Messenger - Vol. 2, No. 3, Page 8 Summer 1993 On Research Trying to shoot zebra mussel in the foot A few years ago, the zebra mussel, a fingernail-sized, freshwater mollusk with black and white stripes, hitched a ride to the U.S. in the ballast water of Eurasian tankers bound for ports on the Great Lakes. Once discharged into the lakes, the mollusks began clogging intakes to water treatment plants, power companies and even golf courses. The zebra mussel has now spread to the Mississippi and Susquehanna rivers and is expected to pose a threat to fresh and brackish waterways of the mid-Atlantic. Herbert Waite and Leszek Rzepecki of the University's College of Marine Studies have been working to analyze the "glue" the zebra mussel produces to attach itself to surfaces under water. The researchers say they believe their research may not only unlock the door to better zebra mussel control, but may also identify a unique bioadhesive with potential applications in dentistry, ophthalmology and other medical fields. Past research by Waite and his colleagues resulted in the patenting of Cell-Tak, an imitation of the "glue" of the blue mussel, a marine species. It reportedly has produced excellent results in repairing corneas and retinas and may have potential in securing dental fillings and dentures. These applications now are being tested by the Food and Drug Administration. Rooted at the base of a zebra mussel's foot is a bundle of threads known as the byssus. At the end of each thread is an adhesive plaque that contains the glue that enables the mussel to anchor itself to solid surfaces. "The mussel's foot is an ingenious device that surveys available surfaces, scrubs them clean, and then, during a three-four minute period, spins a new byssal thread," says Waite. "All the proteins of the byssus are synthesized and stockpiled within special glands in the mussel's foot." Yet determining the chemical nature of the proteins in the zebra mussel's foot is no easy feat. Hundreds of the half-inch mussels are shipped from the Niagara River to Waite's lab where they are shucked and their feet removed, frozen, homogenized and prepared for chemical analysis by gel electrophoresis. This technique consists of sandwiching a slab of gel between two glass plates, applying the mussel material to the top of the gel and then subjecting the "sandwich" to an electrical current. The current causes the mussel protein to migrate vertically down into the gel. Since each different protein migrates in a different manner, the result is a readily distinguishable pattern of proteins. So far, Waite and Rzepecki have purified and identified a number of proteins from the zebra mussel's glue-producing foot. They are now focusing on characterizing the mussel glue proteins by DNA sequencing and assessing each protein's function. "One may serve as a varnish that protects the byssus, for example, while another actually serves as the animal's glue," says Rzepecki. "At this point, we know what most of the proteins are, but we don't know which one is the glue. Our next step is to find it." If they can pinpoint the protein that is the glue, a control technique to effectively "shoot the mussel in the foot" could be developed, not to mention a new adhesive with the ability to hold tight to surfaces in water. Waite equates his research on the zebra mussel to taking lessons from the master. "Mussels are probably at the cutting edge of adhesive technology," he says. -Tracey Bryant