The chemical composition of the egg shells of the potato cyst-nematode, Heterodera rostochiensis Woll

Abstract

1. Eggs of the potato cyst-nematode (Heterodera rostochiensis Woll.) were isolated by sieving a suspension of crushed cysts. Eggs were broken open by ultrasonic vibration and the egg shells separated from the released larvae by centrifuging in a potassium tartrate density gradient. About 1 mg. of dried egg shells was obtained from 1000 cysts. 2. The major constituent of the egg shells was protein (59%, calculated from nitrogen content). About 80% of the egg shells went into solution on acid hydrolysis. Of the 18 amino acids determined with the Technicon Auto-Analyser, proline was most abundant and, with aspartic acid, glycine and serine, made up about 64% by weight of the total amino acids. The small amounts of aromatic and sulphur-containing amino acids, and the presence of hydroxy-proline, indicate a collagen-like protein. 3. The egg shells gave a positive van Wisselingh colour test for chitin, and glucosamine was detected in their acid hydrolysate by chromatography. The glucosamine content of the egg shells, determined by the Elson-Morgan colorimetric method, was 7%, corresponding to about 9% chitin. 4. Dried egg shells contained about 7% of lipid, 6% of carbohydrate and 3% of ash. Polyphenols (3% by weight of the egg shells) were detected in the acid hydrolysates. 5. Neither the collagen nor the chitin showed evidence of crystallinity when examined by X-ray diffraction.

Gene cloning, molecular modeling, and phylogenetics of serine protease P32 and serine carboxypeptidase SCP1 from nematophagous fungiPochonia rubescensandPochonia chlamydosporia

“…1). P32 showed a positively charged surface at neutral and alkaline pH values, a feature that should allow it to bind to predominant negatively charged residues, such as proline, present in the nematode eggshell (Clarke et al 1967;Morton et al 2003) and the nematode female (Lopez-Llorca and Fry 1989). A comparison of the P32 pro-peptide sequence with that of characterized serine proteases from fungal pathogens of invertebrates is shown in Fig.…”

Relationships between sterol/phospholipid composition and xenobiotic transport in nematodes

“…For the egg stages, Clarke et al (1967) showed that the eggshells of another two nematodes (Ascaris spp. and Heterodera rostochiensis) contain 7% lipids.…”

The chemical composition of the cyst wall of the potato cyst-nematode, Heterodera rostochiensis

“…The cyst walls gave a negative van Wisselingh test, so the glucosamine may not be present as chitin. The egg shells of H. rostochiensis (Clarke et al 1967) contained chitin and gave 7% of glucosamine on hydrolysis.…”

“…The amino acid composition of H. ro8tochiensi8 cyst wall suggests that a similar collagen may be present in the untanned cuticle of the living females and probably of the larvae of this species. Table 1 compares the amino acid composition of H. ro8tochien8i8 cyst-wall hydrolysates with that of the hydrolysates of the egg shells of this species (Clarke et al 1967). The hydrolysates showed some distinct quantitative differences in the amino acids present, although the composition of each suggested that collagen predominated in the parent material.…”