Worm Uses Copper to Harden Jaws, Fangs, Report Says
A marine bloodworm is the first known living organism that makes a copper-containing mineral as part of its skeleton, according to UCSB researchers. This finding is also remarkable because the amount of copper detected in the jaw tip of the bloodworm would normally be toxic to an organism its size.
"The marriage of protein with copper mineral, as well as with bound copper ions, is an intriguing concept per se, but may also serve as a design prototype for new materials that need to be hard, lightweight, and durable," according to the authors of a recent report in Science magazine.
They include UCSB's Herbert Waite, professor of molecular, cellular, and developmental biology, and Galen Stucky, professor of chemistry and materials. Helga Lichtenegger, who was trained in Austria as a physicist, is a skilled x-ray scattering specialist. She and another postdoc in Stucky's group, Michael Bartl, were coauthors on the paper,
When Lichtenegger approached Waite and Stucky about working with them on a research project, Waite suggested Glycera dibranchiatabetter known to fishermen as the common bloodworm. "Back in 1980, two British investigators reported high levels of copper [up to 13 percent by weight] and zinc in the jaws or fangs of two rather common species of polychaete worms," said Waite, an expert on mussels and the fibers mussels make.
"The thing that really galvanized our attention," said Waite, "was Helga's detection of copper biomineral at the bloodworm's jaw tip." The 1980 findings gave no indication that the copper was associated with a mineral.
The bloodworm lives in the gravel of marine sediments and smells out its prey, explained Waite. "The worm is going to miss its prey a fair number of times," he said. "And that means that its jaws are being abraded by gravel. So they need to be made of more robust material than the jaws of the clamworm, which is a scavenger."
Ten to 15 inches long, the bloodworm comes equipped with a proboscis not ordinarily visible. At the end of the fleshy red-pink proboscis are four black jaws that resemble in shape the thorns on a rose bush. The jaws at the end of the proboscis grab and bite prey. The bloodworm's jaws are hollow like syringes, and conduct venom into the prey.
"Copper is very nasty stuff," said Waite. "Though needed in trace amounts for en zymatic processes, copper in greater quantities is toxic. Our research leaves us with questions: How does the worm collect all this copper and concentrate it in a safe form until it is invested in these jaws? What kind of biochemical pathways has this organism evolved to prevent copper toxicity?"
This research is an example of biomimetics, where an organism's biomolecular strategies for adaptation are studied and then employed to make new materials and devices.
Stucky, who is an expert on the molecular assembly of organic and inorganic species into three-dimensional materials and whose research group has extensively studied marine organism biomineralization, is a participant in the California NanoSystems Institute. Waite is a participant in UCSB's Marine Science Institute.