Saturday, August 10, 2019

My, What A Green Glow You Have

Image result for swell sharkEnvironmental & Science Education
Edward Hessler

Writing for Science, Elizabeth Pennisi reports that scientists have found the source of the fluorescence that allows the chain catshark and the swell shark to give off a green glow. The chemical process was previously unknown.

I had known about the existence of glowing jellyfish but was surprised to learn that there are 180 fish that also glow, at least so far. The proteins from jellyfish are widely used in studies of proteins in cells, e.g., to trace the spread of cancer cells.

The process is known as biofluorescence which is different from bioluminescence. This Wiki entry describes the difference. In bioluminescence light is made by chemical reactions within an organism, e.g., a firefly. In biofluorescence light is transformed when it is absorbed and then reemitted.

Pennisi's essay includes a short video of catsharks and swell sharks going about their business. She notes that it is not known how these sharks make use of their green glow but it is known that "one of the glowing compounds kills bacteria. And given that these animals wallow in bacteria-laden sediments on the ocean bottom, such antibacterial properties likely come in very handy."

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