|
|
Role of tau phosphorylation in formation of tau envelopes
Karhanová, Adéla ; Lánský, Zdeněk (advisor) ; Štěpánek, Luděk (referee)
Tau is an intrinsically-disordered microtubule-associated protein important for axonal development and a critical regulator of microtubule functions in axons. Tau activity is controlled by phosphorylation and its deregulation resulting in tau hyperphosphorylation and aggregation has been linked to multiple neurodegenerative disorders, collectively termed tauopathies. On microtubules, tau molecules segregate into two kinetically distinct phases, consisting of either independently diffusing molecules or interacting molecules that form cohesive "envelopes" around microtubules. Tau envelopes regulate the action of other microtubule-associated proteins, such as the motility of molecular motors, and protect microtubules against degradation by microtubule-severing enzymes. How the formation, dynamics, and function of tau envelopes are regulated, however, is unknown. Here we show that tau phosphorylation impedes the formation and functioning of protective tau envelopes. Using a combination of reconstitution experiments and live cell imaging, we show that phosphorylated tau incorporates into tau envelopes and that it slows down the envelope growth. Importantly, we demonstrate that phosphorylated tau also destabilizes already existing envelopes leading to their disassembly. Together, our results demonstrate...
|
|
|
Interference of selected DNA viruses with apoptotic processes
Sauerová, Pavla ; Forstová, Jitka (advisor) ; Štěpánek, Luděk (referee)
This work is focused on selected DNA viruses and some of their mechanisms used for inhibition or induction of the apoptotic processes. The selected DNA viruses are Hepatitis B virus, polyomaviruses, papillomaviruses and herpesviruses. Viruses developed different strategies for fighting the host defense mechanism during their evolution. One of the host defense mechanisms that reacts against virus infection is apoptosis. In case of viruses we can observe the phenomenon of inhibition or induction of apoptosis (which both depend on the life cycle phase of the virus). The purpose of these "fighting" strategies is to ensure successful replication, virus releasing from the cell and finally to let it spread in an organism or among them. Some "fighting" strategies are similar e.g. targeting and manipulation on p53 oncosupresor level or production of Bcl-2 homologs; other strategies are very specific. Certain viruses have mechanisms which allow them to survive in a host organism for a long time.
|
|
| |
|
|
Swimming of the Disabled in the Context of History
Štěpánek, Luděk ; Hronzová, Marie (referee)
Title Swimming and the disabled in the contexts of history Name: Luděk Štěpánek Tutor: PhDr. et PaedDr. Miroslav Kašpar, Ph.D Objective: On the basis of a historical analysis of a thematically relevant sources and literature to asses and make an interpretation the relation of the society to the swimming of the disabled within historical stages, historical relations, and selected points of view. Methods: Historical study, comarative, inductive method. Results: A complex view of swimming as a physical activity of the disabled in the context of (1) European historical relations between the society and the disabled, (2) Swimming activities of unhandicapped people, and (3) medical phisical education incl. actual news. Keywords: history, swimming, the disabled, sports games, phisical education, sport, society
|
|
|
Analysis of the Yeast Colony Structure: Peroxisomes and Autophagy
Štěpánek, Luděk
Analysis of yeast colony structure: peroxisomes and autophagy Abstract This study is a part of the project "Molecular biology and physiology of yeast communities". Yeast colonies grown on solid complex medium communicate by periodical release of volatile ammonia (PALKOVÁ et al. 1997), which is accompanied by periodical alkalization of colonies and growth substrate. Transition of colonies to the ammonia producing period of their life is accompanied by global changes of gene expression, as was shown using RNA microarrays (PALKOVÁ et al. 2002). Changes in many metabolic genes were observed, indicating activation of peroxisomal fatty acids β-oxidation, activation of glyoxylate cycle enzymes and inhibition of mitochondrial oxidative phosphorylation. These data suggest a significant switch of cellular metabolism during early alkali phase, based on peroxisomal induction and mitochondrial decline. This switch could be facilitated by autophagy, the process which can selectively or non-selectively remove unnecessary cellular components, providing the cell with energy and removing parts interfering with the new metabolism. Saccharomyces cerevisiae strain expressing peroxisomal GFP was constructed in order to visualise peroxisomes and strain containing GFP-tagged autophagic protein Atg8p was prepared to monitor...
|
|
|
Codon usage and isoacceptor tRNA expression as a mechanism to control gene expression
Daumová, Lenka ; Čáp, Michal (advisor) ; Štěpánek, Luděk (referee)
Genetic code is defined as a set of rules, which encode aminoacid sequences in proteins, according to codon usage. It is widely known, that there are multiple codons for most aminoacids, thanks to the degeneracy of the genetic code. There was a hypothesis, that silent mutations, which result in a synonymous codon and not in incorporating of a different aminoacid into the peptide chain, don't affect the gene expression. Later however, it was found through more detailed research on molecular level, that codon usage bias is in fact one of the factors, that regulate translation effectivity and rate, mRNA stability or even protein folding and gene expression. There has been many studies published on these topics. This bachelor thesis is a review of these studies. First, I summarize basic information on tRNA, its structure and modifications in anticodon loop. Next I write about base pairing between codon and anticodon, including the non-canonical wobble base pairing. Then I emphasize on codon bias, its causes, its relationship with genome GC content. I also include some author's conjectures about how to approach this phenomenon, which codons are optimal and what is the impact of codon usage bias on translation efficiency. I cite many studies on this topis, which was researched on many model organisms,...
|
|
| |
|
| |
|
| |
|
|
Swimming of the Disabled in the Context of History
Štěpánek, Luděk ; Hronzová, Marie (referee)
Title Swimming and the disabled in the contexts of history Name: Luděk Štěpánek Tutor: PhDr. et PaedDr. Miroslav Kašpar, Ph.D Objective: On the basis of a historical analysis of a thematically relevant sources and literature to asses and make an interpretation the relation of the society to the swimming of the disabled within historical stages, historical relations, and selected points of view. Methods: Historical study, comarative, inductive method. Results: A complex view of swimming as a physical activity of the disabled in the context of (1) European historical relations between the society and the disabled, (2) Swimming activities of unhandicapped people, and (3) medical phisical education incl. actual news. Keywords: history, swimming, the disabled, sports games, phisical education, sport, society
|
guest ::
RSS feed.