Horseshoe crabs (Limulous) are used as bait for eels and whelk and as a component in fertilizer, but this peculiar-looking marine arthropod apparently has a crucial role in the field of medical research because of a special protein found in its blood.
In Cape Charles, Va., Wako Chemicals USA, an international company that specializes in bioproducts, clinical diagnostic reagents and specialty chemicals operates a facility that extracts the pale blue blood of horseshoe crabs to extract a protein that has crucial uses in the medical industry. The protein protects the animal from impurities and is also used to test medical instruments, implants and pharmaceuticals.
Site manager Christina Lecker said that virtually everything that comes in contact with blood undergoes litmulus amebocyte lysate (LAL) test. It is a process that ensures drugs and devices are safe for human use and this test is based on the protective mechanism of the horseshoes crab, which produces LAL enzymes that bind and inactivate endotoxin from invading bacteria protecting it from infection.
"The repercussions of dispensing products to the general public, which are contaminated by bacteria and their endotoxin, are overwhelming," Wako Chemicals USA wrote on its site. "The U.S. Food and Drug Administration (FDA), has approved the use of Limulus Amebocyte Lysate testing to detect the presence of endotoxins in manufactured products before they are sent out into the market."
The ability of the protein to isolate impurities is also something that scientists attribute to the species' exceptional endurance. Horseshoe crabs have been around for millions of years and the protein, which is found in animal's white blood cells known as amebocytes, isolates and thickens around impurities, a protective mechanism that is crucial for the animal's survival in their bacteria-saturated habitat.
It takes half an hour to extract one-third of the crab's blood, the standard amount that needs to be extracted. Some crabs die following extraction and the mortality rate is estimated to be between 8 percent to 15 percent, but Wako Chemicals said it has measures in place to ensure the viability of the species' population, minimize injury and protect the animals.
The company said that donor crabs typically stay out of their habitat for 48 hours but are eventually returned to the same water where they were taken after the extraction. The crabs are also marked so they won't be used for extraction again until they have molted and developed new and unmarked shells.