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Structure and function of chloroplasts in selected woody plants grown under increased CO2 concentration
Hlízová, Eliška ; Albrechtová, Jana (advisor) ; Kutík, Jaromír (referee)
The effect of elevated CO2 concentration (EC CO2) on photosynthesis has been observed on many hierarchical levels. There was a significant increase in the rate of photosynthesis of examined trees observed in previous studies thus I hypothesised these changes are accompanied by changes of chloroplast ultrastructure and photosystem content and function and the main aim of this study is to evaluate these adjustments. In this study 13 - 14 years old seedlings of Norway spruce (Picea abies L. Karst.) grown in glass domes with adjustable windows - one with ambient CO2 concentration as a control, the other one with simulated EC CO2 (700 ppm) - during the vegetative season were examined. Pigment content, fluorescence and reflectance indexes, activity of photosystem 1 (PS1) and 2 (PS 2) of isolated chloroplasts, size of cross-sectional area of chloroplast and proportion of stromal to granal thylakoids under EC CO2 treatment were investigated. Although there was a significant increase in the maximum rate of photosynthetic assimilation of trees from EC CO2 (observed by other researchers of our team), decreased chlorophyll and carotenoid content as well as the activity of both photosystems were observed, which is usually atributed to photosynthetic acclimation. As the rate of decrease of photosystem 1 and photosystem 2...
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Structure-functional study of electrotransport protein systems
Tuzhilkin, Roman ; Šulc, Miroslav (advisor) ; Kukačka, Zdeněk (referee)
Electron transport processes are an extremely important field of study in modern biochemistry and structural/functional proteomics. Azurin is one of the most utilised model systems for study of redox and electron transport processes in proteins. We have utilised photo-induced crosslinking (PIXL) to study oligomerization of azurin in solution and the effect of L-2-amino-5,5-azi-hexanoic acid (photo-Met) - a structural photoinducible analogue of canonical amino acid Met - on electron transport processes in azurin. The optimisation of expression conditions of recombinant azurin in auxotrophic E. coli B834 cells was done to maximise photo-Met incorporation percentage in azurin sequence (70% incorporation was measured via MALDI-TOF mass spectrometry). Through the optimisation of purification protocol (example: cell disintegration, acid precipitation of proteins, adding metallic ligand during cell sonication) we have increased the purity and yield of final product and reduced the purification time. Final preparations (wild-type azurin (WT) with Met, WT with photo-Met and "All-Phe" mutant (all Trp/Tyr replaced by Phe) with photo-Met) were exposed to intense UV-light (PIXL) and evaluated via UV-VIS spectroscopy and SDS-PAGE. During PIXL experiment some photo-Mets incorporated into azurin were able to: (i)...
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Model průchodu dvojitou bariérou s anharmonickými vibracemi
Gráf, Lukáš ; Čížek, Martin (advisor) ; Houfek, Karel (referee)
In the presented thesis we study the electron scattering off a molecular junction with anharmonic vibrations. This junction we simulate by a double barrier in- cluding the cosine dependence on the vibrational coordinate. The electron trans- mission through the barrier can be viewed as movement of the electron on the surface of infinitely long cylinder with zero potential energy everywhere except for a finite region where it is described by delta function terms. We solve this 2D problem employing the transfer matrix method and we present also the scat- tering theory approach to the problem. Using our own program we compute the numerically exact transmission probability and we investigate its dependence on parameters characterizing the model. We compare particular parametric regimes with various approximations which can be used for given settings. The elastic scattering is approximated by one-dimensional and Chase approximations where- as in case of vibrational excitation we employ the LCP approximation. Resulting graphs affirm that these approximation methods often used in molecular physics work very well.
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Structure and function of chloroplasts in selected woody plants grown under increased CO2 concentration
Hlízová, Eliška ; Albrechtová, Jana (advisor) ; Kutík, Jaromír (referee)
The effect of elevated CO2 concentration (EC CO2) on photosynthesis has been observed on many hierarchical levels. There was a significant increase in the rate of photosynthesis of examined trees observed in previous studies thus I hypothesised these changes are accompanied by changes of chloroplast ultrastructure and photosystem content and function and the main aim of this study is to evaluate these adjustments. In this study 13 - 14 years old seedlings of Norway spruce (Picea abies L. Karst.) grown in glass domes with adjustable windows - one with ambient CO2 concentration as a control, the other one with simulated EC CO2 (700 ppm) - during the vegetative season were examined. Pigment content, fluorescence and reflectance indexes, activity of photosystem 1 (PS1) and 2 (PS 2) of isolated chloroplasts, size of cross-sectional area of chloroplast and proportion of stromal to granal thylakoids under EC CO2 treatment were investigated. Although there was a significant increase in the maximum rate of photosynthetic assimilation of trees from EC CO2 (observed by other researchers of our team), decreased chlorophyll and carotenoid content as well as the activity of both photosystems were observed, which is usually atributed to photosynthetic acclimation. As the rate of decrease of photosystem 1 and photosystem 2...
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Insight into the structure of tetrameric flavoprotein WrbA involved in oxidative-stress response
WOLFOVÁ, Julie
This Ph.D. thesis addresses the structural characterization of the unique family of tetrameric flavoproteins WrbA, the role of which in the life of cells is still largely unknown but its enzymatic activity and expression properties implicate it in the cell protection against oxidative stress. Proteins of the WrbA family were proved to carry out two-electron reductions of quinones and in this way to prevent generation of the free radicals, similarly to other flavoproteins known as quinone oxidoreductases. Crystal structures of the liganded and unliganded forms of the prototypical WrbA from Escherichia coli were determined. Comparative analyses of these structures with the related flavoproteins were intended to identify and explain the defining structural features of the WrbA family and to clarify its structural and functional relationships to the other flavoproteins.
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