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Host specificity, genetic variability and genealogy in populations of model parasite species
MARTINŮ, Jana
Parasites represent one of the most common ecological strategies and host-parasite coevolution belongs among the major processes governing evolution of biodiversity on the global scale. Genetic structure and diversity of populations of parasites and their hosts, and their genetic connectivity are the key elements in long-term population survival and evolution. Host switches often disturb the parallel evolution of interacting taxa, even in highly host-specific parasites. Evaluation of importance of the degree of intimacy between parasites and hosts is not a trivial task, because evolutionary patterns observed today were formed by an interplay of many (sometimes previously unforeseen) historical and ecological factors. To reveal the mechanisms of coevolution between parasites and their hosts, inter- and intra-specific genealogical structures in three model systems were analyzed: namely, the sucking lice Polyplax serrata and Apodemus hosts, chewing lice of the genus Menacanthus and endoparasitic coccidean genus Eimeria from Apodemus mice.
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Virulence factors of dermatophytes
Machová, Lenka ; Čmoková, Adéla (advisor) ; Dobiáš, Radim (referee)
Dermatophytes are a group of phylogenetically related microscopic fungi of the order Onygenales, the Arthrodermateceae family, capable of using keratin as a source of nutrition. Some species are important pathogens of vertebrates including humans. The aim of my bachelor thesis was to summarize the current knowledge about virulence factors of dermatophytes, taking into account their possible role in the host specificity. In the main part, I describe the virulence factors, pathogenesis mediating molecules, in the context of the individual stages of infection, such as adherence, degradation of the keratin, or suppression of the immune response. The study of these factors in general, deserves increased attention because their knowledge can lead to the development of targeted treatment. Some aspects of pathogenesis, e.g. keratolysis and fighting the immune system, are relatively well studied. However, we know almost nothing about the other factors, especially about those mediating host sensing and adherence, but they could provide important information on identifying the host specificity of dermatophytes. The final chapter is dedicated to a discussion about the potential ability of these virulence factors to influence the selection of the host. My thesis brings a comprehensive overview of the...
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Monoxenous trypanosomatids of invertebrates
Havlová, Jolana ; Votýpka, Jan (advisor) ; Varga, Vladimír (referee)
The class Kinetoplastea contains free-living and parasitic species. One of the most dominant group within the class is the order Trypanosomatida which includes obligate parasites (Trypanosoma, Leishmania) infecting a wide range of hosts. Some species are serious pathogens of humans and domestic animals and cause considerable losses. However, the majority of trypanosomatids belongs to monoxenous parasites of insect which are usually harmless to their hosts. Monoxenous trypanosomatids predominantly infect Hemiptera and Diptera. This diploma thesis is focused on the detection of monoxenous trypanosomatids in cockroaches captured in the Czech Republic and cockroaches from different breedings. Cockroaches are very suitable mechanical vectors of many different pathogens (including parasites) and are significant health threat for humans and animals. First trypanosomatids in cockroaches were documented at the beginning of the 20th century, but there is no study focused on this topic specifically. Another aim of this thesis is morphological and ultramicroscopic analysis and the study of the host specificity of the recently described species Herpetomonas tarakana, isolated from a cockroach. My findings were partly used in the already published study "Diversity of trypanosomatids in cockroaches and the...
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Evolution of host specificity and phylogeography of Strepsiptera parsites of the family Xenidae
Benda, Daniel ; Straka, Jakub (advisor) ; Malenovský, Igor (referee)
The twisted-wing parasites (Strepsiptera) are an endoparasitic order of insects with cosmopolitan distribution, which are sister group of Coleoptera. There are about 600 known species up to date. Strepsiptera parasitize seven insect orders (Thysanura, Orthoptera, Blattodea, Mantodea, Hemiptera, Diptera, Hymenoptera). The family Xenidae is one of the most derived groups of Strepsiptera. Its representatives parasitize aculeate Hymenoptera of three families (Vespidae, Sphecidae, Crabronidae). In comparison to the basal groups, there are well-known hosts for genera of the family Xenidae. Therefore, this group is suitable object for study of the evolution of host specialization. Phylogeny of the family Xenidae was constructed on the basis of molecular analysis of three genes. Moreover, the mapping of ancestral host major groups and biogeographic areas was performed using two methods (parsimony, maximum likelihood). According to the results, the family Xenidae is monophyletic group with Old World origin. There were a several independent switches to the same host groups. This significantly changes the existing ideas about evolution of host specialization and requires a taxonomic revision. Within the family Xenidae, there were several cases of dispersal between the Old World and the New World. Furthermore,...
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Phylogeny of selected species groups of the genus Torymus (Hymenoptera: Torymidae)
Křížková, Barbora
Chalcid wasps (Chalciodiodea) is superfamily within parasitic group of the order Hymenoptera. These insects attack other arthropods. My thesis is focused on phylogeny of selected species groups of the genus Torymus Dalman 1820, whose range of hosts includes mainly gall-forming insect as gall wasps (Hymenoptera: Cynipidae) and gall midges (Diptera: Cecidomyiidae). Using genes 28D2 rDNA, COI and CytB, I constructed phylogenetic trees, which helped with discussing current view on classification of the genus and with inferring new findings about co-evolution with host organisms. Previously established morphological - ecological species groups were not supported by my analyses in many cases. Morphological traits seem to be convergent for many species. They often do not support observed monophyla as apomorphies. On the other hand, ecology and natural habitat of species was common for many branches in my cladograms. It was found out, that recent hosts are not probably original hosts of the group. Adaptive radiation in different habitats is likely to be the phenomenon that stands behind present-day host range of Torymus species. This process could have occurred after swapping to gall midges and gall wasps. Key words: Chalcidoidea, Torymus, phylogeny, parasitoid, host specifity, co-evolution
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Phylogeny of selected species groups of the genus Torymus (Hymenoptera: Torymidae)
Křížková, Barbora ; Janšta, Petr (advisor) ; Skuhrovec, Jiří (referee)
Chalcid wasps (Chalciodiodea) is superfamily within parasitic group of the order Hymenoptera. These insects attack other arthropods. My thesis is focused on phylogeny of selected species groups of the genus Torymus Dalman 1820, whose range of hosts includes mainly gall-forming insect as gall wasps (Hymenoptera: Cynipidae) and gall midges (Diptera: Cecidomyiidae). Using genes 28D2 rDNA, COI and CytB, I constructed phylogenetic trees, which helped with discussing current view on classification of the genus and with inferring new findings about co-evolution with host organisms. Previously established morphological - ecological species groups were not supported by my analyses in many cases. Morphological traits seem to be convergent for many species. They often do not support observed monophyla as apomorphies. On the other hand, ecology and natural habitat of species was common for many branches in my cladograms. It was found out, that recent hosts are not probably original hosts of the group. Adaptive radiation in different habitats is likely to be the phenomenon that stands behind present-day host range of Torymus species. This process could have occurred after swapping to gall midges and gall wasps. Key words: Chalcidoidea, Torymus, phylogeny, parasitoid, host specifity, co-evolution
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Host specialization and species diversity in Strepsiptera of the genus Stylops
Jůzová, Kateřina ; Straka, Jakub (advisor) ; Malenovský, Igor (referee)
The twisted-wing parasites (Strepsiptera) are entomophagous insect order with cosmopolitan distribution. There are about 600 known species up to date. In spite of this, they have very broad host spectrum. Strepsiptera parasites in seven insect groups (Thysanura, Blattodea, Mantodea, Orthoptera, Hemiptera, Diptera, Hymenoptera). The mutual relationship between genera or even between species are not known, except for the species list and the host specification. Moreover, there is an anambiguous use of their species concept. Some authors consider Strepsiptera as the specialists and they match almost every host species with one separate strepsipteran parasite. The opposite concept is to consider strepsiptera as the generalists. The presence of the crypctic species also affect our understanding of the diversity of Strepsiptera. Therefore, the knowledge of Strepsiptera phylogeny provide us the important information about species diversity of studied group as well as about their coevolution with their hosts. On the basis of molecular analyses of three genes constructed the phylogeny genus Stylops. This genus has the wider spetrum of the host species from other strepsipterans of Stylopidae, It is obvious, that strepsipterans of genus Stylops are mainly specialised on their host subgenus. There was detected two...
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Specificity between partners in arbuscular mycorrhizal symbiosis
Voříšková, Alena ; Janoušková, Martina (advisor) ; Püschel, David (referee)
Arbuscular mycorrhiza (AM) is a symbiotic interaction between vascular plants and arbuscular mycorrhizal fungi from phylum Glomeromycota. AM symbiosis is considered as a nonspecific interaction, because AM fungi are able to colonize roots of all plant species which are hosts for this type of symbiosis, nevertheless certain specific interactions exist between the partners. The specificity can be evident on the level of the formation of mycorrhiza, which means that different species of plants can vary in the composition of fungal community in their roots or AM fungi can differ in an ability of colonization and sporulation depending on host plant species. The specificity can also manifest as different functionality of the symbiosis in dependence on the particular partners affecting the mycorrhizal response of the host plants. All of these specific interactions can have an impact on the coexistence and diversity of plants in communities.
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Tapeworms of family Gryporhynchidae from Africa
HAASOVÁ, Ivana
Morphological-taxonomical study of gryporhynchid cestodes from Africa is presented. New material from Kenya, Senegal and Sudan was studied and we belong to 17 species in 8 orders - Amirthalingamia macracantha (Joyeux et Baer, 1935) Bray, 1974; Anomotaenia riccii (Fuhrmann et Baer, 1943) Baer et Bona, 1960; Cyclustera magna (Baer, 1959) Bona, 1975; Cyclustera sp.; Dendrouterina macrosphincter (Fuhrmann, 1909) Baer et Bona, 1960; Neogryporhynchus sp.; Paradilepis lloydi (Southwell, 1926) Spasski, 1954; Paradilepis maleki (Khalil, 1961); Paradilepis urceina Bona, 1975; Paradilepis urceus (Wedl, 1855) Joyeux et Baer, 1950; Parvitaenia macrocoleo Bona, 1975; Parvitaenia macropeos (Wedl, 1855) Baer et Bona, 1960; Parvitaenia megascolecina Bona, 1975; Parvitaenia purpurea Johri, 1959; Parvitaenia samfyia Mettrick, 1967; Valipora ardeolae (Singh, 1952) Baer et Bona, 1960 and Valipora mutabilis (Linton, 1927). Known larval stages and adults from Africa are presented in review of species.
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