No description available.

No description available.

No description available.

No description available.

No description available.

In forest ecosystems, substantial part of carbon enters soil in the form of plant litter. The decomposition of litter and soil organic matter represents an important process affecting nutrient cycling and carbon balance in soils. Fungi are considered the primary decomposers in terrestrial ecosystems due to the production of wide range of extracellular enzymes that allow them to attack the lignocellulose matrix in litter. Even if fungi represent key players in organic matter decomposition, the information about the structure and diversity of their communities is still limited and the roles of individual fungal taxa in forest soils remain unclear. This Ph.D. thesis focused on the characterization of fungal communities in forest soils and their potential to decompose plant litter. The method for in-depth analysis of complex microbial communities from environmental samples was established and used. In addition, single eukaryotic functional gene was analysed in soil for the first time at a depth that allowed reliable estimation of diversity. It was demonstrated that microbial community composition differs among horizons of forest soil profile. Despite similar diversity, significant differences in microbial community composition were observed between the DNA and RNA. Several microbial groups highly...

Dead plant biomass is a key pool of carbon in terrestrial ecosystems. Its decomposition in soil environments is thus an essential process of the carbon cycle. Fungi are considered to be the primary decomposers in soil ecosystems because of their physiological adaptations and enzymatic apparatus composed from highly effective oxidative and hydrolytic enzymes. Many recent works show that in addition to fungi, bacteria may also play a significant role in lignocellulose decomposition and among bacteria, the members of the phylum Actinobacteria are often regarded to significantly contribute to cellulose and lignocellulose decomposition. This thesis is focused on the evaluation of the role that fungi and Actinobacteria play in dead plant biomass degradation. First, it explored mechanisms involved in degradation, in particular the enzymatic breakdown of major lignocellulose components as cellulose, hemicelluloses and lignin. Enzymatic apparatus of the saprotrophic fungus Fomes fomentarius was explored both in vitro as well as in vivo. Several Actinobacteria were isolated from soil and comparative experiments, investigating production of hydrolytic enzymes, were carried out to track the transformation of polysaccharides and lignin by these strains. To explain the roles of lignocellulose decomposers in...

Vegetation of post-mining sites determines soil microbial community structure and soil processes Mgr. Michaela Urbanová Abstract The aim of this thesis, which consists of four published articles, was to investigate the effect of vegetation on soil microbial communities and processes in de novo developing soil substrate on the brown-coal spoil heaps in the surrounding of city Sokolov. Spoil material - soil clayey substrate, which had been gradually mined from the opencast brown coal mine, stratified onto spoil heaps and reclaimed by assisted afforestation with selected tree species or left for spontaneous plant succession, changes its biotic and abiotic characteristic in the course of time and particularly under the influence of plants. Changes of spoil substrate characteristics are related to the growth of plant roots and particularly also to the production of plant biomass, which is decomposed gradually and takes part of soil, where participates to soil organic matter. The process of plant dead materials decomposition and transformation is the function of the activity of soil organisms and among them notably soil microorganisms. Moreover, the presence of many of them is closely related to the presence of vegetation, whose symbionts or pathogens are. The exact mechanisms of the plant-microbes interactions...

The theoretical part is focused on the production, distribution, and defects of cheese made from cow's milk, and its importance in nutrition. There are also described important species of beneficial and pathogenic microorganisms as well as the fight against undesirable microorganisms. In the last part of the literature review there are characteristics of selected groups of bioactive substances. The practical part of the thesis deals with analysis of microbiological fresh cheeses treated with natural substances due to their durability. Within microbiological analysis were determined selected groups of microorganisms - total number of microorganisms, lactic acid bacteria, psychrotrophic microorganisms, coliforms, enterococci, fungi and yeasts. Samples of fresh cheeses were treated with an extract of peppermint (Mentha piperita L.), mugwort tarragon (Artemisia dracunculus L.) and pumpkin seed oil. Subsequently, they were packed in an atmosphere free, containing CO2 or N2. The results showed that at a storage temperature of 8 ° C neither the used natural raw materials nor the atmosphere affects the shelf life of fresh cheeses.

This thesis consists of three published articles and one submitted article, and is focused on the evaluation of the effects of vegetation on soil microbial communities and processes on brown coal post-mining sites. The research sites served as deposits of infertile waste material, by which the indigenous vegetation has been buried and thus the whole ecosystem was destroyed. The restoration of the ecosystem structure and functions at these areas was based on the improvement of biotic and abiotic properties of excavated soil substrate either using assisted afforestation or using spontaneous plant succession. In this work, biochemical and molecular techniques were employed in order to testify the effect of the vegetation on soil microbial processes, structure of soil microbial communities and to follow the chemical changes in the litter composition during its decomposition. Litter chemistry, enzymatic activities and microbial biomass were followed by standard biochemical procedures including spectrometry and HPLC. Bacterial microarray was used for assessing the composition of bacterial communities in the soil of successional plots. 454-pyrosequencing was employed for detailed identification of fungal and bacterial community composition in the litter layer and the bulk soil under different tree...