Involvement of sulfated biopolymers in adhesive secretions produced by marine invertebrates

Abstract

Many marine invertebrates use adhesive secretions to attach to underwater surfaces and functional groups borne by their adhesive proteins and carbohydrates, such as catechols and phosphates, play a key role in adhesion. The occurrence of sulfates as recurrent moieties in marine bioadhesives suggests that they could also be involved. However, in most cases, their presence in the adhesive material remains speculative. We investigated the presence of sulfated biopolymers in five marine invertebrates representative of the four types of adhesion encountered in the sea: mussels and tubeworms for permanent adhesion, limpets for transitory adhesion, sea stars for temporary adhesion and sea cucumbers for instantaneous adhesion. The dry adhesive material of mussels, sea stars and sea cucumbers contained about 1% of sulfate. Using anti-sulfotyrosine antibodies and Alcian Blue staining, sulfated proteins and sulfated proteoglycans and/or polysaccharides were identified in the secretory cells and adhesive secretions of all species except the tubeworm. Sulfated proteoglycans appear to play a role only in the non-permanent adhesion of sea stars and limpets in which they could mediate cohesion within the adhesive material. In mussels and sea cucumbers, sulfated biopolymers would rather have an anti-adhesive function, precluding self-adhesion.

Molecular insights into the powerful mucus-based adhesion of limpets ( Patella vulgata L.)

“…All proteins were predicted to have post-translational modifications (PTMs), with at least one type of glycosylation and numerous phosphorylation sites. While half of the proteins were predicted to have sulfated tyrosine, this PTM was not detected in P. vulgata (neither on foot sections nor on mucus trails) using an anti-sulfotyrosine antibody [ 48 ].…”

“…Several studies have previously investigated the chemical constituents of limpet pedal mucus using histochemistry and gel electrophoresis [14,15,17,48]. Our results from lectin-binding assays and transcriptome-assisted proteomics have revealed novel insights into the biochemical properties of P. vulgata pedal mucus.…”

“…The following characteristics of the 14 sequences are summarized in table 2: the type of mucus it was isolated from (IPAM, BPAM, SAM), fragment per kilobase million (FPKM), While half of the proteins were predicted to have sulfated tyrosine, this PTM was not detected in P. vulgata (neither on foot sections nor on mucus trails) using an anti-sulfotyrosine antibody [48]. BLAST analysis of the limpet proteins highlighted homology to a number of characterized proteins.…”

“…All these proteins also share similarities with the aforementioned group of proteins (fibrillin, zonadhesin, alpha-tectorin, IgGFc-binding protein). Moreover, a study examining the role of sulfated biopolymers in marine bio-adhesives also highlighted the similarities between transitory and temporary adhesive secretions, where such moieties may serve a cohesive function in the adhesive material of limpets and sea stars but not in tubeworms or sea cucumbers [48]. Moreover, a review of adhesive secretions from marine invertebrates demonstrated that, based on comparisons between the amino acid compositions of whole adhesives, there are similarities between secretions from all species using non-permanent adhesion (i.e.…”

Comparative and functional analysis of the digital mucus glands and secretions of tree frogs

“…To further explore these trade-offs, dynamic measurements of the mucus composition and of the generated attachment forces are required. Also, a more elaborate analysis of the protein content of tree frog mucus, as outlined by Hennebert et al [92], may help to understand the role of these potentially adhesive molecules in attachment.…”