These proteins are usually formed within the late phase of the viral infectious cycle, after viral genes have been replicated. Much information regarding viral teguments has been gathered from studying Herpes simplex virus.
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Viral teguments can be symmetrically arranged via structural and scaffolding protein or can also be asymmetrically arranged, depending on the virus. Teguments are rarely haphazardly placed and usually involve scaffolding proteins in their formation around the nucleocapsid. Non-essential proteins included in the tegument may aid in immune response suppression, suppression of host mRNA transcription or suppression of intrinsic or cellular defenses. Essential proteins will include factors that help in trafficking of the viral capsid to the nucleus (for herpesviruses), recruiting host transcription or translation factors, or directly transcribing or translating viral genes.
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Teguments are generally in enveloped viruses which have nucleocapsids, as tegument proteins cannot be stored in an efficient fashion in capsid-only viruses. The best studied examples are the herpesvirus family, in which the tegument is most prominent.
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Bogitsh BJ, Carter CE, Oeltman TN (2005). Human Parasitology, 3rd Edition. Academic Press, pp. 177-179. The microtriches in cestodes, and pits and spines in trematodes increase the surface area of the teguments for enhanced absorption of nutrients.
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Praziquantel, a quinolone derivative. The effect of praziquantel on H. heterophyes causes deep lesions on their teguments, and when exposed to praziquantel over a longer period of time leads to even deeper lesions.Taraschewski, H., Mehlhorn, H., Bunnag, D., Andrews, P., & Thomas, H. (1986). Effects of praziquantel on human intestinal flukes (Fasciolopsis buski and Heterophyes heterophyes).
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In addition, they have pairs of large refractive vacuoles, which are found near the flame cells. They differ in structure and physiological phenotypes depending on its habitat. However, specimens found in herons were smooth, had thick teguments, and absorbed food (such as glucose) through facilitated diffusion. Along with a thick tegument, these flukes were also found to have bacteria on them.
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The teguments are soft or subcoriaceous. The striae of the cephalothorax and of the three last abdominal segments are very distinct; those of the anterior segments are scarcely or not at all distinct. The anterior and lateral borders of the cephalothorax are smooth. The eye eminence is relatively small; smooth or, rarely, provided with small, slightly distinct, tubercles; widely separated from the cephalic border.
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The tegument is the host-parasite interface, and metabolically active body covering performing all the vital activities such as protection, absorption and secretion. The glycocalyx is responsible for inhibition of the host digestive enzymes, absorption of cations and bile salts, and enhancement of the host amylase activity. The acidic glycosaminoglycans of the glycocalyx are specific for inhibiting a number of digestive enzymes of the host. The microtriches in cestodes, and pits and spines in trematodes increase the surface area of the teguments for enhanced absorption of nutrients.
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