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Scientists Find New Medicines in the Sea
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Sharon Kay The Boston Globe |
| August 7, 2001 |
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Part 1>> Not all the fish at the Marine Biological Lab are as easy to come by as toadfish and skates. One beautiful and dangerous creature does not hail from the Atlantic Ocean, but rather arrives in a Federal Express package all the way from Fiji. This mysterious stranger, the cone snail, is actually a distant cousin of the human. The same enzyme that is critical for human blood clotting is crucial to creating the deadly toxin a cone snail uses to paralyze its prey. Vitamin K fuels the function of the enzyme in both humans and cone snails. Bruce Furie, a hematologist based at Harvard Medical School, never imagined that he would be splitting his time between Boston and a seaside lab. But when he discovered that the same enzyme crucial to his patients was also critical to the welfare of the cone snail, he needed to learn more. Furie is used to treating patients with blood disorders such as hemophilia, a condition in which unusual and sometimes severe bleeding is caused by the absence of normal blood clotting factors. Doctors treat hemophilia B patients with Factor IX, the missing clotting agent in their blood that requires vitamin K for its synthesis. "Recently, when we cloned the cone snail gene, we were amazed to see it is so similar," Furie said. "We think it has some kind of housekeeping function in all animals that's critical for survival. That's what we need to learn next." "Some day it could yield information for treatment of blood disorders," said Eva Czerwiec, a biologist who works full time with the snails at the Marine Biological Lab. Perhaps the most commercially successful marine model for biomedical research so far has been meeting and spawning on beaches and living in the sea for more than 250 million years. For the past 25 years, the horseshoe crab has played an important role in the life of humans. Its blood identifies dangerous bacteria in pharmaceuticals, and its latest mission involves the U.S. space program. Back in the 1950s, while studying blood circulation, Marine Biological Lab scientist Frederick Bang discovered that the horseshoe crab had a remarkable ability to protect itself from the multitude of bacteria in the ocean: Its blood clotted dramatically in response to bacteria. To Bang and other scientists, it became clear that this response could produce a beneficial test for unwanted bacteria in vaccines and other pharmaceuticals injected into humans. Previously, rabbits had been used to test products, but the test was slow, expensive, and harmful to the rabbits. A new test was developed in the 1970s, whereby blood could be extracted from the horseshoe crab without killing the animal and yielding test results within 45 minutes. The Limulus test is now an international business. Now, the horseshoe crab's highly developed sensitivity has been seized upon by another industry that worries about bacteria: NASA. NASA's Planetary Protection Program has discovered the value of the Limulus test in maintaining a sterile environment for its Mars missions. "There is an international agreement that any spacecraft that intentionally lands on another planet must be certified clean of Earth microbes, but there is also a possibility of dangerous new organisms coming back," explained Norman Wainwright, a cell biologist who has studied the horseshoe crab for many years. He is now collaborating with NASA to improve the Limulus test, which they hope to use for the Mars 2003 mission. The horseshoe crab's blood could prevent scientists from mistaking Earth microbes that accidentally make their way to Martian soil for Martian life. At the same time, crab blood could discover a new microbe never before detected. "We are looking deeper and harder because the technology forces us to look deeper. In Darwin's time, little technology was needed to make simple yet profound observations, but now we have the technology to ask different questions," Wainwright said. The answers, he said, may lead to both newly discovered life and prolonged human life. Copyright 2001 The Boston Globe Return to Part 1>> |
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