National Repository of Grey Literature 8 records found  Search took 0.00 seconds. 
Functional morphology of schistosome miracidia
Svobodová, Kateřina ; Horák, Petr (advisor) ; Bulantová, Jana (referee)
Trematodes of the family Schistosomatidae are important pathogens invading various species of birds and mammals, including man. Miracidium is the first larval stage in the complex life cycle of these parasites. The fate of the parasite depends on the ability of the larva to find, recognize and penetrate into a suitable snail host. Miracidium locates its snail host actively. Miracidium respond to environmental cues and also by recognition of specific glycoproteins produced by snails to the water environment. Free-living miracidium has limited energy reserves, so it has to find and penetrate into a suitable host as quickly as possible. Cilia serve to fast movement in the aquatic environment. The surface of the miracidium is covered with flat ciliated epidermal plates arranged in four tiers. These plates are separated from each other by epidermal ridges. The anterior end of miracidia is cone-shaped and is called apical papilla. Apical papilla is a key tool for penetration and it contains openings of penetration glands. Miracidia display a variety of sensory receptors which help miracidium in orientation. However, there is not much known about miracidial receptor function. Miracidial morphology can serve as a suitable characteristic for schistosome species identification. The thesis summarizes the...
Ultrastructural interactions of larval bird schistosome Trichobilharzia regenti and immune cells of hosts nervous system
Krčmářová, Veronika ; Bulantová, Jana (advisor) ; Hodová, Iveta (referee)
Trichobilharzia regenti is a neurotropic fluke belonging to family Schistosomatidae. Larvae called schistosomula migrate in the definitive hosts (anseriform birds) throuth the central nervous system (CNS) to their final location in nasal mucosa, where they mature and lay eggs. In contrast with that, the infection of accidental mammalian hosts (including human), is often stopped already in the skin immediately after entering the host. However, some schistosomula are able to reach CNS of experimentally infected mice, and survive there temporarily. Reaction to the CNS infection of mice is usually provided by microglia, astrocytes or the other immune cells infiltrated from the hosts blood. Parasite protects itself against the host reaction with its tegument. It does not serve only as mechanical barrier, but also as main secretoric organ that is capable of active immune evasion. Changes within CNS of the vertebrate hosts, caused by migrating schistosomula of T. regenti, were already described by routine histological and immunohistochemical methods. Till now, there was a lack of informations about interactions of immune cells of the host and the tegument of the parasite on ultrastructural level. To fill this gap in knowledge, two different methods were used: (1) imunohistochemistry in light and electron...
Morphological and functional variability of secretory glands in cercariae of chosen trematode groups
Krčmářová, Veronika ; Bulantová, Jana (advisor) ; Mikeš, Libor (referee)
Trematodes are characterized by their complex life cycles that include definitive hosts and variable number of intermediate hosts. Transfer of the parasite from the first intermediate host to the other is usually realized by larval stage called cercaria. After finishing of their development within the first intermediate host, morphology and fate of these larval stages vary according to the way of infection of the next host. Some cercariae actively penetrate directly to their definitive hosts trough their body surface, other encystate in the outer environment where they wait in a form of metacercariae to be ingested by definitive host. Both of these ways can be combinated and cercariae encystate inside second intermediate host after they actively penetrate them. Exceptionally, cercariae do not leave the sporocyst in which they were developing inside the first intermediate host. They encyst there waiting for ingestion by the definitive host. Various types of secretory glands have been developed in cercariae for successful direct infection of next hosts, survival of parasite in adverse conditions of outer environment or for transformation of one larval stage to subsequent one. Variability in morphology and function of these secretory glands in cercariae is closely connected with differences in life...
Larval toxocarosis and CNS
Bernardová, Nicol ; Chanová, Marta (advisor) ; Bulantová, Jana (referee)
Toxocara spp. is an obligate endoparasitic worm of digestive system of canine and feline. During its life cycle the larvae of this parasite can get even into humans and encapsulate in their tissues. If the presence of toxocara larvae in body causes clinical manifestation, then we talk about larval toxocarosis. We can divide it into several forms and this bachelor's thesis is focused on neurotoxocarosis which is caused by toxocara larvae in the nervous system. This thesis summarises basic information about toxocara, its life cycle and hosts and also about its extension in the world (epidemiology), diagnosis, model animals and finally focusing on clinical manifestation of neurotoxocarosis. Key words: larval toxocarosis, neurotoxocarosis, Toxocara canis, migration, paratenic host, definitive host
Development of surface and body musculature of the bird schistosome Trichobilharzia regenti
Bulantová, Jana ; Horák, Petr (advisor) ; Nebesářová, Jana (referee) ; Toledo, Rafael (referee)
Description of Trichobilharzia regenti as a new species of nasal bird schistosome in 1998 was only the first step in our knowledge of this extraordinary parasite. Natural definitive hosts of T. regeni are anseriform birds, but infective larvae - cercariae - are able to penetrate also into mammalian hosts including humans. There they are causative agents of hypersensitive skin immune reaction called cercarial dermatitis or swimmer's itch. Contrary to other schistosomes, miracidia of T. regenti hatch directly inside the definitive host tissue. Schistosomula migrate through the nervous system of vertebrates and, together with adult worms, they have predominantly extravascular localization in definitive hosts. Adult worms have a short lifespan and low degree of sexual dimorphism, connected with lower dependence of adult females on long-term contact with males. During the life cycle, T. regenti can be found within three different environments (freshwater, tissue of intermediate molluscan host and tissue of vertebrate host). Each of the seven developmental stages has a different role in the life cycle which corresponds with different organization of various organ systems. The introductory part of the thesis is focused entirely on ontogenetic changes of surface ultrastructure and body musculature of...
Development of surface and body musculature of the bird schistosome Trichobilharzia regenti
Bulantová, Jana
Description of Trichobilharzia regenti as a new species of nasal bird schistosome in 1998 was only the first step in our knowledge of this extraordinary parasite. Natural definitive hosts of T. regeni are anseriform birds, but infective larvae - cercariae - are able to penetrate also into mammalian hosts including humans. There they are causative agents of hypersensitive skin immune reaction called cercarial dermatitis or swimmer's itch. Contrary to other schistosomes, miracidia of T. regenti hatch directly inside the definitive host tissue. Schistosomula migrate through the nervous system of vertebrates and, together with adult worms, they have predominantly extravascular localization in definitive hosts. Adult worms have a short lifespan and low degree of sexual dimorphism, connected with lower dependence of adult females on long-term contact with males. During the life cycle, T. regenti can be found within three different environments (freshwater, tissue of intermediate molluscan host and tissue of vertebrate host). Each of the seven developmental stages has a different role in the life cycle which corresponds with different organization of various organ systems. The introductory part of the thesis is focused entirely on ontogenetic changes of surface ultrastructure and body musculature of...
The role of nematodes in transmission of parasitic protozoans to a new host
Choutková, Jana ; Bulantová, Jana (referee) ; Horák, Petr (advisor)
A question of transmission to new hosts is fundamental for all parasitic organisms. Some parasites are adjusted to transmit themselves to new hosts by direct way thanks to the resistant life stage, some others use one or more intermediate hosts. An extreme case is transfer by parasitization of another parasite from the same host. Use of another parasite as a transport vehicle helps to realize transmission and this phenomenon can be termed. One example is the protozoan Histomonas meleagridis. This protozoan lives in the intestine of galliform birds where it can attack the roundworm, Heterakis gallinarum, another parasite of the bird intestine. This protozoan, which does not produce any resistant cyst stage in its life cycle and migrates into the roundworm eggs. After release of the eggs to the external environment, the egg provides a protection against external factors and ensures transfer of the protozoan to the new host. Some data suggests that a similar mode of transmission to new hosts can also be used by some others protozoans. One of them is a protozoan from human intestine, Dientamoeba fragilis. Enterobius vermicularis, a pinworm which parasitizes the same host, could serve as a vector of this protozoan. Another potential example of this phenomenon could be Tritrichomonas muris from mouse in...

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