|
|
Prions in yeast
Bezdíčka, Martin ; Palková, Zdena (advisor) ; Žíla, Vojtěch (referee)
The thesis describes yeast prions and their biological effects on yeast in general. It defines the basic characteristics of yeast prions, that distinguish prions from other proteins. The thesis introduces various possibilities of prion formation, and propagation as well as specific types of yeast prions, including various functions of most studied types of prions. The thesis also focuses on chaperones that affect the state of yeast prions in cells. Lastly, the thesis indicates similarities between yeast prions and mammalian prions that are related to neurodegenerative diseases. Key words: Yeast prions, features of yeast prions, chaperones, neurodegenerative disease, Saccharomyces cerevisiae
|
|
|
Proteins demaged by oxidative stress, their role in physiology and ageing of yest cells
Mikešová, Jana ; Palková, Zdena (advisor) ; Borčin, Kateřina (referee)
Reactive oxygen species (ROS) are regularly produced in cells as a by-product of aerobic metabolism. Hence, organisms developed various defence mechanisms, which are able to avoid molecular damages caused by ROS under physiological conditions. In stress conditions, however, such defence mechanisms are not sufficient to avoid molecular damages. Accumulation of oxidized proteins is supposed to be a reason for ageing and many diseases including Friedreich's ataxia, Amylotrophic lateral sclerosis, Alzheimer's disease and many others. During oxidative stress, reactive oxygen species are reflected in oxidation of cystein residues in transcription factors, regulation proteins and active canters centers of enzymes. Oxidative modifications however could lead also to changes in transcription factor activity and activation of specific pathways, including changes in gene expression, cell cycle and proteolysis. This work shows defence mechanisms, ROS and proteins altered by reactive oxygen species that may function as important signalling molecules, which are essential for many cellular processes.
|
|
|
Regulation of yeast chronological ageing
Némethová, Ema ; Palková, Zdena (advisor) ; Motlová, Lucia (referee)
Yeast cells are able to differentiate during chronological aging and form different cell- types which acquire different viability. Chronological aging cells do not divide and thus mimic the aging of cells within multicellular organisms, such as mammals. Understanding of mechanisms of chronological aging of yeasts thus could help to understand similar processes of more complex organisms. Two types of cells, called "quiescent" and "non- quiescent" cells, are formed when yeast are grown in liquid medium. These cells have different morphology and gene expression and also differ in their metabolism. Yeast cells within agar-plate-grown colonies can sense different gradients of nutrients and signaling compounds and diversify to different cell types such as U and L cells, located in different colony regions. Both the "quiescent" and U cells are more vital and able to proliferate, whereas "non-quiescent" and L cells are less viable and exhibit stress features. Chronological aging involves many cellular processes including accumulation of storage compounds, mitochondrial activity, functions of specific genes and can be affected by calorie restriction and mild stress. Key words: chronological aging, yeast, differenciation of cell populations, metabolic change
|
|
|
Pronunciation of two distinct "i" Vowels in the East Lach dialect
Blažková, Jana ; Palková, Zdena (advisor) ; Veroňková, Jitka (referee)
The vowel inventory of standard Czech includes five short vowels /a/, /e/, /i/, /o/, /u/ and five long vowels /a:/, /e:/, /i:/, /o:/, /u:/. Nevertheless, the dialectological literature indicates two distinct /i/ vowels, /i/ and /y/, in all the groups of the Lach dialects. The contrast of these two phonemes has a historical origin and has already disappeared in most of Czech and Moravian dialects. The objective of the diploma thesis "Pronunciation of Two Distinct /i/ vowels in the East Lach Dialect" is to witness the present state of the production and perception of two /i/ vowels in the East Lach dialect. Former dialectological texts still indicate the opposition as conserved, though considering the general recession of Czech dialects, the diploma thesis aims to verify if the East Lach dialect still distinguishes the /i/ and /y/ vowel and if this should prove to be the case, to determine the acoustic features that assure its perception. The research was based on minimal pairs and syllables, where the /i/ vowels were preceded by different consonants. The minimal pairs and syllables were inserted in text which was read by the speakers and recorded. Within the framework of the diploma thesis, 30 senior speakers of the East Lach dialect were recorded. Afterwards, six speakers were chosen to feature in two...
|
|
|
Yeast retrograde signaling pathway between mitochondria and the nucleus
Podholová, Kristýna ; Palková, Zdena (advisor) ; Fraiberk, Martin (referee)
Retrograde signaling pathway is the pathway between mitochondria and nucleus. This pathway helps Saccharomyces cerevisiae to cope with worsening of conditions of life, such as depletion of rich nutrient sources and necessity of use poor resources, reduction of mitochondrial membrane potential, or loss of mitochondrial DNA causing disturbances in the citric acid cycle. Most of these conditions are associated with aging yeast populations. Key retrograde pathway proteins include RTG transcription factors Rtg1p/Rtg3p and cytoplasmic protein Rtg2p. Retrograde pathway is upregulated by several positive and negative regulators including the TOR pathway, which negatively regulates retrograde pathway. The retrograde pathway target genes include genes coding for tricarboxylic cycle enzymes, peroxisomal enzymes, transporters and other enzymes of anaplerotic pathways. Retrograde response help cells to modify their metabolism so that they are able to overcome unfavorable environmental conditions in which they live. Powered by TCPDF (www.tcpdf.org)
|
|
|
Acoustic properties of Czech diphthongs
Studenovský, David ; Palková, Zdenka (advisor) ; Zimmermann, Július (referee) ; Hes Svobodová, Marie (referee)
This thesis aims to contribute to the basic acoustic description of Czech diphthongs [ou, au, eu]. The diphthong is a unit characterized by the change of quality within its duration, thus dividing it into two parts. The analysis of this change and the phonologic interpretation of these two-part segments in the system of a given language is however difficult. This is why the description of diphthongs was frequently neglected. At the present time, the need for investigating such units is increasing - neurophonetic and psychological research on the one hand and speech technology on the other are more and more interested in examining speech segments with short temporal changes. To obtain a detailed acoustic description of diphthongs is a topical problem of current language description. In this thesis we studied the aspects of duration, spectrum and intensity changes at the local level and compared them with results acquired for simple vowels. In the temporal domain we observed the duration values divided by the initial, transient and final part of the diphthongs on the basis of auditory perception and also their total duration. The material used was partly taken from the database of the Institute of Phonetics, Faculty of Arts, Charles University in Prague, partly from specifically created texts. The...
|
|
|
TOR signalling in yeast
Šimek, Jan ; Palková, Zdena (advisor) ; Španielová, Hana (referee)
TOR ("Target of rapamycin") protein, a highly conserved Ser/Thr protein kinase, is a central component of signalling network that controls cell growth in diverse eukaryotic organism, ranging from yeast to man. TOR proteins were first identified in yeast Saccharomyces cerevisiae in 1991 as the targets of the antifungal and immunosupressive agent rapamycine. In contrast to most eukaryotes, yeast contains two TOR homologues , Tor1p and Tor2p. These proteins are components of multiprotein complexes TORC1 and TORC2. TORC1 is specifically inhibited by rapamycine and controls cell growth in response to quality of the available nutrients. TORC2, which is insensite to rapamycine, regulates actin polymerization, sphingolipid biosynthesis and endocytosis. This work is focused on description of both TOR complexes, especially on downstream and upstream regulation of TORC1. Powered by TCPDF (www.tcpdf.org)
|
|
| |
|
|
The influence of syntactic structure (conjunctions) on spoken language (utterance section, intonation, pauses). Auditory analyses
Jelínková, Ivana ; Saicová Římalová, Lucie (advisor) ; Palková, Zdena (referee)
The presented thesis "The Influence of Syntactic Structure (Conjunctions) on Spoken Language (Tone Unit, Intonation, Pauses) - Auditory Analyses" explores the relations between conjunctions A (AND), ŽE (THAT), ABY (IN ORDER THAT), PROTOŽE (BECAUSE), ALE (BUT) in an exactly given syntactic structure and a system descritption of phonetic form of language - the tone unite, the intonation, and the pause. This research is based on the comparison of the public read and the public notread, but prepared utterances. At first we segment the chosen examples into the stress units; then we try to confirm the hypothesis that a conjuction begins a new tone unit; within the intonation, we monitor what is typical for the melodic line in the stress unit before the conjunction; the last part of our research is dedicated to pause and to their positions near the stress unit containing the conjunction. The research is based on the auditory analyses, therefore it does not use the instrumental analyses.
|
|
|
Formation of protein granules in differentiated cells of yeast colonies
Kočířová, Eliška ; Palková, Zdena (advisor) ; Heidingsfeld, Olga (referee)
Saccharomyces cerevisiae is a unicellular eukaryotic organism capable of forming organized multicellular communities - colonies and biofilms. During development, colonies of laboratory strains differentiate into specifically localized cell subpopulations - U and L cells, located in the upper and lower part of the colony, respectively. The U and L subpopulations of cells vary in morphology, metabolic processes and stress resistance. Protein granules are membrane-less "organelles" found in both unicellular and multicellular eukaryotic organisms. The formation of protein granules is related to the physiological state of the cell (e.g. chronological and replicative aging), but also to changing environmental conditions and to cellular responses to stress factors. A relatively large fraction of proteins relocalizes to some type of protein granule during the lifespan of the cell. Granule formation can increase fitness of cells, help them to cope with limiting energy resources, and plays a crucial role in the adaptation of cells to stress conditions. Localization of many proteins in the cell varies depending on its physiology. Therefore the specific localization of such proteins may be considered as a "marker" of a specific physiological condition. There are proteins in each type of granule that can be...
|
guest ::
RSS feed.