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Factors regulating the expression and activity of digestive enzymes in the tick \kur{Ixodes ricinus}
KONVIČKOVÁ, Jitka
The intracellular proteolysis of ingested meal plays an essential role in tick development. The thesis focuses on the factors influencing the expressions and activities of digestive enzymes in Ixodes ricinus females during the feeding and post-feeding period. We have revealed the effect of fertilization on blood feeding and digestion. The females cannot reach the rapid engorgement phase without being fertilized. The rate of mated females in the nature proved the presumption that mating can occur even off the host. Implementation of in vitro feeding technique further extended our current knowledge about tick digestive apparatus. Adult females were fed on hemoglobin-rich and hemoglobin-poor diet and the mRNA expression levels of digestive proteases were determined. In line with obtained data, we assumed that albuminolysis is conducted by the same or similar pathway as hemoglobinolysis. The gene silencing method and protein immuno-detection were used to unequivocally identify the isoforms of 'early expressed' IrCL1 and 'late expressed' IrCL3 isoform of cathepsin L.
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Effect of \kur{Ixodes ricinus} feeding duration on transmission of the spirochete \kur{Borrelia afzelii}
CHLASTÁKOVÁ, Adéla
Lyme borreliosis is a multisystem infectious disease caused by tick-borne spirochetes belonging to the \kur{Borrelia burgdorferi} sensu lato complex. It is generally believed that if a tick is attached for less than 24 hours, infection is unlikely because it requires between 36 and 48 hours of attachment for \kur{Borrelia burgdorferi} to travel from within the tick into its saliva. Nevertheless, there is evidence that transmission to a host may even occur in the early phases of tick feeding. We investigated the dynamics of \kur{Borrelia afzelii} transmission by nymphal \kur{Ixodes ricinus} ticks with special respect to the first day of tick attachment.
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Characterization and function of Factor C from the tick \kur{Ixodes ricinus}
HARTMANN, David
Factor C is a multi-domain serine protease which recognizes Gram-negative bacteria via binding to lipopolysaccharides and triggers hemolymph clotting cascade in the horseshoe crab. A closely related molecule was also found to be present in the genome of the tick Ixodes scapularis. In this work, the full sequence of Factor C ortholog from Ixodes ricinus (IrFC) was determined. IrFC is mainly expressed in tick hemocytes and the heavy chain of the activated molecules is present in tick hemolymph as confirmed by Western blotting with antibodies raised against recombinant fragments of IrFC. The function of the IrFC in tick innate immunity was assessed using its silencing by RNA interference.
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Molecular characterization of NADPH oxidase in the gut of the tick \kur{Ixodes ricinus}
KUČERA, Matěj
This thesis focuses on characterization of one member of NADPH oxidases - dual oxidase (DUOX) which has been described as the main factor of epithelial immunity in the gut of model organism Drosophila melanogaster. We have identified an orthologous gene coding for DUOX in the tick I. ricinus and described its tissue expression profile. The DUOX is mainly expressed in the gut of unfed ticks and seems to be downregulated upon artificial microbial infection. A fragment of tick DUOX was prepared as recombinant protein and used for preparation of specific antibodies to be used for further characterization of the enzyme. Our main aim is to highlight the importance of tick DUOX producing the reactive oxygen species and their role in the defence against pathogenic organisms within the tick gut.
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Presence of tick-borne encephalitis in Pribram district with its level of awareness and general attitude to vaccination against it in selected populations
KUCHAŘOVÁ, Eliška
Central European tick-borne encephalitis is a disease belonging to the group of zoonosis, which is transmitted by the tick Ixodes ricinus. It is an acute neuroinfection caused by the RNA virus that can seriously endanger people?s lives. Tick-borne encephalitis is one of the diseases typical for its natural pocket. The most common way of transmission onto a human being is by the bite of an infected tick. However, there have been cases where the contagion took place by consuming unpasteurized milk or dairy products. Although it is a disease which can be easily prevented, vaccination is still very low in our country. If we do not press people to improve this situation, we can expect frequency of tick-borne encephalities will be increased.
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Preparation of recombinant inhibitor of serine proteases from the tick \kur{Ixodes ricinus}
VLNOVÁ, Ivana
Tick serine protease inhibitors could be important anti-tick vaccines targets because of their properties and functions. The aim of this work was to prepare recombinant inhibitor of serine proteases from the tick Ixodes ricinus in baculovirus expression system. Two tick saliva proteins of the serpine superfamily were selected for this purpose and transformed into plasmids. One recombinant protein was expressed in baculovirus expression system, purified and its biochemical analyses were done.
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Vaccine potentiality of cystatin from tick \kur{Ixodes ricinus}
HARCUBOVÁ, Adéla
Ticks belong to the ectoparasites which are dangerous for the human beings because of the transmission of bacterial, viral, and protozoan pathogens. The development of a vaccine against tick is very important. Cystatins play important role in tick digestion and they have an immunomodulation effects. For this reason cystatins are possible candidates for this vaccines. This thesis focuses on experimental mice vaccination with recombinant cystatin from Ixodes ricinus.
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The effect of tick´s serpin IRS-2 on dendritic cells activated by TLR4 ligand
POSPÍŠILOVÁ, Šárka
IRS-2 is the inhibitor of serine proteases from the Ixodes ricinus tick. My task in this thesis was to find out the effect of the IRS-2 on dendritic cells activated by TLR4 ligand or by Borrelia afzelii. This effect was studied on several levels. I focused on the cytokine production, the expression of costimulatory molecules and cell signaling pathways. The results show that the IRS-2 may inhibit the expression of costimulatory molecules CD-80 a CD-86 on the cell surface, but this finding needs to be confirmed again. The production of cytokines was not affected by the IRS-2. The effect of the IRS-2 on the activity of p38, Erk1/2 nor NF-?B in LPS stimulated cells vas not observed. The fosforylation of STAT 3 in cells activated by the B. afzelii was lowered by the IRS-2.
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