Project description:The base of the barnacle Amphibalanus amphitrite has a layer of protein and cuticle that adheres the barnacle to the surface. The proteins in the adhesive have been characterized, but it is unknown whether the adhesive proteins are associated with the cuticle. To address this possibility, we examined the proteins associated with the molt (exuviae) from the main body, which is also composed of cuticle.
Project description:Background: Marine biofouling negatively impacts industries reliant upon submerged stationary surfaces. The acorn barnacle Amphibalanus amphitrite is a major biofouler that permanently attaches to a wide array of substrates by producing a proteinaceous adhesive at the surface interface. These interface proteins are difficult to solubilize, and the understanding of what proteins exist in the adhesive has only been expanded with the use of the strong polar solvent hexafluoroisopropanol in combination with standard gel-based sample processing methods for proteomics analysis. Although effective, existing sample processing methods are labor and time intensive, hindering progress in this field. Results: We have developed a more efficient sample processing method by exploiting pressure cycling technology, which aids in protein extraction and digestion for proteomics analysis, and explored the efficacy of multiple solvents in combination with pressure on protein identification. We found that barnacle adhesive proteins can be extracted and digested in the same tube using pressure cycling technology, minimizing sample loss, increasing throughput to 16 concurrently processed samples, and decreasing sample processing time to under 8 hours. Pressure cycling technology methods produced similar proteomes in comparison to previous methods. Two solvents which were ineffective at extracting proteins from the adhesive at ambient pressure (urea and methanol) produced more protein identifications under pressure than hexafluoroisopropanol, leading to the identification and our description of >40 novel proteins at the interface. Many A. amphitrite adhesive proteins have no sequence similarity to publically available proteins, highlighting the unique adherent processes evolved by barnacles. Conclusion: Using pressure cycling technology, we describe methods that produce robust and consistent protein identifications from barnacle adhesive. These methods can be used to examine changes in barnacle adhesive, enabling future research on the effects of environmental and surface substrate composition on barnacle cement, a critical step for both broadening the understanding of barnacle adhesion and the development of new coatings for submerged surfaces to combat hard biofoulants.
Project description:A complete understanding of barnacle adhesion remains elusive as the process occurs within and beneath the confines of a rigid calcified shell. Barnacle cement is mainly proteinaceous and several individual proteins have been identified in the hardened cement at the barnacle-substrate interface.We report the discovery of a novel 114kD cement protein, which is identified in material secreted onto various surfaces by adult barnacles and with the encoding gene highly expressed in the sub-mantle tissue.
