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Taxonomic overview of the genus Arthroderma with focus on species associated with reptiles and bats
Kolarczyková, Daniela ; Hubka, Vít (advisor) ; Dobiáš, Radim (referee)
The genus Arthroderma belongs to a group of geophilic dermatophytes that primarily degrade keratin in soil and occasionally cause infections in humans and animals. This species-rich genus has received particular attention in recent years in terms of species occurring in human clinical material or clinical samples isolated from rodents and other mammals, which has been associated with a significant increase in the number of its species. In this thesis, the species diversity of the genus Arthroderma was investigated in material isolated from snakes, bats and cave sediment, a substrate that has been almost unexplored in terms of the occurrence of this genus. The strains studied were isolated during research on bats diseased by "white nose syndrome" and snakes by "snake fungal disease". In the past, the genus Arthroderma has been studied either on the basis of morphology or, after the advent of molecular methods, in terms of multigene phylogeny. However, no monographs have simultaneously combined phenotypic and molecular genetic criteria to assess species boundaries across the genus or a significant part of it. This is one of the reasons why species boundaries are often unclearly defined. Thus, another aim of this work was to improve the multigene phylogeny of the genus by incorporating new strains,...
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Verification of species boundaries in clinically relevant Arthroderma species
Míková, Ivana ; Hubka, Vít (advisor) ; Dobiáš, Radim (referee)
The genus Arthroderma contains predominantly geophilic dermatophytes (naturally occuring in soil). Some species, especially those from Trichophyton terrestre complex, cause human and animal dermatomycosis. In the past, the species boundaries were determined mainly on the basis of biological species concept using in vitro mating experiments. But these nearly 70-years-old findings have not been tested by means of modern taxonomic methods. In total 194 species of the genus Arthroderma (including all available ex-type strains) originating predominantly in USA, Canada and Europe were studied in this thesis. They were mostly isolated from soil (n = 77), animals (n = 50), human clinical material (n = 41) and cave sediment (n = 9). The main goal of the thesis was to elucidate the species boundaries between species A. insingulare, A. lenticulare and A. quadrifidum, that were classified into the T. terrestre complex because of their seemingly identical asexual stage. Further, this work aimed to resolve the relationship between Arthroderma species using the multigene phylogeny and clarify which species are clinically relevant. A multigene phylogeny of the genus Arthroderma was based on the sequences of the ITS rDNA region, β-tubulin (TUB2) and translation elongation factor 1α (TEF1α) genes. The genus...
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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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