Volume 18 Issue 21
Horseshoe crabs are fascinating animals. They may look like prehistoric crabs but are actually more closely related to scorpions and spiders. They also happen to be one of the most important animals when it comes to keeping humans alive. Much more than the strange looking arthropods your children can pet in an interactive tank at the local aquarium, these animals are vital to human medicine.
The pale blue blood that circulates within the bodies of horseshoe crabs is extremely sensitive to bacterial pathogens. This has allowed biomedical scientists to use the blood of horseshoe crabs to test whether or not potentially life-saving medicines and medical devices are safe for humans. While this is extremely helpful for humans, it may not be so for horseshoe crabs. Scientists extract blood from the horseshoe crabs and then return them to the ocean. This is relatively safe; however, around 50,000 horseshoe crabs die during this process every year. Additionally, Asian horseshoe crabs have experienced dramatic population losses from habitat loss, as well as overfishing. In order to keep the horseshoe crab populations constant, some change needs to occur. If not, the biomedical industry could be seriously threatened.
Jeak Ling Ding is one scientist who has decided to expedite the change needed to preserve horseshoe crabs. Thirty years previously, Frederick Bang had discovered the amebocytes (or blood cells) in horseshoe crabs were especially resistant to bacteria. Over the course of thirty years, Bang standardized a way to remove these amebocytes in order to test if the certain medical equipment was sterile. Ding worked in a hospital attempting to discover the reason for the death of in-vitro fertilization embryos and she needed one of the kits developed by Bang. However, they were too expensive for her. So, she decided to make her own.
Factor C is a specific molecule in horseshoe crab amebocytes that detects the bacterial toxins. So, if she could find the gene that made factor C and could manipulate the DNA, she could make the factor C without the need to harm more horseshoe crabs. After many trials and errors, Ding discovered she could splice the DNA from the horseshoe crabs into insects that would then manufacture the factor C. This meant it was no longer necessary to bleed horseshoe crabs.
Although Ding has arrived at a solution, biomedical companies have been slow to adopt her method. They could potentially lose money if they adopt the factor C method and drop the traditional way of bleeding horseshoe crabs. But the population numbers of horseshoe crabs are dwindling, and they will continue to dwindle if nothing is done to help them. Additionally, many other species of animals rely on horseshoe crabs to survive, such as the red knot, a threatened species of bird. If we want to save the horseshoe crab, other threatened species, and our own biomedical industry, the factor C method should be adopted. By continuing to use the old method of blood extraction, horseshoe crabs may become fascinating animals of the past.
Zhang, Sarah. “The Last Days of the Blue-Blood Harvest.” Atlantic. Atlantic. May 9, 2018. Web. May 15, 2018.