bioluminescence, and describe the use of simple synthetic α-pyrones as luciferins to produce multicolor enzymatic chemiluminescence. A high-energy endoperoxide is proposed as an intermediate of the oxidation of the native luciferin to the oxyluciferin, which is a pyruvic acid adduct of caffeic acid. Luciferase promiscuity allows the use of simple α-pyrones as chemiluminescent substrates.