Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-30T15:32:02.542Z Has data issue: false hasContentIssue false
  • English
  • Français

Studies on gut ultrastructure and digestive physiology in Cyathostoma lari (Nematoda: Strongylida)

Published online by Cambridge University Press:  06 April 2009

J. Barry Colam
J. Barry Colam
Affiliation:
Department of Zoology, The University, Leeds, LS2 9JT
Get access Rights & Permissions [Opens in a new window]

Extract

Histological, histochemical and ultrastructural methods have been used to study the gut structure and digestive physiology in the parasitic nematode Cyathostomalari E. Banchard, 1849. The nematode is parasitic in the orbito-nasal sinuses of its host and feeds exclusively upon blood.

Three gland cells are present in the oesophagus, one in each sector. The two subventral gland ducts open into the lumen of the oesophagus at the level of the nerve ring, and the dorsal gland duct into the base of the buccal capsule. It is suggested that the latter gland may produce an anticoagulin, histolytic and/or haemolytic secretions, histochemically-inactive in situ. The intestine is syncytial, with no differentiation into secretory components, and its distal surface is provided with a prominent brush border of long microvilli.

A non-specific esterase, thought to originate in the oesophageal gland secretions, causes haemolysis of ingested erythrocytes. The major part of haemoglobin digestion is extracellular, partly by a process of contact digestion on the microvilli, initiated by the esterase, and the protein is then further broken down by an exopeptidase of the ‘leucine aminopeptidase’ type, and the products absorbed into the gastrodermis possibly with the aid of an acid phosphatase present on or in the microvilli. An insoluble iron-containing compound, which is not haematin, results from breakdown of the prosthetic group. A smaller proportion of haemoglobin is taken up by the gastrodermis and digested intracellularly by the action of lysosomal hydrolases. An endopeptidase and an acid phosphatase are present in the gastrodermis, possibly in sacs of GER which are suggested to be primary lysosomes and which fuse with the endocytosed heterophagosomes. The insoluble pigment haematin results from digestion within the heterolysosomes, and this gives rise to the iron-containing gastrodermal pigment granules. The products of extracellular digestion are absorbed by the gastrodermis where they are synthetized into lipid by a lipase, which probably resides in whorls of GER.

This investigation was supported in part by Research Grant AI 06295 of the United States Public Health Service. The final manuscript was prepared during the tenure of a Postdoctoral Fellowship from the British Egg Marketing Board. I wish to extend my gratitude to Dr J. B. Jennings for advice and encouragement throughout this work.

Type
Research Article
Information
Parasitology , Volume 62 , Issue 2 , April 1971 , pp. 273 - 283
Copyright
Copyright © Cambridge University Press 1971

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

Andreassen, J. (1968). Fine structure of the intestine of the nematodes, Ancylostoma caninum and Phocanema decipiens. Zeitschrift für Parasitenkunde 30, 318–36.CrossRefGoogle ScholarPubMed
Chitwood, B. G. & Chitwood, M. B. (1937). An Introduction to Nematology. Baltimore: Monumental Printing Company.Google Scholar
Colam, J. B. (1969). Histochemical, biochemical and ultrastructural studies on certain species of Nematoda, with special reference to their nutrition. Ph.D. Thesis, University of Leeds.Google Scholar
Colam, J. B. (1970). Studies on gut ultrastructure and digestive physiology in Rhabdias bufonis and R. sphaerocephala (Nematoda: Rhabtidida). Parasitology 62, 247–58.Google Scholar
Diem, K. (Ed.) (1962). Documenta Geigy. Scientific Tables. Sixth edition. Manchester: Geigy Pharmaceutical Company Ltd.Google Scholar
Ernst, J. (1888). Einige Fälle von Ankylostomiasis, nebst Sectionsbefunden. Deutsche medizinische Wochenschrift 14, 291–4.CrossRefGoogle Scholar
Hsü, H. F. (1938). Studies on the food and the digestive system of certain parasites. I. On the food of the dog hookworm, Ancylostoma caninum. Bulletin of the Fan Memorial Institute of Biology 8, 121–31.Google Scholar
Hsü, H. F. & Li, S. Y. (1940). Studies on the food and the digestive system of certain parasites. VI. On the food of certain parasites living in the digestive tract of vertebrates. Chinese Medical Journal 57, 559–67.Google Scholar
Jennings, J. B. & Colam, J. B. (1970). Gut structure, digestive physiology and food storage in Pontonema vulgaris (Nematoda: Enoplida). Journal of Zoology, London 161, 211–21.CrossRefGoogle Scholar
Lee, C-C. (1969). Ancylostoma caninum: fine structure of the intestinal epithelium. Experimental Parasitology 24, 336–47.CrossRefGoogle Scholar
Leichtenstern, O. (1886). Weitere beiträge zur Ankylostomofrage. Deutsche medizinische Wochenschrift 12, 173–6.CrossRefGoogle Scholar
Magath, T. B. (1919). Camallanus americanus, nov. spec. Transactions of the American Microscopical Society 38, 49–170.CrossRefGoogle Scholar
Miller, J. H. (1967). Fine structure of the striated border of the intestinal cells of Ancylostoma caninum. Journal of Parasitology 53, 94–9.Google Scholar
Roche, M. (1963). In vitro experiments on Ancylostoma caninum. In Perspectives in Biology. Amsterdam: Elsevier Publishing Co.Google Scholar
Thorson, R. E. (1955). The effects of extractions of the amphidial glands, excretory glands, and oesophagus of adult Ancylostoma caninum on the coagulation of dog's blood. Journal of Parasitology, 41, 41–2 (abstract).Google Scholar
Thorson, R. E. (1956). Proteolytic activity in extracts of the oesophagus of adult Ancylostoma caninum and the effect of immune serum on this activity. Journal of Parasitology, 42, 21–5.CrossRefGoogle ScholarPubMed
Threlfall, W. (1966). The mode of attachment of Cyathostoma lari E. Blanchard, 1849 (Nematoda: Strongyloidea). Canadian Journal of Zoology 44, 1091–2.CrossRefGoogle Scholar
Ugolev, A. M. (1965). Membrane (contact) digestion. Physiological Reviews 45, 555–95.CrossRefGoogle ScholarPubMed
Wells, H. S. (1931). Observations on the blood sucking activities of the hookworm, Ancylostoma caninum. Journal of Parasitology 17, 167–82.CrossRefGoogle Scholar
Whipple, G. H. (1909). The presence of a weak haemolysin in hookworm and its relation to the anaemia of uncinariasis. Journal of Experimental Medicine 11, 331–43.CrossRefGoogle Scholar