Barnacles are capable of attaching themselves to virtually any underwater surface; from whale skin and turtle shells to ship hulls and pier structures. Just how they manage to keep themselves anchored has remained a mystery; a multimillion mystery since barnacles increase fuel consumption by adding additional drag to the submerged parts of marine vessels. Scientists knew that the barnacles used a type of glue, but they didn’t understand how it worked and why it was so strong.

Traditionally, toxic paint has been used to keep the barnacles away but dry-docking huge cargo ships every so often to have them repainted is naturally expensive. Also, the toxic paint is not only affecting the barnacles; it is causing problems for entire ecosystems and many countries have therefore decided to ban or limit the use of some of the most harmful ones.

Using modern techniques such as force microscopy and mass spectrometry, a team of scientists from Duke University’s Marine Laboratory in Durham has now managed to find out how barnacles stick to surfaces; a discovery which they hope will lead to the development of more environmentally friendly anti-barnacle remedies.

The research team unveiled that barnacle glue from the species Amphibalanus amphitrite binds together much the same way as red blood cells bind together when our blood clots. When our blood clot, several different enzymes work together to form protein fibres that bind the cells together. In barnacle glue, similar enzymes – known as trypsin-like serine proteases – do the same thing. Interestingly enough, one of these enzymes are remarkably similar to Factor XIII, and essential blood clotting agent present in human blood.

“We’ve found homologous enzymes in barnacles and humans, which serve the same function of clotting proteins underwater, despite roughly a billion years of evolutionary separation,” says research team member Dr Gary Dickinson.

Another team member, Professor Dan Rittschof, explains that this similarity does make evolutionary sense.

“Virtually no biochemical pathway is brand new. Everything is related and really important pathways are used over and over,” says Rittschof. “Really key parts of those pathways can’t change because if they do, the pathway fails and the animal dies.”

According to Dickinson, it wouldn’t be surprising to find this glue in other organisms besides the barnacles.

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

For more information, read the article in The Journal of Experimental Biology.

http://jeb.biologists.org