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
     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
     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
     "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