horseshoe crab blood
Horseshoe crabs use hemocyanin to carry oxygen through their blood. … Amebocytes from the blood of L. polyphemus are used to make Limulus amebocyte lysate (LAL), which is used for the detection of bacterial endotoxins in medical applications.
Horseshoe crabs are used as bait to fish for eels (mostly in the United States) and whelk, or conch. However, fishing with horseshoe crab was banned indefinitely in New Jersey in 2008 with a moratorium on harvesting to protect the red knot wading bird, which eats the crab’s eggs. A moratorium was restricted to male crabs in Delaware, and a permanent moratorium is in effect in South Carolina. The eggs are eaten in parts of Southeast Asia and China.
Each year, half a million horseshoe crabs are captured and bled alive to create an unparalleled biomedical technology and use of horseshoe crab blood
To take advantage of this biological idiosyncrasy, pharmaceutical companies burst the cells that contain the chemical, called coagulogen. Then, they can use the coagulogen to detect contamination in any solution that might come into contact with blood. If there are dangerous bacterial endotoxins in the liquid—even at a concentration of one part per trillion—the horseshoe crab blood extract will go to work, turning the solution into what scientist Fred Bang, who co-discovered the substance, called a “gel.”
If there is no bacterial contamination, then the coagulation does not occur, and the solution can be considered free of bacteria. It’s a simple, nearly instantaneous test that goes by the name of the LAL, or Limulus amebocyte lysate, test (after the species name of the crab, Limulus polyphemus).
I don’t know about you, but the idea that every single person in America who has ever had an injection has been protected because we harvest the blood of a forgettable sea creature with a hidden chemical superpower makes me feel a little bit crazy. This horseshoe crab blood scenario is not even sci-fi, it’s postmodern technology.
The only problem is that the companies need a large supply of the blood of live crabs. Horseshoe crabs live on the seafloor, near the shore. When they want to mate, they swim into very shallow water, and horseshoe crab collectors wade along, snatching the crabs out of their habitat.