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Presence and localization of local DNA structures in papillomavirus genomes
Vyoralová, Andrea ; Kollerová, Silvia (referee) ; Brázda, Václav (advisor)
Papillomaviruses are sexually transmitted pathogens with a genome length of about 8 kbp. The probability that an adult person will suffer from a papillomavirus infection is up to 80–90%. In most cases, the immune system will eliminate the infection. However, in women it can lead to the development of cervical cancer. That is caused by the high-risk human papillomaviruses, against which vaccination is available. Sequences rich in guanine have been found in the genomes of papillomaviruses, in these sequences the formation of G-quadruplexes occur. They are formed by stacked G-tetrads and are stabilized by monovalent cations, most often K+ and Na+. They are found e.g. in telomeres, oncogene promoters, transcription factor binding sites and recombination sites. Inverted repeats (IR) are also found in the genomes of these viruses. They consist of sequences of nucleotides followed by its reverse complement. Inverted repeats are being referred to as hotspots of genomic instability because they fold into hairpin or cruciform structures that disrupt DNA replication. G4Hunter and Palindrome analyzer were used to analyze the genomes. The analysis revealed that the presence of PQS (Potential Quadruplex-forming Sequence) is higher in papillomaviruses infecting vertebrates than in viruses infecting humans due to the higher content of guanine and cytosine which are connected to the formation of PQS. A higher frequency of PQS presence was found in the genomes of papillomaviruses than in Archaea, Bacteria and Homo sapiens. IR analysis showed that the shortest IRs (6 bases) are the mostly present in the genome and also that IRs formed of 25–30 bases are found in only a few genomes.
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Interference of selected DNA viruses with apoptotic processes
Sauerová, Pavla ; Forstová, Jitka (advisor) ; Štěpánek, Luděk (referee)
This work is focused on selected DNA viruses and some of their mechanisms used for inhibition or induction of the apoptotic processes. The selected DNA viruses are Hepatitis B virus, polyomaviruses, papillomaviruses and herpesviruses. Viruses developed different strategies for fighting the host defense mechanism during their evolution. One of the host defense mechanisms that reacts against virus infection is apoptosis. In case of viruses we can observe the phenomenon of inhibition or induction of apoptosis (which both depend on the life cycle phase of the virus). The purpose of these "fighting" strategies is to ensure successful replication, virus releasing from the cell and finally to let it spread in an organism or among them. Some "fighting" strategies are similar e.g. targeting and manipulation on p53 oncosupresor level or production of Bcl-2 homologs; other strategies are very specific. Certain viruses have mechanisms which allow them to survive in a host organism for a long time.
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Significantion of sumoylation for infection by selected viruses replicated in the cell nucleus
Sejpková, Marie ; Forstová, Jitka (advisor) ; Frydrýšková, Klára (referee)
This work introduces association between viruses and host cell with respect to sumoylation process. The main aim is referring to influence of this modification both on virus replication strategy and cell cycle. Sumoylation is essential process for cell regulation interfering with general regulation pathways including those performed by e.g. p53 or PML bodies and also epigenetic changes of chromatin. For viruses, sumoylation means stabilization of viral proteins and better timing each phase of viral cycle through viral protein. One point of view is competition of cell and virus for SUMO machinery. Viruses take advantage of sumoylation for inhibition antiviral defense of cells, regulation cell cycle mainly in apoptosis induction and in general for more successful infection. There are cumulating evidence of new proteins and phenomena connected with sumoylation mechanisms as well as viruses exploiting sumoylation for their benefit. Utilization and abuse of sumoylation by viruses point to future possibilities of cell manipulation and virus ability to intervene to this still relatively poorly understood type of cell regulation.
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Biological treatment and its influence on the course of latent viral infections in patients with psoriasis
Laurin, Josef ; Šmahelová, Jana (advisor) ; Janovec, Václav (referee)
There are more than 80 identified autoimmune diseases. One of the most prevalent ones is psoriasis. Its prevalence is around 2-5 % worldwide. The treatment of this inflammatory skin disease can be divided as follows: in cases of low severity, topical therapies are used for local treatment and in the cases of insufficient effect, stronger therapies are used. Phototherapy is used for moderate severity, and systemic therapy is used in moderate to severe disease. Systemic agents include cytostatic methotrexate, immunosuppressant cyclosporin, or retinoids (vitamin A analogues). However, even systemic therapies may not yield the desired effects or may have adverse effects on the overall condition of the patient. In those cases, biological therapy comes to use. Biological therapy is usually conducted using antibodies and fusion proteins, which are made using recombinant technologies. Tumour necrosis factor α (TNF-α) and interleukin 12, 17 and 23 (IL-12, IL-17 and IL-23) inhibitors are the most commonly used in the treatment of psoriasis. During the inhibition of the immune system, it has been confirmed that a reactivation of viral infections can occur. These reactivations may subsequently lead to the development of various diseases caused by latent viral infections.
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Bovinne papillomaviruses
Voběrková, Eva ; Drda Morávková, Alena (advisor) ; Kuthan, Martin (referee)
Bovine papillomaviruses (BPV) are small nonenveloped dsDNA viruses belong to the family Papillomaviridae. One of the characters of this family is strong species and tissue specificity, but some BPVs are represent an exception and they are able to infecting other groups of vertebrates. However transmission on human has not been proved yet. All viruses from this groups, including BPV have considerable tumorigenic potential, in particular for the infection non-permissive cells. In the natural host, they are causing clinical disease, which manifest papillomas, that may interfere with host of life what cause considerable economic loss. BPV served as model organisms for study. Papillomavirus family and these findings helps understand their human counterparts (human papillomaviruses, HPV). Recently, studies of BPV are not so frequent, overshadowed the success of vaccines against HPV. To the other hand, this success is encouradged for as to develop the similar vaccines against BPV order to avoid disease of farm animals. The successful development working on such a vaccine, is needed understand function virus and viral proteins and mechanism their interaction with the host cell. It is also necessary to map individual BPV their similarites and differences that to the specifics of each types. This work...
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Significantion of sumoylation for infection by selected viruses replicated in the cell nucleus
Sejpková, Marie ; Forstová, Jitka (advisor) ; Frydrýšková, Klára (referee)
This work introduces association between viruses and host cell with respect to sumoylation process. The main aim is referring to influence of this modification both on virus replication strategy and cell cycle. Sumoylation is essential process for cell regulation interfering with general regulation pathways including those performed by e.g. p53 or PML bodies and also epigenetic changes of chromatin. For viruses, sumoylation means stabilization of viral proteins and better timing each phase of viral cycle through viral protein. One point of view is competition of cell and virus for SUMO machinery. Viruses take advantage of sumoylation for inhibition antiviral defense of cells, regulation cell cycle mainly in apoptosis induction and in general for more successful infection. There are cumulating evidence of new proteins and phenomena connected with sumoylation mechanisms as well as viruses exploiting sumoylation for their benefit. Utilization and abuse of sumoylation by viruses point to future possibilities of cell manipulation and virus ability to intervene to this still relatively poorly understood type of cell regulation.
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Interference of selected DNA viruses with apoptotic processes
Sauerová, Pavla ; Forstová, Jitka (advisor) ; Štěpánek, Luděk (referee)
This work is focused on selected DNA viruses and some of their mechanisms used for inhibition or induction of the apoptotic processes. The selected DNA viruses are Hepatitis B virus, polyomaviruses, papillomaviruses and herpesviruses. Viruses developed different strategies for fighting the host defense mechanism during their evolution. One of the host defense mechanisms that reacts against virus infection is apoptosis. In case of viruses we can observe the phenomenon of inhibition or induction of apoptosis (which both depend on the life cycle phase of the virus). The purpose of these "fighting" strategies is to ensure successful replication, virus releasing from the cell and finally to let it spread in an organism or among them. Some "fighting" strategies are similar e.g. targeting and manipulation on p53 oncosupresor level or production of Bcl-2 homologs; other strategies are very specific. Certain viruses have mechanisms which allow them to survive in a host organism for a long time.
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