Hostname: page-component-7b7567c8c-7pwfn Total loading time: 0 Render date: 2026-11-12T08:12:42.894Z Has data issue: false hasContentIssue false
  • English
  • Français

The tylenchid (Nematoda) egg shell: structure, composition and permeability

Published online by Cambridge University Press:  06 April 2009

Alan F. Bird and
M. A. McClure
Alan F. Bird
Affiliation:
Division of Horticultural Research, C.S.I.R.O., Box 350, G.P.O., Adelaide, South Australia 5001
M. A. McClure
Affiliation:
Division of Horticultural Research, C.S.I.R.O., Box 350, G.P.O., Adelaide, South Australia 5001
Get accessRights & Permissions [Opens in a new window]

Summary

The fine structure of egg shells of four different genera belonging to the order Tylenchida has been examined. The species examined were Meloidogyne javanica, Rotylenchulus reniformis, Tylenchulus semipenetrans and Pratylenchus minyus. They are all similar in their basic structure, being composed of vitelline membrane, chitin and lipid layers, but there is considerable variability in the thickness of these layers.

We have retained the conventional nomenclature because of its convenience, but it is clear that these layers have a variety of chemical components. However, they do appear to contain the compounds from which they take their name. Thus chitin occurs in the chitin layer, and lipid in the lipid layer. The latter is removed by the technique used in isolating the shell from the egg. Chemical analysis of the hydrolysis products of these shells has revealed a high (35 %) proline content which appears to be a characteristic of those nematode egg shells which have been examined so far. These analyses and treatment with enzymes indicate that the chitin layer is a chitin–protein complex.

Experiments on the permeability of eggs of M. javanica at different temperatures indicate that changes in permeability are not due to the melting of a single lipid with a distinct melting point as had been thought in the past. We have found that Arrhenius activation energies calculated from the two slopes of an Arrhenius plot were 17·8 kcal/mol and 43·0 kcal/mol respectively, the transition from one to the other taking place at 62°C. We think that these changes are due to changes in the properties of lipoprotein membranes in the lipid layer. These membranes appear to be of paramount importance in controlling the permeability of the nematode egg shell.

Information

Type
Research Article
Information
Parasitology , Volume 72 , Issue 1 , February 1976, pp. 19 - 28
Copyright
Copyright © Cambridge University Press 1976

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

REFERENCES

Bird, A. F. (1968). Changes associated with parasitism in nematodes. III. Ultrastructure of the egg shell, larval cuticle, and contents of the subventral oesophageal glands in Meloidogyne javanica, with some observations on hatching. Journal of Parasitology 54, 475–89.Google Scholar
Bird, A. F. (1971). The Structure of Nematodes. New York and London: Academic Press.Google Scholar
Clarke, A. J., Cox, P. M. & Shepherd, A. M. (1967). The chemical composition of the egg shells of the potato cyst-nematode, Heterodera rostochiensis Woll. Biochemical Journal 104, 1056—60.CrossRefGoogle ScholarPubMed
Doncaster, C. C. (1962). A counting dish for nematodes. Nematologica 7, 334—7.Google Scholar
Foor, W. E. (1967). Ultrastructural aspects of oocyte development and shell formation in Ascaris lumbricoides. Journal of Parasitology 53, 1245–61.CrossRefGoogle ScholarPubMed
Lee, D. L. & Lešťan, P. (1971). Oogenesis and egg shell formation in Heterakis gallinarum (Nematoda). Journal of Zoology, London 164, 189–96.CrossRefGoogle Scholar
Mcclure, M. A. &Bird, A. F. (1976). The tylenchid (Nematoda) egg shell. II. Formation of the egg shell in Meloidogyne javanica. Parasitology 72, 29–39.Google Scholar
Mcclure, M. A., Kruk, T. H. & Misaghi, I. (1973). A method for obtaining quantities of clean Meloidogyne eggs. Journal of Nematology 5, 230.Google Scholar
Moor, H., Mühlethaler, K., Waldner, H. & Fry-Wyssling, A. (1961). A new freezing ultramicrotome. Journal of Biophysical and Biochemical Cytology 10, 1–13.CrossRefGoogle ScholarPubMed
Raison, J. K. (1973). Temperature-induced phase changes in membrane lipids and their influence on metabolic regulation. Society of Experimental Biology Symposium 27, 485–512.Google ScholarPubMed
Sizer, I. W. (1943). Effects of temperature on enzyme kinetics. Advances in Enzymology 3, 35–62.Google Scholar
Timm, R. W. (1950). Chemical composition of the vitelline membrane of Ascaris lumbricoides var. suis. Science 112, 167–8.Google Scholar
Tracey, M. V. (1955). ‘Chitin’ in Moderne Methoden des Pflanzenanalyse vol. 2 (ed. Paech, K. and Tracey, M. V.), pp. 264—74. Berlin-Springer.CrossRefGoogle Scholar