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Experimental Infection of Mice and Ticks with the Human Isolate of Anaplasma phagocytophilum NY-18
KALINOVÁ, Eliška
Anaplasma phagocytophilum is a significant tick-borne pathogen that colonizes granulocytic cells in vertebrate hosts. It is found in North America and in several European countries. It causes severe diseases in domestic animals and potentially fatal disease in humans called human granulocytic anaplasmosis (HGA). The implementation of animal models is necessary due to the increasing prevalence of A. phagocytophilum. This study addresses the transmission of the human isolate of the bacterium A. phagocytophilum NY-18 by two tick species (Ixodes ricinus and Ixodes scapularis) and implements a laboratory model for the transmission of A. phagocytophilum by the tick I. ricinus in mice. The thesis also compares both transmissions and infection dynamics.
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Parasite cystatins as inhibitors of cysteine proteases: structural aspects of functional specificity and their evolution
Buša, Michal ; Mareš, Michael (advisor) ; Hudeček, Jiří (referee) ; Kukačka, Zdeněk (referee)
Members of the cystatin family are important inhibitors of cathepsin-type cysteine proteases and are involved in a number of pathologies. Parasite cystatins are attractive target molecules for parasite control, but our knowledge about them is still limited. This work is focused on cystatins of two blood-feeding parasites: the common tick (Ixodes ricinus) as the main vector of Lyme disease and tick-borne encephalitis, and the liver fluke (Fasciola hepatica), the causative agent of fasciolosis. Four novel cystatins were functionally and structurally characterized to determine the structural determinants of their inhibitory specificity and describe them in the context of evolution and physiological role of cystatins. The cystatin FhCyLS-2 from F. hepatica has broad inhibitory specificity and is suggested to play a dual role in the regulation of proteolytic systems in host tissue and the parasite gut. FhCyLS-2 combines the characteristics of two cystatin subfamilies in a unique way and is a model representative of a novel evolutionary group of cystatins identified in several orders of parasitic flukes. Ricistatin and iristatin are salivary cystatins of I. ricinus with immunomodulatory effects on the host caused by an exceptionally narrow inhibitory specificity. It was explained by structural modifications of...
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Strukturní studie serpinu Iripin-5 z klíšťat \kur{Ixodes ricinus}
SPĚVÁKOVÁ, Nikola
The aim of this bachelor thesis was a crystallization of serpin Iripin-5 from ticks Ixodes ricinus. Iripin-5 is the most produced serpin in the salivary glands of ticks. The focus of this thesis was to prepare protein Iripin-5 and perform crystallization experiments. Obtained crystals of Iripin-5 were in diffraction quality.
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Problems of laboratory examination in Lyme disease
HAVLEOVÁ, Lucie
Lyme borreliosis is a multisystem infectious disease most often transmitted by ticks of the genus Ixodes. In the Czech Republic, specifically by ticks Ixodes ricinus. The initiator of this disease is a complex of spirochetal bacteria Borrelia burgdorferi sensu lato. The incidence of the disease is relatively often as several thousand cases are reported in the Czech Republic every year. However the knowledge about Lyme borreliosis is relatively extensive and simultaneously an intensive research is constantly ongoing, the opinions of experts on this issue are still unfolding accordingly. So far, it is still rather difficult to diagnose Lyme disease, especially because of the various and sometimes non-specific clinical symptoms that might often lead to failure in diagnosis. As no effective vaccine has yet been developed, the only way to reduce the risk of infection is prevention and protection against the ticks. This work investigates and summarizes current knowledge about the history, etiology, epidemiology, pathogenesis, clinical course, prevention, therapy, and diagnosis of Lyme disease. Patients suspected of having contracted Lyme disease were tested using a two-level screening, firstly by applying ELISA method in order to select either positive patients or patients with uncertain results so that a confirmation Western blot method could follow subsequently. The outcome of my work confirmed the well-known fact that Lyme disease is seasonal. The higher number of positive samples in the summer months is related to the increased activity of ticks during this period. However, the results of positive patients who are divided into groups by age or gender represent very interesting findings. Particularly the higher incidence of the positive samples can be found among women.
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Analýza slinných serpínů klíšťat Ixodes ricinus z hlediska strukturní biologie
KAŠČÁKOVÁ, Barbora
The knowledge of the detailed structure of proteins and their complexes with other proteins, such as serpins, helps to understand the mechanism of action. Serpins, a large protein group of protease inhibitors that possess almost identical secondary-structural folds, represent the perfect example of expanding the knowledge of their inhibition process through detailed structural analyses. The universal process of serpin inhibition is known, but also is known that serpins are structurally similar whereas their functional diversity is significant. Therefore, each serpin will have some properties specific to its own and knowledge of the serpin structures can explain high functional diversity. X-ray crystallography was one of the most common tools used for serpin structural analysis. This thesis describes the structural information of serpins found in Ixodes ricinus ticks. Serpins of this species are mainly responsible for the modulation of the host immune response via inhibiting involved proteases. Serpins with proteases form covalent complexes. This process leads to a suicide mechanism that inactivates the protease as well as serpin. Here are presented results of the X-ray structural analysis of four I. ricinus serpins named Iripin-3, Iripin-5, Iripin-4, and Iripin-1. All of them help the tick in different ways to stay attached to the host for sufficient time for feeding by inhibiting the proteases involved in host immune defense responses to a tick bite.
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Detekce glyoxylátové dráhy v klíštěti \kur{Ixodes ricinus}
PAVLASOVÁ, Veronika
Ticks are important blood-feeding ectoparasites and vectors of human and animal diseases. The development of rational anti-tick vaccines and drugs is strongly dependent on the identification of biochemical differences between ticks and vertebrates. The glyoxylate cycle was so far found only in bacteria, plants, fungi, and nematodes. Surprisingly, one article described an increase of glyoxylate, a product of the glyoxylate cycle, during embryogenesis in ticks. Aim of my work was to confirm the presence of the glyoxylate cycle (isocitrate lyase) in ticks, mainly in the developing eggs of Ixodes ricinus, by setting-up the biochemical test coupled with a specific inhibitor.
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Growth kinetics of the Lyme disease spirochetes in vector ticks \kur{Ixodes ricinus} and \kur{Ixodes scapularis}
VELANOVÁ, Hana
Growth kinetics of Borrelia afzelii CB43 in Ixodes ricinus and Ixodes scapularis were obtained. Based on this data, I. scapularis was marked as capable of acquiring B. afzelii infection. Growth kinetics of B. burgdorferi N40 in I. ricinus was obtained as well with the same outcome, I. ricinus was able to acquire B. burgdorferi infection. Following transmission experiments showed that I. ricinus as well as I. scapularis are able to acquire the infection by B. burgdorferi and B. afzelii. Moreover, we proved that both ticks are able to transmit the infection back to na?ve mice.
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