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Bacteria associated with decomposing deadwood
Tláskal, Vojtěch ; Baldrian, Petr (advisor) ; Uhlík, Ondřej (referee) ; Bárta, Jiří (referee)
Deadwood is a hotspot of microbial diversity and its decomposition contributes to carbon and nitrogen cycling in temperate forests. The historically recognized importance of fungi in the decomposition of deadwood has recently been complemented by the description of bacterial functions thanks to the rapid progress of culture-independent methods based on the analysis of nucleic acids. To study different aspects of deadwood decomposition, a temperate mixed forest in Zofinsky prales National Nature Reserve was selected as a site with rich historical forestry data where deadwood decomposition represents an important process in wood turnover. The aim of this thesis is to describe role of bacteria in deadwood decomposition at fine scale resolution with respect to community composition, enzyme transcription, and metabolic potential of dominant species. Effects of deadwood age together with pH and water content on the bacterial community composition proved to be more important than tree species identity. Bacteria showed distinct composition between early and late community in decomposing deadwood. The bacterial community was also under a significant influence of fungal community composition. Despite being in a close contact, bacterial and fungal communities differed significantly between deadwood and the...
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Vegetation of post-mining sites determines soil microbial community structure and soil processes
Urbanová, Michaela ; Baldrian, Petr (advisor) ; Chroňáková, Alica (referee) ; Bárta, Jiří (referee)
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...
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The importance of bacteria for deadwood decomposition in forest ecosystems
Némethová, Ema ; Baldrian, Petr (advisor) ; Bárta, Jiří (referee)
Forest ecosystems represent a huge reservoir of carbon. The volume of deadwood in managed forests is in the tens of m3 h-1, while unmanaged forests have the volume of deadwood in hundreds of m3 ha- 1. Deadwood is a substrate with a high potential for decomposition. However, deadwood is a specific habitat that has a high C/N ratio and changes due to ongoing decomposition. The C/N ratio decreases with increasing decay time. In addition to the C/N ratio, the pH also changes during the wood pulping process, due to the decomposition of plant biomass by fungi. Moreover, deadwood has a high impermeability. The main decomposers of dead wood are fungi. In addition to them, bacteria, which are numerous in deadwood, also contribute to decomposition. Bacterial communities that decompose woody biomass are affected by these factors, and their distribution is also affected by dead tree species. The aim of this study was to describe how bacterial communities associated with deadwood change during decay. The most significant factor in the decomposition by bacterial communities is the time of decay. Bacteria found in short-decaying wood (less than 16 years old) are more diverse than those found in long-decaying wood. Methylotrophic bacteria and N-fixing bacteria are common in short-decaying wood as well. N-fixing...
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Vliv teploty plnícího vzduchu na parametry přeplňovaného motoru
Bárta, Jiří
The thesis entitled ,The influence of charge air temperature on supercharged engine parameters, deals with thermodynamics of internal combustion engine in the first part. Next part describes systems of supercharging internal combustion engines and charge air cooling systems for supercharged engines. The final part is dedicated to analysis of measured data. The measurement took place at the engine testing room of XXX in Brno. The aim of the thesis is to determine the influence of intake air temperature on supercharged engine parameters.
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Coordination behaviour of substituted cyclen derivatives
Bárta, Jiří ; Kotek, Jan (advisor) ; Vargová, Zuzana (referee) ; Lubal, Přemysl (referee)
Magnetic resonance imaging (MRI) is one of the none-invasive techniques of human body examination. The only disadvantage of MRI is a low resolution and specificity, therefore, MRI contrast agents (CAs) are widely used in clinical practice (approximately in 40 % of all examinations). They increase not only resolution and specificity but also efficiency of the examination. The CAs consist of paramagnetic ion (Gd3+ or Mn2+ ) and strong chelator such as H4DOTA. Macrocycle cyclen (1,4,7,10-tetraazacyclododecane) is basis of many derivatives which are being used, including mentioned the H4DOTA ligand. 1,4-phosphonic or 1,4-phosphinic acid cyclen derivatives could be a better alternative to commercially available ones. In this thesis, a synthetic pathway to 5 of these novel derivatives is introduced. The protonation constants and stability constants with metals used in CAs (Mn2+ , Gd3+ ) and other selected ones using the potentiometric titrations are determined for 1,4-H4DO2P, 1,4-H2DO2POEt and 1,4-H2DO2Bn2PH . All three ligands have higher stability constant with Mn2+ - log KLM around 12, than with Ca2+ - log KLM around 8, which is the closest rival for transmetallation under physiological conditions. Strong Gd3+ -complex is formed by hexadentate ligand 1,4-H4DO2P - log KLM = 19.15, which is comparable...
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Vegetation of post-mining sites determines soil microbial community structure and soil processes
Urbanová, Michaela ; Baldrian, Petr (advisor) ; Bárta, Jiří (referee) ; Chroňáková, Alica (referee)
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...
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Synthesis of 1,4-phosphonic and phosphinic acid derivatives of cyclen
Bárta, Jiří ; Kotek, Jan (advisor) ; Vojtíšek, Pavel (referee)
Title: Synthesis of 1,4-phosphonic and phosphinic acid derivatives of cyclen Author: Bc. Jiří Bárta Department: Department of Inorganic Chemistry, Faculty of Science Supervisor: Doc. RNDr. Jan Kotek, Ph.D. Supervisor's e-mail adress: modrej@natur.cuni.cz Abstract This thesis is focused on synthesis of diphosphonic and diphosphinic derivatives of cyclen at 1,4 positions as potential MRI contrast agents. Preparation of 1,4-dibenzylcyclen was optimized in a gramme scale for synthesis of derivatives mentioned above. 1,4-dibenzyl-7,10-bis(diethylphosphonomethyl)cyclen was prepared in a gramme scale. It's fully hydrolyzed and monoester forms were prepared. 1,4-bis(diethylphosphonomethyl)cyclen was synthesized. It's fully hydrolyzed and monoester forms were synthesized. 1,4-dibenzyl-7,10- bis(phosphinomethyl)cyclen was synthesized. The carboxylic function in ester form was attached on diesterphosphonic derivative of cyclen. Altogether 8 derivatives in positions 1,4 and 7,10 of cyclen was prepared, mostly in a gramme scale and with a high yield. All compounds were characterized by NMR and MS. Key words: cyclen, phosphonate, phosphinate, sythesis, MRI
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