Lentil lectin inhibits adult extract-induced settlement of the barnacle, Balanus amphitrite

For barnacles that live gregariously, chemical cues from conspecifics are believed to induce settlement of cypris larvae. A new assay system, using nitrocellulose membranes, has been developed to study cyprid settlement in response to adsorbed proteins. Using this assay, water‐soluble extracts from the adult barnacle, Balanus amphitrite, were found to promote settlement of conspecific cyprids. Adult extract‐induced settlement was inhibited by lentil lectin (LCA) and concanavalin A (ConA), but not by wheat germ agglutinin (WGA) or peanut agglutinin (PNA). LCA and ConA did not affect cyprid motility. Pretreatment of cyprids with LCA did not affect settlement, whereas pretreatment of adult extracts with LCA suppressed settlement. Moreover, inhibition of settlement by LCA was cancelled in the presence of methyl α‐D‐mannopyranoside. It is suggested that an LCA‐binding sugar chain of the settlement‐inducing glycoprotein is involved in settlement of the barnacle, B. amphitrite. J. Exp. Zool. 280:213–219, 1998. © 1998 Wiley‐Liss, Inc.