Locating the barnacle settlement pheromone: spatial and ontogenetic expression of the settlement-inducing protein complex ofBalanus amphitrite

Abstract

Barnacles are prominent members of hard substratum benthic communities and their study has been important to advances in experimental ecology and contemporary ecological theory. Having recently characterized the cue to gregarious settlement of Balanus amphitrite, the settlement-inducing protein complex (SIPC), we use two polyclonal antibodies to examine the tissue distribution and ontogenetic expression of this glycoprotein. These antibodies were raised against two separate peptides located near the N-and C-termini of the SIPC and were used to detect the glycoprotein by western blotting and immunohistochemistry. By in situ hybridization we also show that the SIPC mRNA co-occurs with the expressed glycoprotein in the cuticles of both nauplius and cypris larval stages and the adult. In the larvae, the SIPC is expressed most strongly in the mouthparts and the hindgut of the stage 2 nauplius and in the thoracopods, antennules and bivalved carapace of the cyprid. In adult B. amphitrite, the expressed SIPC is present in protein extracts of the shell and in all organs that are lined by cuticular tissues. We suggest that the SIPC is produced by the epidermal cells that secrete the cuticle and discuss these observations with regard to earlier studies and the role of the SIPC as a contact pheromone.

The regulatory role of the NO/cGMP signal transduction cascade during larval attachment and metamorphosis of the barnacleBalanus (=Amphibalanus) amphitrite

“…These results indicated that SIPC may be involved in adult-larva and larva-larva interactions during settlement. More detailed studies on the spatial and ontogenetic expression of SIPC have confirmed the previous findings and suggested that cyprids might detect this cue through contact with cuticle of adult barnacle (Dreanno et al, 2006a;Dreanno et al, 2006b;Dreanno et al, 2006c). Nevertheless, the SIPC receptor in cyprids is still unknown.…”

“…SIPC is a cuticle glycoprotein involved in gregarious settlement behavior of B. amphitrite (Dreanno et al, 2006a;Dreanno et al, 2006b). On basis of its localization at cuticles, the authors suggested that besides functioning as a contact pheromone, SIPC may also act as a waterborne cue, possibly released through cuticle regeneration and bacterial degradation (Dreanno et al, 2006c).…”

Deep sequencing of naupliar-, cyprid- and adult-specific normalised Expressed Sequence Tag (EST) libraries of the acorn barnacleBalanus amphitrite

“…The data show that the SIPC is expressed in all developmental stages investigated, confirming that this protein is not only produced by adults, but that it may also possess a function in larval-larval interactions (Dreanno et al 2006a). The SIPC is a large glycoprotein present in all organs that are lined by adult cuticular tissues, and evidence seems to indicate that the carbohydrate component of the SIPC plays a fundamental role in species recognition (Matsumura et al 1998a(Matsumura et al , 1998b.…”

Barnacle cement: a polymerization model based on evolutionary concepts

“…The presence of hemocytes and proteins previously identified in hemolymph [i.e. SIPC (Dreanno et al, 2006)] in barnacle cement leads us to believe that barnacle hemolymph functions as a cement (Dickinson, 2008).…”