Location of the viral tegument. A viral tegument or tegument, more commonly known as a viral matrix, is a cluster of proteins that lines the space between the envelope and nucleocapsid of all herpesviruses. The tegument generally contains proteins that aid in viral DNA replication and evasion of the immune response, typically with inhibition of signalling in the immune system and activation of interferons. The tegument is usually released shortly after infection into the cytoplasm.
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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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This granuloma formation induces chronic inflammation. In response to infection, the hosts' antibodies bind to the tegument of the schistosome. But they are quickly removed the tegument itself is shed every few hours. The schistosome can also take on host proteins.
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Cambridge University Press, UK, pp. 192-297. The external surface of tegument is associated with unique defining structures in cestodes and trematodes. In cestodes the tegument is further covered with highly specialized microvilli, called "microtriches", projecting from the outer limiting membrane of the tegument. These microtriches are fine hair-like filaments distributed throughout the surface of the body, and give the body surface a smooth and silky appearance.
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Entobdella soleae utilizes suction through a posterior disc-shaped haptor to achieve semi-permanent attachment to the sole's skin. E. soleae demonstrate host-specific behavior by attaching to the sole epidermis by the presence of sole mucous cells. The characteristic of the pad tegument might demonstrate a possible role in detachment of the parasite to the host. These features include an isolated tegument and the microvillus surface network of the pad tegument.
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Since cestodes are devoid of any digestive and excretory systems, the tegument with its microtriches is the principal site of absorption and secretion. In fact the tegument highly resembles the gut of animals turned inside out.Smyth JD, McManus DP (1989). The Physiology and Biochemistry of Cestodes.
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Since cestodes are devoid of any digestive and excretory systems, the tegument with its microtriches constitute the principal site of absorption of nutrients and elimination of waste materials. In fact the tegument highly resembles the gut of animals turned inside out.Smyth JD, McManus DP (1989). The Physiology and Biochemistry of Cestodes.
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The tegument proteins are involved in nucleic acid metabolism, DNA synthesis and processing of proteins. The proteins in the tegument are thymidine kinase, thymidylate synthetase, dUTPase, ribonuclease reductase, DNA polymerase, DNA helicase, DNA Primase and Protein Kinases.Knipe, D.M., Howley, P.M., Cohen, J.I. and Knipe, P.D.D.M. (2013) Fields virology. 6th edn.
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The biosynthesis of prunasin occurs in the tegument, then transported to other tissues for conversion to amygdalin or degraded.
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The fine structure of tegument is essentially the same in both the cestodes and trematodes. A typical tegument is 7-16 μm thick, with distinct layers. It is a syncytium consisting of multinucleated tissues with no distinct cell boundaries. The outer zone of the syncytium, called the "distal cytoplasm," is lined with a plasma membrane.
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The fine structure of tegument is essentially the same in both the cestodes and trematodes. A typical tegument is 7-16 μm thick, with distinct layers. It is a syncytium consisting of multinucleated tissues with no distinct cell boundaries. The outer zone of the syncytium, called the "distal cytoplasm," is lined with a plasma membrane.
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It is an amphistome worm such that the ventral sucker is close to the posterior end. The body covering, called a tegument, is smooth in appearance, but contains a fine structure in a series of concentric folds bearing numerous tightly packed tubercles. Ventral surface contains a specialised region of the tegument. Ciliated and non-ciliated papillae are arranged around the oral sucker.
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Based on the similar tegument integrity of M. temperatus, in comparison with other anthelmintics, Praziquantel (PZQ) may be used as treatment to combat infection.
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Characteristic features of the Digenea include a syncytial tegument; that is, a tegument where the junctions between cells are broken down and a single continuous cytoplasm surrounds the entire animal. A similar tegument is found in other members of the Neodermata; a group of platyhelminths comprising the Digenea, Aspidogastrea, Monogenea and Cestoda. Digeneans possess a vermiform, unsegmented body-plan and have a solid parenchyma with no body cavity (coelom) as in all platyhelminths. Anterior sucker of Overstreetia cribbi a zoogonid digenean There are typically two suckers, an anterior oral sucker surrounding the mouth, and a ventral sucker sometimes termed the acetabulum, on the ventral surface.
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The rest of the fluke is covered in microvilli that are used to anchor it to the inside of the cloaca. Leucochloridium variae tegument is considered finely spined.
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The large tegument protein UL36 domain is important in the regulation of the viral cycle of Human Herpes Virus 1 (HHV-1), including transporting the viral capsid to the nuclear pore complex, and linking the inner and outer viral tegument capsids together. Lastly, the WH2 domain, WASP-homology domain 2, is approximately 18 amino acids long, and serves as an actin binding domain. WH2 binds actin monomers enabling the production of actin filaments.
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Adult and larval worms migrate through the host's blood circulation avoiding the host's immune system. The worms have many tools that help in this evasion, including the tegument, antioxidant proteins, and defenses against host membrane attack complex (MAC). The tegument coats the worm and acts as a physical barrier to host antibodies and complement. Host immune defenses are capable of producing superoxide, but these are counterattacked by antioxidant proteins produced by the parasite.
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The blade may be hollow or solid depending on the species. The base is connected to the underlying cytoplasm. Rostellum is innervated by a single bilateral pair of ganglia, which provide motor innervation of the anterior canal, and the circular muscles of the rostellar capsule; this connection controls the protrusion and retraction movements. The tegument lining the anterior canal and covering the apical rostellum is syncytial and continuous with the tegument of the scolex proper.
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T. saginata does not have a digestive system, mouth, anus, or digestive tract. It derives nutrients from the host through its tegument, as the tegument is completely covered with absorptive hair-like microtriches. It is also an acoelomate, having no body cavity. The inside of each mature proglottid is filled with muscular layers and complete male and female reproductive systems, including the tubular unbranched uterus, ovary, genital pore, testes, and vitelline gland.
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The surface of the adhesive pads of E. soleae is encompassed by tegument that contains perforations of numerous rod-carrying ducts through pepper-pot apertures and ducts of spheroidal secretory bodies. Rods are distributed uniformly and intensely electron-dense within their ducts. Spheroidal secretory bodies are both tightly packed and have less electron density than rods. Moreover, the tegument on the surface of the parasite is isolated from the general tegumentary syncytium by a cell boundary.
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Shared characteristics of the group are a large ventral disc with a large number of small alveoli ("suckerlets") or a row of suckers and a tegument with short protrusions, so- called "microtubercles".
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Adult schistosomes share all the fundamental features of the digenea. They have a basic bilateral symmetry, oral and ventral suckers, a body covering of a syncytial tegument, a blind-ending digestive system consisting of mouth, esophagus and bifurcated caeca; the area between the tegument and alimentary canal filled with a loose network of mesoderm cells, and an excretory or osmoregulatory system based on flame cells. Adult worms tend to be long and use globins from their hosts' hemoglobin for their own circulatory system.
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The tegument thickness increase, and the epidermis transforms from a transparent to opaque appearance. At 2 cm in length, the coloration fades to a brown that is characteristic of an adult brown sea cucumber.
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The body is pear-shaped and measures 0.24 mm in length and 0.1 mm in width. Its tegument is fully covered with spine. A conspicuous oral sucker is at the tip of the body.
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Tegumental contents are released into the cytoplasm upon entrance into the cell upon which many tegumental proteins become active. The tegument may also aid in insertion of the viral genome into host cell cytoplasm or nucleus.
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DEV has similar morphology to other Herpesvirales viruses. Common elements of herpviruses include a "DNA core, icosahedral capsid, tegument, and envelope." The nucleocapsid of HPV-1 is 75 micrometers wide and the envelope diameter is 181 micrometers.
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Their lipid envelope encloses the 100 nm nucleocapsid of 162 hexameric and pentameric capsomeres arranged in an icosahedral form. Its DNA is a single, linear, double-stranded molecule, 125,000 nt long. The capsid is surrounded by loosely associated proteins known collectively as the tegument; many of these proteins play critical roles in initiating the process of virus reproduction in the infected cell. The tegument is in turn covered by a lipid envelope studded with glycoproteins that are displayed on the exterior of the virion, each approximately 8 nm long.
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After the introduction of the viral particle, unpacking of the contents (viral proteins in the tegument and the viral genome via some form of nucleic acid) occurs as preparation of the next stage of viral infection: viral replication.
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Cestodes have no digestive tract, and instead, they absorb nutrients along their tegument, which contains microvilli and glycocalyxes. The microvilli are used to absorb nutrients. The glycocalyx is a fuzzy coat that absorbs host enzymes and inhibits host proteases.
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It is typically an amphistome with the ventral sucker close to the posterior end. The body is bilaterally symmetrical and is acoelomate. It is dorsoventrally flatted, with a unique pyramidal shape. The body is covered by a tegument bearing numerous tubercles.
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The tegument also contains secretory bodies. A 4-5 µm layer of cement bonds the adhesive pad of E. soleae via tegumental microvilli and the sole's epidermal furrows during attachment. Rod-shaped secretory bodies are the major substance of the cement.
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Burton, Bogitsh. Cytochemical and Ultrastructural Observations on the Tegument of the Trematode Megalodiscus temperatus. Department of Biology, Vanderbilt University 1968. 87(4):477-286. Nollen, P. and Pyne, J. Observations on Spermatogenesis and Inseminative Behavior of Megalodiscus temperatus Adults in Frogs.
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All cestodes lack digestive and excretory systems, therefore, the tegument with its microtriches constitute the principal site of absorption of nutrients and elimination of waste materials. Moreover, the microtriches are the primary structures for host-parasite interface, and are metabolically active performing all the vital activities such as sensory, absorptive and secretory functions. Thus their structural significance is clearly to amplify the total surface area of the tegument. The surface carbohydrate complex called glycocalyx is responsible for inhibition of the host digestive enzymes, absorption of cations and bile salts, and enhancement of the host amylase activity.
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The immune system responds to eggs in liver causing hypersensitivity; an immune response is necessary to prevent damage to hepatocytes. The hosts' antibodies bind to the tegument of the Schistosome but not for long since the tegument is shed every few hours. The schistosome can also take on host proteins. Schistomiasis can be divided into three phases; Within the haematobium group S. bovis and S. curassoni appear to be closely related : (1) the migratory phase lasting from penetration to maturity,(2) the acute phase which occurs when the schistosomes begin producing eggs, and (3) the chronic phase which occurs mainly in endemic areas.
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II. Muscidae acalypterae, Scatophagidae. Paris: Éditions Faune de France 28 Bibliotheque Virtuelle Numerique pdf Male Arista with 8-10 hairs. Abdomen: tergite IV with 8-16 marginal macrochaetes : Female tegument shining black; chaetotaxy normal. Wing: transverse MA2c slightly angled; 2 subequal costal spines.
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Cestodes have no gut or mouth and absorb nutrients from the host's alimentary tract through their specialised neodermal cuticle, or tegument, through which gas exchange also takes place. The tegument also protects the parasite from the host's digestive enzymes and allows it to transfer molecules back to the host. The body form of adult eucestodes is simple, with a scolex, or grasping head, adapted for attachment to the definitive host, a short neck, and a strobila, or segmented trunk formed of proglottids, which makes up the worm's body. Members of the subclass Cestodaria, the Amphilinidea and Gyrocotylidea, are wormlike but not divided into proglottids.
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It is entirely covered by a tegument. The body is white in colour and consists of three portions: scolex, neck, and strobila. The scolex has four suckers, but they have no hooks. Lack of hooks and a rostellum is an identifying feature from other Taenia species.
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Udonellids are symbiotic to fishes, on which body they remain attached using a sucker. The sucker is a membranous extension of the posterior end. It has an indistinct stalk and the anterior surface is lined with microvilli. Some portion of the tegument has interconnected surface extension appearing as loops.
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A large number of important enzymes has been detected in the tegument. Glutathione S-transferase, ATP diphosphorylase, alkaline and acid phosphatases, β-glucuronidase, amino peptidase, acetylcholine esterase, phosphofructokinase, glucose transporters, serine hydrolases and several glycolytic enzymes have been detected with their biological roles.Mansour TE, mansour JM (2002). Chemotherapeutic Targets in Parasites.
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In addition, they act as sensory organs for detecting the surrounding environmental cues. The capacity of the tegument to absorb exogenous materials is proportional to the number and extent of pits or microtriches and the number of mitochondria in the distal cytoplasm.Smyth JD, Halton DW (1983). The Physiology of Trematodes.
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PDF and cestodes. Blood parasites include members of the Apicomplexa such as Schellackia occidentalis and species of Lankesterella. The tegument is infected by several species of mites. Parasites can alter alter metabolism and reproductive success of side-blotched lizards due to body temperature changes in response to fighting the infection.
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The tail is highly flexible and its beating propels the ceracaria in water. It is about 0.2 mm long and 47 μm wide, somewhat loosely attached to the main body. The body is pear-shaped and measures 0.24 mm in length and 0.1 mm in width. Its tegument is fully covered with spine.
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Paragonimus kellicotti parasites have dorsoventrally flattened, brown, oval-shaped bodies. They are soft-bodied parasites with oral and ventral suckers that are relatively similar in size. They use their ventral suckers to attach to a host. Their tegument is covered with spines, which is a characteristic that sets them apart among other Paragonimus species.
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Stichopus horrens is a variable, grey to green/black sea cucumber from the Indo-Pacific. It is often variegated with dark patches. It is a medium-sized species (to 30 cm) with a smooth tegument but large and irregular papillae. The big tubercles and irregular body form give an "irregular, soft and almost repulsive" appearance .
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This is a specific body type of cecaria known as a gastrostome. The adults occur in the gut of marine and fresh-water fish. The metacercariae encyst in smaller fish, sometimes in the nervous system. These parasitic flatworms are dorso-ventrally flattened animals characterized by a bilaterally symmetrical body enclosed within a syncytial tegument.
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Praziquantel has been used to effectively treat paragonimiasis by separating the tegument. An effectively complete rate of cure may be expected after three days of treatment if there has not been too much permanent damage, such as from intracranial effects. Other medications can also be used such as bithionol, niclofan, and triclabendazole with high cure rates.
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The microtriches are fine cylindrical tubular filaments, with smooth rounded ends, and arranged in rows corresponding to the regular ridges of the tegument. Microtriches are documented to exhibit wide range of morphology in different species of tapeworms, and serve as an identifying character among the members of Eucestoda.Lumsden RD, Hildreth MB (1983). The fine structure of adult tapeworms.
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In addition, they act as sensory organs for detecting the surrounding environmental cues and primary target site of anthelmintic drugs. The capacity of the tegument to absorb exogenous materials is proportional to the number and extent of pits or microtriches and the number of mitochondria in the distal cytoplasm.Smyth JD, Halton DW (1983). The Physiology of Trematodes.
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Acanthocephalans do not have digestive tracts and absorb nutrients through the tegument, the external layer. The scolex of this worm has a cylindrical proboscis and a multitude of curved hooks. The main parts of the worm body are the proboscis, neck, and trunk. Because of horizontal markings on the worm, there is the appearance of segmentation.
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A. conchicola has a large ventral opisthaptor that extends most of its body's length, which is divided into sections called alveoli or loculi. It also possesses a longitudinal septum, a horizontal layer of muscle and connective tissue that separates the dorsal and ventral compartments of the body. The tegument is similar to that of other parasitic flatworms.
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The vagina includes a sclerotized part, which is a complex structure. The redescription by Kritsky, Bakenhaster & Adams in 2015 includes the following: Body dorsoventrally flattened. Tegument smooth, scales absent. Cephalic region broad, with two terminal and two bilateral poorly developed lobes, three bilateral pairs of head organs, pair of bilateral groups of cephalic-gland cells at level of pharynx.
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When viewed using scanning electron microscopy, it can be observed that the S. intercalatum's surface has a much lower amount of integumental elevations, or bosses, than S. mansoni. This feature is consistent with the tegument appearance of other terminally spined schistosomes.Kuntz RE (1977) Scanning electron microscopy of intergumental surfaces of Schistosoma intercalatum. J Parasitol 63: 401-406.
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The diameter of an HHV-6 virion is about 2000 Angstroms. The virion's outer portion consists of a lipid bilayer membrane that contains viral glycoproteins and is derived from that of the host. Below this membrane envelope is a tegument which surrounds an icosahedral capsid, composed of 162 capsomeres. The protective capsid of HHV-6 contains double stranded linear DNA.
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R. cesticillus is a small tapeworm measuring about in length, and in width. It is whitish in colour, highly elongated, dorso-ventrally flattened, and entirely covered with a tegument. The body consists of the head region called 'scolex', an unsegmented 'neck', and a highly segmented body proper called strobila. The strobila is composed of a chain of ribbon-like proglottids.
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Tegument is a term in helminthology for the outer body covering of members of the phylum Platyhelminthes. The name is derived from a Latin word tegumentum or tegere, meaning "to cover". It is characteristic of flatworms including the broad groups of tapeworms and flukes. Once considered to be a non-living component, it is now known to be a dynamic cellular structure.
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Academic Press, pp. 5-8. In trematodes the tegument contains a number of invaginations or surface pits, and is externally lined with minute tubercles among which are dispersed bristle-like projections called "spines". Spines are embedded in the basal lamina and the tip is finely pointed to the external surface. They are made up of paracrystalline arrays of actin filaments.
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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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Biospeedotrema parajolliveti is a species of trematodes inhabiting hydrothermal vent fishes (particularly Thermichthys hollisi) in the south eastern Pacific Ocean. It can be distinguished from its family by its symmetrical testicular configuration; its uterus passing between the testes. Furthermore, it differs from Biospeedotrema jolliveti by being squat; wider than long; its tegument being wrinkled; its lobate testes, and the caeca "only just reach to the testes".
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The parasitic flatworms, which includes tapeworms, flukes and monogeneans, evolved from a single major lineage of free-living flatworm ancestors. The switch from a free-living to a parasitic lifestyle in the common ancestor of the parasitic flatworms involved a fundamental change in their tegument, which is found in all contemporary groups. Early-branching tapeworm groups are found in bony (e.g. teleost) and cartilaginous fishes (e.g.
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These genes encode a variety of proteins involved in forming the capsid, tegument and envelope of the virus, as well as controlling the replication and infectivity of the virus. These genes and their functions are summarized in the table below. The genomes of HSV-1 and HSV-2 are complex and contain two unique regions called the long unique region (UL) and the short unique region (US).
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Its body is covered by tegument and the worm is divided into a scolex, a short neck, and three to six proglottids. Its body shape is ribbon-like. In humans, this causes a disease called echinococcosis. The three types of echinococcosis are cystic echinococcosis caused by E. granulosus, alveolar echinococcosis caused by E. multilocularis, and polycystic echinococcosis caused by E. vogeli or E. oligarthrus.
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Female specimens bear megaspores that are found in large numbers in the upper part of the stem, with the appearance of pinnate leaves that enclose the ovules, in clumps of 4. The seeds are oblong, 50–60 mm long, coated with an orange-brown tegument when ripe. The megasporophyll is a defining feature, with laminae which de Louriero described as "laciniate" (fringed with lateral narrow pointed lobes).
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The viruses in this family are non occluded, enveloped, rod-shaped virions measuring 500–1,000 nanometers (nm) in length and 50–80 nm in diameter . The virions contain a thin, dense central nucleocapsid that encases the DNA-protein core. The nucleocapsid core is surrounded by an amorphous proteinaceous tegument layer. The outer surface of the virions is studded with helical polymeric structure composed of virally- encoded and host-derived protein dimers.
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The body surface of the acanthocephala is peculiar. Externally, the skin has a thin tegument covering the epidermis, which consists of a syncytium with no cell walls. The syncytium is traversed by a series of branching tubules containing fluid and is controlled by a few wandering, amoeboid nuclei. Inside the syncytium is an irregular layer of circular muscle fibres, and within this again some rather scattered longitudinal fibres; there is no endothelium.
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The tegument bears a large number of small tubercules. The suckers have small thorns in their inner part as well as in the buttons around them. The male genital apparatus is composed of 6 to 9 testicular masses, situated dorsally. There is one deferent canal beginning at each testicle, which is connected to a single deferent that dilates into a reservatory, the seminal vesicle, located at the beginning of the gynaecophoric canal.
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Schistosomes have four superoxide dismutases, and levels of these proteins increase as the schistosome grows. Antioxidant pathways were first recognised as a chokepoints for schistosomes, and later extended to other trematodes and cestodes. Targeting of this pathway with different inhibitors of the central antioxidant enzyme thioredoxin glutathione reductase (TGR) results in reduced viability of worms. Decay accelerating factor (DAF) protein is present on the parasite tegument and protects host cells by blocking formation of MAC.
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Microtriches (singular microtrix) are the highly specialized microvilli covering the entire surface of the tegument of cestodes. They are fine hair- like filaments distributed throughout the surface of the body, both unique to and ubiquitous among cestodes, giving the body surface a smooth and silky appearance. They are different from typical microvilli in that they contain conspicuous electron dense materials at the tip. Due to their morphological variation they make up unique defining structures in cestodes.
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Macacine alphaherpesvirus 1 is approximately 200 nm in diameter and has a structure almost identical to that of HSV1 and HSV2. It has an icosahedral capsid (T=16) which consists of 150 hexons and 12 pentons, formed from 6 proteins. The envelope is loose around the viral capsid and contains at least 10 glycoproteins which are critical for adsorption and penetration into host cells. The tegument containing at least 14 viral proteins lies between the capsid and the envelope.
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This assembly complex will now bud out of the cell as new mature viruses. Viral matrix proteins, like many other viral proteins, can exert different functions during the course of the infection. For example, in rhabdoviruses, binding of M proteins to nucleocapsids is accountable for the formation of its “bullet” shaped virions. In herpesviruses, the viral matrix is usually called viral tegument and contains many proteins involved in viral entry, early gene expression and immune evasion.
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It has an elongate body, with a length of about 670 µm and a width of about 290 µm. It possesses a scaly tegument, 3 pairs of head organs and 2 pairs of eyespots. The haptor is differentiated from its body, being less wide (about 220 µm), and exhibits 2 round squamodiscs, 2 pairs of lateral hamuli, 3 bars and 14 hooklets. There is a groove visible on the ventral side of its flat ventral bar.
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Maritrema subdolum has 2 layers: an inner transparent and an outer light-refractory layer. The latter encloses either the entire body or only the anterior end. It lies in a pouch formed by an invagination of the tegument of the oral sucker and its posterior end is surrounded in the syncytial layer at the base of the pouch in close contact with the basal membrane. The anterior end is limited only by an external plasmatic membrane.
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Oxamniquine acts mainly on male worms, but also induces small changes on a small proportion of females. Like praziquantel, it promotes more severe damage of the dorsal tegument than of the ventral surface. The drug causes the male worms to shift from the mesenteric circulation to the liver, where the cellular host response causes its final elimination. The changes caused in the females are reversible and are due primarily to the discontinued male stimulation rather than the direct effect of oxamniquine.
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Tegumental angiomyxoma-neurothekeoma (TAN syndrome) is a syndrome, an acronym, and eponym proposed by Malaysian ophthalmologist of Chinese Descent, Tan Aik Kah (b. June 1975). Angiomyxomas are associated with LAMB (lentigines, atrial myxomas, muco-cutaneous myxomas, and blue naevi) syndrome, NAME (nevi, atrial myxoma, myxoid neurofibromas, and ephelides) syndrome and Carney syndrome (atrial, cutaneous and mammary myxomas, lentigines, blue naevi, endocrine disorders and testicular tumours). TAN syndrome is characterized by multiple superficial angiomyxoma and neurothekeoma confined only to the skin (tegument).
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The life cycle of a virus typically consists of its entry, replication, and eventual shedding. Upon initial infection, herpes simplex virus (HSV) causes acute lytic infection of epithelial cells, usually at either genital or orolabial mucus membranes. During this initial infection, the virus also infects local nerve cells, such as in the trigeminal ganglion in the case of HSV-1. HSV enters the cell when its membrane fuses with the cellular membrane, releasing tegument proteins and the naked capsid into the cytoplasm.
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Digenea (Gr. Dis – double, Genos – race) is a class of trematodes in the Platyhelminthes phylum, consisting of parasitic flatworms (known as flukes) with a syncytial tegument and, usually, two suckers, one ventral and one oral. Adults commonly live within the digestive tract, but occur throughout the organ systems of all classes of vertebrates. Once thought to be related to the Monogenea, it is now recognised that they are closest to the Aspidogastrea and that the Monogenea are more closely allied with the Cestoda.
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The body of an adult Raillietina is a typical tapeworm structure, composed of a series of ribbon-like body segments, gradually enlarging from the anterior end towards the posterior. It is whitish in colour, highly elongated, dorso-ventrally flat, and entirely covered with a tegument. The entire body is divisible into 3 parts, namely the head region called scolex, followed by an unsegmented neck or growth region, and then by highly segmented body proper called strobila.Li, M., Li, H, & Yan, B. (2009).
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The generic name (Greek: para meaning "similar" [to Amphistoma], amphi meaning "on both sides", and stoma for "mouth") is given due to the presence of an anterior oral sucker and a posterior larger ventral sucker in adult worms. The body is minute, measuring less than a centimetre. The body is covered with a highly folded tegument, which in turn is provided with sensory papillae. Paramphistomum are all hermaphrodite, having both male and female reproductive systems in the posterior region of the body.
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R. tetragona is the largest among avian tapeworms, measuring up to 30 cm in length and 1–1.5 cm in breadth. It is whitish in colour, highly elongated, dorso-ventrally flattened, and entirely covered with a tegument. The body is divisible into the head region called 'scolex', followed by an unsegmented 'neck', and then by highly segmented body proper called strobila. The strobila is composed of a series of ribbon-like body segments called proglottids, gradually enlarging from the anterior end towards the posterior.
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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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Life-history stages of the trematode flatworm Fasciola hepatica from 1911 Encyclopædia Britannica Trematodes are parasitic flatworms of the class Trematoda, specifically parasitic flukes with two suckers: one ventral and the other oral. Trematodes are covered by a tegument, that protects the organism from the environment by providing secretory and absorptive functions. The life cycle of a typical trematode begins with an egg. Some trematode eggs hatch directly in the environment (water), while others are eaten and hatched within a host, typically a mollusc.
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The two drugs that have been well-described for the treatment of hymenolepiasis are praziquantel and niclosamide. Praziquantel, which is parasiticidal in a single dose for all the stages of the parasite, is the drug of choice because it acts very rapidly against H. nana. Although structurally unrelated to other anthelminthics, it kills both adult worms and larvae. In vitro, the drug produces vacuolization and disruption of the tegument in the neck of the worms, but not in more posterior portions of the strobila.
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The body of an adult R. echinobothrida is a characteristic tapeworm structure, composed of a series of ribbon-like body segments, gradually enlarging from the anterior end towards the posterior. It is whitish in colour, highly elongated, dorsoventrally flattened, and entirely covered with a tegument. The body can be as long as 25 cm, and generally 1–1.5 cm broad. The body is divisible into the head region called 'scolex', followed by an unsegmented 'neck', and then by highly segmented body proper called 'strobila'.
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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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Because amygdalin is responsible for the bitter almond taste, almond growers have selected genotypes which minimize the biosynthesis of amydgalin. The CYP enzymes responsible for generation of prunasin are conserved across Prunus species. There is a correlation between high concentration of prunasin in the vegetative regions of the plant and the sweetness of the almond, which is relevant to the almond agricultural industry. In almonds, the amygdalin biosynthetic genes are expressed at different levels in the tegument (mother tissue, or outer section) and cotyledon (kernel, or father tissue), and vary significantly during almond ontogeny.
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A larva develops in the egg and hatches through the operculum; the swimming larva is ciliated and called an oncomiracidium. The larva finds its host by swimming to it, first attaches to the skin and migrates to the gills, and eventually transforms itself into a young monogenean which is attached to the gill filament by its haptor. During transformation from larva to adult, the monogenean loses its cilia and produces a new tegument, a phenomenon which is considered a general characteristic of the parasitic Platyhelminthes or Neodermata.Ehlers, U. (1985).
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Flowers with the calyx tube are minute, the lobes lanceolate; corolla is between , pentagonal and yellow. Ovary is globose, glabrous or with a few minute trichomes at the apex; the style being between ; stigma capitate and green. The fruit is between in diameter, globose and green with a dark green stripe around it that may change to purple at maturity. Seeds are obovate, narrowly winged at the apex and acute at the base, pale brown, pubescent with hair-like outgrowths of the tegument cell radial walls, which give the surface a silky appearance.
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In addition, the proximal two chambers of the male copulatory organ of P. contubernalis have comparatively thin walls which frequently have collapsed or are absent. Pseudorhabdosynochus contubernalis is a member of the group of species of Pseudorhabdosynochus parasitizing groupers assigned to Mycteroperca and characterized by having a distally reflexed tube and a single chamber in the vaginal sclerite. The group includes P. kritskyi, P. capurroi, P. vascellum, P. contubernalis, P. hyphessometochus, and P. mycteropercae. P. contubernalis differs from all of these species by having a scaled tegument on the peduncle.
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Varied trematodes, from 1911 Encyclopædia Britannica Trematodes are flattened oval or worm-like animals, usually no more than a few centimetres in length, although species as small as are known. Their most distinctive external feature is the presence of two suckers, one close to the mouth, and the other on the underside of the animal. The body surface of trematodes comprises a tough syncitial tegument, which helps protect against digestive enzymes in those species that inhabit the gut of larger animals. It is also the surface of gas exchange; there are no respiratory organs.
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As adults, most digeneans possess a terminal or subterminal mouth, a muscular pharynx that provides the force for ingesting food, and a forked, blind digestive system consisting of two tubular sacs called caeca (sing. caecum). In some species the two gut caeca join posteriorly to make a ring-shaped gut or cyclocoel. In others the caeca may fuse with the body wall posteriorly to make one or more anuses, or with the excretory vesicle to form a uroproct. Digeneans are also capable of direct nutrient uptake through the tegument by pinocytosis and phagocytosis by the syncitium.
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All members of the order have a virion structure that consists of a DNA core surrounded by an icosahedral capsid composed of 12 pentavalent and 150 hexavalent capsomeres (T = 16). The capsid has a diameter of ~110 nanometers (nm) and is embedded in a proteinaceous matrix called the tegument, which in its turn is enclosed by a glycoprotein- containing lipid envelope with a diameter of about 200 nm. The DNA genome is linear and double stranded, with sizes in the range 125–290 kbp. The genome contains terminal and internal reiterated sequences, with their number and disposition varying depending on the different subclades.
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Although the excretion of nitrogenous waste occurs mostly through the tegument, trematodes do possess an excretory system, which is instead mainly concerned with osmoregulation. This consists of two or more protonephridia, with those on each side of the body opening into a collecting duct. The two collecting ducts typically meet up at a single bladder, opening to the exterior through one or two pores near the posterior end of the animal. The brain consists of a pair of ganglia in the head region, from which two or three pairs of nerve cords run down the length of the body.
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Microcotyle peprili has the general morphology of all species of Microcotyle, with an elongate fusiform body tapered toward the anterior end and the haptor-bearing region, provided with a thin and smooth tegument, comprising an anterior part which contains most organs and a posterior part called the haptor. The tapering haptor is 0.12 mm long, and bears about 175 clamps similar in shape, arranged as two rows, one on each side. The clamps of the haptor attach the animal to the gill of the fish. There are also two lateral muscular buccal suckers anterior to the pharynx at the anterior extremity.
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LOC101928193 may not follow a normal inheritance pattern or occur regularly in the genome as it has a scattered occurrence throughout evolutionarily related species. Furthermore, the similarity between orthologs of LOC101928193 is constant over time and is not higher in closely related taxonomic groups or lower in distantly related taxonomic groups. It is possible that LOC101928193 incorporates into the genome of different species through viral pathways as LOC101928193 has been found to have ligand binding sites for cyanobacteria proteins, like chlorophyll a. Orthologs of LOC101928193 have been found to contain UL36, which is a large tegument protein that functions in the viral cycle and is commonly found in human herpesvirus simplex virus 1.
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This mode of feeding could be unique in the animal kingdom: the particles, collected in a slime layer, are drawn through the intercellular gaps (cellular interstices) of the epitheloid by the fibre cells and then digested by phagocytosis ("cell-eating"). Such "collecting" of nutrient particles through an intact tegument is only possible because some "insulating" elements (specifically, a basal lamina under the epitheloid and certain types of cell-cell junctions) are not present in the Placozoa. Not all bacteria in the interior of Placozoa are digested as food: in the endoplasmic reticulum, an organelle of the fibre syncytium, bacteria are frequently found that appear to live in symbiosis with Trichoplax adhaerens. In particular it has been proposed that there is a rickettsial endosymbiont.
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A three-dimensional reconstruction and animation of a tail-like assembly on HSV-1 capsid 3D reconstruction of the HSV-1 capsid Herpes Simplex Virus 2 Animal herpes viruses all share some common properties. The structure of herpes viruses consists of a relatively large, double-stranded, linear DNA genome encased within an icosahedral protein cage called the capsid, which is wrapped in a lipid bilayer called the envelope. The envelope is joined to the capsid by means of a tegument. This complete particle is known as the virion. HSV-1 and HSV-2 each contain at least 74 genes (or open reading frames, ORFs) within their genomes, although speculation over gene crowding allows as many as 84 unique protein coding genes by 94 putative ORFs.
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KSHV is a herpesvirus, and is a large double-stranded DNA virus with a protein covering that packages its nucleic acids, called the capsid, which is then surrounded by an amorphous protein layer called the tegument, and finally enclosed in a lipid envelope derived in part from the cell membrane. KSHV has a genome which is approximately 165,000 nucleic acid bases in length. KSHV is a rhadinovirus, a Herpes genus remarkable since it has stolen numerous genes from host cells including in the case of KSHV genes that encode for complement-binding protein, IL-6, BCL-2, cyclin-D, a G protein-coupled receptor, interferon regulatory factor and Flice inhibitory protein (FLIP), as well as DNA synthesis proteins including dihydrofolate reductase, thymidine kinase, thymidylate synthetase, DNA polymerase and many others. While no other human tumor virus possesses these same genes, other tumor viruses target the same cellular pathways illustrating that at a basic level, all tumor viruses appear to attack the same cellular control pathways, so-called tumor suppressor pathways.
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They contain sets of muscles that are common to all Acanthocephala including a proboscis receptacle, a receptacle- surrounding muscle called a receptacle protrusor, retinacula (connective tissue that stabilizes tendons), a neck retractor, proboscis and receptacle retractors, circular and longitudinal musculature under the metasomal (trunk) tegument, and a single muscular layer beneath the proboscis wall. Two regions of musculature are considerably different in Apororhynchus compared to the other acanthocephalan orders: the proboscis receptacle and receptacle protrusor are both reorganized in Apororhynchus with the muscles subdivided into strands extending from the cerebral ganglion, or nerve bundle, to the proboscis wall. These two muscles suspend the cerebral ganglion but are not involved in the eversion of the proboscis. Additional anatomical features that can be used to distinguish this genus among other acanthocephalans include a cerebral ganglion located under the anterior wall of the proboscis, long and tubular lemnisci (bundles of sensory nerve fibers) that run along a central canal, the lack of any protonephrida (an organ which functions as a kidney), and the presence of eight pear-shaped cement glands used to temporarily close the posterior end of the female after copulation.
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