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<p>The aim of this work was to understand the molecular mechanism of translation and the mechanism of translation termination, in particular. Cleavage of peptidyl-tRNA and peptide release terminates translation of mRNA on the ribosome. In prokaryotes, three release factors (RFs) are involved in this process. RF1 and RF2 recognise the three stop codons on mRNA and induce hydrolysis of the ester bond in peptidyl-tRNA. RF3 accelerates the rate of RF1 and RF2 recycling between ribosome in a GTP-dependent manner. We have clarified the mechanism of action of peptide release factor RF3. In the cell, free RF3 is in the GDP conformation. When RF3∙GDP binds to ribosome in complex with RF1 or RF2, these ribosome complexes act as guanine exchange factors for RF3 by inducing rapid dissociation of GDP. If, and only if, the peptide has been removed from tRNA, GDP is quickly replaced by GTP. Binding of GTP to RF3 induces a conformation of the factor with high affinity for the ribosome, which forces RF1 or RF2 to rapidly dissociate. Subsequent hydrolysis of GTP on RF3 induces a factor conformation with low affinity for the ribosome and rapid release of RF3∙GDP. It was further shown how the position of peptidyl-tRNA on the ribosome and the presence or absence of its peptide regulates the binding and GTPase activity of translation factors IF2, EF-G and EF-Tu. The result explains how idling GTPase hydrolysis and negative interference between different translation factors are minimized in living cells. The present biochemical observations, in conjunction with cryo-EM results, lead to new proposals for the role of hybrid sites in translocation of tRNAs, recycling of RF1 and RF2 by RF3 and recycling of post-termination ribosomes back to a new round of initiation.</p>

The aim of this work was to understand the molecular mechanism of translation and the mechanism of translation termination, in particular. Cleavage of peptidyl-tRNA and peptide release terminates translation of mRNA on the ribosome. In prokaryotes, three release factors (RFs) are involved in this process. RF1 and RF2 recognise the three stop codons on mRNA and induce hydrolysis of the ester bond in peptidyl-tRNA. RF3 accelerates the rate of RF1 and RF2 recycling between ribosome in a GTP-dependent manner. We have clarified the mechanism of action of peptide release factor RF3. In the cell, free RF3 is in the GDP conformation. When RF3∙GDP binds to ribosome in complex with RF1 or RF2, these ribosome complexes act as guanine exchange factors for RF3 by inducing rapid dissociation of GDP. If, and only if, the peptide has been removed from tRNA, GDP is quickly replaced by GTP. Binding of GTP to RF3 induces a conformation of the factor with high affinity for the ribosome, which forces RF1 or RF2 to rapidly dissociate. Subsequent hydrolysis of GTP on RF3 induces a factor conformation with low affinity for the ribosome and rapid release of RF3∙GDP. It was further shown how the position of peptidyl-tRNA on the ribosome and the presence or absence of its peptide regulates the binding and GTPase activity of translation factors IF2, EF-G and EF-Tu. The result explains how idling GTPase hydrolysis and negative interference between different translation factors are minimized in living cells. The present biochemical observations, in conjunction with cryo-EM results, lead to new proposals for the role of hybrid sites in translocation of tRNAs, recycling of RF1 and RF2 by RF3 and recycling of post-termination ribosomes back to a new round of initiation.

The content of this master´s thesis is a geodetic measuring of movements and deformations of skeleton and underwork of „Gagarin“ railway bridge during the seventh period and processing of the data got. This was done by comparison of the movements according to the fifth and sixth period. The work includes also the calibration of appliance used. The results involve figures of the movements with their graphic interpretation and calibration sheets of the appliance.

The work deals with a complex analysis of displacements and deformations of one bridge span of the railway bridge "Gagarin". The bridge structure was since 2009 annually measured. In addition to long-term monitoring of the bridge a 24-hour automatized monitoring was conducted in 2015 using robotic total station. The results of monitoring enables the analysis of displacements and deformations, analysis of measurement accuracy and also environmental influences on the structure - determination of the temperature dependence of deformations. Another part of the work is evaluating the long-term stability of the height reference frame that was used for geodetic epoch measuring of the bridge columns. The results of the work are the values of detected displacements and deformations, their graphical illustration, geometric interpretation and relevant characteristics of accuracy.

The Space Race during the Cold War was an era when the World saw great possibilities and scientific discoveries. Before 1957, the thing we call space had never been scaled by man. The Soviet Union turned this over with Sputnik 1, the very first artificial satellite which would change our way to research everything beyond Earth. Although this is true, there is also another side of Space Race which has more or less nothing to do with space at all – the politics. There is no denying that the politics about Space Race was far more essential for the United States and the Soviet Union than any scientific research. Kennedy talked about prestige and to “be ahead” in the race for space. Of course, the Americans and the Russians were fully involved and knew what could be gained from winning the race. But what about other nations? What about the Swedes? This thesis brings the Space Race to Sweden and examines two Swedish newspapers to get a clear view on how the people of Sweden actually encountered Space Race. To narrow the thesis down, the author picked two important events where the political side of Space Race is distinct – Yuri Gagarin’s orbit of the Earth in 1961 and John Glenn’s orbit of the Earth in 1962. What kind of position in the Space Race did Sweden have, and how is it reflected in the newspapers? Does the political differences in two leading tabloids affect the outcome of the articles? And which kind of theories about the Cold War could be applied on these tabloids? This kind of research is uncommon to encounter in Sweden, but it ought to be dealt with here.

Nostalgia for the Soviet past has been relevant for more than three decades since the demise of the USSR in 1991. The first scholars who studied this phenomenon believed that it related to backward Soviet mentality typical of the old generations. However, with the passage of time it has become clear that young people also not only express interest in the Soviet legacy, but many of them clearly state that they have nostalgia for the USSR. Here, we encounter an intriguing question: can we contend that nostalgia may be provoked by the live experience only, or it can be a longing for the unexperienced past? Nowadays, there are many online nostalgic Russian-speaking communities that provide rich material for studying post-Soviet nostalgia. But Russian language should not be confused with “Russianness”. Moreover, as we go deeper into this topic, we understand that those people who are nostalgic for the USSR, experience longing for different aspects of the Soviet life, depending on their ethnic belonging. This study addresses the difference between Russians who long for the grandeur of the Soviet Union which was the most powerful and effective embodiment of the Russian empire, and the representatives of other nationalities who have another perspective on their Soviet past. This thesis deals a lot with the issue of values, because, as it is shown in the research, longing for socialism is not a matter of age, but rather a matter of values. The most essential point which is recalled by many nostalgic persons is aspiration for the future. Now Russia and other post-Soviet countries do not have a clear plan for the future, while the USSR provided its population with a goal for future development. On the other hand, many nostalgic subjects admit, that a unique spirituality that was embedded in Soviet life is lost. It is another paradox, because the Soviet state was atheist, and now in Russia and other former Soviet republics, religion plays a significant role, however, the decrease of morals in comparison to Soviet times is apparent. Therefore, this thesis discusses compatibility of Communist (socialist) values and religion. Many nostalgic subjects feel that the USSR was a bastion of science and technological advancement in comparison to the backward obscurantist Russia of today. They mourn the downfall of the USSR as a failed project of modernity. This is another important topic that is addressed in the thesis. This study is based on online ethnographies of a few nostalgic communities on three Russian-speaking internet platforms: VKontakte, Odnoklassniki and Facebook. Initially, the focus of the study was on a group level of analysis, but the most valuable portion of this project turned out to be interviews conducted with individual participants of the studied communities. The research participants were from the following countries: Belarus, Latvia, Lithuania, Moldova, Russian and Ukraine. The task of this research was to understand the nature of their nostalgia and to reveal their visions of the to-be-restored USSR. Depending on their worldviews (socialist/ non-socialist, nationalist/internationalist) the research participants provided very different and instructive pictures of this new potential unity which the researcher approached from the perspective of Benedict Anderson’s theory on imagined communities.