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Subunit c of mammalian F1Fo ATP synthase - from molecular mechanisms of assembly to potential therapies
Marković, Aleksandra ; Mráček, Tomáš (advisor) ; Trnka, Jan (referee) ; Rohlena, Jakub (referee)
Mammalian F1Fo ATP synthase plays a crucial role in ATP production through the process of oxidative phosphorylation. Assembly of this multisubunit protein complex requires specific assembly factors. Notably, the assembling of subunit c in mammals requires several factors, yet despite decades of research, the import of subunit c, its incorporation into the inner mitochondrial membrane, and the assembly of monomers towards octameric c-ring remain enigmatic. To shed new light on this process, we first screened for interacting partners of subunit c using a mass spectrometry-based approach. Our screen identified three proteins as the most prominent interactors of subunit c- TMEM70, TMEM242, and c15orf61, which we subsequently characterized. For the initial characterization of the TMEM242 function, we generated both knockdown and knockout HEK293 models. TMEM242 knockdown led to impaired biogenesis and decreased levels of assembled ATP synthase without affecting the content of other OXPHOS complexes. On the contrary, complete deficiency of TMEM242 lead also to the downregulation of complexes I and IV, which indicates that the primary target of TMEM242 is ATP synthase. While other studies suggested that both TMEM242 and TMEM70 interact with mitochondria complex I intermediate assembly (MCIA), our...
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Effect of lipophilic cation on the toxicity of phosphonium salts in parasitic protists
Čadková, Aneta ; Mach, Jan (advisor) ; Trnka, Jan (referee)
The mitochondrion is an essential organelle responsible for energy metabolism and maintaining cellular homeostasis. Disruption of their function can have serious consequences for the entire cell and organism. Given their key role in the organism, they become an attractive target for drugs. In this thesis, we examine the impact and significance of phosphonium salts as potential mitochondrial-targeted therapeutics. The investigated compounds have modified anchors based on the commonly used triphenylphosphonium cation (TPP+ ). These substances have the ability to permeate the phospholipid bilayer and accumulate on the inner mitochondrial membrane. Our research focuses on selected model organisms of the class Kinetoplastida and opportunistic pathogenic fungi. These pathogenic organisms are responsible for severe infectious diseases in humans. Our aim is to compare the effectiveness of phosphonium salts with different anchor modifications against these organisms and attempt to elucidate their mechanism of action. We have found that the modified salts are capable of inhibiting the growth of parasitic protists at nM concentrations, affecting mitochondrial respiration, membrane potential, and mitochondrial integrity. However, there is no increase in the level of oxygen radicals. We are assuming that the...
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Physiological interactions and stabilities of inner mitochondrial membrane complexes.
Kafková, Anežka ; Trnka, Jan (advisor) ; Mráček, Tomáš (referee) ; Vaňhara, Petr (referee)
Inner mitochondrial membrane (IMM) is composed of a phospholipid bilayer with a typically high ratio of protein complexes forming different complexes which execute different functions being reflected into the physiology of the whole organism. To maintain all these functions, as well as to have an ability to respond to various stress stimuli, the individual complexes of the respiratory chain interact, most likely to enhance the electron flow between these complexes, allowing the respiration steps from electron transfer from NADH to molecular oxygen to occur more efficiently. Other interactions between the complexes of the respiratory chain and other IMM complexes have been suggested. However, the underlying molecular details and functional relevance of such interactions are far from being elucidated. One of these many uncharacterised interactions involves the cytochrome c oxidase (COX), the terminal oxidase complex of the respiratory chain, and mitochondrial calcium uniporter complex (MCUC), the main gate to calcium entry into the mitochondrial matrix. Perhaps surprisingly, preliminary data from a systematic unbiased BioID analysis of MCUC subunits has consistently revealed an interaction between MCUC and COX subunits and assembly factors. In addition, SILAC-based quantitative proteomics also showed...
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Determination of stress wave pulse attenuation in chocolate with different sample thickness
Buchar, Jaroslav ; Trnka, Jan ; Kober, Jan
The report presents the results of an analysis of the attenuation of a mechanical pulse in samples of five types of chocolate, where each type had five different thicknesses. These are data established on the basis of an economic contract between the Institute of Thermomechanics of the Academy of Sciences of the Czech Republic and the Mendel University in Brno. The chocolate samples were loaded using both the Split Hopkinson Pressure Bar (SHPB) and the Hopkinson measuring split bar direct loading method. The measurement results are processed in the time and frequency domains.
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Determination of mechanical properties of chocolate under impact loading
Buchar, Jaroslav ; Trnka, Jan ; Kober, Jan
The report based on the Economic Contract No. 5/2021 with the MU in Brno and contains the results of research of the deformation behavior of five types of chocolate when loaded with high strain rates of the order 103 s-1. Two methods were used in the research, the Split Hopkinson Pressure Bar method (SHPB) and the modified Hopkinson bar method, where higher deformation rates can be achieved. Attention is also focused to the fracture behavior of chocolate under dynamic tensile loading. This method of loading is based on the SHPB method using the arrangement of the so-called Brazilian test. In this research, high-speed cinematography was also used to study the formation and development of the fracture of the chocolate sample. The measurement results are processed in the time and frequency domains.
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The role of mitochondrial energy metabolism in cell senescence
Zima, Michal ; Trnka, Jan (advisor) ; Pecinová, Alena (referee)
Cellular senescence represents status, when the cells cease to divide and remain in permanent cell cycle arrest. Senescence is considered to be an active response of the cell to various extrinsic and intrinsic types of stress such as certain oncogene activation, exposing to several cytokines or drugs and damaged and/or uncapped telomeres. Senescent cells are characterised by extensive modification of gene expression, flattened and enlargement of cellular body. Hypothetically, altered gene expression may lead also to increase of certain surface proteins expression. Such protein can be L1 cell adhesive molecule (L1CAM), which is expressed heterogeneously within the population. This Thesis describes current knowledge of cellular senescence, the mechanism, which may result in establishment of senescence phenotype, and also the characteristic markers of senescence. Thesis also puts together the heterogeneity of L1CAM expression in A375 senescent cells with oxygen consumption rate and extracellular acidification rate performed by Seahorse XFe24 metabolic analyser. Therefore, ells were sorted according to their levels of expressing L1CAM onto low and high L1CAM expressing subpopulations. Obtained data show potential correlation between the rate of L1CAM expression in A375 cells and the metabolic rate. Key...
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Strenghtening European Commission's external actorness through internationalisation of SMEs: An institutional analysis of Competitiveness and Innovation Framework Programme (CIP), 2002-2009
Trnka, Jan ; Šlosarčík, Ivo (advisor) ; Kasáková, Zuzana (referee)
European Union faced several external challenges in the beginning of the 21st century. Its enlargement to 24 member states led to a state of dissimilar and not well interconnected economies in need of a new model of external competitiveness. Finding the model and, more importantly, delivering it on community level, was a new task of the European Commission, especially after re-launch of the Lisbon strategy in 2005. Yet, there was another challenge for EU that was not so easy to address by the Commission: the relative weakening of EU's external economic action comparing to new increasingly assertive policies of other international players, especially BRICs. Was it possible for the Commission focus only on supporting EU competitiveness without any external action, as was expected by articles of the Treaty of Nice? As the thesis argues, indeed there was an external action of the Commission before the Lisbon treaty, through its public support of SME internationalization within the Competitiveness and Innovation Framework Programme (CIP). A neoinstitutional analysis of the issues on two levels is carried out: Firstly on the level of European institutions (motives, relevant contexts and institutional rules), secondly, on the level of secondary actors (SMEs, NGOs, CIP executive agency EACI), where the...
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Finite element modeling of the signal propagation in a thin tube and comparison with experimental data
Kruisová, Alena ; Kolman, Radek ; Trnka, Jan ; Mračko, Michal
In finite element modeling of wave propagation problems, both the spatial and temporal discretization lead to dispersion errors. It means that the phase velocity of propagated wave is related to its frequency. In framework of temporal-spatial dispersion analysis, the time step size for implicit time integration method based on the Newmark method is proposed for linear and quadratic serendipity plane finite elements. In this paper, we verify the theoretical dispersion analysis by elastic wave propagation in thin tube, where experimental results are known. Such time step size was used in finite element modeling of the stress wave propagating in this thin steel tube, the results of simulations were compared with experimental results.
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