National Repository of Grey Literature 93 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Effect of Nanoparticles on Plant Metabolism
Cyrusová, Tereza ; Szotáková, Barbora (advisor) ; Hnilička, František (referee) ; Smrček, Stanislav (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Mgr. Tereza CYRUSOVÁ Supervisor: prof. Ing. Barbora SZOTÁKOVÁ, Ph.D. Consultant: RNDr. Radka PODLIPNÁ, Ph.D. Title of Doctoral Thesis: Effect of Nanoparticles on Plant Metabolism Along with the expansion of nanotechnologies, which are used in many disciplines, the field of nanotoxicology has recently been developed. It deals with the negative effects of engineered nanoparticles on the environment and biota. Considerable attention has already been paid to the toxicity of nanoparticles to plants, however, the mechanisms responsible for their effects are not fully understood yet. At the same time, the possible positive effect of nanoparticles on plants has been investigated in recent years. The aim of our work was to study and evaluate the effect of nanoparticles on the growth of selected plant species and to evaluate their phytotoxicity. We focused on the study of nanoparticles in the form of metal oxides. The content of accumulated metals in germinating plants of mustard (Sinapis alba L.), in in vitro cultures of true-fox sedge (Carex vulpina L.) and the concentration of metal ions released into the culture media were measured by atomic absorption spectrometry (Cu, Fe, Mn, Zn). and inductively...
Synthesis of nucleoside analogs based on derivatives of 2-deoxy-2-fluoro- and 3-deoxy-3-fluoro-D-ribose and pyrazines
Smolka, Ondřej ; Jindřich, Jindřich (advisor) ; Smrček, Stanislav (referee)
This thesis deals with the synthesis of prodrugs based on analogs of nucleoside phosphonates derived from 6-fluoro-3-hydroxypyrazine-2-carboxamide (T-705) and 3- hydroxypyrazine-2-carboxamide (T-1105). T-705 and T-1105 act as inhibitors of an influenza RNA polymerase. Both compounds mimic naturally occurring nucleobases, so their fluorinated nucleoside phosphonates could also be biologically active. Derivatives of 2-deoxy-2-fluoro-D-ribose (2-FdR) were prepared in this work. Because of complications during the syntthesis of 3-deoxy-3-fluoro-D-ribose (3-FdR) derivatives, 5- deoxy-5-fluoro-D-xylose (5-FdX) derivatives were prepared instead. Deoxyfluorination was done after incorporation of suitable protecting groups followed by selective deprotection and phosphonate binding. Furthermore nucleosides were synthetised using silyl-Hilbert-Johnson method and their bis-POM derivattives were also prepared. Key words: favipiravir (T-705), T-1105, prodrugs, phosphonates, fluorinated nucleosides
Effect of selected cosmetic products on estrogen formation
Drejslarová, Iva ; Hodek, Petr (advisor) ; Smrček, Stanislav (referee)
Cytochrome P450 enzymes play a key role in the metabolism of endogenous and exogenous compounds. These enzymes are involved both in biotransformation and steroid hormone biosynthesis. An important member of this family is cytochrome P450 19, aromatase, which catalyzes the final step of estrogen hormone biosynthesis, conversion of androgens into estrogens. The physiologic functions of estrogens include development of secondary sexual characteristicts, maintenance of bone mass or regulation of gonadotropin secretion. However, hormonal imbalance due to endocrine disruptors can result in development of certain cancers or impaired reproduction. Compounds with these effects include, in addition to environmetal pollutants, some drugs and cosmetic additives which people are exposed to on a daily basis. In the present study, the effect of selected perfumes and antiperspirants on the metabolic conversion of testosterone into estradiol, catalyzed by aromatase, was examined. The activity of this enzyme was detected using TLC chromatography. The experiments showed that selected antiperspirants do not affect aromatase activity. For most of the perfumes tested, only a very low aromatase inhibition was observed. Only one sample showed this effect to a higher extent. Based on the comparision of perfume...
New method of peptide separation using electrostatic binding
Palágyi, Attila ; Jindřich, Jindřich (advisor) ; Smrček, Stanislav (referee)
The diploma thesis deals with the development of a new method of synthetic peptide separation using electrostatic binding. It deals with the development of a multi-charged anchored linker attachable to a synthetic peptide after its synthesis on solid phase. Subsequently, it investigates the separation using electrostatic binding; however, after peptide cleavage from the anchored linker and Boc deprotection with TFA, the peptide formed so strong electrostatic interactions with the cation exchanger that we were unable to recover it. The thesis is finished with discussion and method improvement proposal. Key words: peptide separation, solid-phase peptide synthesis, SPPS, electrostatic binding
Synthesis of 9-deazaguanine derivatives as potential inhibitors of tRNA-guanine transglycosylase (TGT)
Chylíková, Barbora ; Hocek, Michal (advisor) ; Smrček, Stanislav (referee)
Shigellosis is an acute diarrheal disease caused by enterobacteria of the genus Shigella. Worldwide, these bacteria are responsible for about 1 million deaths out of 165 million cases of the disease yearly, of which children under the age of 5 from developing countries are the most vulnerable group. The enzyme tRNA-guanine transglycolase (TGT for short) has been identified as essential for the effective pathogenesis of Shigella bacteria and therefore becomes a potential target for the selective treatment of shigellosis. This bachelor thesis describes the optimization of the preparation of a key intermediate for the synthesis of potential TGT inhibitors based on 8-aryl-9-deazaguanine structure. The synthesis starts from commercially available 2,6-dichloro-9-deazapurine. The main steps of the synthesis are the hydrolysis at position 6, the nucleophilic aromatic substitution of the chlorine group for the amino group in position 2, further the iodation and the introduction of the 3-thienyl group in position 8 by Suzuki coupling.
Acyclic nucleosides of 3-hydroxypyrazine-2-carboxamide bases
Chaloupecká, Ema ; Jindřich, Jindřich (advisor) ; Smrček, Stanislav (referee)
This thesis deals with the preparation of acyclic nucleosides and nucleoside phosphonates of compounds T-705 (6-fluoro-3-hydroxypyrazine-2-carboxamide) and T-1105 (3-hydroxypyrazine-2-carboxamide). Acyclic nucleoside phosphonates are substances that can terminate viral RNA or DNA replication, and some of them are used in the treatment of viral diseases. T-705 and T-1105 have shown activity against the influenza virus, and T-705 has already been approved for its treatment in Japan. Since both compounds mimic natural nucleobases in the body, their acyclic nucleosides and nucleoside phosphonates also have the potential to be biologically active. Methods for the synthesis of 3-fluoro-2-(phosphonomethoxy)propyl and 3-hydroxy-2-(phosphonomethoxy)propyl derivatives of T-705 and T-1105, their prodrugs containing lipophilic groups for the improvement of the pharmacokinetic properties and also their phosphonate diphosphates, suitable for the biological activity measurements, have been proposed. Some of these derivatives were subsequently prepared. Key words: acyclic nucleosides, acyclic nucleoside phosphonates, T-705, T-1105, favipiravir, antiviral activity, influenza
Interaction of selected cosmetic additives with biotransformation enzymes
Bušovská, Radka ; Hodek, Petr (advisor) ; Smrček, Stanislav (referee)
Substances which cause an endocrine dysfunction have a negative impact on the human body and can be found all around us. One of the main mechanisms of their action is the binding to cell receptors or the inhibition of key enzymes involved in steroid hormone synthesis. In this study, the inhibitory effect of selected perfumes and car air fresheners on the activity of aromatase, the key enzyme of steroidogenesis, was examined. Aromatase converts male sex hormones into the female ones. Inhibition of this enzyme results in decreased estrogen concentrations and may thus affects human fertility. The aromatase activity was examined based on the aromatization reaction of testosterone into estradiol. The formation of estradiol was monitored by TLC method. Based on the results of the pilot study the tested perfumes do not significantly inhibit the aromatase activity, while air fresheners in cars appear to be potential aromatase inhibitors. Keywords: Endocrine dysfunction, steroidogenesis, aromatase, perfumes, air fresheners, TLC, chromatography

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