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Specificity of insect-plant associations and their role in the formation of plant defenses and speciation
VOLF, Martin
The aim of this dissertation is to investigate what role insect-plant interactions play in the formation of host-plant defenses and in the diversification of both groups. We show that various groups of herbivore respond differently to host-plant defenses. Therefore plant defenses diversify into suites of complementary traits, as individual traits fail to provide protection against specialized herbivores. Further, we identify what levels of host-phylogeny shape the food-web structure of insect herbivores. We show that specialized herbivores are affected mainly by the terminal parts of the host-phylogeny. In contrast, more polyphagous guilds are affected mainly by the mid-levels of the host phylogeny because the effects of terminal or deeper phylogeny seem to be surpassed by other factors in more generalist insect species. In the last chapter, we show how specialized insect-plant interactions generated by tight insect-plant coevolution can influence the speciation in plants over environmental gradients.
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Crystallographic study of the iron-regulated outer membrane lipoprotein (FrpD) from Neisseria meningitidis
SVIRIDOVA, Ekaterina
Neisseria meningitidis (N. meningitidis) is a Gram-negative commensal bacterium colonizing nasopharynx of about 10 % of healthy individuals, which can cause invasive diseases, such sepsis and meningitis, upon occasional penetration into bloodstream. Pathogenesis of N. meningitidis appears to be directly related to conditions of limited iron availability. Under these conditions two proteins of unknown function: FrpC and FrpD, are synthesized. FrpD is a highly conserved lipoprotein of N. meningitidis anchored to the bacterial outer membrane. It is known that FrpD tightly binds the FrpC protein, which belongs to the Repeat-in-Toxin (RTX) protein family and may act as bacterial exotoxin. However, the mechanism of FrpD-FrpC interaction and the exact function of this complex are unknown due to the absence of structural information on these proteins. Therefore, we set out to determine the structure of FrpD and provide insights into its interaction mechanism with FrpC and structure-functional relationships of these two proteins. We determined the first crystal and solution structures of the FrpD protein. We found that atomic structures of FrpD reveal a novel protein fold. We uncovered the structure-function relationships underlying the mechanism of interaction between the FrpD and FrpC proteins and tested the putative function of the FrpD-FrpC1-414 complex in vitro. Finally, we proposed the putative function of the FrpD-FrpC1-414 complex as a new minor adhesin of N. meningitidis, which mediates the bacterial adhesion to the host epithelial cells and facilitate the colonization. Our work constitutes the first step in clarifying the molecular basis of the FrpD-FrpC interaction and sets the base for further investigation of the role of FrpD and FrpC in the virulence mechanism of N. meningitidis.
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Estrogen receptor beta (ERβ) in testicular cells and sperm
Dostálová, Pavla ; Žatecká, Eva ; Děd, Lukáš ; Dorosh, Andriy ; Postlerová, Pavla ; Jonáková, Věra ; Dvořáková-Hortová, Kateřina ; Pěknicová, Jana
Estrogen is a steroid hormone that plays an important role during sperm development in the male and female reproductive tract. Estrogen signalling is a complex process that depends on cell milieu and presence of receptors. Thanks to the steroid nature of estrogens, they can pass through the plasmatic membrane and bind to the intracellular estrogen receptors (ERs). Within the cell, there are several pools of ERs. One of them is localized to the cell nucleus and their activation leads to direct or indirect binding to DNA and ultimately to alternation in gene expression (genomic pathway). Other pools of ERs are associated with plasma membrane or are located in cytosol. Activation of membrane associated ERs leads to rapid non-genomic responses. Nowadays, two classical estrogen receptors are known – ERα and ERβ. Since ERβ is a predominant variant in testes, we focused our study on expression of ERβ variants in murine testes and sperm. We detected two variants of ERβ at mRNA level in both, testes and sperm. These variants differ in 54 nucleotids within the ligand binding domain and this variability results in different affinity to estrogen. We analyzed individual testicular cell types (spermatogonia, spermatocytes, spermatids, Sertoli cells) by RT-qPCR. Our results suggest that both ERβ variants are coexpressed in the same cell type and may therefore interact together. This may have consequences in mediating of estrogen signalling. Moreover, ERβ is expressed more in the later stages of spermatogenesis suggesting the role of ERβ in these stages or alternatively in spermatozoa alone. At the protein level, we detected ERβ in nuclear, membrane and cytosolic fraction prepared from testicular tissue suggesting the involvement of both, genomic and non-genomic, pathways of estrogen signaling in testes. In sperm, anti-ERβ antibodies localized ERβ in acrosome region and tail which is in accordance with the known role of estrogen on capacitation, acrosome reaction and motility.
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The economic and social costs of firearm regulation: Impacts of regulation of output, sale, export and import of firearms on state economy and citizens.
Kukač, Petr ; Procházka, Pavel (advisor) ; Hřebík, Tomáš (referee)
This thesis analyzes effect of firearm regulation on crime rate and selected macroeconomic indicators and compares the results with previous findings. The starting point is Gary Becker's economics of crime adapted to the topic of civilian gun ownership. It contains correlation analysis observing the interaction of legally held firearms and gun crime committed with those firearms. The result of the analysis is strong negative correlation between two variables. The second part of this thesis also contains crime statistics from selected OECD countries. The final part shows us the macroeconomic impact of regulation of civilian gun ownership. The result is that changes in gun policy will cause significant impact on employment, collected taxes, output and international trade.
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Tester Stand for Testing Tire Chains
Bednář, Petr ; Plšek,, Ladislav (referee) ; Foller, Bronislav (advisor)
The output of this diploma work (dissertation) will be design of a construction for a tester enabling simulation of riding a vehicle with mounted snow chain in winter season on road without snow. The result of testing will be abrasion of single link of the chain caused interaction with surface of road and strength test of weld link e.g. when is pass gravelly surface.
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High-Frequency Pulsations Modeling
Střecha, Ludvík ; Kubálek, Jiří (referee) ; Habán, Vladimír (advisor)
The diploma thesis deals with the mathematical modeling of high-frequency pressure pulsations in water turbines. Pulsations are caused by the interaction between stator a rotor blades. These high-frequency pressure pulsations then cause high cycle fatigue of the head cover, spiral casing, runner and distributor. The mathematical model is solved by transfer matrix method. Data are processed in F-A char and MS Excel programs. Final results are demonstrated by frequency amplitude characteristics and by pressure mode shapes, where comparison of the mathematical model with the measurement is shown.
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Psychological aspects of teamwork
Voskár, Michal ; Jarošová, Eva (advisor) ; Pauknerová, Daniela (referee)
Forming individuals into work groups is a common practice to effectively achieve given goals. However, people are not well aware of psychological aspects affecting group work. This paper introduces chosen psychological phenomena and summarizes their influence on teamwork into one comprehensive unit. Second, it examines emergence of groupthink based on Janis' model (1972) in a decision-making environment with high impact on subjects involved. The results confirm implications of Janis' model in practice and suggest that groupthink may have an indirect effect on team performance mediated by interaction within the group. The findings of this study indicate more attention should be paid to internal activities of the team in future research of Janis' model of groupthink.
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Interaction of humans and the environment in residential hauses with walls from inorganic masonry
Brada, Lukáš ; Kocourková, Jana (advisor) ; Zemanová, Lucie (referee)
Interaction of humans and the environment, is subject to the occurrence of mold in
residential buildings. Mold development has been the ultimate result of a variety of
phenomena, processes and causes that have penetrated in various stages of preparation,
implementation and operation of buildings. The negative effects which the mold in a residential area buildings exhibit is primarily a reduction in the use of comfort living
space in the form of health risks in the form of allergic reactions and possibly causing
chronic problems. Chronic problems over time can lead to serious illness. A big role in
the occurrence of mold also plays a reduction of aesthetic values of residential spaces
requiring repair and remedy these deficiencies. When removing adverse events leads to
an unnecessary additional environmental burden.
Problems of fungi in ground buildings are very expansive and interdisciplinary
problems, which incorporates structural, termomechanic, chemical and biologic aspects.
In this undergraduate work I concentrated on the origin of fungi in ground buildings
with inorganic materials and I am discribing at least some important sources and aspects
of fungi origin in each phases origin and exploitation building, with usage of specialised
literature. Model compultations and examples of origin fungi are performed.
Autocephalous origin of fungi in residencial buildings is yet fallback situation, which
can be possibly prevented. But due to conditions for origin fugi can begin long ago this
fallback situation. Store of bias each phases living buildings is accentuated on possibly
fugi production in buildings from project up to operation.
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