When it comes to blue blood, the first thing to remember is the blood of the horseshoe crab horseshoe crabs. This bluish liquid has been widely used in medicine since the 1970s, as it helps fight various diseases and is an important element in testing the safety of vaccines and new drugs. A liter of horseshoe crab blood costs $ 15,000, making it one of the most expensive resources in the world. However, despite the prohibitive cost, hunting for horseshoe crabs has put this amazing species on the brink of extinction. The blue color of blood is due to the presence of copper in it, but this is not its most interesting feature.
The oldest animals on Earth
Horseshoe crabs are the oldest species on our planet, for which they received the title of "living fossil": in one form or another, these horseshoe crabs that live off the eastern shores of North America and Asia have existed for at least 450 million years. Horseshoe crabs are not crustaceans, but belong to the order of arthropods and are more related to scorpions than crabs. But how did the blood of these animals become such a valuable resource?
Pathologist Frederick Burns wanted to understand how the animal's immune system works. To study the properties of the blood of horseshoe crabs, he conducted a series of experiments, for example, injected bacteria from seawater into the blood of a horseshoe crab to see how the animal would react to it. It turned out that after water contaminated with bacteria got into the blood of the horseshoe crab, the blood turned into a jelly mass. The same thing happened after the scientist injected water with bacteria into the blood of horseshoe crabs, which was boiled for 5-10 minutes before. As a result, the pathologist concluded that this thickening of the blood is a natural mechanism that is designed to protect the rest of the horseshoe crab's body from a foreign pathogen.
Now it is clear who was inspired by Riddley Scott, creating "Alien".
Frederick Burns found that a special clotting agent, which is used to prepare a mixture called Limulus amebocyte lysate, or LAL, is responsible for the high efficiency of the horseshoe crabs' immune system. Before the advent of LAL, there was no easy way for scientists to know if a vaccine or medical device was contaminated with bacteria, such as E.coli or Salmonella. The medical industry catches about 600,000 horseshoe crabs each year.
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How the blood of horseshoe crabs is obtained
Being very ancient creatures, horseshoe crabs are able to "give" a certain amount of blood without harm to themselves. In the laboratory, trained personnel stick a hollow, cylindrical rod under the arthropod's carapace, which pumps out blood as long as the sea animal allows it. It all looks like this:
This is how the blood of horseshoe crabs is collected.
In general, horseshoe crabs drain 30% of their blood, but up to 30% of crabs do not survive to the end of this process. Researchers return the surviving animals to the water, but no one really knows if they recover. In 2016, the United States' International Union for Conservation of Nature named the horseshoe crab a vulnerable species - that is, one notch below the endangered species. If the situation does not change, their population in the United States will continue to decline by as much as 30% over the next 40 years.
The latest findings, Business Insider writes, suggest that many horseshoe crabs do not survive. After blood collection, 10% to 25% of the animals will die within the first two days. Due to the procedure, crabs become weak and disoriented in space for a while. It is noted that females may have problems with spawning. Meanwhile, thanks to the blue blood of horseshoe crabs, millions of patients can safely take medicine every day.
Given the threat of extinction of these stunning animals, scientists are trying to find a synthetic alternative that will help reduce the burden on the horseshoe crabs population. Well, you and I can only hope that they will succeed and these ancient creatures continue to save thousands of lives.
Lyubov Sokovikova