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Protein diversity in human stress granules
Kráčmarová, Jana ; Frydrýšková, Klára (advisor) ; Motlová, Lucia (referee)
During unfavourable conditions eukaryotic cells inhibit translation of certain mRNAs and preferably synthesize proteins that are involved in the stress response. The saved energy is used for repair of cellular damages. The untranslated mRNAs are accumulated in the form of ribonucleoprotein complexes. This accumulation results in the formation of the cytoplasmic stress granules. These granules are sites of structure remodeling and triage of the ribonucleoprotein complexes - they can be stored, degraded or sent back to the cytoplasm for translation reinitiation. The mRNA molecules carry their associated proteins, which include also proteins implicated in the cell signaling. Stress granules can thus indirectly regulate some processes, such as apoptosis, and play role in the survival of the cell. This thesis focuses on protein content of stress granules in human cell lines, briefly characterizes stress factors that induce their formation and discusses differences between the content of stress granules induced by different stress stimuli. An important part of this thesis is a table summarizing proteins found in the stress granules. The second part of this work is dedicated to the characterization of the proteins of the fragile X mental retardation protein family. It outlines the possible link between...
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Antibiotic resistance in clinically important strains of Enterococcus spp.
Kozická, Barbora ; Petráčková, Denisa (advisor) ; Motlová, Lucia (referee)
The Enterococcus spp. is a common part of microflora in the digestive tract; it is used in the food industry and added to probiotics. However, in the last few decades it comes to the fore particularly as a cause of nosocomial diseases. Its importance grows with its increasing resistance to antibiotics. The Enterococcus is intrinsically resistant to many types of antibiotics. In addition to that it may acquire additional resistance determinants by mutations or horizontal gene transfer. This work focuses on the Enterococcus faecium and the Enterococcus faecalis intrinsic and acquired resistances, as these two strains have the major clinical importance. In this work, the most attention is dedicated to the antibiotics vancomycin and linezolid. For several decades, vancomycin was the last treatment option in the case of a failure of commonly used antibiotics. The fact that the resistance to this antibiotic was spreading rapidly became a significant problem in these cases of treatment. Hence the antibiotic linezolid was developed as a response to the growing resistance of gram-positive bacteria to available antibiotics. It is also proved to be effective against the vancomycin- resistant strains E. faecium and E. faecalis.
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Proteasomes and DNA virus infection
Vinšová, Barbora ; Drda Morávková, Alena (advisor) ; Motlová, Lucia (referee)
The development of virus infection depends on virus - host interactions. Millions of years of ongoing virus - host coevolution led to formation of many antiviral defense mechanisms as same as virus evasion strategies. Viruses have learned to intervene in the various cellular processes, modify it and take advantage of particular cellular components. One of those cellular components widely utilised by viruses is the ubiquitin-proteasome system. Proteasomes are multisubunit protein structures that under normal conditions provide degradation of damaged, missfolded or redundant cellular proteins. With their function proteasomes contribute to regulation of various cellular processes and maintain balance of proteins ratio. Viruses utilise those structures for protein degradation in order to evade host immunity system and deregulate cell cycle, to entry and unpacking of virions or in order to favor virus replication. This thesis is conceived to briefly summarize interactions of cellular ubiquitin-proteasome system and DNA viruses.
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Adenylate cyclase toxin of Bordetella pertussis, its conformation and ion balance in host cell.
Motlová, Lucia ; Konopásek, Ivo (advisor) ; Krůšek, Jan (referee)
Adenylate cyclase (CyaA, ACT) toxin is one of the major virulence factors of Bordetella pertussis. Although CyaA binds to many types of membranes, it is assumed that the integrin CD11b/CD18 is its receptor which is expressed on the surface of myeloid cells. CyaA belongs to the family of RTX toxin-hemolysins. CyaA acts on the host cells by two independent activities. One of them is the conversion of ATP to cyclic AMP, which is catalyzed by adenylate cyclase (AC) domain after its translocation into the cytosol of the host cell, which leads to the entry of calcium cations into the host cell. Translocation is probably initiated by interaction of CyaA monomer with the target membrane. The second activity is the formation of CyaA channel selective for cations, which probably causes colloid osmotic lysis of target cells. The channel forming activity is provided by RTX hemolysin domain which most probably forms oligomers, although it was found that CyaA as a monomer causes leakage of potassium cations from the host cell. It is also not clear whether the oligomerization of CyaA would occur in solution, or after interaction with the host membrane. The aim of this study was to examine the flow of sodium ions on the membrane of murine macrophages J774A.1, which express integrin CD11b/CD18 on their surface....
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