Identifying adhesive components in a model tunicate

Abstract

Tunicates populate a great variety of marine underwater substrates worldwide and represent a significant concern in marine shipping and aquaculture. Adhesives are secreted from the anterior papillae of their swimming larvae, which attach and metamorphose into permanently adhering, filter-feeding adults. We recently described the cellular composition of the sensory adhesive organ of the model tunicate Ciona intestinalis in great detail. Notably, the adhesive secretions of collocytes accumulate at the tip of the organ and contain glycoproteins. Here, we further explore the components of adhesive secretions and have screened for additional specificities that may influence adhesion or cohesion of the Ciona glue, including other carbohydrate moieties, catechols and substrate properties. We found a distinct set of sugar residues in the glue recognized by specific lectins with little overlap to other known marine adhesives. Surprisingly, we also detect catechol residues that likely originate from an adjacent cellular reservoir, the test cells. Furthermore, we provide information on substrate preferences where hydrophobicity outperforms charge in the attachment. Finally, we can influence the settlement process by the addition of hydrophilic heparin. The further analysis of tunicate adhesive strategies should provide a valuable knowledge source in designing physiological adhesives or green antifoulants. This article is part of the theme issue ‘Transdisciplinary approaches to the study of adhesion and adhesives in biological systems’.

Expression of smooth muscle-like effectors and core cardiomyocyte regulators in the contractile papillae of Ciona

“…In Ciona, exactly four CryBG +ACCs are found at the center of each papilla (Fig. 1 b, c), and are morphologically distinct from the other cell types of the papillae, which also include putative adhesive-secreting collocytes and sensory neurons [ 120 , 121 ] (Fig. 1 d).…”

“…Expression of Mylk at the larval stage was also broadly expressed in the papillae (Fig. 3 e), being especially pronounced in cells surrounding or in between the three papillae presumed to be collocytes [ 120 , 121 ], but two-color double in situ hybridization with CryBG probe and scRNAseq visualization (Fig. 2 ) suggested expression in the ACCs as well (Fig.…”

“…It is unclear if the ACCs are homologous to any particular type of myoepithelial cell in extant vertebrates. The papillae of tunicate larvae secrete adhesive substances [ 120 ] and might share a common origin with various secretory glands in vertebrates. The most obvious candidate would be the cement gland of various vertebrates, though myoepithelia have not been reported in these glands.…”

Omics‐based molecular analyses of adhesion by aquatic invertebrates

“…Adhesion is mediated by rostral papillae that secrete adhesive material from collocytes (reviewed in Pennati & Rothbächer, 2015). The collocytes contain two types of vesicles with fibrous polysaccharides and glycoproteinaceous contents, respectively (Zeng et al, 2019a). Adhesion continues throughout growth of the animal via the ampullae, which are holdfast extensions of the tunic that lack glandular organs but that seem to produce adhesive material by epithelial secretion (Ueki et al, 2018).…”

Substrate Selection of Ascidian Larva: Wettability and Nano-Structures

“…Laboratory experiments are mainly carried out to examine particular factor(s), such as texture, wettability, or color of substrata, on pre-settlement selection, but as results do not always reflect the natural settlement process, care should be taken in interpreting these results. These experiments can be subdivided into single-choice [3][4][5][6], dual-choice [7,8], and multi-choice tests [9][10][11].…”