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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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Virom of lower urinary tracts
Cirbusová, Adéla ; Saláková, Martina (advisor) ; Španielová, Hana (referee)
The human urinary tract was considered to be a sterile environment for many years. However, studies over the past decade have shown that urine harbours rich microbial community which includes also viruses. Nevertheless, there is only very little known about urinary virome so far. Optimised Next Generation Sequencing (NGS) protocol was used to describe the urinary virome of three individuals. However, characterization of the virome from urine samples using NGS proved to be quite challenging, mainly due to observed viral genomes fragmentation. Despite this problem, it was possible to identify human endogenous retroviruses in all individuals and also JC polyomavirus in two of them. Quantitative PCR was further used to characterize part of the urinary virome represented by human DNA viruses. Possible differences in prevalence and viral load of human DNA viruses were observed in individuals with and without bladder carcinoma (bc). Urine of these patients was obtained from different sites of the urinary tract to further establish, if there is a difference in these samples. Torque Teno virus and JC polyomavirus were found as the most common viruses. Torque Teno virus was detected in 75 % patients with and 60 % patients without bc, JC polyomavirus in 43,8 % patients with and 50 % patients without bc. BK...
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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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Experimental model systems to study small DNA viral infection
Bučková, Alžbeta ; Saláková, Martina (advisor) ; Horníková, Lenka (referee)
Merkel cell polyomavirus (MCPyV) and Human papillomavirus 16 (HPV 16) are members of small tumour DNA viruses Polyomaviridae and Papillomaviridae, which represent increasing risk for humans resulting from their oncogenic potential. After the acquisition HPV 16 and MCPyV are able to persist for long term in a form of asymptomatic infection, while the aggressive disease is mostly being cleared by the host immune system. Integration of viral genome into the host DNA causes cell transformation resulting in rare but fatal skin carcinomas and epithelial lesions of anogenital tract, head and oropharynx, that may progress into malignant tumours. Their mechanisms of immune system evasion and complete life cycles are not fully understood to this day which highlights some of the reasons why continuing research in this field is of importance. The aim of this thesis is to review model systems used to study infection of MCPyV and HPV 16 in vitro and in vivo. Key words: Papillomaviruses, polyomaviruses, virus-like particles, pseudoparticles, animal models, cell culture, human papillomavirus 16, Merkel cell polyomavirus, HPV 16, MCPyV
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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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The use of plants for the expression of Human papillomavirus vaccine
Dlabalová, Lucie ; Moravec, Tomáš (advisor) ; Fischer, Lukáš (referee)
Papillomaviruses are causing various diseases from skin warts to the lesions leading to malignant tumours and are widespread among people. For this reason, the current research is trying to develop methods for the production of inexpensive and effective vaccines against both Papillomaviruses and against all other infectious diseases. Currently animal and microbial expression systems are most frequently used for the production of biopharmaceuticals which have several drawbacks and their capacity is limited. This opens up the doors for plants - potentially very efficient producers of biopharmaceuticals. Currently there is rapid development towards the optimization and improvement of the results of plant expression systems and establishing the best and safest methods of their use. This paper summarizes and compares the advantages and disadvantages of different methods of plant transformation, leading either to stable production of the protein of interest in transgenic plants or to transient expression of recombinant virus infecting non-transgenic plants. Furthermore it analyzes the most appropriate plant species, which provide high yields combined with a transformation method and ease of cultivation, describes few basic ways of optimizing expression levels and outlines the future of plant expression systems.
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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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