October 16, 2009

Researchers Discover How Barnacles Attach To Other Objects

Researchers have solved the mystery of how barnacles attach themselves to other objects, showing that barnacle glue binds together exactly the same way as human blood does when it clots, BBC News reported.

Barnacles are crustaceans that live in shallow ocean environments. As larvae they affix to hard substrates, then remain stationary for the rest of their lives.

The barnacles secrete an adhesive substance in order to attach themselves to a surface.

Scientists have long been aware of the chemical properties of this glue, but they could never explain how these chemicals interact to create a suction effect.

The research, published in the Journal of Experimental Biology, began when the researchers finally obtained some barnacle glue.

Dr Gary Dickinson, a member of the research team from Duke University's Marine Laboratory in Durham, North Carolina, said no one really knew how to work with barnacle glue before the study.

He explained that most people try to cut it off the bottom of a barnacle and then dissolve it, but they knew that was a limited approach.

Therefore, Dickinson and his colleagues figured out how to gently remove glue from the barnacles (Amphibalanus amphitrite) as they secreted it. They were then able to deconstruct the glue to find out exactly how it works.

The researchers initially compared the glue to red blood cells, another substance that clots in solution.

While they expected the mechanism by which glue particles bind, and red blood cells bind, to be different -- they found they are remarkably similar.

With blood, a number of enzymes work to create long protein fibers that bind red blood cells, or platelets, together into a clot and create a scab.

The team used atomic force microscopy and mass spectrometry to find that very similar enzymes, known as trypsin-like serine proteases, are at work in barnacle glue.

They soon discovered that one of those glue enzymes was remarkably like Factor XIII, an essential blood-clotting agent in human blood.

Dickinson said they found homologous enzymes in barnacles and humans, which serve the same function of clotting proteins underwater, despite roughly a billion years of evolutionary separation.

Team member Professor Dan Rittschof, also from Duke University's Marine Laboratory, said that surprising result does make evolutionary sense.

"Virtually no biochemical pathway is brand new. Everything is related and really important pathways are used over and over," he explained.

He noted that the key parts of those pathways don't change because if they do, the pathway fails and the animal dies.

Other organisms might also use this glue, according to Dickinson.

"The enzymes are highly conserved because they are very effective at what they do. There are bound to be a number of other organisms that use the same enzymes for the same purpose," he said.

Further research could even lead to a solution to the problem of marine fouling, where barnacles stick to boat hulls creating drag.

Dickinson said that many anti-fouling compounds used to paint the undersides of boats are toxic, so his team hopes to find a more environmentally friendly solution to curb the problem.


On the Net: