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Molekulárně-biologická diagnostika lidských polyomavirů
Ryšavá, Markéta
Most of the human population encounters human polyomaviruses during childhood, when the first infection is asymptomatic or with mild symptoms. However, these viruses persist in the human body and most often, they reactivate during immunosuppression. Together with JC virus reactivation, the progressive multifocal encephalopathy is associated. Hemorrhagic cystitis is associated with BK virus, resulting in the loss of allograft during kidney transplantation. Accurate diagnostics can detect viruses in a timely manner and mitigate tissue damage. This diploma thesis deals with biotechnologies, which can be used in virus detection with a focus on real time PCR, which is the gold standard in virus diagnostics. The literary research summarizes basic information about polyomaviruses with a focus on human BKV and JCV polyomaviruses. It summarizes the biotechnological methods used for detection of polyomaviruses, both in routine diagnosis and in alternative approaches involving biosensors and CRISPR. The experimental part of the work includes the design of a detection system for polyomaviruses from in silico genome analysis, through the design of potential primers, to theoretical specificity analysis. The practical part of the work compares the efficiency and sensitivity of amplification of two reaction mixtures, where one is intended for simple systems and the other for multiplexes. It also includes testing of selected additives of PCR and determining the sensitivity and validity parameters of the reaction mixture test selected for PCR system development. The results showed that detection using a multiplex reaction mixture is sufficiently sensitive, as it meets the conditions and requi-rements of clinical recommendations and at the same time shows very good values of sensitivity and specificity of the test comparable to published technologies. This reaction mixture appears to be relevant to the use of the development and optimization of a PCR system for the detection of polyomaviruses.
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Minor Structural Proteins of Polyomaviruses: Attributes and Interactions with Cellular Structures
Vinšová, Barbora ; Horníková, Lenka (advisor) ; Saláková, Martina (referee)
Even though polyomaviruses have been intensively studied for more than 60 years, the role of minor structural proteins VP2 and VP3 in some important steps of viral life cycle has still not been fully elucidated, explicitly their role in viral genome delivery to the cell nucleus and their involvement in late phases of viral life cycle. This diploma thesis focuses on the study of minor proteins of Mouse polyomavirus (MPyV) and Human polyomavirus BK (BKV). Four rabbit polyclonal antibodies against minor proteins of polyomaviruses MPyV or BKV have been prepared within this diploma thesis. Two of these prepared antibodies target minor proteins of MPyV (α-MPyV VP2/3) or BKV virus (α-BKV VP2/3), other two prepared antibodies recognize C-terminal sequence common to minor proteins VP2 and VP3 of MPyV (α-MPyV C-termVP2/3) or BKV virus (α-BKV C-termVP2/3). In the second part of this diploma thesis we aimed to study toxicity of BKV virus minor proteins during individual production in mammalian cells. Obtained results suggest that minor proteins of BKV virus might not exhibit as high levels of cytotoxicity as minor proteins of MPyV virus. Third part of this diploma thesis is devoted to investigation of interactions of BKV and MPyV minor proteins with cellular proteins and within one another respectively....
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MicroRNAs encoded by polyomaviruses.
Zachovalová, Veronika ; Bruštíková, Kateřina (advisor) ; Malík, Radek (referee)
MicroRNAs are small regulating molecules of RNA that are encoded by orgamism's genome. Biogenesis of microRNA takes place partly in the nucleus and partly in the cytoplasm. Result of this biogenesis is a 22 nt long microRNA molecule. They are able to silence the genes thanks to sequence- specific degradation of a target mRNA or thanks to the repression of translation of target, complementary mRNA. In mammalian cells the mechanism of translational repression is more common. During this mechanism the microRNA molecule is not entirely complementary to 3'UTR of its target mRNA. Polyomaviruses are small, non-enveloped dsDNA viruses with a circular genome and icosahedral capsid composed of VP1 protein pentamers. These viruses belong in a group called onkoviruses, which can transform infected cells and contribute to development of serious illnesses such as Merkell cell carcinoma. Their genome encodes regulating proteins called T antigens, structural capsid proteins and also microRNAs. My main focus in this thesis will be SV40, MPyV, MCPyV, BKPyV and JCPyV encoded microRNA molecules. Key words: polyomaviruses, small interfering RNA, microRNA, siRNA, RNA interference, mouse polyomavirus, BK virus, JC virus, SV40
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Analysis of antibody response during BK virus infection
Tomanová, Tereza ; Španielová, Hana (advisor) ; Saláková, Martina (referee)
BK virus is a human polyomavirus which is highly prevalent in the population. The virus is usually not very dangerous to its host, but it may cause complicati- ons in immunosuppressed patients. These complications commonly appear after kidney transplantation because BK virus persists in kidney epithelial cells. There are four subtypes of BK virus and it might be clinically important to screen for the identity of subtypes in matched pairs of donors and recipients of the kidney. This determination of the subtype specific antibodies by simple test could help to manage complications after the surgery. During previous project the ELISA test that could serologically differentiate between two main BK virus subtypes (I and IV) was designed, but its development is complicated by the fact that there is a strong cross-reactivity between the BK virus subtypes and antibodies. The modification of antigen towards better specificity might be required to succeed. Consequently, the main aim of this diploma thesis was to map important spots of major capsid protein VP1 of BK virus, particulary in EF and DE loops, which could participate in binding of antibodies. This aim was addressed by targeted mutagenesis of the gene coding VP1 protein in the region of the respective loop. Nucleotides coding two surface aminoacids...
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BK virus infection in kidney transplant patients.
Girmanová, Eva ; Viklický, Ondřej (advisor) ; Stříž, Ilja (referee) ; Krejčí, Karel (referee)
Polyoma BK virus is associated with graft dysfunction leading to BK viral nephropathy (BKVN) in 1-10% of kidney transplant recipients, moreover 30-80% of kidney transplant recipients experience asymptomatic reactivation of the virus that does not result in BKV associated damage of the renal allograft. The first aim of this study was to introduce monitoring of BK virus replication in the blood and urine of patients within first year after transplantation. Risk factors were evaluated and limit values for viremia and viruria for BKVN development was established. Positive BK viruria >107 copies/ml and positive BK viremia >104 copies/ml occurred in 25.8% and 5%; respectively. 3 patients out of monitoring study developed BKVN. Using ROC analysis, limit values for the development of BKVN were set at 103 copies/ml serum for BK viremia and 6.7x107 copies/ml BK viruria. The second objective was to determine the expression profile of the immune genes in kidney biopsies in three groups of patients with varying degrees of reactivation of the BK virus (without virus reactivation, with asymptomatic viruria, BKVN). 90 genes of immune response were measured by the TaqMan® low density array RT-qPCR. The analysis of biopsies from patients with non-signalling viruses led to the identification of 5 differentially...
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Analysis of antibody response during BK virus infection
Tomanová, Tereza ; Španielová, Hana (advisor) ; Saláková, Martina (referee)
BK virus is a human polyomavirus which is highly prevalent in the population. The virus is usually not very dangerous to its host, but it may cause complicati- ons in immunosuppressed patients. These complications commonly appear after kidney transplantation because BK virus persists in kidney epithelial cells. There are four subtypes of BK virus and it might be clinically important to screen for the identity of subtypes in matched pairs of donors and recipients of the kidney. This determination of the subtype specific antibodies by simple test could help to manage complications after the surgery. During previous project the ELISA test that could serologically differentiate between two main BK virus subtypes (I and IV) was designed, but its development is complicated by the fact that there is a strong cross-reactivity between the BK virus subtypes and antibodies. The modification of antigen towards better specificity might be required to succeed. Consequently, the main aim of this diploma thesis was to map important spots of major capsid protein VP1 of BK virus, particulary in EF and DE loops, which could participate in binding of antibodies. This aim was addressed by targeted mutagenesis of the gene coding VP1 protein in the region of the respective loop. Nucleotides coding two surface aminoacids...
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Minor Structural Proteins of Polyomaviruses: Attributes and Interactions with Cellular Structures
Vinšová, Barbora ; Horníková, Lenka (advisor) ; Saláková, Martina (referee)
Even though polyomaviruses have been intensively studied for more than 60 years, the role of minor structural proteins VP2 and VP3 in some important steps of viral life cycle has still not been fully elucidated, explicitly their role in viral genome delivery to the cell nucleus and their involvement in late phases of viral life cycle. This diploma thesis focuses on the study of minor proteins of Mouse polyomavirus (MPyV) and Human polyomavirus BK (BKV). Four rabbit polyclonal antibodies against minor proteins of polyomaviruses MPyV or BKV have been prepared within this diploma thesis. Two of these prepared antibodies target minor proteins of MPyV (α-MPyV VP2/3) or BKV virus (α-BKV VP2/3), other two prepared antibodies recognize C-terminal sequence common to minor proteins VP2 and VP3 of MPyV (α-MPyV C-termVP2/3) or BKV virus (α-BKV C-termVP2/3). In the second part of this diploma thesis we aimed to study toxicity of BKV virus minor proteins during individual production in mammalian cells. Obtained results suggest that minor proteins of BKV virus might not exhibit as high levels of cytotoxicity as minor proteins of MPyV virus. Third part of this diploma thesis is devoted to investigation of interactions of BKV and MPyV minor proteins with cellular proteins and within one another respectively....
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Preparation of Monoclonal Antibodies Against VP2 Protein of Human Polyomaviruses
Vochyánová, Klára ; Drda Morávková, Alena (advisor) ; Růžičková, Šárka (referee)
Aim of this diploma thesis was to prepare two protein antigens and two monoclonal antibodies, all based on VP2 minor protein of human polyomaviruses BK virus and Merkel Cell Polyomavirus. One monoclonal antibody was being prepared against unique part of VP2 protein (N-terminal epitope, not present in VP3 protein). A cell line producing such monoclonal antibody has never been established before due to low immunogenicity of the epitope. Our approach was successful in terms of mouse immunization, however, serious problems with hybridoma line stability appeared later during the preparation process. Preparation of antibody targeted to the sequence of VP2 protein of Merkel Cell Polyomavirus was another aim of this thesis. Mouse immunization and hybridoma fusion were performed successfully. After four rounds of cloning in order to purify an established clone, nine clones were cultivated in larger scale. This cultivation probably led to diminished antibody specificity and loss of production ability in most of the hybridoma cells. One more cloning should give rise to an established clone with sufficient production. Two preparations of protein antigens were performed in two expression systems. DNA encoding C-terminally truncated protein VP2 of BK virus fused with His-tag was cloned into a vector suitable for...
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Analysis of BK virus life cycle
Bakardjieva - Mihaylova, Violeta ; Drda Morávková, Alena (advisor) ; Mindlová, Martina (referee)
Polyomaviruses are small unenvelope DNA viruses, whose replication take place in cell nucleus. Despite its small genome size, these viruses can cause significant changes in the host cell, one of the most significant is cell transformation. Most studies of human pathogens from this family is the focus of clinical research, but do not provide enough information about the individual events of the life cycle of viruses. This thesis mainly aims to determining the exact time when the creation of the individual viral products and generate a timeline of events during natural infection in cells that are targets for BKV in the human body. It was found that the time course of the life cycle of BKV is very similar to those for model polyomaviruses MPyV and SV40 and in permissive cells takes about 40 - 50 hours.
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