So we all know about horse shoe crabs those infamous hideous looking gentle and harmless organism sometimes termed as the living fossil because of their presence on our planet since millions and millions of years. So blood harvest happens on the blood of a horse shoe crab which has a striking baby blue colored blood due to presence of copper rich haemocyanin agents(like we have iron rich haemoglobin).The marvelous thing about horseshoe crab blood, though, isn’t the color. It’s a chemical found only in the amoebocytes of its blood cells that can detect mere traces of bacterial presence and trap them in inescapable clots. 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.”
“This gel immobilized the bacteria but did not kill them,” Bang wrote in the 1956 paper announcing the substance. “The gel or clot was stable and tough and remained so for several weeks at room temperature.”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).The LAL testreplaced the rather horrifying prospect of possibly contaminated substances being tested on “large colonies of rabbits.” Pharma companies didn’t like the rabbit process, either, because it was slow and expensive.
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. The biomedical collectors are not the first to make use of the crabs’ bodies. As far back as colonial times, “cancerine fertilizer” was used to enrich fields. In the 20th century, though, this became an organized industry around the Delaware Bay. The crabs were steamed and then ground into meal for the fields. Others were fed to hogs. Millions of crabs were harvested.
After the biomedical horseshoe crab collectors get them back to a lab, they pierce the tissue around the animals’ hearts and drain up to 30 percent of the animals’ blood. The LAL is extracted from the blood, and can go for $15,000 per quart. Only five companies bleed the crabs: Associates of Cape Cod, Lonza, Wako Chemicals, Charles River Endosafe, and Limuli Labs .The horseshoe crabs are returned to the ocean a great distance from where they were initially picked up to avoid rebleeding animals. The whole process takes between 24 and 72 hours.The industry says that not that many of the animals die. Between 10 and 30 percent of the bled animals, according to varying estimates, actually die. We can imagine that it’s like us giving blood. The crabs get some apple juice and animal crackers and are fine soon thereafter.But some people have noticed problems. In the regions where horseshoe crabs are harvested in large numbers for biomedical purposes
Horseshoe crabs are an ancient animal, more than half a billion years old. They have their own ways of doing things, a fact we’ve been exploiting for decades.Our own species evolved a thousand times more recently, coming into our current anatomical form a couple hundred thousand years ago. Let’s hope we don’t wipe horseshoe crabs out after we finish cloning their ancient chemical wisdom.