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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.
101

Ekologie hub, asociovaných s tlejícím dřevem v ekosystémech přirozených lesů / Ecology of deadwood-associated fungi in the ecosystems of nature-like forests

Zrůstová, Petra January 2014 (has links)
Dead wood plays an important role in forest ecosystems in the context of C dynamics, nutrient cycling, forest regeneration and biodiversity. Decaying wood sustains biodiversity by providing habitats and energy for fungi, bacteria, invertebrates, and many other organisms. Dead wood is resistant to decomposition and its decay is driven mainly by filamentous fungi. Community structure of wood- inhabiting fungi changes during decomposition, but the relationship between substrate quality and decomposer community is still poorly understood. This work studied fungal community composition with respect to tree species, stage of decay, volume and physico-chemical properties (such as pH, carbon and nitrogen content) of dead wood. Fungi were identified using next generation sequencing approaches - 454-pyrosequencing and Illumina MiSeq sequencing. Tree species, volume of dead wood (branches x logs) and stage of decay were the main variables affecting fungal community composition. Higher enzyme activities and content of fungal biomass indicate faster colonization of small branches than tree trunks by fungi. Fungal community composition, wood chemical properties and enzyme activities changed during decomposition. Both content of nitrogen and fungal biomass increased during decomposition. Enzyme activites peaked...
102

Bioremediace persistentních aromatických polutantů / Bioremediation of persistent aromatic pollutants

Stella, Tatiana January 2014 (has links)
The remediation of persistent chlorinated aromatic compounds has become a priority of great relevance due to the teratogenic, carcinogenic and endocrine-disrupting properties of these xenobiotics. The use of biological methodologies for the clean-up of contaminated sites, collectively referred to as "bioremediation", has been gaining an increasing interest in recent years because it represents an effective, cost-competitive and environmentally friendly alternative to the physico-chemical and thermal treatments. In this respect, "white rot" fungi, an ecological subgroup of filamentous fungi, display features that make them excellent candidates to design an effective remediation technology ("mycoremediation"). In spite of this, fungi have not been widely exploited for their metabolic capabilities and the mechanism by which they are able to degrade the aforementioned pollutants has not been fully elucidated yet. Within this frame, the present Ph.D thesis was aimed at: i) assessing the efficiency of different mycoremediation strategies for the clean-up of a polychlorinated biphenyl (PCBs)-contaminated soil; ii) understanding the fungal degradation pathways of polychlorinated biphenyls and their major metabolites, namely chlorobenzoic acids (CBAs) and hydroxylated polychlorinated biphenyls (OH-PCBs). i)...
103

Hostitelská specificita tropických kůrovcovitých (Coleoptera: Curculionidae: Scolytinae, Platypodinae) / Host specificity of tropical bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae, Platypodinae)

HULCR, Jiří January 2007 (has links)
Host specificity of tropical bark and ambrosia beetles was surveyed by rearing the beetles from 13 host trees in a lowland rainforest in Papua New Guinea. Ploeophagous bark beetles show narrow host specificity (usually family-level) typical for herbivorous insects, fungus-growing ambrosia beetles display almost no host fidelity. In both groups of species, the local diversity of plants is unlikely to have played a role in the clade diversification. The ambrosia symbiosis (scolytine beetles and fungi) is shown to be less specific than previously assumed, based on a discovery of new association between Scolytodes unipunctatus (genus of phloem feeders) and three unrelated groups of ambrosia fungi. The hypothesis that apparent polyphagy may conceal specialized populations within a species of a herbivore is tested for Homona mermerodes (Lepidoptera, Tortricidae). The haplotype diversity of the species show no congruence with host plants or geographic origin, confirming polyphagy of the species.
104

Vliv fyzikálních metod a nových chemických preparátů na bázi nanočástic na vybrané dřevokazné houby napadajících dřevěné konstrukce - možnosti a limitace moderních metod prevence / The impact of physical methods and new chemical preparations based on nanoparticles on selected wood-rotting fungi invading wooden structures - possibilities and limitations of modern techniques of prevention

Švec, Karel January 2016 (has links)
83 Abstract The work focuses on the physiology of wood-rotting fungi and the possibilities of their inhibition by physical methods (microwave and gamma irradiations, dry heat) or newly developed chemical preparatives contaning metallic nanoparticles. The effect of abovementioned treatments on mycelial growth, activities of extracellular enzymes responsible for wood degradation and on spore germination or viability was studied in selected strains of wood-rotting fungi obtained from culture collection (Coniophora puteana, Fibroporia vaillantii, Gloeophyllum sepiarium) or isolated from infected buildings (Serpula lacrymans).
105

Průzkum a hodnocení stavu dřevěné konstrukce / Survey and evaluation of wooden construction

Křivánková, Soňa January 2014 (has links)
This work is focused on compilation of general diagnostic methods used for diagnostic of wooden structures specifically listed wooden roof truss of church st. Bartholomew in Ivan. The main impulse of diagnosis was extensive damage and attack of truss and effort on rehabilitation and construction of the entire building of the church with an emphasis on preserving historical values. Diagnosis of truss was based on the research used sense and instrumental methods. In the first step, identify all dimensions of the individual elements of the structure was determined, the type truss system was intended. Follow-up survey was focused on determining the extent and causes of damage. In design of the rehabilitation process emphasis is placed on structural rehabilitation provided by follow-up processes, such as preventive chemical protection.
106

Vliv dominantní dřeviny a zrnitosti substrátu na složení mikrobiálního společenstva studovaného pomocí PLFA / The influence of the dominant trees and grain substrate the composition of the microbial community studied by PLFA

Stachová, Sandra January 2016 (has links)
The aim of the thesis was to analyze soil microbial communities of three ecologically different locations, about 25 years old, forestry reclaimed dumps in the Republic of Poland, namely dumps of brown coal mine Bełchatów and sand mines Piaseczno and Szczakowa. I evaluated the degree of dependence of structure and composition of these communities on various substrate grain sizes and the influence of the dominant tree species. These were stands of birch (Betula pendula), pine (Pinus silvestris), oak (Quercus robur) and alder (Alnus glutinosa). Analysis of soil microbial communities was made by evaluating specific phospholipid fatty acids (PLFA) of microorganisms. It is the most appropriate way to implement the relatively rapid analysis of large numbers of samples, since PLFA are easily extractable and act as biomarkers indicating the presence of a number of different microorganisms (fungi, G- and G + bacteria, Actinobacteria, etc.) and thus allowing a qualitative and quantitative assessment of whole microbial communities. PLFA analysis enables to detect a total concentration of PLFA only in living soil microbial biomass. I analyzed 66 soil samples, 33 from an Oe layer and 33 from an A layer, every in three replications, i.e. three replications were collected at each location below each tree...
107

Struktura, vývoj a funkce mikrobiálních společenstev v odumřelém dřevě / Assembly, successional development and functioning of microbial communities in deadwood

Bernardová, Natálie January 2020 (has links)
Dead wood is one of the most important reservoirs associated with forest ecosystems. In natural forests, its volume is counted in hundreds of m3 ha-1 , whereas it reaches only tens of m3 ha-1 in productive commercial forests. In contrast to soil and plant litter, deadwood is unevenly distributed on the forest floor. The specific physicochemical properties such as high content of recalcitrant polymers, low nitrogen level and impermeability negatively affect the rate of decomposition especially in the initial stages of wood deconstruction. The deadwood decomposition is very slow in comparisons with other substrates, it accumulates and thus it represents the important reservoir of nutrients. This thesis is focused on the structure, development and function of microbial (fungal) community in decomposing deadwood in unmanaged forest. Functional screening of fungi isolated from fruit bodies collected from coarse deadwood was set aside. Physico-chemical properties of deadwood including pH, carbon and nitrogen content and microbial biomass were estimated for four wood decomposition stages and three different tree species. New generation sequencing (Illumina MiSeq platform) was applied for fungal community structure analysis based on ITS2 fragment. Fungal functional screening was based on physico-chemical...
108

Interakce mikroskopických hub a krytenek v opadu smrku ztepilého / Interactions of microscopic fungi and testate amoebae in Norway spruce litter

Konvalinková, Tereza January 2011 (has links)
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...
109

Interakce iniciálně mykoheterotrofních rostlin s prostředím / Interactions of initially mycoheterotrophic plants with environment

Figura, Tomáš January 2021 (has links)
Initially mycoheterotrophic plants have recently been declining in the wild, even without apparent causes. They are affected by a number of biotic and abiotic factors. The aim of this work is to investigate how selected factors, such as nitrate or symbiotic fungi, may influence their distribution in nature. In particular, the work applies in vitro experiments, molecular determination of fungal symbionts and stable isotope analyses. It describes both the effects of abiotic factor, specifically nitrate, and biotic interactions of initially mycoheterotrophic plants with fungal symbionts. The inhibition of germination by extremely low concentrations of nitrate in asymbiotic in vitro cultures was observed in several orchid species. The degree of sensitivity of each species to nitrate corresponds with the nitrate content of the soil and the nutrient availability requirements of the species according to Ellenberg indicator values. The inhibitory effect of nitrate on orchid germination was also observed in symbiotic in vitro cultures. Out of five tested fungal strains, only one Ceratobasidium was capable of eliminating the inhibitory effect of nitrate. Furthermore, the work reveals that green mixotrophic orchids use photosynthates to nourish the aboveground parts, whereas the belowground parts are...
110

Aplikace ligninolytických hub na pevných substrátech pro degradace endokrinních disruptorů / Application of ligninolytic fungi on solid substrates for degradation of endocrine disrupters

Slavíková - Amemori, Anna January 2012 (has links)
Today a lot of attention is focused on compounds called endocrine disrupters (EDs) among substances released to environment by humans. They are a group of substances which can disturb function of hormonal system of organisms including humans. Their poor removal at wastewater treatment plants (WwTP) were shown at various studies, thus they can reach the environment in water. A prospective way for the degradation of EDs at WwTP can be their removal by ligninolytic fungi. They are able to degrade lots of lignin-like aromatic substances because of their highly nonspecific enzymes. In this work growth and enzyme production capability of four ligninolytic fungal strains were monitored on three solid substrates (straw pellets, poplar sawdust mixed with straw pellets, oak sawdust with straw pellets), which may be suitable substrates for fungal growth in bioreactors for wastewater treatment. Ability of these enzymes to degrade EDs were tested in in-vitro degradation experiment. Trametes versicolor was found as best degrading strain with 20 μg/ml of bisphenol A, 17 α- ethynylestradiol and nonylphenol degraded below a quantification limit within 24 hours. Fungal strains degraded EDs well on all of the three substrates but wood sawdust seemed to be a better substrate for fungal growth because straw pellets...

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