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Electron bifurcation - a new phenomenon in bioenergetics
Bazger, Jan ; Hrdý, Ivan (advisor) ; Ženíšková, Kateřina (referee)
Electron bifurcation is a type of enzymatic catalysis that involves the reduction of two spatially separated electron acceptors of different redox potentials by a single electron donor. A characteristic feature of this type of catalysis is the gain of a product with a higher free energy than that of the original electron donor. The energy for this endergonic reduction is obtained from a second, exergonic electron transport reaction pathway. Since 2008, when the observation of this biochemical process, previously known only from the Q-cycle in complex III, was extended by the discovery of flavin- based electron bifurcation, a total of 12 flavoproteins catalyzing this process have been described. The use of flavin-based electron bifurcation has so far been observed mainly in anaerobic prokaryotes, such as acetogens or methanogens, which live in environments with low-energy substrates. For these organisms, the possibility to reduce ferredoxin or flavodoxin, the electron acceptors of the endergonic part of the reaction, is an important physiological advantage, since these molecules can be used as electron donors for the subsequent reduction of other low-potential acceptors under favourable thermodynamic conditions. Phylogenetic analyses that give a comprehensive overview of the overall possible spread...
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Electron bifurcation - a new phenomenon in bioenergetics
Bazger, Jan ; Hrdý, Ivan (advisor) ; Ženíšková, Kateřina (referee)
Electron bifurcation is a mechanism of enzyme catalysis in which a cofactor of lower redox potential is reduced by an electron donor of higher redox potential. Since 2008, when the observation of this event, previously known only from the Q-cycle in complex III, was extended by the discovery of flavin-based electron bifurcation, a total of 12 flavoproteins have been described that catalyze this event. The use of this catalysis has so far been observed mainly in anaerobic organisms, such as methanogens or acetogens, which live in environments with low-energy substrates. For these organisms, the ability to reduce high-energy molecules, in the form of ferredoxin or flavodoxin, capable of reducing molecules whose reduction they would have to catalyze at the expense of a chemiosmotic gradient or ATP hydrolysis is a significant advantage. Phylogenetic analyses that give a comprehensive overview of the possibilities for the overall spread of flavin-based electron bifurcation among organisms are still scarce in the literature. A similar situation applies to molecular mechanisms, for most enzyme complexes, such data are not yet available.
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Does Daylight Saving Time Save Energy?: A Meta-Analysis
Herman, Dominik ; Havránek, Tomáš (advisor) ; Zeynalov, Ayaz (referee)
Daylight saving time energy savings have always represented a contentious topic requiring empirical evidence for, or against. Unfortunately, as the conclusions are miscellaneous-without an evident pattern of heterogeneity occurrence-insisting on particular case studies and narrative literature reviews seems to be insufficient. In this thesis, set of various studies concerning the effect of daylight saving time on energy savings is examined through meta-regression analysis to provide an accurate estimate of the effect corrected from publication bias, and other distorting and deflecting effects. We find that the mean reported estimate in the literature suggests 0.3% energy savings; our results suggest no signs of publication bias. On the contrary, the study design turned to be a substantial determinant of the primary literature findings. The thesis provides a unique overview for this is the first meta-analysis conducted on the daylight saving time energy savings. Powered by TCPDF (www.tcpdf.org)
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Low-energy houses in Czech Republic
Svobodová, Jana ; Vejchodská, Eliška (advisor) ; Slavíková, Lenka (referee)
The main goal of the thesis is building up low-energy houses in the Czech Republic, especially family houses. In my thesis, I describe the history of low-energy development in the Czech Republic, a possible future and some foreign experience. I compare the standard version of development, which is demanded by Czech laws, with the low-energy version by means of SWOT and financial analysis. I try to define a life cycle assessment of a building, its environmental impact during its construction and usage by means of LCA method. Based on the findings of LCA method I would like to draw attention to the necessity to focus more on the low-energy development. The results of financial analysis shows that it is necessary to implement some instruments of environmental policy in order to support the low-energy development and project, such as tax preferences for low-energy development etc.
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