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Nest construction
Jenšovský, Václav ; Kreisinger, Jakub (advisor) ; Šulc, Michal (referee)
The nest is in the life of birds important structure. It's a place where kept for posterity during the entire period of reproduction. For this to be nest offspring suitable place for development, must have a specific structure which is variable for each species. Variability, whether at the level of intraspecific and interspecific level and is influenced by several factors. These factors include thermal insulation properties, antipredatory properties, further property to protect the nest before (ecto) parasites, but also can design nest pose as a selectable character sexually. Each of those factors differently closer together, but often one factor may disadvantage second and thus reduce the success of rearing offspring. Key words: nest construction, thermal insulation properties, antipredatory properties, ectoparasites, sexual selection
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Analogues of IGF-1 for the study of interactions of the hormone with the receptors for IGF-1 and insulin
Macháčková, Kateřina ; Jiráček, Jiří (advisor) ; Obšilová, Veronika (referee) ; Šulc, Miroslav (referee)
Insulin/IGF system is a complex network of three similar hormones (insulin, IGF-1 and IGF-2) and their three similar receptors (IR-A, IR-B and IGF-1R,), which play important roles in maintaining basal energy homeostasis of the organism, in growth, development, life-span but also in development of diseases such as diabetes mellitus, cancer, acromegaly or Laron dwarfism. Despite structural similarities between family members, each member have its unique role in the system. Identification of structural determinants in insulin and IGFs that trigger their specific signalling pathways is important for rational drug design for safer treatment of diabetes or for more efficient combating of cancer or growth-related disorders. In this thesis, we focused on identification of such structural determinants in IGF-1. Comparison of our data with parallel studies with IGF-2 and insulin could give a more complex picture of the problem. First of all, we developed necessary methodologies for the preparation of IGF-1 analogues. We developed a new methodology for the total chemical synthesis of IGF-1 analogues based on the solid-phase synthesis of fragments and their ligation by a CuI -catalyzed cycloaddition of azides and alkynes. In parallel, we developed a procedure for a recombinant production of IGF- 1 and its...
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Kinetic properties of β-N-acetylhexosaminidase from tobacco plants
Valenta, Robert ; Ryšlavá, Helena (advisor) ; Šulc, Miroslav (referee)
β-N-acetylhexosaminidase from tobacco leaves (Nicotiana tabacum L.) was partially purified to final specific activity 1,72 µmol . min-1 . mg-1 using p-nitrofenyl-β-N- acetyl-D-glucosaminide as substrate. The enzyme exhibited one band after both isoelectric focusing and native electrophoresis. Molecular mass of native enzyme was determined by gel chromatography (MR 275000) and native electrophoresis (MR 285000). Isoelectric point pI 5.4 was determined by isoelectric focusing. Activity of β-N-acetylhexosaminidase was measured using substrates p-nitrofenyl-β-N-acetyl-D-galactosaminide, p-nitrofenyl-β- N-acetyl-D-glucosaminide, N,N'-diacetylchitobiose, p-nitrofenyl-N,N'- diacetylchitobioside and N,N',N''-triacetylchitotriose. For substrates N,N'- diacetylchitobiose, p-nitrofenyl-N,N'-diacetylchitobioside and N,N',N''-triacetylchitotriose an enzyme assay of β-N-acetylhexosaminidase using capillary zone electrophoresis was developed. Optimal pH and temperature of β-N-acetylhexosaminidase were determined with individual substrates, as well as products of hydrolysis. Activity of β-N- acetylhexosaminidase was highest using p-nitrofenyl-β-N-acetyl-D-glucosaminide as substrate and lowest using N,N',N''-triacetylchitotriose (35% in relative comparison). Maximum velocity and Michaelis constant of...
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Preparation of mutated forms of fosfatidylinositol kinase IIα
Gregor, Jiří ; Šulc, Miroslav (advisor) ; Košek, Dalibor (referee)
Phosphatidylinositol 4-kinases (PI4K) are enzymes that form phosphatidylinositol-4- phosphate, which is an important regulatory molecule and precursor for the synthesis of other regulatory molecules. PI4K are interesting from medical aspect, because of connection between their function and viral, malignant, metabolic and neurodegenerative diseases. PI4K type II are inhibited by calcium cations, whereas PI4K type III aren't. The goal of this thesis was to elucidate the relationship between structure and regulation of function of PI4K IIα, specifically regulation by calcium cations. We failed in preparation of mutated forms of PI4K IIα that wouldn't be inhibited by calcium cations. However, the results obtained suggest, how aminoacids N313, D346 and E193 affect the kinase activity of PI4K IIα. (In Czech)
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A study of the temperature sensitivity of the human TRPA1 channel
Barvíková, Kristýna ; Šulc, Miroslav (advisor) ; Černá, Věra (referee)
Transient receptor potential (TRP) ion channels play important physiological roles in the detection of environmental stimuli that occur primarily at the peripheral terminals of specialized sensory neurons. The recently resolved cryo-electron microscopy structures and molecular biological techniques have provided new tools that enable to study these channels in relation to their function, and thus to understand more deeply their pharmacology and physiology. The aim of this bachelor thesis is to give an overview of the current status of research on the ankyrin TRP channel subtype 1 (TRPA1), a channel activated by diverse irritant chemical stimuli but also by temperature changes. The experimental part is focused on the elucidation of the role of the sensor domain in thermal sensitivity of the TRPA1 channel. Using whole-cell patch-clamp electrophysiological technique, the presented results demonstrate that the sensor is an important determinant of voltage-dependent gating. Mutation of the conserved tyrosine in the center of the sensor resulted in channels with clearly different activation kinetics and increased chemical responses upon increasing the temperature from 25 řC to 35 řC. Key words: TRP ion channel, ankyrin receptor, nociception, structure-function, carvacrol
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Excitation of molecules by cold electrons
Šulc, Miroslav ; Horáček, Jiří (advisor) ; Čárský, Petr (referee) ; Čížek, Martin (referee)
Title: Excitation of molecules by cold electrons Author: Miroslav Šulc Department / Institute: Institute of Theoretical Physics, Charles University in Prague Supervisor of the doctoral thesis: prof. RNDr. Jiří Horáček, DrSc., Institute of Theoretical Physics, Charles University Abstract: Several methods for low energy collisional processes are investigated. In the first part, attention is especially devoted to examination of applicability of the R-matrix method combined with the Schwinger-Lanczos (SL) variational principle for potential scattering with long-range forces. Next sections deal with the development of the interaction correlation-polarization (CP) potential in the framework of the Dis- crete Momentum Representation (DMR) method on the grounds of the Local Density Approximation in the Density Functional Theory (DFT) context. Obtained results are then utilized in body-frame (BF), static exchange + polarization (SEP), calcula- tions within an analysis of experimental data for e−-N2 scattering comprising a part of a larger project addressing theoretical examination of rotational excitations of small molecules in the gas phase induced by electron impact. For N2, a new phenomenon consisting in suppression of backward cross-section below 95 meV is observed and con- sequently attributed to...
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