National Repository of Grey Literature 21 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Role of exotic woody plant species in introductions of non-native symbiontic fungi
Vlk, Lukáš ; Kohout, Petr (advisor) ; Bárta, Jiří (referee) ; Anthony, Mark (referee)
The introduction of alien microorganisms so far received much less attention compared to macroorganisms. The introduction of alien fungi is currently considered an important and understudied component of global environmental change. Outbreaks of alien fungal pathogens threaten native plant and animal communities and cause immense ecological and economic damage. The introduction of alien mycorrhizal fungi enables the invasion of their hosts and could significantly alter key ecosystem functions and the soil biogeochemistry of recipient ecosystems. Evidence suggests that the introduction of alien plants serves as a major pathway for the spread of alien fungi. The main goal of this dissertation was to significantly contribute to the understanding of the phenomenon of the introduction of alien fungi. Specifically, this work aims to (1) assess the difference in the strategy of the two most commonly introduced alien tree groups on a global scale, pines and eucalypts, to obtain suitable ECM fungal partners in new areas, (2) assess the prevailing ecology of alien ECM fungi on a global scale, and (3) determine the extent of the introduction of alien fungi associated with alien trees in the chateau parks of the Czech Republic and identify environmental factors that affect their relative abundance, richness...
Natural enemies of the European spruce bark beetle \kur{Ips typographus}
BÁRTA, Jiří
Bark beetles (Scolitynae) are among the most important pests of forest stands, where they cause extensive damage, especially in spruce monocultures. Their negative effect is to attack the host tree, which is its source of food and at the same time provides them with space for reproduction. The bark beetle is able to have several generations per year under suitable temperature conditions. One of the most widespread is consi-dered to be the European spruce bark beetle Ips typographus. This species is able to search for weakened and abiotically damaged trees. Integrated Pest Management of forests includes several effective methods against bark beetles. The most used met-hods include the installation of feromone traps, traps trees and poisoned tripods. The European spruce bark beetle is in their population regulated by many natural enemies. From parasitoids such as Coeloides bostrichorum and Rhopalicus tutela and predators Thanasimus formicarius and Medetera spp. to pathogenic microorganisms such as entomopathogenic viruses, bacteria, protozoa, microsporidia and especially entomo-pathogenic fungi belonging to the order Hypocreales. The most important species is the fungus Beauveria bassiana, which has the greatest potential in the biological pro-tection of spruce stands.
Molecular biology and ecology of microbial decomposition of plant-derived biopolymers in forest ecosystems
Žifčáková, Lucia ; Baldrian, Petr (advisor) ; Uhlík, Ondřej (referee) ; Bárta, Jiří (referee)
The abilities of fungi and bacteria to degrade simple and complex carbon compounds derived from different sources, such as root exudates, litter, soil organic matter or fungal mycelium were studied in this dissertation. Knowledge of functional traits, especially degradation abilities of fungi and bacteria, are important for deciphering the black box of microbial functioning in topsoil and thus aiding in modeling and predicting future directions of microbial communities development in face of global changes. Among fungal cultures form culture collection representing strains with different taxonomy and ecophysiology, the ecophysiology of fungi was more important in manifestation of functional traits than taxonomy. Among bacterial isolates from the litter and soil of spruce forest, Acidobacteria were confirmed to express multiple decomposition enzymes in high rates in vitro and were also abundant and active degraders in acidic spruce forest soil. The expression of degradation capacities of both bacteria and fungi were further studied in situ in spruce forest topsoil, that represents an important environment due to the ubiquity of coniferous forests on the Northern hemisphere. There is an obvious gap of knowledge, when comes to our understanding of seasonal effect on microbial functioning, and this is...
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...
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...
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...
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...
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.

National Repository of Grey Literature : 21 records found   1 - 10nextend  jump to record:
See also: similar author names
8 BÁRTA, Jakub
36 BÁRTA, Jan
11 BÁRTA, Jiří
2 Bárta, J.
8 Bárta, Jakub
36 Bárta, Jan
1 Bárta, Jaroslav
1 Bárta, Jaroslav,
1 Bárta, Josef
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