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Funkční a patologické změny žaludku hostitelů reinfikovaných různými druhy a genotypy žaludečních kryptosporidií
MARKOVÁ, Marie
Representatives of the genus Cryptosporidium are intracellular parasites from the phylum Apicomplexa that parasitise the gastrointestinal tract of vertebrates. Within the genus, the species are divided into two groups depending on the site of infection: intestinal and gastric cryptosporidia. Infection with intestinal species is associated with watery diarrhoea, while infection with gastric species is usually asymptomatic. However, studies have indicated histopathological changes in gastric tissue during infection with these species. This work focuses on the influence of infection and reinfection with Cryptosporidium proliferans and Cryptosporidium muris CAT21 on gastric pH, morphological and pathological changes of the gastric mucosa in experimental mastomys and the mouse strains BALB/c and C57Bl6. In mice infected with C. muris CAT21, an increase in stomach pH was observed only after the primary infection; during reinfection, no increase in pH was observed on any of the days observed. In both groups, an increase in mucosal thickness was observed during infection, but was not as pronounced in BALB/c mice during reinfection as during primary infection. In C57Bl6 mice, reinfection resulted in a slight thickening, but no significant peak was observed and mucosal thickness remained similar. Inflammatory infiltrates were present in the tissue of both BALB/c and C57Bl6 mice during both infection and reinfection. Reinfection with C. proliferans led to an increase in gastric pH in both BALB/c and C57Bl6 mice. Although morphological changes were observed after reinfection, they were less pronounced. The results indicate that reinfection can influence the immune response and gastric morphology, but does not cause significant changes in pH. In addition, the influence of acidic water administration on the course of C. proliferans infection was investigated. No significant differences in the course of infection and pathological changes were observed between groups of mastomys supplied with acidic and tap water and infected with C. proliferans.
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The effect of amoeba predation on the evolution of virulence in human pathogenic microorganisms
Drncová, Eliška ; Šuťák, Róbert (advisor) ; Konupková, Anežka (referee)
Amoebae act as one of the main regulators of microbial communities, where, as a result of their predation, selection pressure is exerted for the emergence of defence mechanisms to achieve resistance. This adaptation allows microorganisms to randomly infect the human body and successfully defend against components of innate immunity, especially macrophages, which, like amoebae, are phagocytic cells. The manifestation of virulence in opportunistic pathogens is due to conserved macrophage pathways used for degradation of ingested material, which the microorganism has already encountered in amoebae. Because of this similarity, amoebae can be used to investigate the interaction between a pathogen and its host, which includes research on the virulence mechanisms of many human microbial infections. Among the most extensively studied organisms whose pathogenicity results from long-term interaction with amoebae are the bacterium Legionella pneumophila and the microscopic fungus Cryptococcus neoformans, with very different virulence strategies and manifestations. Understanding the evolutionary context and the advantages that microorganisms gain during interaction with amoebae informs us about the origins of virulence of opportunistic human pathogens.
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Functional and pathological changes in the stomach of hosts infected with gastric cryptosporidia
MARKOVÁ, Marie
The aim of this study was to observe and record the effect of infection with gastric species of the genus Cryptosporidium on the gastric characteristics of their hosts. The species Cryptosporidium proliferans was used for a series of experimental infections, and three types of model hosts - BALB/c mice, C57Bl6 mice and multimammate mice (Mastomys coucha) - were used as experimental animals. Oocysts were detected in the faeces of infected animals by standard parasitological, specific staining and molecular methods and the course of infection and pathogenicity of the Cryptosporidium species were described. Groups of animals comprising of 1-3 animals were humanely euthanized at seven-day intervals up to 70 days after infection. C. proliferans was found to have a direct effect on pH change in selected host types, with an increase in pH at the peak of infection and, depending on the host type, either an increase until the end of the experiment or, in the case of self-healing, a gradual return to physiological values. Pathological changes of the gastric mucosa during the course of the infection were recorded by histological methods, which were its thickening and increased mucus production, as well as the presence of inflammatory infiltrates and the intensity of the infection, to varying degrees across the selected hosts and the course of the infection. We found that even with short-term infection in BALB/c and C57Bl6 mice, there is both mucosal enlargement and thickening, although the pathological changes in these types of mice are not as extensive as in multimammate mice, which do not self-heal.
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Reakce imunitního systému na spirochéty Lymské boreliózy v závislosti na jejich patogenním potenciálu
ŠMÍDOVÁ, Hana
An infectious disease known as Lyme borreliosis is caused by the bacterium Borrelia, which is transmitted to humans by ticks. The bachelor thesis deals with the comparison of the pathogenic potential of three species of bacteria from the Borrelia burgdorferi sensu lato complex, which are characterized by their antigenic equipment. Differences between these species result in different responses of the host immune system and also affect tissue specificity, it determines the target area in the body where a given bacterium persists and causes symptoms typical of its species.
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Influence of sigle nucleotide mutations on influenza pathogenicity
Nitkulincová, Lucie ; Drda Morávková, Alena (advisor) ; Král, Jiří (referee)
Influenza virus caused several times the global concerns about the emergence of pandemics, in recent years. The most serious problem, in the fight against this virus, is its ability to quickly change its unusually antigenic specificity by reassortment and point mutations, especially in surface glycoproteins - haemagglutinin and neuraminidase. In this thesis I focused on point mutations in the hemagglutinin of influenza virus causing change in binding preference, which enables both influenza virus transmission between different hosts and unlimited proliferation in their tissues. The permanent change in amino acid sequence and thus the surface of hemagglutinin also largely prevents the host's immune system to destroy the virus efficiently and quickly enough to recognize when another infection. Each of the haemagglutinin subtypes has a different amino acid positions affecting its binding preference. Their summary is included in this thesis. Key words: influenza, single nucleotide mutations, pandemia, patoghenicity, hemagglutinin
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Role of exosomes and ectosomes in Trichomonas vaginalis virulence
Göblová, Rebeka ; Tachezy, Jan (advisor) ; Ditrich, Oleg (referee)
Trichomonas vaginalis is a causative agent of the most common non-viral sexually transmitted disease with approximately 275 mil new cases annually. Virulence of this parasitic depends on at least four factors: cell shape transformation, cytoadherence, secretion of cysteine proteases, and presence of endosymbionts. Over the past decades, extracellular vesicles appeared being another important player in the host-parasite interaction. It was discovered that T. vaginalis is one of the protists that can shed the extracellular vesicles such as exosomes and ectosomes. These vesicles are possibly involved in host-parasite communications, however limited information is available about their function. To investigate a possible role of exosomes in T. vaginalis virulence, we first selected suitable strain, which is free of endosymbionts (TV 17-2MI). Next we prepared six clones of TV 17-2MI strain to test whether the strain is homogenous concerning the virulence, or there are differences in virulence among individual cells. Mouse intraperitoneal virulence tests revealed that the clones displayed significant differences in virulence level, particularly in abscess formation and mortality of infected animals. Thus, for the first time we demonstrated heterogeneity of cells derived from a single T. vaginalis strain...
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Testování náchylnosti českých proveniencí jehličnatých dřevin vůči patogenní houbě Fusarium circinatum v laboratorních podmínkách
Lukačevičová, Aneta
Pine pitch canker (PPC), which is caused by Fusarium circinatum, is considered to belong among the most important destructive diseases affecting coniferous tree species in many locations throughout the world. In Europe, F. circinatum is currently present in Spain and Portugal, posing a high risk of its spread into currently disease-free countries in Europe. In the present study, the susceptibility of Pinus sylvestris, Picea abies, and Larix decidua originating in the Czech Republic to F. circinatum was tested. Furthermore, the presence of asymptomatic yet infected seedlings was also checked.
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Influence of sigle nucleotide mutations on influenza pathogenicity
Nitkulincová, Lucie ; Drda Morávková, Alena (advisor) ; Král, Jiří (referee)
Influenza virus caused several times the global concerns about the emergence of pandemics, in recent years. The most serious problem, in the fight against this virus, is its ability to quickly change its unusually antigenic specificity by reassortment and point mutations, especially in surface glycoproteins - haemagglutinin and neuraminidase. In this thesis I focused on point mutations in the hemagglutinin of influenza virus causing change in binding preference, which enables both influenza virus transmission between different hosts and unlimited proliferation in their tissues. The permanent change in amino acid sequence and thus the surface of hemagglutinin also largely prevents the host's immune system to destroy the virus efficiently and quickly enough to recognize when another infection. Each of the haemagglutinin subtypes has a different amino acid positions affecting its binding preference. Their summary is included in this thesis. Key words: influenza, single nucleotide mutations, pandemia, patoghenicity, hemagglutinin
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