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The role of personality in social interactions
NOVÁKOVÁ, Ivana
The aim of this study is to get together issues about animal personality and the way it is influenced by social environment. One part of this thesis is designing my own experiment, which is focused on the influence of social environment on mole-rat personality traits. This experiment will be done in masters degree.
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High-Quality Shadow Rendering from Complex Light Sources
Navrátil, Jan ; Sochor, Jiří (referee) ; Navrátil, Jan (referee) ; Zemčík, Pavel (advisor)
V interaktivních aplikacích jsou stíny tradičně zobrazovány s pomocí algoritmu založeným na stínových mapách. Nevýhodou toho algoritmu je, že stínová mapa, reprezentovaná texturou, má pouze omezené rozlišení. To může vést k nepěkným vizuálním artefaktům objevujících se na hranách stínů. Tato práce představuje postup, který je založen na vylepšené deformaci textury. To umožní zobrazit scénu obsahující složité světelné zdroje, zredukovat artefakty na hranicích stínů a také vylepšit kvalitu stínů bez ohledu na typu scény a její konfiguraci.
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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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Distribution of CD46 and β1 integrin molecules with respect to different membrane structures of the sperm head
Šebková, Nataša ; Frolíková, Michaela ; Děd, Lukáš ; Dvořáková-Hortová, Kateřina
CD46 protein plays an important role during fertilization and its role is associated with acrosome stability. CD46 is probably involved in signalling pathways triggering the acrosome reaction (AR). It also associates through membrane integrins with specific MAP kinases involved in the AR. Our aim was to monitor the dynamics of relocation of CD46 and β1 integrin during sperm maturation and its preparation for the fertilization. The dependence of this localization changes on the dynamic of actin cytoskeleton was studied. Our results show the changes in the localization of these proteins associated with the AR and their co-localization was observed using proximity ligation assay. After the AR CD46 and β1 integrin spreads across the sperm head, entering the post-acrosomal compartment, and permeates the borders of different domains. It was shown previously that actin dynamics is necessary for acrosome reaction-associated translocation of Izumo1 protein that is required for sperm-egg fusion. Therefore Latrunculin A was used during sperm incubation. The co-incubation of capacitated sperm with Latrunculin A leads to a decrease of the percentages of sperm, which express relocation pattern after induced AR. 3D models and visualizations of potential membrane processes responsible for the relocation of proteins from the acrosomal area to the other compartments of the sperm head were prepared. Our results deliver new information that proteins CD46 and β1 integrin undergo dynamic relocation towards the sites of sperm-egg fusion during the AR in vitro. The inhibitor of actin dynamics abrogates significantly the AR-associated changes in proteins localization. We speculate that this relocation is of importance for the successful sperm-egg interaction, adhesion and subsequent gamete fusion.
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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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Possible role of spermatogenic protein glyceraldehyde-3-phosphate dehydrogenase (GAPDHS) in mammalian sperm
Margaryan, Hasmik ; Dorosh, Andriy ; Čapková, Jana ; Postlerová, Pavla ; Philimonenko, Anatoly ; Hozák, Pavel ; Pěknicová, Jana
Sperm proteins are important for the structure and function of these specific, highly differentiated cells. Certain of these proteins play a role in sperm-egg recognition during primary or secondary binding at zona pellucida glycoprotein matrix. The aim of this study was to characterize the acrosomal sperm protein recognized by a monoclonal antibody (MoAb) Hs-8, prepared in our laboratory by immunization of BALB/c mice with human ejaculated sperm, and to test the possible role of this protein in gamete interaction. MoAb Hs-8 specifically labelled a 45 kDa protein from the sperm extract in the immunoblotting test. Sequence analysis identified this Hs-8 protein as GAPDHS. In order to perform a control tests, a commercial mouse anti-GAPDHS MoAb was applied. Both antibodies showed similar staining patterns using immunofluorescence labelling, transmission electron microscopy and immunoblot analysis. Moreover, both Hs-8 and commercial anti-GAPDHS antibodies blocked the secondary sperm-zona pellucida binding. Generally, GAPDHS was considered mainly as sperm-specific glycolytic enzyme involved in energy production during spermatogenesis and sperm motility and its role in the sperm head was unknown. In this study, we confirmed the potential additional role of GAPDHS as a binding protein that is involved in the sperm-zona pellucida interaction.
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Change trajectories of wood pastures using landscape metrics
Štěch, Petr ; Skaloš, Jan (advisor) ; Pavel, Pavel (referee)
This work is processed in a form of study on a topic of description of change trajectories in a historical development of woody pastures in selected areas of Moravian Silesian region and Olomouc region, Czech Republic. There were chosen 6 cadastrals of stable cadastral in the study areas. These were studied for the change trajectories between the 19. and 21. century. The analysis were processed in geographic information systems with usage of landscape metric methods. The main goal of this work is description, interpretation and explanation of change trajectories of woody pastures in studied areas. This work also shows the interactions between changes in the landscape and the character of the landscape.
The first part discusses definitions and descriptions of woody pastures in general and also brings the newest information of the studied topic. The main part of this work is the study itself.
The main benefits of this work lies mainly in describtion of the changes in development of the woody pastures in the studied areas. The information and data obtained may contribute to better understanding of the ways of historical development of woody pastures. Obtained data will be used for future studies on a level of whole Czech republic.
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Analysis and modeling of the structure and development of mixed forest stands in the Sudety mountains
Vacek, Zdeněk ; Remeš, Jiří (advisor) ; Hlásny, Tomáš (referee)
The thesis deals with analysis and modeling of the structure and development of selected mixed forests in protected areas of the Sudeten system, especially in the Giant Mountains national parks, Protected Landscape Area Broumovsko and Orlické Mountains, but also in other areas of the Czech Republic. This study is composed of a set of six published manuscripts that are covering three thematic ranges: structure of forest stands, regeneration of forest stands and forest modeling. The main objective of this work was to evaluate a vertical, horizontal and species structure, total diversity and development of mixed forest stands in central Sudetes. The partial aim was to analyse production parameters of forest stands, effect of microrelief and game on natural regeneration and assessment of dead wood in the area of interest. Further, the objective of the study was to develop explicit and non-explicit crown width and slenderness quotient models for Norway spruce (Picea abies L.) and European beech (Fagus sylvatica L.) and to predict the development of mixed forest ecosystem using growth simulations and to evaluate parameters and interactions among stand structure, climatic factors and natural regeneration, using especially analysis of variance, correlation matrix, spatial statistic and multivariate analysis. For this purpose a system of permanent research plots was used, which are regularly monitored since 1980 or were newly established. Using mapping technology FieldMap, selected parameters were measured for tree layer, natural regeneration individuals and dead wood. The results showed that the spatial distribution of beech stands in optimum stadium changes with the altitude from the regular pattern through random to aggregated spatial pattern of beech forests near the timberline. The spatial distribution of natural regeneration is highly aggregated, distribution of stumps is random and horizontal structure of the centroids of the crowns is always more regularly distributed than stems due to crown plasticity. Browsing damage of the leading shoot by game is an important limiting factor for height growth of natural regeneration, especially for silver fir (Abies alba Mill.), rowan (Sorbus aucuparia L.) and sycamore maple (Acer pseudoplatanus L.). The study of the influence of microrelief on the growth of beech regeneration showed that the highest average height was found on slope and pits, while the lowest on the mounds. From the effect of climatic factors on the radial growth of trees, it was found that temperature is a limiting factor for growth in mountain areas, respectively that positive effect of temperature decreases with decreasing altitude and conversely the influence of precipitation increases. Finally, spatially explicit models (as opposed to non-explicit) described a larger part of the crown width variations for spruce and beech and of the slenderness quotient for spruce. The largest contribution to the models after breast diameter was dominant height.
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