Abstract
Barnacles are the only sessile crustaceans, and their larva, the cyprid, is supremely adapted for attachment to surfaces. Barnacles have a universal requirement for strong adhesion at the point of larval attachment. Selective pressure on the cyprid adhesive has been intense and led to evolution of a tenacious and versatile natural glue. Here we provide evidence that carbohydrate polymers in the form of chitin provide stability to the cyprid adhesive of Balanus amphitrite. Chitin was identified surrounding lipid-rich vesicles in the cyprid cement glands. The functional role of chitin was demonstrated via removal of freshly attached cyprids from surfaces using a chitinase. Proteomic analysis identified a single cement gland-specific protein via its association with chitin and localized this protein to the same vesicles. The role of chitin in cyprid adhesion raises intriguing questions about the evolution of barnacle adhesion, as well as providing a new target for antifouling technologies.
Highlights
Barnacles are the only sessile crustaceans, and their larva, the cyprid, is supremely adapted for attachment to surfaces
Chitin is usually present as nanofibers that are produced via a membrane-bound chitin synthase and crosslinked by hydrogen bonding between proteins with conserved chitinbinding domains (CBDs)[27]
Cement glands from 3-day-old Balanus amphitrite cyprids (Fig. 1a, b) were labelled using the CBD conjugated with SNAP-reactive Alexa Fluor 546 (CBD-546, New England Biolabs) and counter-stained with DAPI (Fig. 1c, d, g)
Summary
Barnacles are the only sessile crustaceans, and their larva, the cyprid, is supremely adapted for attachment to surfaces. Among Crustacea, many barnacle species must position themselves close to a future mate at attachment and allow for growth and adhesion in the adult form[7], which has led to supreme surface selectivity. Adult barnacle adhesion is linked to the moulting cycle, e.g.24,25, and cyprid cement secretion is quickly followed by ecdysis. It is possible, considering the evidence provided by Walker[18], that both adult and larval adhesion processes evolved from a modification of the cuticle secretion process. Adopting his terminology for discussion of the present results, we refer to homopolymers of N-acetyl-D-glucosamine covalently linked to proteins (glycosylation) as native chitin[29], while nanofibers extruded via a chitin synthase are referred to as chitin
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
