Scientists: Crab Blood Can Be Alien Hunter
July 9 -- One hundred million years before dinosaurs pounded upon the Earth, the humble horseshoe crab scuttled along its shores. Soon the blood of this primitive creature could be used to detect primitive life on faraway planets.
"One of the reasons the horseshoe crab has survived for so long is its advanced immune system," said Norman Wainwright, a senior scientist at the Marine Biological Laboratory (MBL) in Woods Hole, Mass. "This system can be used to find microbial life."
When one of these armored arthropods is injured, bleeding and exposed to bug-laden ocean water, its blue blood hardens and keeps infection out.
The crab's trick takes the form of a cascade of enzymes that causes clotting when it encounters cell wall material of most bacteria, yeast and mold.
Run By Freeze-Dried Enzymes
Since the 1950s, the unique coagulating reaction of the horseshoe crab's blood has been tapped by pharmaceutical companies to test the purity of sterilized medical equipment and products. Now scientists have packaged the blood's enzymes into a hand-held instrument that can test for signs of life.
"If there are microbial species that evolved outside the Earth, that life may have originated here and spread throughout the solar system," said Wainwright. "It's possible the cells walls of microbes on other planets may be similar enough to detect using the test."
The calculator-sized device developed by researchers at MBL and Charles River Laboratories in Wilmington, Mass., is filled with the unique set of enzymes contained inside horseshoe crab blood. To supply the tools, scientists insert a large needle into the crab's heart and extract up to 300 milliliters of blood per crab. The crabs are then released back into the ocean.
Although the process sounds traumatic, most of the helmeted animals survive the ordeal, says Robert Barlow, a State University of New York neurobiologist who conducts research on horseshoe crabs at the MBL.
"There's about a 10 percent mortality rate," he said.
