Observations on tanning of the potato cyst-nematode,Globodera rostochiensis

Abstract

SUMMARYColour changes that occur during tanning of intact and puncturedGlobodera rostochiensisfemales and of isolated cuticle are described. Experiments with catechol and enzyme inhibitors show that the tanning enzyme, a phenoloxidase, is located in the cuticle, soluble in aqueous media and relatively abundant. Substrate for the enzyme is limited in the cuticle. Pseudocoelomic fluid of yellow females promoted tanning and contains either phenolic substrate(s) for the enzyme or part of a biochemical system responsible for release of the substrate. The substrate or biochemical system is thermolabile. Apparently, the tanning enzyme and its substrate(s) are partitioned in living females but the partitioning breaks down after death and the cuticle tans to form the cyst.

Electron microscopical localization of chitin in the cuticle of Halicryptus spinulosus and Priapulus caudatus (Priapulida) using gold-labelled wheat germ agglutinin: phylogenetic implications for the evolution of the cuticle within the Nemathelminthes

“…Also the observations, that both the sclerotized endocuticle and the overlying exocuticle I are resistant to pronase and chitinase (this article) may indicate a tanning process of the proteins in these layers. Whether this sclerotization is caused by quinone or polyphenols, as is well known for arthropods (see Hackman 1984), remains unresolved, but at least in the body cuticle of some Nematoda (species of Heterodera and Globodera) quinone tanning has been observed (Awan andHominick 1982, Shepherd et al 1972). However, further investigations are needed to clarify the nature of the sclerotization processes in the cuticle of the Priapulida.…”

“…Anya 1966; Awan and Hominick 1982;Cox et al 1981;Shepherd et al 1972), but observations on the histochemistry of the cuticular layers in species of the Priapulida are very scarce. The occurrence of chitin has been tested by alkali treatment or the chitosan test (Carlisle 1959;Por and Bromley 1974).…”

Phenolic Metabolites as a Chemotaxonomic Aid for the Identification of Cyst Forming Nematodes

“…Other workers have investigated the role of phenolics in the tanning process (Awan and Hominick, 1982) while Awan (1985) studied the tanning mechanism of the PCN and found on the basis of substrate specificity that the enzymes responsible for the process were of the catecholase type.…”