Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-06T06:53:18.319Z Has data issue: false hasContentIssue false
  • English
  • Français

A fine structural study on the merozoite of Eimeria tenella with special reference to the conoid apparatus

Published online by Cambridge University Press:  06 April 2009

Diane J. Mclaren  and
G. E. Paget
Diane J. Mclaren
Affiliation:
Research Institute, Smith Kline and French Laboratories Ltd., Welwyn Garden City, Hertfordshire
G. E. Paget
Affiliation:
Research Institute, Smith Kline and French Laboratories Ltd., Welwyn Garden City, Hertfordshire
Get access Rights & Permissions [Opens in a new window]

Extract

The ultrastructure of the merozoite of Eimeria tenella has been studied by means of electron microscopy. The first-generation merozoite is approximately 3·4 μm in length, and 1·2 μm in width, while the second-generation merozoite is approximately 10·5 μm in length and 1·5 μm in width.

The cell wall of the merozoite consists of a double membrane, but at the anterior extremity the existence of a fluted collar gives the appearance of two narrow double membranes separated by a zone of less electron-dense material. Twenty-four surface fibrils are distributed around the periphery; they extend along the entire length of the organism and lie beneath the double limiting membrane.

The anterior end of the merozoite is distinguished by a conoid apparatus which includes several components. A bulbiform outer annulus is invested by a fluted collar, and itself encloses an extrusible papilla. Two osmiophilic fibrils, the paired organelles, arise within the extrusible papilla and extend longitudinally into the cytoplasm. Twenty-four smaller fibrils, or toxonemes, also arise within the conoid and pass back into the main body of the organism.

The cytoplasm of the merozoite includes mitochondria, glycogen, dense elliptical granules and endoplasmic reticulum, together with a definite Golgi complex. A nucleus is located in the posterior third of the organism and is enclosed by a perforated double membrane. At the posterior extremity the double membrane which bounds the organism is broken by a pore 700 A in diameter.

Our sincere thanks are due to Mr P. Richmond for technical assistance, and we are grateful to the Central Veterinary Research Laboratory, Weybridge, for supplying the strain of Eimeria tenella.

Type
Research Article
Information
Parasitology , Volume 58 , Issue 3 , August 1968 , pp. 561 - 571
Copyright
Copyright © Cambridge University Press 1968

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.)

References

REFERENCES

Brenner, S. & Horne, R. W. (1959). A negative staining method for high resolution electron microscopy of viruses. Biochim. biophys. Acta 34, 103–10.CrossRefGoogle ScholarPubMed
Davies, S. F. M., Joyner, L. P. & Kendall, S. B. (1963). Coccidiosis. Edinburgh and London: Oliver and Boyd.Google Scholar
Garnham, P. C. C., Bird, R. G. & Baker, J. R. (1960). Electron microscope studies of motile stages of malaria parasites. I. The fine structure of the sporozoites of Haemamoeba (= Plasmodium) gallinacea. Trans. R. Soc. trop. Med. Hyg. 54, 274–78.CrossRefGoogle ScholarPubMed
Garnham, P. C. C., Bird, R. G., Baker, J. R. & Bray, R. S. (1961). Electron microscope studies of motile stages of malaria parasites. II. The fine structure of the sporozoite of Laverania ( = Plasmodium) falcipara. Trans. R. Soc. trop. Med. Hyg. 55, 98–102.CrossRefGoogle Scholar
Hepler, P. K., Huff, C. G. & Sprinz, H. (1966). Fine structure of erythrocytic stages of Plasmodium fallax. J. Cell Biol. 30, 333–58.CrossRefGoogle Scholar
Jeon, K. W. (1965). Simple method of staining epoxy sections. Life Sci. 4, 1839–41.CrossRefGoogle Scholar
Millonig, G. (1961). Advantages of a phosphate buffer for osmium tetroxide solutions in fixation. J. appl. Phys. 32, 1637.Google Scholar
Mossevitch, T. N. & Cheissin, E. M. (1961). Certain data on electron microscope study of merozoites of the Eimeria intestinalis from rabbit intestine. Cytologia (Tokyo) 3, 34–9.Google Scholar
Scholtyseck, E. & Piekarski, G. (1965). Elektronenmikroskopische Untersuchungen an Merozoiten von Eimerien (Eimeria perforans und Eimeria stiedae) und Toxoplasma gondii. Z. ParasitKde 26, 91–115.CrossRefGoogle ScholarPubMed
Stehbens, W. E. & Johnston, M. R. L. (1967). The ultrastructure of a haemogregarine parasitic in Gehyra variegata (Duméril & Bibron, 1836). Parasitology 57, 251–61.CrossRefGoogle ScholarPubMed
Tyzzer, E. E. (1929). Coccidiosis in gallinaceous birds. Am. J. Hyg. 10, 269–383.Google Scholar
Venable, J. H. & Coggeshall, R. (1965). A simplified lead citrate stain for use in electron microscopy. J. Cell Biol. 25, 407–8.CrossRefGoogle ScholarPubMed