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The biology of the external surfaces of helminth parasites

Published online by Cambridge University Press:  05 December 2011

L. H. Chappell
L. H. Chappell
Affiliation:
Department of Zoology, University of Aberdeen, Aberdeen AB9 2TN
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Synopsis

The biological properties of the surface of helminth parasites are examined under three headings, morphology, digestive-absorptive function and defence. The concept of the host-parasite interface is explored.

Platyhelminth parasites are covered by a syncytial tegument with sunken parenchymal cell bodies. The surface is either microvillous or deeply folded, presenting a large surface area relative to volume. The acanthocephalan surface is structurally unique, possessing a branching pore-canal system. The majority of nematodes are surrounded by a thick cuticle composed of distinct layers; exceptions include the entomophilic nematodes.

The absorptive properties of the surface of helminth parasites are discussed and the published data on transtegumental transport of nutrient molecules examined. Most nematodes are impermeable to small molecules, but all other helminths utilise surface transport mechanisms. Cestodes and acanthocephalans lack a gut and the tegument becomes the major site of nutrient uptake.

Surface-bound enzymes have been described in several helminths and indicate the possible extent of surface digestion by parasites. Binding of host digestive enzymes to the helminth surface may also serve a protective as well as nutritional function.

Surface defence mechanisms are described whereby physiological interactions between host and parasite at the helminth surface effect evasion of the host's defences. The essence of these mechanisms is surface disguise.

Type
Research Article
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Proceedings of the Royal Society of Edinburgh, Section B: Biological Sciences , Volume 79 , Issue 1-3: Surface ecosystems and the interactions within them which overcome skin defence mechanisms , 1980 , pp. 145 - 172
Copyright
Copyright © Royal Society of Edinburgh 1980

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References

Arme, C., 1981. Parasite Nutrition. In Modern Parasitology. Ed. Cox, F. E. G.. Oxford: Blackwell, in press.Google Scholar
Arme, C. and Read, C. P., 1968. Studies on membrane transport. II. The absorption of acetate and butyrate by Hymenolepis diminuta (Cestoda). Biol. Bull. Mar. Biol. Lab. Woods Hole, 135, 80–91.CrossRefGoogle ScholarPubMed
Arme, C. and Read, C. P., 1970. A surface enzyme in Hymenolepis diminuta (Cestoda). J. Parasit., 56, 514–516.CrossRefGoogle ScholarPubMed
Asch, H. L. and Read, C. P., 1975a. Transtegumental absorption of amino acids by male Schistosoma mansoni. J. Parasit., 61, 378–379.CrossRefGoogle ScholarPubMed
Asch, H. L. and Read, C. P., 1975b. Membrane transport in Schistosoma mansoni: Transport of amino acids by adult males. Expl. Parasit., 38, 123–135.CrossRefGoogle ScholarPubMed
Bailey, H. H. and Fairbairn, D., 1968. Lipid metabolism in helminth parasites. V. Absorption of fatty acids and monoglycerides from micellar solution by Hymenolepis diminuta (Cestoda). Comp. Biochem. Physiol., 26, 819–936.CrossRefGoogle Scholar
Barnes, R. D., 1974. Invertebrate Zoology, 3rd edn. Philadelphia: W. B. Saunders.Google Scholar
Baron, P., 1968. On the histology and ultrastructure of Cysticercus longicollis, the cysticercus of Taenia crassiceps Zeder, 1800 (Cestoda: Cyclophyllidea). Parasitology, 58, 497–513.CrossRefGoogle Scholar
Beerman, I., Arai, H. P. and Costerton, J. W., 1974. The ultrastructure of the lemnisci and body wall of Octospinifer macilentus (Acanthocephala). Can. J. Zool., 52, 553–555.CrossRefGoogle Scholar
Berger, J. and Mettrick, D., 1971. Microtrichial polymorphism among hymenolepid tapeworms as seen by scanning electron microscopy. Trans. Am. Microsc. Soc., 90, 393–403.CrossRefGoogle ScholarPubMed
Bird, A., 1971. The Structure of Nematodes. New York: Academic Press.Google Scholar
Bloom, B. R., 1979. Games parasites play: how parasites evade immune surveillance. Nature, Lond., 279, 21–26.CrossRefGoogle ScholarPubMed
Bogitsh, B. J., 1968. Cytochemical and ultrastructural observations on the tegument of the trematode, Megalodiscus temperatus. Trans. Am. Microsc. Soc., 87, 477–486.CrossRefGoogle ScholarPubMed
Bogitsh, B. J. and Krupa, P., 1971. Schistosoma mansoni and Haematoloechus medioplexus: nucleoside-diphosphatase localization in tegument. Expl Parasit., 30, 418–425CrossRefGoogle Scholar
Bonner, T. P., Weinstein, P. P. and Saz, H., 1971. Synthesis of cuticular protein during the third moult in the nematode Nippostrongylus brasiliensis. Comp. Biochem. Physiol., 40B, 121–127.Google Scholar
Branch, S. I., 1970. Accumulation of amino acids by Moniliformis dubius (Acanthocephala). E.xpl Parasit., 27, 95–99.CrossRefGoogle ScholarPubMed
Bresciani, J., 1972. The ultrastructure of the integument of the monogenean Polystoma integerrimum (Frolich, 1791). Arsskr. K. Vet.—Landbohøøjsk., 1973, 14–27.Google Scholar
Butterworth, P., 1969. The development of the body wall of Polymorphus minutus (Acanthocephala) in its intermediate host Gammarus pulex. Parasitology, 59, 373–388.CrossRefGoogle ScholarPubMed
Byram, J. and Fisher, F. M., 1973. The absorptive surface of Moniliformis dubius (Acanthocephala). I. Fine structure. Tissue and Cell, 5, 553–579.CrossRefGoogle ScholarPubMed
Byram, J. and Fisher, F. M., 1974. The absorptive surface of Moniliformis dubius (Acanthocephala). II. Functional aspects. Tissue and Cell, 6, 21–42.CrossRefGoogle ScholarPubMed
Chappell, L. H., 1974. Methionine uptake by larval and adult Schistosoma mansoni. Intl. J. Parasit., 4, 361–369.CrossRefGoogle ScholarPubMed
Chappell, L. H., Arme, C. and Read, C. P., 1969. Studies on membrane transport. V. Transport of long chain fatty acids in Hymenolepis diminuta (Cestoda). Biol. Bull. Mar. Biol. Lab. Woods Hole, 136, 313–326.CrossRefGoogle ScholarPubMed
Chubb, J. C., 1965. Mass occurrence of Pomphorhynchus laevis (Muller, 1776), Monticelli 1905 (Acanthocephala) in the chub Squalius cephalus (L) from the river Avon, Hampshire. Parasitology, 55, 5.Google Scholar
Clegg, J. A., Smithers, S. R. and Terry, R. J., 1971a. Acquisition of human antigens by Schistosoma mansoni during cultivation in vitro. Nature, Lond., 232, 653–654.CrossRefGoogle ScholarPubMed
Clegg, J. A., Smithers, S. R. and Terry, R. J., 1971b. Concomitant immunity and host antigens associated with schistosomiasis. Intl J. Parasit., 1, 43–49.CrossRefGoogle ScholarPubMed
Crompton, D. W. T., 1970. An Ecological Approach to Acanthocephalan Physiology. Cambridge University Press.Google Scholar
Crompton, D. W. T. and Lockwood, A. P. M. 1968. Studies on the absorption and metabolism of D-(U-14C) glucose by Polymorphus minutus (Acanthocephala) in vitro. J. Expl Biol., 48, 411–425.CrossRefGoogle ScholarPubMed
Cross, G. A. M., 1975. Identification, purification and properties of clone-specific glycoprotein antigens constituting the surface coat of Trypanosoma brucei. Parasitology, 71, 393–417.CrossRefGoogle ScholarPubMed
Cross, G. A. M., 1977. Isolation, structure and function of variant specific surface antigens. Ann. Belg. Soc. Trop. Med., 57, 389–399.Google ScholarPubMed
Daugherty, J. W., 1957a. Intermediary protein metabolism in helminths—IV. The active absorption of methionine by the cestode H. diminuta. Expl Parasit., 6, 60–67.CrossRefGoogle ScholarPubMed
Daugherty, J. W., 1957b. The active absorption of certain metabolites by helminths. Am. J. Trop. Med. Hyg., 6, 464–472.CrossRefGoogle ScholarPubMed
Davey, K. G., 1971. Moulting in a parasitic nematode, Phocanema decipiens—VI. The mode of action of insect juvenile hormone and farnesyl methyl ether. Intl J. Parasit., 1, 61–66.CrossRefGoogle Scholar
Davey, K. G. and Kan, S. P., 1968. Moulting in a parasitic nematode, Phocanema decipiens—IV. Ecdysis and its control. Can. J. Zool., 46, 893–898.CrossRefGoogle Scholar
Davey, K. G. and Sommerville, R. I., 1974. Moulting in a parasitic nematode, Phocanema decipiens—VII. The mode of action of the ecdysial hormone. Intl J. Parasit., 4, 241–259.CrossRefGoogle Scholar
Dike, S. C. and Read, C. P., 1971a. Tegumentary phosphohydrolases of Hymenolepis diminuta. J. Parasit., 57, 81–87.CrossRefGoogle ScholarPubMed
Dike, S. C. and Read, C. P., 1971b. Relation of tegumentary phosphohydrolases and sugar transport in Hymenolepis diminuta. J. Parasit., 57, 1251–1255.CrossRefGoogle ScholarPubMed
Doyle, J. J., 1977. Antigenic variation in salivarian trypanosomes. In Immunity to Blood Parasites of Animals and Man Eds. Miller, L. H., Pino, J. A. and McKelvey, J. J.. Pp. 31–64. Advances in Experimental Biology and Medicine. New York: Plenum Press.CrossRefGoogle Scholar
Edmonds, S. J., 1965. Some experiments on the nutrition of Moniliformis dubius Meyer (Acanthocephala). Parasitology, 55, 337–344.CrossRefGoogle ScholarPubMed
Erasmus, D. A., 1977. The host-parasite interface of trematodes. Adv. Parasit., 15, 201–242.CrossRefGoogle ScholarPubMed
Fisher, F. M. and Read, C. P., 1971. Transport of sugars in the tapeworm Calliobothrium verticillatum. Biol. Bull., Mar. Biol. Lab. Woods Hole 140, 46–62.CrossRefGoogle ScholarPubMed
Fujimoto, D. and Prokop, D. J., 1969. Protocollagen proline hydroxylase from Ascaris lumbricoides. J. Biol. Chem., 244, 205–210.CrossRefGoogle ScholarPubMed
Halton, D. W., 1978. Transtegumental absorption of L-alanine and L-leucine by a monogenean, Diclidophora merlangi. Parasitology, 76, 29–38.CrossRefGoogle ScholarPubMed
Halton, D. W. and Arme, C., 1971. In vitro technique for detecting tegument damage in Diclidophora merlangi: possible screening method for selection of undamaged tissues or organisms prior to physiological investigation. Expl Parasit., 30, 54–57.CrossRefGoogle ScholarPubMed
Hammond, R. A., 1967. The fine structure of the trunk and praesoma wall of Acanthocephalus ranae (Schrank, 1788) Luhe 1911. Parasitology, 57, 475–486.CrossRefGoogle ScholarPubMed
Hammond, R. A., 1968. Some observations on the role of the body wall of Acanthocephalus ranae in lipid uptake. J. Expl Biol., 48, 217–225.CrossRefGoogle ScholarPubMed
Haynes, W. D. G., 1970. Taenia crassiceps: Uptake of basic and aromatic amino acids and imino acids. Expl Parasit., 27, 256–264.CrossRefGoogle ScholarPubMed
Hockley, D. J., 1973. Ultrastructure of the tegument of Schistosoma. Adv. Parasit., 11, 233–305.CrossRefGoogle ScholarPubMed
Hockley, D. J., McLaren, D.J., Ward, B. J. and Nermut, M. V., 1975. A freeze-fracture study of the tegumental membrane of Schistosoma mansoni (Platyhelminthes: Trematoda). Tissue and Cell, 7, 485–496.CrossRefGoogle ScholarPubMed
Hyman, L. H., 1951. The Invertebrates III. Acanthocephala, Aschelminthes and Entoprocta. New York: McGrew-Hill.Google Scholar
Isseroff, H., Bonta, C. Y. and Levy, M. G., 1972. Monosaccharide absorption by Schistosoma mansoni. I. Kinetic characteristics. Comp. Biochem. Physiol., 43A, 849–858.CrossRefGoogle Scholar
Isseroff, H. and Read, C. P., 1969. Studies on membrane transport. VI. Absorption of amino acids by fascioliid trematodes. Comp. Biochem. Physiol., 30, 1153–1159.CrossRefGoogle ScholarPubMed
Isseroff, H. and Read, C. P., 1974. Studies on membrane transport. VIII. Absorption of monosaccharides by Fasciola hepatica. Comp. Biochem. Physiol., 47A, 141–152.CrossRefGoogle Scholar
Koie, M. and Bresciani, J., 1973. On the ultrastructure of the larva of Kronborgia amphipodicola Christensen and Kannenworff, 1964 (Turbellaria: Neorhabdocoela). Ophelia, 12, 171–203.CrossRefGoogle Scholar
Lee, D. L., 1966. The structure and composition of the helminth cuticle. Adv. Parasit., 4, 187–254. Editor Dawes, B..CrossRefGoogle ScholarPubMed
Lee, D. L., 1972. The structure of the helminth cuticle. Adv. Parasit., 10, 347–379.CrossRefGoogle ScholarPubMed
Lee, D. L. and Atkinson, H. J., 1976. Physiology of Nematodes, 2nd edn. London: Macmillan.CrossRefGoogle Scholar
Lumsden, R. D., 1966. Cytological studies on the absorptive surfaces of cestodes. I. The fine structure of the strobillar integument. Z. Parasitkde, 27, 355–382.Google Scholar
Lumsden, R. D., 1975. Surface ultrastructure and cytochemistry of parasitic helminths. Expl Parasit., 37, 267–339.CrossRefGoogle ScholarPubMed
Lumsden, R. D., Oaks, J. and Alworth, W., 1970. Cytological studies on the absorptive surfaces of cestodes. IV. Localization and cytochemical properties of membrane-fixed cation binding sites. J. Parasit., 56, 736–747.CrossRefGoogle ScholarPubMed
Lussier, P. E., Podesta, R. B. and Mettrick, D. F., 1979. Hymenolepis diminuta: Na+ -dependent and Na+ -independent components of neutral amino acid transport. J. Parasit., 65, 842–848.CrossRefGoogle Scholar
Lyons, K. M., 1968. A comparison of the adult epidermis in some monogeneans: the development of the outer layer of Entobdella soleae. Parasitology, 58, 14P–15P.Google Scholar
Lyons, K. M., 1970. The fine structure and function of the outer epidermis of two skin parasitic monogeneans, Entobdella soleae and Acanthocotyle elegans. Parasitology, 60, 39–52.CrossRefGoogle Scholar
Lyons, K. M., 1972. Ultrastructural observations on the epidermis of the polyopisthocotylean monogeneans, Rajonchocotyle emarginata and Plectanocotyle gurnardi. Z. Parasitkde, 40, 87–100.Google Scholar
Lyons, K. M., 1973. The epidermis and sense organs of the Monogenea and some related groups. Adv. Parasit., 11, 193–232.CrossRefGoogle ScholarPubMed
Marks, C. F., Thomason, I. J., and Castro, C. E., 1968. Dynamics of the permeation of nematodes by water, nematocides and other substances. Expl Parasit., 22, 321–337.CrossRefGoogle ScholarPubMed
McInnis, A. J. and Ridley, R. K., 1969. The molecular configuration of pyrimidines that causes allosteric activation of uracil transport in Hymenolepis diminuta. J. Parasit., 55, 1134–1140.CrossRefGoogle Scholar
McLaren, D. J., 1976a. Sense organs and their secretions. In The Organization of Nematodes, pp. 139–161. Ed. Croll, N. A.. New York: Academic Press.Google Scholar
McLaren, D. J., 1976b. Nematode sense organs. Adv. Parasit., 14, 195–267.CrossRefGoogle ScholarPubMed
McLaren, D. J. and Hockley, D. J., 1976. Schistosoma mansoni: the occurrence of microvilli on the surface of the tegument during transformation from cercaria to schistosomulum. Parasitology, 73, 169–187.CrossRefGoogle ScholarPubMed
Morris, G. P. and Halton, D. W., 1971. Electron microscope studies of Diclidophora merlangi (Monogenea: Polyopisthocotylea). II. Ultrastructure of the tegument. J. Parasit., 57, 49–61.CrossRefGoogle Scholar
Morris, G. P. and Threadgold, L. T., 1968. Ultrastructure of the tegument of adult Schistosoma mansoni. J. Parasit., 54, 15–27.CrossRefGoogle ScholarPubMed
Oaks, J. and Lumsden, R. D., 1971. Cytological studies on the absorptive surfaces of cestodes. V. Incorporation of carbohydrate containing macromolecules into tegument membranes. J. Parasit., 57, 1256–1268.CrossRefGoogle ScholarPubMed
Pappas, P. W. and Freeman, B. A., 1975. Sodium dependent glucose transport in the mouse bile duct tapeworm, Hymenolepis microstoma. J. Parasit., 61, 434–439.CrossRefGoogle Scholar
Pappas, P. W. and Read, C. P., 1972a. Sodium and glucose fluxes across the brush border of a flatworm (Calliobothrium verticillatum, Cestoda). J. Comp. Physiol., 81, 215–228.CrossRefGoogle Scholar
Pappas, P. W. and Read, C. P., 1972b. Thiamine uptake by Hymenolepis diminuta. J. Parasit., 58, 235–239.CrossRefGoogle ScholarPubMed
Pappas, P. W. and Read, C. P., 1972c. The absorption of pyridoxine and riboflavin by Hymenolepis diminuta. J. Parasit., 58, 417–421.CrossRefGoogle ScholarPubMed
Pappas, P. W. and Read, C. P., 1973. Permeability and membrane transport in the larva of Taenia crassiceps. Parasitology, 66, 33–42.CrossRefGoogle ScholarPubMed
Pappas, P. W. and Read, C. P., 1974. Relation of nucleoside transport and surface phosphohydrolase activity in Hymenolepis diminuta. J. Parasit., 60, 447–452.CrossRefGoogle ScholarPubMed
Pappas, P. W. and Read, C. P., 1975. Membrane transport in helminth parasites: a review. Expl Parasit., 37, 469–530.CrossRefGoogle ScholarPubMed
Pappas, P. W., Uglem, G. L. and Read, C. P., 1973a. The influx of purines and pyrimidines across the brush border of Hymenolepis diminuta. Parasitology, 66, 525–538.CrossRefGoogle ScholarPubMed
Pappas, P. W., Uglem, G. L. and Read, C. P., 1973b. Ribonuclease activity associated with intact Hymenolepis diminuta. J. Parasit., 59, 824–828.CrossRefGoogle ScholarPubMed
Pappas, P. W., Uglem, G. L. and Read, C. P., 1973c. Taenia crassiceps: absorption of hexoses and partial characterization of Na+-dependent glucose absorption by larvae. Expl Parasit., 33, 127–137.CrossRefGoogle ScholarPubMed
Pappas, P. W., Uglem, G. L. and Read, C. P., 1974. Anion and cation requirements for glucose and methionine accumulation in Hymenolepis diminuta (Cestoda). Biol. Bull. Mar. Biol. Lab. Woods Hole, 146, 56–66.CrossRefGoogle ScholarPubMed
Phifer, K. O., 1960a. Permeation and membrane transport in animal parasites: the absorption of glucose by Hymenolepis diminuta. J. Parasit., 46, 51–62.CrossRefGoogle ScholarPubMed
Phifer, K. O., 1960b. Permeation and membrane transport in animal parasites: further observation on the uptake of glucose by Hymenolepis diminuta. J. Parasit., 46, 137–144.CrossRefGoogle ScholarPubMed
Phifer, K. O., 1960c. Permeation and membrane transport in animal parasites: on the mechanism of glucose uptake by Hymenolepis diminuta. J. Parasit., 46, 145–153.CrossRefGoogle ScholarPubMed
Pittman, R. G. and Fisher, F. M., 1972. The membrane transport of glycerol by Hymenolepis diminuta. J. Parasit., 58, 742–749.CrossRefGoogle ScholarPubMed
Podesta, R. B., Stallard, H. E., Evans, W. S., Lussier, P. E., Jackson, D. J. and Mettrick, D. F., 1977. Hymenokpis diminuta: determination of unidirectional uptake rates for nonelectrolytes across the surface “epithelial” membrane. Expl Parasit., 42, 300–317.CrossRefGoogle ScholarPubMed
Read, C. P., 1961. Competition between sugars in their absorption by cestodes. J. Parasit., 47, 1015–1016.CrossRefGoogle Scholar
Read, C. P., 1967. Carbohydrate metabolism in Hymenolepis (cestoda). J. Parasit., 53, 1023–1029.CrossRefGoogle ScholarPubMed
Read, C. P., 1973. Contact digestion in tapeworms. J. Parasit., 59, 672–677.CrossRefGoogle ScholarPubMed
Riding, I., 1970. Microvilli on the outside of a nematode. Nature, Lond., 226, 179–180.CrossRefGoogle ScholarPubMed
Rogers, W. P., 1973. Juvenile and moulting hormone from nematodes. Parasitology, 67, 105–113.CrossRefGoogle Scholar
Rothman, A. H., 1959. The physiology of tapeworms correlated to structures seen with the electron microscope. J. Parasit., 45 (Suppl.), 28.Google Scholar
Rothman, A. H., 1963. Electron microscopy studies of tapeworms: the surface structures of Hymenolepis diminuta (Rudolphi, 1819). Trans. Am. Microsc. Soc., 82, 22–30.CrossRefGoogle Scholar
Rothman, A. H., 1966. Ultrastructural studies of enzymatic activity in the cestode cuticle. Expl Parasit., 19, 332–338.CrossRefGoogle Scholar
Rothman, A. H., 1967. Ultrastructural enzyme localization in the surface of Moniliformis dubius (Acanthocephala). Expl Parasit., 21, 42–46.CrossRefGoogle ScholarPubMed
Rothman, A. H., 1968. Enzyme localization and colloid transport in Haematoloechus medioplexus. J. Parasit., 54, 286–294.CrossRefGoogle ScholarPubMed
Rothman, A. H. and Fisher, F. M., 1964. Permeation of amino acids in Moniliformis and Macranthorhynchus (Acanthocephala). J. Parasit., 50, 410–414.CrossRefGoogle Scholar
Rutherford, T. and Webster, J., 1974. Transcuticular uptake of nutrients by the nematode Mermis nigrescens from the haemocoel of the desert locust. J. Parasit., 60, 804–808.CrossRefGoogle Scholar
Rutherford, T. A., Webster, J. M. and Barlow, J. S., 1977. Physiology of nutrient uptake by the entomophilic nematode Mermis nigrescens (Mermithidae). Can. J. Zool., 55, 1773–1781.CrossRefGoogle Scholar
Rybicka, K., 1973. Ultrastructure of the embryonic syncytial epithelium in a cestode, Hymenokpis diminuta. Parasitology, 66, 9–18.CrossRefGoogle Scholar
Sang, J. H., 1938. The antiproteolytic enzyme of Ascaris lumbricoides var. suis. Parasitology, 30, 141–155.CrossRefGoogle Scholar
Sher, A., Hall, B. F. and Vadas, M. A., 1978. Acquisition of murine major histocompatibility complex gene products by schistosomula of Schistosoma mansoni. J. Expl Med., 148, 46–57.CrossRefGoogle ScholarPubMed
Smithers, S. R., and Terry, R. J., 1969. The immunology of schistosomiasis. Adv. Parasit., 7, 41–93.CrossRefGoogle ScholarPubMed
Smithers, S. R., and Terry, R. J., 1976. The immunology of schistosomiasis. Adv. Parasit., 14, 399–422.CrossRefGoogle ScholarPubMed
Smithers, S. R., Terry, R. J. and Hockley, D. J., 1969. Host antigens in schistosomiasis. Proc. Roy. Soc. B, 171, 483–494.Google ScholarPubMed
Smyth, J. D., 1969. The Physiology of Cestodes. Edinburgh: Oliver and Boyd.Google Scholar
Smyth, J. D., 1972. Changes in the digestive-absorptive surface of cestodes during larval-adult differentiation. Symp. Brit. Soc. Parasit., 10, 41–70.Google Scholar
Smyth, J. D., 1976. Introduction to Animal Parasitology, 2nd edn. London: Hodder and Stoughton.Google Scholar
Taylor, E. W. and Thomas, J. N., 1968. Membrane (contact) digestion in three species of tapeworm Hymenolepis diminuta, Hymenolepis microstoma and Moniezia expansa. Parasitology, 58, 535–546.CrossRefGoogle ScholarPubMed
Threadgold, L. T., 1963. The tegument and associated structures of Fasciola hepatica. Q. J. Microsc. Soc., 104, 505–512.Google Scholar
Ubelaker, J. E., Allison, V. F. and Specian, R. D., 1973. Surface topography of Hymenolepis diminuta by scanning electron microscopy. J. Parasit., 59, 667–671.CrossRefGoogle ScholarPubMed
Uglem, G. L. and Read, C. P., 1973. Moniliformis dubius: uptake of leucine and alanine by adults. Expl Parasit., 34, 148–153.CrossRefGoogle ScholarPubMed
Uglem, G. L., Pappas, P. W. and Read, C. P., 1974. Na+-dependent and Na+-independent glycerol fluxes in Hymenolepis diminuta (Cestoda). J. Comp. Physiol., 93, 157–171.CrossRefGoogle Scholar
Ugolev, A. M., 1965. Membrane (contact) digestion. Physiol. Rev., 45, 555–595.CrossRefGoogle ScholarPubMed
Vickerman, K., 1978. Antigenic variation in trypanosomes. Nature, Lond., 273, 613–617.CrossRefGoogle ScholarPubMed
Von Brand, T., 1979. Biochemistry and Physiology of Endoparasites. Amsterdam: Elsevier-North Holland.Google Scholar
Wheater, P. R. and Wilson, R. A., 1976. The tegument of Schistosoma mansoni; a histochemical investigation. Parasitology, 72, 99–109.CrossRefGoogle ScholarPubMed
Wilson, R. A. and Barnes, P. E., 1974a. The tegument of Schistosoma mansoni: observations on the formation, structure and composition of cytoplasmic inclusions in relation to tegument function. Parasitology, 68, 239–258.CrossRefGoogle ScholarPubMed
Wilson, R. A. and Barnes, P. E., 1974b. An in vitro investigation of dynamic processes occurring in the schistosome tegument, using compounds known to disrupt secretory processes. Parasitology, 68, 259–270.CrossRefGoogle Scholar
Wilson, R. A. and Barnes, P. E., 1977. The formation and the turnover of the membranocalyx on the tegument of Schistosoma mansoni. Parasitology, 14, 61–71.CrossRefGoogle Scholar
Wright, R. D. and Lumsden, R. D., 1968. Ultrastructural and histochemical properties of the acanthocephalan epicuticle. J. Parasit., 54, 1111–1123.CrossRefGoogle Scholar
Wright, R. D. and Lumsden, R. D., 1969. Ultrastructure of the tegumentary pore canal system of the acanthocephalan Moniliformis dubius. J. Parasit., 55, 993–1003.CrossRefGoogle Scholar
Wright, R. W. and Isseroff, H., 1973. Further studies on the absorption of acetate by Fasciola hepatica. Comp. Biochem. Physiol., 45B, 95–99.Google Scholar