|
|
Gene regulation in four dimensions
Vaňková Hausnerová, Viola ; Lanctôt, Christian (advisor) ; Převorovský, Martin (referee) ; Krásný, Libor (referee)
Transcription has turned out to be a discontinuous process when imaged at a single cell level. This observation is referred to as transcriptional bursting or pulsing and has been detected in a variety of organisms ranging from bacteria to mammalian cells. The dynamics of transcriptional pulsing are influenced by the properties intrinsic to the transcriptional process, as well as by upstream factors: chromatin environment, signalling molecules, cell cycle stage etc. In the first part of this thesis, we focused on the regulation of transcriptional pulsing in the nucleolus. Using imaging of living cells, we detected pulsatile transcription of a transgene with nucleolar localization whose expression was mediated by RNA polymerase II. In the second part of the thesis, we investigated the relationship between chromatin decondensation and transcriptional dynamics. We used hyperosmotic medium to induce global condensation of chromatin and revealed that upon chromatin decondensation, a transient spike in transcriptional intensity occurs in induvial living cells. Next, we analysed expression of TFRC and POLR2A genes in several cell cycle stages using single molecule RNA FISH. We detected increase in both frequency and size of transcriptional pulses during a limited time window which coincided with chromatin...
|
|
|
Correlated microscopy of electronic and material properties of graphene grown on diamond thin films
Rezek, Bohuslav ; Čermák, Jan ; Varga, Marián ; Tulic, S. ; Skákalová, V. ; Waitz, T. ; Kromka, Alexander
In this work we compare growth of graphene on diamond thin films that enable large area processing. We use films with different crystal size and surface roughness to obtain deeper insight into formation and properties of GoD. The diamond films are coated by a nm thin sputtered Ni layer and heated to 900°C in a forming gas atmosphere (H2/Ar) to initiate catalytic thermal CVD process. The samples are cleaned from residual Ni after the growth process. We employ scanning electron microscopy, Raman micro-spectroscopy and Kelvin probe force microscopy to correlate material, structural, and electronic properties of graphene on diamond. We show how grain size and grain boundaries influence graphene growth and material and electronic properties. For instance we show that the grain boundaries (with non-diamond carbon phases) in diamond films have an important role. They influence the electronic properties and they are beneficial for forming graphene on diamond higher quality.
|
|
|
Biological imaging by super-resolution microscopy
Adamová, Zuzana ; Komrsková, Kateřina (advisor) ; Benda, Aleš (referee)
zuzana_adamova_abstract_eng.txt[11.05.2017 20:26:29] Fluorescence microscopy is one of the most widely used imaging techniques in biological research. Despite its numerous advantages, it can be used only for studies of structures larger than 200 nanometres, due to diffraction limit caused by a wave nature of light. The value of 200 nanometres is the best reachable value of optical resolution, in other words, the smallest distance of two objects, which can be separately recognized by conventional optical systems. Up to the end of the 20th century it was therefore impossible to observe finer details of cells. However, recently several breakthrough imaging techniques, named super-resolution microscopy techniques, managed to bypass the diffraction limit and enabled biologists to study much more delicate structures, such as small organelles, virions, protein complexes or even particular proteins, while still using a visual light. This thesis introduces some selected super-resolution methods, explains briefly their principles and presents some of their applications in biology.
|
|
| |
|
| |
|
|
Methodological study of changes in mechanical properties of collagen tissues from pes equinovarus congenitus
Červený, Gustav ; Lopot, František (advisor) ; Eckhardt, Adam (referee)
The goal of this thesis was to invent and perform a testing protocol, witch can detect connective tissue mechanical and structural properties simultaneously in patients with clubfoot. Based on literature findings, it was presumed that connective tissue differ between medial and lateral side of foot. Because of low availability of specimen, it was important to draw and mention crucial alterations of testing protokol, for minimization of failed measurments. For reasons above, two specimens diveded into two samples was used for experiment. Described and discused methodics may enable of reader to insigt to drawbacks of this examination. For usability of this protocol, a setting and testing of few hypotheses was performed. One axis tensial testing with SHG microscopy examination was used in combination for experiment. One of the main result was finding, that structural differencies witch were expected, were not distinctive in samples in untensioned state. But, distingtive differencies may be drawed in tensioned samples. This differences for low number of specimen, cannot show any tendence. Results of tensial testing showed, that samples from medial side of foot can have higher toughness and higher fragility. For future acquisition of tendencies in specimen differencies, it is important to set particular...
|
|
|
Deconvolution fluorescence microscopy of yeast cells
Štec, Tomáš ; Plášek, Jaromír (advisor) ; Heřman, Petr (referee)
Title: Deconvolution fluorescence microscopy of yeast cells Author: Tomáš Štec Department: Institute of Physics of Charles University Supervisor: prof. RNDr. Jarmoír Plášek, CSc., Institute of Physics of Charles Uni- versity Abstract: Fluorescence microscopy presents an fast and cheap alternative to more advanced imaging methods like confocal and electron microscopy, even though it is subject to heavy image distortion. It is possible to recover most of the original distortion-free image using deconvolution in computer image processing. This al- lows reconstruction of 3D structure of studied objects. Deconvolution procedure of NIS Elements AR program undergoes an thorough inspection in this diploma the- sis. It is then applied on restoration of 3D structure of calcofluor stained cell wall of budding yeast Saccharomyces cerevisiae. Changes of the structure of the cell wall during cell ageing are being examined. Cell wall of aged cells shows increased surface roughness and even ruptures at the end of cell life. Keywords: fluorescence, microscopy, deconvolution, NIS Elements AR, calcofluor, yeast, cell wall, ageing
|
|
|
ASR potential of quartz in experimental mortar bar specimens
Kuchyňová, Markéta ; Kuchařová, Aneta (advisor) ; Vavro, Martin (referee)
The alkali-silica reaction is one of the most damaging chemical reactions taking place in concrete, which can cause fatal damage. ASR originates under following conditions: high moisture (> 80 %), sufficient amount of alkaline ions (Ca2+ , Na+ , K+ ) and use of reactive aggregates (low crystaline or deformed quartz, amorphous SiO2). Reactive aggretates react with high alkaline pore solution and produce hydrofile gels. These gels absorb water and swell. Dilatometric test methods are commonly used to evaluate the reactivity of aggregates. The principle of dilatometric test methods is simple. Mortar or concrete prisms are created in a laboratory, then they are stored in the special environment, which accelerates the inception of ASR. The creation and expansion of alkali-silica gels cause prism's length changes. The major goal of this diploma thesis was to evaluate the alkali-silica reactivity potential of quartz-rich rocks using microscopic (polarizing microscopy, scanning electron microscopy combined with SEM/BSE image analysis) and dilatometric (ASTM C1260, RILEM AAR-4.1) methods. Rocks were assessed as reactive, potentially reactive and non-reactive by the ASTM C1260 method. The reactivity of aggregates was connected with the amount of cryptocrystaline matrix, grain size, shape of grain boundaries,...
|
|
| |
|
|
Microscopy of leaves from different Bergenia species.
Rulfová, Kateřina ; Spilková, Jiřina (advisor) ; Kašparová, Marie (referee)
Plants of the genus Bergenia are part of remedies used in Ayurveda medicine. They also play an important part in traditional healing practice in China, India, Mongolia and Russia. Theoretical part of this thesis sums the newest findings and research results concerning three Bergenia species: Bergenia ciliata (Haw.) Sternb., Bergenia crassifolia (L.) Fritsch a Bergenia ornata Stein. The thesis mainly focuses on their current and potential use in medicine and pharmacy. Bergenia extract is traditionally used for dissolving kidney stones, treating respiratory tract illnesses and to stop bleeding. The most important active substances of these plants, their characteristics and main effects are also noted. Bergenia is an important source of arbutin and bergenin. Bergenin has antitussive, antiflogistic and gastroprotective effects. Arbutin is used to treat urinary tract diseases and in cosmetology to lighten the skin. The experimental part of this thesis includes methods of preparation of permanent microscope slides from leaves of chosen Bergenia species. Photographs have been taken from both permanent and native slides. Anatomy of the leaf and leaf epidermis is described including stomatal index. Presence of calcium oxalate crystals in form of druses is also documented. Basic anatomical features were...
|
guest ::
