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Study of the posttrans lation al modifications of phosducin
Šimůnek, Jiří ; Obšil, Tomáš (advisor) ; Alblová, Miroslava (referee)
The aim of this diploma thesis was to study the role of posttranslational modifications of phosducin and their role in the interaction with the 14-3-3 protein as well as the influence of the complex formation on these modifications. Phosducin is a 33kDa protein commonly present in photoreceptor cells of the retina as well as other tissues. Despite many experiments, its physiological functions are still elusive. It has been speculated that fosducin plays an important regulatory role in visual phototransduction pathway, regulation of blood pressure and expression of G-proteins. The phosducin function is regulated through binding to the 14-3-3 protein, a regulatory protein involved in many biochemical processes. Phosducins binding to 14-3-3 protein requires phosphorylation of two serine residues Ser-54 and Ser-73 within the N-terminal domain of phosducin. However, the role of the 14-3-3 protein binding in the regulation of phosducin function is still unclear. In this diploma thesis proteins 14-3-3ζ∆C and phosducin (mutation Q52K) were successfully expressed and purified. The effect of the complex formation on phosducin posttranslational modifications was investigated using limited proteolysis and dephosphorylation. These experiments revealed that the complex formation significantly slowed down both...
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Study of interaction between phosducin and the 14-3-3 protein
Šimůnek, Jiří ; Obšil, Tomáš (advisor) ; Alblová, Miroslava (referee)
The main goal of this bachelor thesis is to study the interaction between phosducin and the 14-3-3 protein which are involved in the regulation of visual signal transduction in vertebrate retina. This process is mediated by G-protein signaling pathway and is regulated by several proteins including phosducin depending on light intensity. Phosducin, a 33kDa protein, is expressed in many tissues mainly in photoreceptor cells of the retina. The visual signal transduction and its amplification are regulated through inhibition of the G-protein (transducin) function. The signal transduction involves a dissociation of heterotrimeric transducin (Gtαβγ) to the α subunit (Gtα) and the βγ complex (Gtβγ). The signalling is terminated by their reassociation back to the Gtαβγ complex. The phosducin binds to Gtβγ and thus prevents the formation of the Gtαβγ heterotrimer. This decreases the amount of functional Gtαβγ complexes and suppresses the signal transduction. If the signal transduction needs to be amplified (e.g. during the night) then phosducin is phosphorylated and this inhibits its interaction with Gtβγ. The phosphorylated phosducin is bound to the 14-3-3 protein. However, the role of the 14-3-3 protein in the regulation of phosducin is still unclear. The 14-3-3 protein is a 28kDa protein which is...
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Role of Magnetosheath Parameters on Magnetopause Processes
Tkachenko, Oksana ; Šafránková, Jana (advisor) ; Kulhánek, Petr (referee) ; Šimůnek, Jiří (referee)
Title: Role of magnetosheath parameters on magnetopause processes Author: Oksana Tkachenko Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Jana Šafránková, DrSc. e-mail address: Jana.Safrankova@mff.cuni.cz Abstract: The thesis addresses of two regions significant for the solar wind- magnetosphere coupling: the cusp in high geomagnetic latitudes and the low-latitude (LLBL) subsolar magnetopause. A penetration of plasma of a solar origin into the magnetosphere could be realized directly through magnetospheric cusps. The region adjacent to the magnetopause in the cusp vicinity is highly turbulent, occupied by the heated magnetosheath- -like plasma with a low drift velocity for which occurrence of vortices is a very common feature. In the first part of the thesis, we present a de- tailed analysis of a vortex-like structure created by a turbulent plasma flow around the magnetopause indentation above the cusp and using the data from Interball-1 and Magion-4; we find necessary conditions and a possible mechanisms to creation of such structures. The second part concerns the low-latitude boundary layer formation, its spatial structure and temporal changes based on THEMIS multipoint observations. In spite of its cru- cial role in transfer of mass, momentum, and energy from the...
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Magnetopause: location,shape and structure
Dušík, Štefan ; Šafránková, Jana (advisor) ; Kulhánek, Petr (referee) ; Šimůnek, Jiří (referee)
For studies of the solar wind-magnetosphere interaction, the magnetopause is a key region. Prediction of its location and knowledge of its structure in a broad range of upstream parameters are important for further progress on this eld. The present thesis deals with statistical investigations of the magnetopause location as well as case studies of the magnetopause and LLBL structure. Based on simultaneous Themis, Geotail, Interball and Magion measurements, we prepared a study of possible sources of the deviations from magnetopause models including low and high latitudes. We found a signicant deformation of the magnetopause surface in the cusp region at high latitudes and the dependence of the subsolar magnetopause position on the IMF cone angle. The analysis of several events using so called n-T plots brings new results connected with mechanisms of the LLBL formation. We found that during the northward pointing interplanetary magnetic eld, reconnection tailward of the cusp creates the outer part of the LLBL, whereas this sublayer is missing through southward magnetic eld.
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System approach to customer satisfaction and loyality in specific company
Šimůnek, Jiří ; Krejčí, Igor (advisor) ; Horáková, Tereza (referee)
Bachelor thesis deals with the application of system dynamics in customer loyality
and satisfaction towards the company Florbal.com.
The theoretical part briefly describes the history of the system dynamics, evolution and the
definition of system dynamics. The theoretical part is focused on the change of linear
thinking to nonlinear or system thinking and the description and significance of mental
models.
Described is also the creation causal loop diagram and the stocks and flows, the
differences between the two diagrams and their advantages and disadvantages.
In the practical part is creation of model in Vensim PLE software, at first was
created causal loop diagram outlining how it could look like diagram stocks and flows,
also reveal a feedback loops and the interaction toward the model. The next step is creating
diagram stocks and flows, supplemented by mathematical functions and create several
policies. The next step is to run simulations for each policy. Completion of the practical
part is to interpret the results and recommendations of the most appropriate policy.
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Superficies, easements – accounting, tax and legal perspective
Šimůnek, Jiří ; Molín, Jan (advisor) ; Müllerová, Libuše (referee)
This diploma thesis deals with legal, accounting and tax consequences of superficies and easements under the legal system of the Czech Republic. Description of the legal context both subjected institutes is focused on domestic evolution process, as well as historical excursion into the jurisdiction of other states and registration in the Land Registry. Further there is an analysis of superficies and easements reporting approaches of Czech accounting legislation and international accounting standards IAS/ IFRS. This section focuses mainly on the reporting of the superficies in the balance sheet of accounting entity according to the Czech accounting law with regard to the change between 2014 and 2015 and IAS/IFRS standards. Tax chapter deals with income tax, value added tax, transfer tax imposed on both institutes in the Czech tax law, including tax burden on inheritance and donation.
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Sources of the cusp plasma for the different sign of IMF By
Šimůnek, Jiří ; Šafránková, J. ; Němeček, Z. ; Wing, S.
The importance of the interplanetary magnetic field (IMF) direction for the cusp formation was dicovered a long time ago. A sign of the IMF Bz component is believed to be responsible for a location of the plasma entry into the cusp. The paper uses the INTERBALL-1 and MAGION-4 data to study the high-altitude cusp topology for different IMF By orientations. The study reveals the importance of IMF horizontal components on the cusp configuration as well as on small-scale processes at the outer cusp. We discuss an influence of the tilt angle of the Earth's dipole on these processes.
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Response of the outer cusp to the IMF rotation
Šimůnek, Jiří ; Šafránková, J. ; Němeček, Z.
The paper uses the INTERBALL-1 and MAGION=4 data to study the topology and dynamics of high-altitude cusp regions under changing solar wind conditions and interplanetary magnetic field (IMF) orientation. Preliminary analysis of the MAGION-4 ion energy spectra indicates the presence of the magnetosheath-like plasma well below the expected magnetopause position and a large region occupied by low-temperature dense plasma with the very low bulk velocity near the magnetopause.
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