A previously unknown molecule is responsible for shark fluorescence
Usually found at the bottom of the Atlantic ocean, far below twinkling jellyfish and corals, this Chain Catshark emits an eerie glow. But unlike jellyfish, which use green fluorescent proteins (GFPs) to produce their biofluorescence, this shark uses a handful of light-changing chemicals from its natural metabolism, found in the lighter parts of its patterned skin. Filmed here with a special fluorescence camera, in the ocean its light may only be visible to other sharks – perhaps as a form of communication. Surprisingly, these biofluorescent molecules appear to give the shark protection against bacterial infection, too. Further studies will hope to dive deeper, while understanding more about how this 'new' form of fluorescence might be repurposed in the lab as a beacon inside healthy and diseased human cells, adding to the colourful pallet of jellyfish GFPs, and red-coloured coral RFPs, already used to cast light on microscopic life.
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