Hatching agents for the potato cyst‐nematode, Heterodera rostochiensis Woll

Abstract

SUMMARYOf 444 compounds tested for their ability to stimulate eggs of Heterodera rostochiensis to hatch, forty‐five did so to varying extents. Many compounds that hatched H. schachtii Schm. eggs did not hatch H. rostochiensis eggs. The most effective compounds with H. rostochiensis were picrolonic acid, anhydro‐tetronic acid and vanadates. Tests with analogues of picrolonic and anhydro‐tetronic acids suggested some structures that may be concerned in hatching H. rostochiensis and H. schachtii. The simple analogues hatched the eggs of H. schachtii but not those of H. rostochiensis. Suitably placed polarisable atoms seemed to be an essential feature. Picrolonic acid contains pairs of polarizable atoms, about 4 and 6·7 Å apart, that may respectively be associated with the hatching of H. schachtii and H. rostochiensis. Other features of the more active hatching agents were a cis and co‐planar arrangement of the two polarizable atoms with respect to the rest of the molecule. The function of hatching agents is discussed.

Purification and Characterization of Chitinases from the Nematophagous Fungi Verticillium chlamydosporium and V. suchlasporium

“…In our work, using a colorimetric method (Miller, 1959), we have not detected release of N-acetyl-d-glucosamine from G. pallida eggs. Chitin is present in Globodera eggshells to a lesser amount than protein (Clarke et al, 1967). However, the low sensitivity of the detection method used (40 g ⅐ ml Ϫ1 )…”

Nematode chitin synthases: gene structure, expression and function in Caenorhabditis elegans and the plant parasitic nematode Meloidogyne artiellia

“…The presence of chitin has been documented in a variety of nematode species and tissues. The most thorough tests have shown chitin to be a component of the eggshells of many nematodes (reviewed in Bird and Bird 1991), including the plant parasites Meloidogyne javanica (McClure and Bird 1976) and Globodera rostochiensis (Clarke et al 1967), as well as a variety of animal parasites including two Onchocerca species (Brydon et al 1987), Ascaris suum (Dubinsky et al 1986b) and Haemonchus contortus (Mans®eld et al 1992). It seems likely (and it is generally assumed) that chitin is a component of the eggshells of all nematodes.…”

The nematophagous fungus Verticillium chlamydosporium produces a chymoelastase-like protease which hydrolyses host nematode proteins in situ

“…Protein and chitin are main structural components of nematode egg shells, chitin being covered by protein (Clarke et al, 1967;Bird & McClure, 1976). The soluble protein content of the supernatant of M. incognita eggs treated with purified VCPl was 60 pg ml-', whereas eggs treated with the same amount of denatured protease gave an average reading of 31 pg ml-' (one-way ANOVA, F = 9.51, P = 0.037), indicating that the protease hydrolysed proteins from the nematode eggs.…”