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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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Exploration of the tick-Borrelia molecular interactions by employing the transcriptomic approaches
MAHMOOD, Sazzad
Along with climate change and increased sharing of habitat, ticks are coming into more frequent contact with humans. The hard tick Ixodes scapularis and Ixodes ricinus are known disease vectors in Northern America and Europe, respectively. Along with many other pathogenic microorganisms, these ticks spread Borrelia sp. by ectoparasitic blood feeding. Borrelia afzelii is the major European Lyme disease pathogen spread by I. ricinus. Our study focuses on differential gene expression in I. ricinus salivary gland and midgut, induced in the nymphal stage by B. afzelii infection. Tick genes upregulated by infection are considered to play essential roles for the acquisition, persistence, and transmission of Borrelia. We have determined 32,897 full length sequences of tick mRNA from B. afzelii infected/noninfected tick salivary glands and the whole body. In addition, we have obtained MACEseq (Massive Analysis of cDNA Ends) from both midgut and salivary glands while the nymphs were non-infected or infected with B. afzelii during three different phases of blood-feeding. From the MACE database, we obtained 250-500 bp 3'-end sequences with raw quantitative expression values. Total reads, unique sequences and protein coding tick genes from midgut samples were 38,199,641, 88,825 and 24,276, and from salivary gland were 74,651,134, 93,096 and 26,179, respectively. After filtering, using several criteria, expression was validated by qPCR. Hence, the validated genes may most likely interact with Borrelia in its acquisition, persistence, or transmission to the vertebrate host. In our study, RNA interference approaches and vaccination were implemented in order to investigate the impact of upregulated tick midgut and salivary gland genes on Borrelia transmission to C3H mice.
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\kur{Ixodes holocyclus\kur{}} - životní cyklus, toxicita a schopnost přenášet borrelie
VLČKOVÁ, Kamila
Ixodes holocyclus is the most common species of blood-feeding arthropods along the whole eastern coast of Australia. The salivary secretions contain neurotoxins, which cause paralysis and toxicoses to the hosts, especially cats, dogs, livestock, and even man, while native fauna appears to be immune. Despite its wide distribution, the role of paralytic toxins in disease transmission and the spectrum of pathogens carried by this tick are poorly understood. It is impossible to breed the ticks on animals because of their toxicity. However using an artificial feeding membrane helped us to establish a laboratory colony, which was necessary to perform our subsequent experiments. This study was focused on the ability of I. holocyclus to transmit Borrelia afzelii, a spirochete bacterium causing Lyme borreliosis. The next goal was to identify the paralytic neurotoxins.
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Gene expression and infectivity of \kur{Borrelia afzelii} in the course of tick feeding
POSPÍŠILOVÁ, Tereza
Borrelia afzelii differential gene expression in the course of tick blood-feeding, and during chronic infection in mice was studied. Temperature effect on B. afzelii gene expression and infectivity was investigated. Infection rates of mice immunized with B. afzelii tick gut antigen at various stages of tick blood-intake were analyzed. This work was funded by the Grant Agency of the Czech Republic, Project No. 17-27393S to Radek Šíma.
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The effect of tick saliva on the interactions between \kur{Borrelia afzelii} spirochetes and murine dendritic cells.
SLÁMOVÁ, Martina
Interaction between mouse dendritic cells (DCs) and Borrelia afzelii spichochetes was studied on three different levels: phagocytosis of borrelia by DCs, production of cytokines by borrelia-activated DCs and the ablilty of DCs to activate CD4+ T cells. The effect of Ixodes ricinus saliva on each of these levels was examined. Tick saliva was shown to decrease the number of phagocosing DCs. The ability of borrelia-activated DCs to induce both proliferation and IL-2 production in specific CD4+ T cells was significantly reduced by tick saliva. And surprisingly, we have shown an inhibitory effect of I. ricinus saliva on the production of both Th1 (IL-6 and TNF-{$\alpha$}) and Th2 (IL-10) cytokines. Our data reveal a complex inhibitory effect of tick saliva on DC function.
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