Natures wonders: bootlace sea worms longest animals (Introduction)

by David Turell , Thursday, July 29, 2021, 17:50 (1000 days ago) @ David Turell

Lie on the sea floor, up to 55 meters long and skin is highly toxic:

https://www.sciencenews.org/article/toxins-bootlace-worm-can-kill-cockroaches

"Bootlace worms with spooky-stretchy bodies secrete a family of toxins new to scientists. These compounds might inspire novel ways to attack pests such as cockroaches.

"Tests first identified the toxins in mucus coating a bootlace species that holds the record as the world’s longest animal, says pharmacognosist Ulf Göransson of Uppsala University in Sweden. This champion marine worm (Lineus longissimus) can stretch up to 55 meters, longer than an Olympic-sized pool, and coats itself in mucus smelling a bit like iron or sewage. That goo holds small toxic proteins, now dubbed nemertides, that are also found in 16 other bootlace worm species, Göransson and colleagues write March 22 in Scientific Reports.

"The newly described nemertides attack tiny channels in cell walls that control the amount of sodium flowing in and out of the cell. Much vital cell business, such as communications between nerves, depends on the right flux through these voltage-gated sodium channels, as they’re called. Injections of small amounts of one of these nemertides permanently paralyzed or killed invasive green crabs (Carcinus maenas) and young cockroaches (Blattella germanica).

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"Unlike earthworms, the 1,300 or so species of bootlace, or ribbon, worms have no segments. Some scientists give these animals their own phylum, Nemertea. Bootlace worms have a brain but no lungs. Like many other slender marine creatures, bootlace worms breathe directly through the skin. The worms are carnivorous, supping on crustaceans, mollusks and other worms.

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"Göransson proposes that toxic mucus may be useful for defense. He has seen video with Nemertean worms stretched out on the seafloor. “If you’re a crab or a fish, it must be tempting to take a nip,” he says, but there’s little sign of anything bothering them."

Comment: Defense is likely the reason as they are poisonous. Same point about evolutionary origin. Poison and its personal antidote must be deigned simultaneously since the snake is internally exposed to the produced poison.