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Interactions of microscopic fungi and testate amoebae in Norway spruce litter
Konvalinková, Tereza ; Koukol, Ondřej (advisor) ; Nováková, Alena (referee)
Both testate amoebae and fungi are common inhabitants of coniferous litter. Their interactions in this environment were rarely studied, although they reach high biodiversity and can play a significant role in nutrient cycling in this environment. In this study, a cultivation of litter needles in the damp chambers was used to investigate interactions between fungi and testate amoebae. Observation of spruce litter needles in environmental scanning electron microscope was used to better characterize testate amoebae communities directly on the needles. Additionally, two experiments changing the biotic conditions in the microcosm were used to follow a principle of the interactions. Three species of testate amoebae from litter needles were able to colonize the filter paper on the bottom of the damp chambers. Occurrence of Phryganella acropodia and Assulina muscorum on the filter paper was significantly fuelled by the presence of mycelium. Assulina muscorum was associated with the fungal spores and Arcella discoides was attracted by sporulating colonies of Cladosporium spp. in the damp chambers. By contrast, no association of putatively mycophagous Phryganella acropodia with fungal spores was observed. Arcella discoides was attracted both by live and death mycelium in additional experiment. Interestingly, the...
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Sexual system of the ascomycetes from order Pezizales
Janošík, Lukáš ; Koukol, Ondřej (advisor) ; Čmoková, Adéla (referee)
Sexual reproduction is essential part of life for numerous ascomycetes. Based on their requirement for opposite partner to produce fruiting bodies with ascospores, fungi can be in general divided into two mating systems - homothallism and heterothallism. However, several recent studies suggest that this division is clearly simplified and homothallism is an umbrella term for diverse sexual behaviours. First part of this thesis is focused on the reproduction, mating systems and their evolution in division Ascomycota. The main part summarizes present knowledge about the mating systems of the fungi from order Pezizales. Observations about the members of individual families are discussed, summed up and reviewed in the light of phylogeny and ecology.
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The effect of secondary metabolites (essential oils) on endophytic fungi from leaves of Rhododendron tomentosum
Koudelková, Barbora ; Koukol, Ondřej (advisor) ; Žabka, Martin (referee)
Rhododendron tomentosum is an evergreen shrub with a high content of secondary metabolites, particularly essential oils with antimicrobial effects. Diversity of endophytic fungi in this species and their possible adaptation to growth in the essential oil environment is not much explored. Therefore, the first aim of this thesis was to reveal the diversity of endophytic fungi colonising leaves of R. tomentosum on seven localities in the Czech Republic and one in Estonia. I isolated and determined (using comparison of ITS1 and ITS2 rDNA with the sequences from GenBank and morphological signs) 37 species of endophytic fungi. Among them the ubiquitous species colonising the most of the plants as endophytes were dominant. The second aim of my thesis was to explore whether the essential oil from R. tomentosum influences its endophytic fungi. The hypothesis that the strains obtained from R. tomentosum would be adapted to growth in the environment of the essential oil was postulated. I supposed that they would grow better on mediums with different concentrations of these chemical compounds added, in comparison with strains of the same species obtained from different substrates. Within four of seven species tested, the strains obtained from R. tomentosum grew better, but also on the medium without the...
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Distribution and importance of invasive pathogen Cryptostroma corticale on Acer pseudoplatanus in Prague
Kelnarová, Ivana ; Koukol, Ondřej (advisor) ; Sumíková, Taťána (referee)
Sooty bark disease (SBD) caused by pathogen Cryptostroma corticale is one of the current risks to the population of sycamores in Europe. A few dozen individuals were fallen death due to sooty bark disease from the first record in Prague in 2005. However a higher rate of infection in a latent non-symptomatic stage can be assumed. The main goal of the thesis was to quantify the extent of infection C. corticale in Prague on the basis of early detection in tissues of symptomless trees and identify its environmental requirements and stress factors conditioning the progression of the disease. Another goal was to predict the risk for Prague's population of sycamore based on obtained data and identify other vulnerable sites in Prague. A secondary aim was to assess the spectrum of fungi inhabiting xylem of sycamore. Tissue samples collected with an increment borer were subjected to: a) isolation of cultivable fungi on malt agar and b) detection of the DNA C. corticale based on nested PCR with species- specific primers. Latent infection was detected in 28 of the cores. Of 27 positive detections with primer specific nested PCR 10 were supported by isolation of C. corticale on agar plates. Only in one case positive isolation of C. corticale on agar plate was not confirmed by nested PCR. Occurrence of C....
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Endophytic fungi in above-ground tissues of plants of the family Ericaceae
Koudelková, Barbora ; Koukol, Ondřej (advisor) ; Kolařík, Miroslav (referee)
Many studies focus on endophytic fungi. However, above-ground tissues of plants of the family Ericaceae are not largely examined. Most of the literature concerns the fungi forming ericoid mykorhiza. This bachelor thesis sums up the diversity studies of the endophytic fungi in the family Ericaceae, compares the frequency and the overlap of fungi in different host plants and geographical regions and also the occurence of fungi in living and dead plant tissues. The methods of fungal isolation and identification are accented.
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Genetic variability in the Physconia muscigena group (Physciaceae, Ascomycota) in the Northern Hemisphere
Starosta, Jakub ; Koukol, Ondřej (advisor) ; Steinová, Jana (referee)
The principal goal of our study was to test whether ecologically and chemically different populations of lichens in the Physconia muscigena (Ach.) Poelt group belong to multiple species or one. We used sequence data from three markers (ITS rDNA, mtSSU rDNA and TEF1-α) for the reconstruction of phylogenetic trees based on a sampling of mostly European and Canadian populations of P. muscigena (Ach.) Poelt, P. muscigena var. bayeri (Nádv.) Poelt, and P. isidiomuscigena Essl. Further, we sought any possible geographical or ecological trends among chemotypes and haplotypes. Results show that: 1) Sequence data of ITS rDNA and TEF1-α shows large genetic variation in the Physconia muscigena group. This genetic variability does not correlate with geographical distribution or thallus chemistry; 2) Physconia muscigena var. bayeri and P. isidiomuscigena appear undifferentiated in our phylogenetic trees with P. muscigena. These three species cannot be distinguished on the basis of ITS rDNA, mtSSU rDNA and TEF1-α sequences. 3) We synonymized Physconia muscigena var. bayeri with P. muscigena and we recombine P. isidiomuscigena as a variety of P. muscigena.
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Evolution of ascospore morphology and their dispersal in bryophilous Pezizales
Janošík, Lukáš ; Koukol, Ondřej (advisor) ; Trávníček, Pavel (referee)
Bryophilous Pezizales represent a species-rich group of fungi closely associated with bryophytes. Their ascospore morphology is highly variable and they strongly differ also in the genome size and ecology. They could thus represent an interesting model system for the research of evolution of ascospore morphology and their dispersal. The aims of my thesis were to test whether their genome size, number of nuclei in ascospores and ecology of host bryophyte influence their ascospore morphology and to experimentally test the effect of ascospore morphology on their active dispersal. I studied 52 species of bryophilous Pezizales. I reconstructed their phylogeny based on the sequences of three DNA regions, which I then used for the testing of relationships between individual variables using the phylogenetic generalized least squares. For the majority of species, I obtained measurements from morphometric analysis, genome size measurements using flow cytometry, and determined the number of nuclei in their ascospores using the fluorescent microscopy. I localised the infection apparatus and included also the ecological characteristics of the host bryophytes into the analyses. Using the experiments with horizontal ascospore discharge, I measured the distance of active ascospore ejection and recorded whether...
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Mechanisms and mode of action of essential oils on fungi
Ježková, Tereza ; Koukol, Ondřej (advisor) ; Čmoková, Adéla (referee)
Essential oils are volatile compounds from plants with a wide range of effects. Many of them exhibit antifungal activity. As the resistance of pathogenic fungi to antimycotics is increasing, finding new antifungal agents for the treatment of fungal infections is highly desirable. In order to use essential oils for the production of new drugs, it is necessary to know the exact mechanism of their action. Although it is known a lot about the effects of essential oils on fungi, the particular target in a cell is not always described. In this thesis I summarize the present knowledge about the mechanisms of actions on fungi. I gradually deal with effects of essential oils on cell wall, plasma membrane, mitochondrion, nucleus, quorum sensing, virulence factors, mycotoxin production and fungal development. Generally essential oils do not act on one structure but affect multiple structures and processes at the same time. In the last chapter I mention possible directions for further research of these substances. Key words: essential oils, fungi, antifungal activity, mechanism of action, mode of action
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Sexual system of the ascomycetes from order Pezizales
Janošík, Lukáš ; Koukol, Ondřej (advisor) ; Čmoková, Adéla (referee)
Sexual reproduction is essential part of life for numerous ascomycetes. Based on their requirement for opposite partner to produce fruiting bodies with ascospores, fungi can be in general divided into two mating systems - homothallism and heterothallism. However, several recent studies suggest that this division is clearly simplified and homothallism is an umbrella term for diverse sexual behaviours. First part of this thesis is focused on the reproduction, mating systems and their evolution in division Ascomycota. The main part summarizes present knowledge about the mating systems of the fungi from order Pezizales. Observations about the members of individual families are discussed, summed up and reviewed in the light of phylogeny and ecology.
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