The Adhesive Glycoprotein of the Orb Web ofArgiope Aurantia(Araneae, Araneidae)

Abstract

A phosphorylated, glycoprotein preparation has been obtained from orb webs of the araneid spider Argiope aurantia. This preparation probably contains proteins from more than one gland type, but resolution of these proteins has not yet been achieved. Nevertheless, a major component appears to be the adhesive glycoprotein(s) from the adhesive spiral. A product of the aggregate glands, this glycoprotein(s) occurs as discrete nodules along the core fibers of the adhesive spiral, within the viscid, aqueous droplets.The glycoprotein preparation has a high apparent molecular weight (> 200 kDa) and is polydisperse. The only monosaccharide constituent identified by gas-liquid chromatography or in lectin studies is N-acetylgalactosamine and this is at least primarily O-linked to threonine. By electron microscopy, linear, unbranched and apparently flexible filaments are observed. Phosphorylated serine and threonine residues are present in the preparation and glycine, proline and threonine together account for about 57 mole % of the preparation's amino acid content. Thus, in some, but not all, respects, this glycoprotein preparation is reminiscent of a secretory mucin.

Temperature mediates the effect of humidity on the viscoelasticity of glycoprotein glue within the droplets of an orb-weaving spider's prey capture threads

“…The molecular structure of spider glue glycoprotein from Nephila clavipes is thought to incorporate components that are similar to those of mucin glycoprotein (Tillinghast et al, 1992;Choresh et al, 2009), which is highly O-glycosylated (Rhodes and Ching, 1993). These carbohydrate side chains of glycoproteins are very hydrophilic and usually have all possible hydrogen bonds fulfilled with either water molecules or neighboring saccharides (Cambillau, 1995).…”

Constraints on the adhesion of viscous threads spun by orb-weaving spiders: the tensile strength of glycoprotein glue exceeds its adhesion

“…The sticky viscous prey-capture threads spun by orb-weaving spiders of the Orbiculariae subclade Araneoidea are composed of regularly spaced droplets (Fig.1), each containing a viscoelastic glycoprotein mass that confers thread adhesion (Peters, 1986;Vollrath et al, 1990;Vollrath and Tillinghast, 1991;Vollrath, 1992;Tillinghast et al, 1993;Sahni et al, 2010). These threads form the spiral component of an orb-web and are responsible for retaining insects that strike the web, providing spiders with more time to locate, run to and subdue prey before they escape (Chacón and Eberhard, 1980).…”

“…Glycoprotein within each droplet confers thread adhesion (Peters, 1995;Vollrath and Tillinghast, 1991;Tillinghast et al, 1993;Opell and Hendricks, 2010). This glycoprotein adheres to a surface and, as force is applied to the thread, these viscoelastic molecules and the droplets that contain them elongate (Opell and Hendricks, 2010;Sahni et al, 2010).…”

Molecular Structural Analysis of Spider’s Capture Thread and Viscid Droplets Studied by Microscopic FT-IR Spectroscopy

“…In a previous study, viscid droplets consisted of aqueous solutions of sugar protein and low-molecular-weight hygroscopic salts; also, the chemical components were different between the center and outer parts of the viscid droplets. [8][9][10][11] Upon spraying distilled water, the viscid droplets gradually dissolved, and the chemical component was recrystallized on a CaF2 substrate by dry up. A photomicrograph of the recrystallized material is shown in Fig.…”

“…7 The capture threads of orb-web spiders consist of two extensible axial fibers surrounded by aqueous adhesive glue. [8][9][10][11] At first, the glue covers the fibers evenly, but it is soon spontaneously forms into a series of regularly distributed droplets. [12][13][14] It has also been reported that the property of a viscid droplet shows strange behavior, such as an in-drop capillary spooling of the thread.…”