Natures wonders: jellyfish family defense weapons (Introduction)

by David Turell , Wednesday, May 29, 2024, 17:31 (110 days ago) @ David Turell

Some are like hypodermic needles:

https://www.the-scientist.com/with-neither-brains-nor-brawn-jellyfish-and-relatives-dev...

"Cnidarians produce a wide array of toxins, from sea anemone neurotoxins that act on sodium channels to the potently hemolytic toxins in box jellyfish. These creatures also administer their venom in an unusual manner: Specialized organelles called nematocysts are highly pressurized, touch-sensitive capsules that burst open with incredible speed to eject toxin-laden darts into any creature unfortunate enough to brush against them. Understanding the biomechanics of these capsules may inspire new microdevice designs for drug delivery and other applications.

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"Their venoms contain a variety of biomolecules that have different mechanisms of action. A lot of the drug discovery work using cnidarians has focused on sea anemones, including Nematostella vectensis. That’s because sea anemone venoms often contain many neurotoxins that target different ion channels with a high specificity.

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"Jellyfish venoms have fewer neurotoxins; instead, they have pore-forming toxins as well as different types of enzymes that break down proteins and lipids.

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"For example, when we analyzed tissue from an entire polyp from the species Hydractinia symbiolongicarpus, we found more than 150 venom-like genes in the transcriptome. In an animal like a snake, researchers might focus on the venom gland transcriptome to help narrow down which genes encode true venom toxins. However, cnidarians’ venom systems are not centralized in this way, making it difficult to determine which genes are actually important for venom.

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"Cnidarians are decorated in tens of thousands of tiny nematocysts produced by specialized stinging cells. Nematocysts can be anywhere from five to 15 microns in size, which is thinner than a sheet of paper. This is one of the only examples of a full-body venom system as opposed to a gland attached to fangs or spines.

"The way a nematocyst injects its venom is really interesting. Nematocysts are made of collagen-like proteins that allow them to be super pressurized and able to fire extremely quickly. In one recording, the harpoon-like structure of a Hydra nematocyst accelerated to more than five million g in 700 nanoseconds. It could be days before they have the opportunity to fire these stinging cells into their unsuspecting prey, so they need to be able to hold that pressure for long periods of time.

"The protein structures of the nematocysts are unique. They're almost like little, hollow hypodermic needles with various kinds of barbs. From a biomechanical standpoint, they’re innovative. Cnidarians manufacture thousands to tens of thousands of these complex structures all the time, and we just don’t know how that process works."

Comment: taken from an interview. These highly complex designed structures require a multiplex of specialized mutations to develop. Naturally the way is trial and error. Not really likely. The theory of a designer wins.