Monday, August 8, 2022

Horseshoe crabs: ‘living fossils’ key to vaccine safety

Dover (United States of America) (AFP) – On a bright moonlit night, a team of scientists and volunteers head out to a protected beach along Delaware Bay to survey the horseshoe crabs that roam their millions along the U.S. East Coast from late spring to early summer. does.

Groups make their way to the shoreline by laying a measuring frame on the sand, counting the individuals inside it to help generate population estimates, and correct those unfortunate enough to be flipped on their backs by high tide went.

With their helmet-like shells, tails that resemble spikes and five pairs of legs attached to their mouths, horseshoe crabs, or Limulidae, are not immediately cute.

But if you’ve ever had a vaccine in your life, you have these strange marine animals to thank: Their bright blue blood, which clots in the presence of harmful bacterial components called endotoxins, tests the safety of biomedical products. has been necessary for. In the 1970s, when it replaced rabbit testing.

“Once you understand them, it’s really easy to love them,” Laurel Sullivan, who works to educate members of the state government about invertebrates, told AFP.

“They’re not threatening at all. They’re just going about their day, trying to make more horseshoe crabs.”

For 450 million years, these other creatures have patrolled the planet’s oceans, while dinosaurs arose and went extinct, and early fish transformed into land animals that would eventually give rise to humans.

Now, however, the “living fossil” is listed as vulnerable in the Americas and as endangered in Asia, as a result of habitat loss and over-harvesting for use in the food, feed and pharmaceutical industries. Which is on a major growth trajectory, especially in the wake of the COVID pandemic.

For 450 million years, these other creatures have patrolled the planet’s oceans, while dinosaurs arose and went extinct, and early fishes transformed into land animals that would eventually give rise to humans. Bastian Injourralde AFP

The survey project’s environmental scientist Taylor Beck explains that recruiting citizen scientists helps to enhance the government’s data collection efforts as well as engage the public.

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– Important ecological role-

“Crabs” is a misnomer for animals that are actually more closely related to spiders and scorpions, and are composed of four subspecies: one that lives in the eastern and Gulf coasts of North America, and the other three in the Southeast. in Asia.

Laughing gulls feed on horseshoe crab eggs on the beach at James Farm Ecological Preserve on June 16, 2022 in Ocean View, Delaware
Laughing gulls feed on horseshoe crab eggs on the beach at James Farm Ecological Preserve on June 16, 2022 in Ocean View, Delaware Bastian Injourralde AFP

Atlantic horseshoe crabs have 10 eyes and pass the food to their mouths by crushing food, such as worms and clams, between their legs.

Males are significantly smaller than females, which they herd in groups of up to 15 when breeding. Males hatch females as they move ashore, where females deposit golf ball-sized clusters of 5,000 eggs for males to spray their sperm with.

Millions of these eggs, tiny green balls, are inadvertently churning out on the surface of the beach, where they are an important food source for migrating shorebirds, including the near-threatened Red Knot.

Nivet Perez-Perez, manager of community science at the Delaware Center for the Inland Bays, points to a giant band of eggs that straddle nearly the entire beach at the James Farm Ecological Preserve.

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As she gestures, the aptly named laughing gull with the bright orange beak swoops in to feast.

"You are very beautiful," Conservationist Nivet Perez-Perez describes a female horseshoe crab she has raised to indicate the animal's physical characteristics
“You’re so cute,” conservationist Nivet Perez-Perez tells a female horseshoe crab she has raised to pinpoint the animal’s physical characteristics. Bastian Injourralde AFP

Like others in the area, Perez-Perez succumbed to the allure of crabs long ago.

“You’re so cute,” she says to a woman she’s picked up to point out her physical features.

just flip them

Breeding for horseshoe crabs is a dangerous business because it is on the beach that they are at their most vulnerable: as the tide washes, some end up on their backs, and while their long stiff tails some help themselves. Maybe, not all are so lucky.

(From left) Christy Liske, Wyatt Mosimon and Matthew Oswald survey a beach-born horseshoe crabs at the Ted Harvey Wildlife Area near Dover, Delaware
(From left) Christy Liske, Wyatt Mosimon and Matthew Oswald survey a beach-born horseshoe crabs at the Ted Harvey Wildlife Area near Dover, Delaware Bastian Injourralde AFP

About 10 percent of the population is lost each year because their exposed undersides are sunburned.

In 1998, Glen Gowry, founder of the Ecological Research and Development Group, helped launch the “Just Flip ‘Em” campaign, encouraging members of the public to do their part by raising slowly overgrown crabs that are still alive. .

“Where it matters most is a change of heart,” he told AFP at Pickering Beach in Delaware Bay, sporting a “Just Flip ‘Em” baseball cap with horseshoe crab pins.

“If we can’t get people to care for and engage with these animals, they want laws to protect them.”

Each year about 500,000 horseshoe crabs are harvested and flown for a chemical called Limulus amebocyte lysate, which is important for testing against a type of bacteria that can contaminate drugs, needles, and equipment such as hip replacements.

Glen Gowry, president of the Ecological Research and Development Group, a nonprofit advocating for the conservation of horseshoe crabs, keeps a horseshoe crab in Pickering Beach, Delaware.
Glen Gowry, president of the Ecological Research and Development Group, a nonprofit advocating for the conservation of horseshoe crabs, keeps a horseshoe crab in Pickering Beach, Delaware. Bastian Injourralde AFP

The procedure is estimated to have a mortality rate of 15 percent, with survivors released back into the ocean.

A new synthetic alternative called recombinant factor C appears promising, but faces regulatory challenges.

Horseshoe crabs are “a limited source with potentially infinite demand, and those two things are mutually exclusive,” Alan Bergensen of the Swiss biotech Lonza, which conducts the new test, told AFP.

Nation World News Desk
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