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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vztah biodiverzity a produktivity ve společenstvech krásivek / Biodiversity-productivity relationship in desmid communities

Škvorová, Marie January 2019 (has links)
This thesis deals with biodiversity-productivity relationship in desmid communities. Biodiversity is found to be changing globally. The biodiversity-productivity relationship is therefore an important research topic. Three aspects of biodiversity are thought to play an important role: species richness, functional diversity and phylogenetic diversity. It is known that in general, productivity is positively correlated with diversity. Interactions between different metrics of biodiversity are known less. Existing studies have shown that these interactions might be present. In general, biodiversity-productivity studies were mostly focused on plants. Less is known about other organisms, including algae. In this work I explore the relationship between overyielding and functional or phylogenetic diversity on a species richness gradient of desmid communities. I conducted an artificial biodiversity- ecosystem functioning experiment using combinations of two to 12 desmid species. Communities differed in the diversity aspects. I had measured the biomass growth. For the analysis, I have used the overyielding index, which is based on a comparison of a polyculture production with the production expected based on monoculture yields. The relationship of overyielding on functional diversity depended on species...
12

Význam neolitické expanze ve střední Evropě - posouzení fylogenetického stáří mtDNA haploskupin u české populace. / The importance of Neolithic expansion in Central Europe - an assessment of phylogenetic age of mtDNA haplogroups in the Czech population.

Priehodová, Edita January 2011 (has links)
Agriculture, with different Neolithic cultures, starts in the Near East more than 10,000 years ago. This new way of life has very different archaeological manifestations that previous Mesolithic. After its Near Eastern emergence, the farming practices rapidly penetrated into southeastern Europe and the first signs of Neolithic in Central Europe are already 7,000 years old. It is being considered that the cultural innovations influenced demographic growth of the populations that have taken part in the Neolithic spread. In such situation, new mutations would have to fix and could form new specific haplogroups for Europe with ancestral ties to the Near East. Phylogeographic studies such as founder analysis of European and Near Eastern mtDNA sequences found that the European Neolithic component was enriched mainly by haplogroups J and T1, and that the genetic contribution of farming economy in European gene pool is about 10 - 20%. However, studies like these have not been yet realized in particular parts of Europe. The aim of this thesis is to disentangle the internal variability of Central European haplogroups J and T1 thought to be involved in the Neolithic demic diffusion. We classified these haplogroups from the HVS-I mtDNA sequences of 281 samples of the recent population of the Czech Republic. We...
13

Krevní paraziti ryb na Svalbardu / Blood parasites of fish from Svalbard

POSPÍŠILOVÁ, Iva January 2014 (has links)
This thesis reviews knowledge about diversity of blood parasites of fish. Blood smears of fish used in this study were obtained in Billefjorden (Svalbard archipelago, Arctic). Desseria myoxocephali, the type species of Desseria, is the only one parasite that was found in the smears. A partial 18S rDNA sequence of D. myoxocephali was prepared and phylogenetic analyses were computed. D. myoxocephali forms a lineage together with Dactylosoma ranarum and Babesiosoma stableri within adeleorinid clade.
14

Predikce škodlivosti aminokyselinových mutací s využitím metody MAPP / Predicting the Effect of Amino Acid Substitutions on Protein Function Using MAPP Method

Pelikán, Ondřej January 2014 (has links)
This thesis discusses the issue of predicting the effect of amino acid substitutions on protein function using MAPP method. This method requires the multiple sequence alignment and phylogenetic tree constructed by third-party tools. Main goal of this thesis is to find the combination of suitable tools and their parameters to generate the inputs of MAPP method on the basis of analysis on one massively mutated protein. Then, the MAPP method is tested with chosen combination of parameters and tools on two large independent datasets and consequently is compared with the other tools focused on prediction of the effect of mutations. Apart from this the web interface for the MAPP method was created. This interface simplifies the use of the method since the user need not to install any tools or set any parameters.
15

Dermatofyty izolované ze srsti volně žijících hlodavců / Dermatophytes isolated from the hair of free-living rodents

Žárová, Štěpánka January 2020 (has links)
Dermatophytes (order Onygenales, Ascomycota) are microscopic filamentous keratinophilic fungi that can cause skin infections known as dermatophytosis. The most diverse but not very studied genus Arthroderma has been revised recently (Míková 2018) which was essential for further research. This genus comprises mostly species with a supposed reservoir in soil. Lack of information about their ecology and frequent isolation of some species from the hair of free- living mammals (mainly rodents) may testify a strong host association. Rodents could thus represent the hidden reservoir of this species. For this thesis, I have chosen three ecologically distinct rodent species: Mus musculus, Apodemus flavicollis, and Clethrionomys glareolus. I obtained the material by brushing the hair of asymptomatic individuals and used this material for cultivation on selective medium. I identified the isolates of dermatophytes (n = 30) using molecular methods. I used sequences of three highly variable loci (ITS, tubb a tef1α) to incorporate these isolates in the phylogenetic analysis based on the monography of the genus Arthroderma (Míková 2018). I characterized the phenotype of selected strains based on morphological and physiological data including the ability to utilize keratin and the production of siderophores. The...
16

Encystace a životní cyklus volně žijících améb rodu Acanthamoeba spp. / Encystation and life cycle of free living amoebae of the genus Acanthamoeba spp.

Bínová, Eva January 2021 (has links)
Amoebae of the genus Acanthamoeba spp. are free-living unicellular organisms found in disparate ecosystems all over the world. Due to their ability to invade human body, evade its defensive mechanisms and cause extensive tissue damage, Acanthamoeba infection can lead to serious, if rare, diseases, affecting most commonly the eye and the central nervous system. Specific therapy for Acanthamoeba infections is not available. A major reason for therapeutic failure in ameobiasis is the ability of the protist to differentiate into resistant stages. These are cysts, known to be formed under prolonged unfavorable conditions, both in the environment and the infected tissues, and the pseudocysts, less durable but rapidly formed under acute stress. The present thesis focuses on as yet unexplored mechanisms of resistance of cysts and pseudocysts. Moreover, further characteristics distinguishing cysts and pseudocysts as well as the processes involved in their formation are investigated. One of the issues addressed is a presence of protective carbohydrate compounds mannitol and trehalose that participate in defensive reactions against abiotic stress in many organisms. Although putative genes for enzymes of the trehalose and mannitol synthetic pathways are present in the genome of Acanthamoeba, only one of the...
17

Ověření druhových hranic mezi klinicky významnými geofilními druhy Arthroderma / Verification of species boundaries in clinically relevant Arthroderma species

Míková, Ivana January 2018 (has links)
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...
18

Interakce rostlin a půdy a další faktory ovlivňující invazivnost rostlin / Interaction of plants and soil and other factors affecting plant invasiveness

Aldorfová, Anna January 2019 (has links)
Plant invasions represent a major ecological and socio-economical issue and understanding the drivers as well as consequences of plant invasions is thus one of the main goals of plant ecology. It is equally important to reveal general patterns underlying plant invasions and to understand the details of biology of individual invaders. In this thesis I explored plant-soil feedback (PSF) as a possible general mechanism underlying plant invasiveness, and also focused in detail on drivers and consequences of Impatiens parviflora invasion. The aims of this thesis were to i) assess the differences in intraspecific PSF between invasive and alien non-invasive species using a large set of species; ii) explore the relationship between PSF, residence time and phylogenetic novelty of the alien species; iii) compare the importance of PSF and other plant characteristics for plant invasiveness; iv) compare PSF between invasive and native congeners of similar level of dominance in the field; v) evaluate the effect of cultivating conditions on results of PSF experiments; vi) describe invasion dynamics and determine factors affecting spread of invasive I. parviflora using a method of monitoring its natural spread in several types of habitats, and vii) assess the impact of I. parviflora on native vegetation of oak-...

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