Characterisation of the slime gland secretion from the peripatus, Euperipatoides kanangrensis (Onychophora : Peripatopsidae)

The Onychophora display a distinctive mechanism of feeding that involves the entanglement of prey in a sticky secretion. This secretion is produced in the slime glands and ejected as adhesive threads from a pair of oral papillae on either side of the head. Biochemical analyses of the secretion reveals it to be a composite material containing protein, sugar, lipid and a surfactant, nonylphenol. The identification of nonylphenol in the secretion is significant in that this is the first report of this compound from a natural source. The proteins are the principal component of the slime and the amino acid composition of the crude secretion suggests the presence of collagen or a ‘collagen-like’ domain. One or more of the high molecular weight proteins are O-glycosylated where the predominant modification is a single N-acetylgalactosamine (GalNAc). This study adds to our understanding of the chemical and biochemical composition of the unusual onycophoran slime gland secretion.