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Helminths as causative agents of vertebrate cancers
Schreiber, Manfred ; Horák, Petr (advisor) ; Kolářová, Iva (referee)
Opisthorchis viverrini, Clonorchis sinensis, and Schistosoma haematobium have been classified as the group 1 of carcinogens by the International Agency for Research on Cancer. Infections with opisthorchid flukes may lead to the development of cholangiocarcinoma of the liver, and those with schistosomes to the squamous carcinoma of the bladder. The link between helminth infections and carcinomas has been confirmed, and the exact mechanisms of carcinoma induction are at present intensively studied. There are some other representatives of helminths that are probably associated with cancers, but their direct effect on the process of carcinogenesis has not been confirmed yet. The formation of tumors can also occur via malignant transformation of totipotent parasite cells that become invasive and metastasize to different parts of the host body. However, some types of helminths may exhibit an opposite effect and show an anti-tumor activity. This review primarily focuses on the helminths associated with the development of cancer and the currently described mechanisms of carcinogenesis caused by such infections.
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Molecular and serologic diagnosis of infections caused by Trichobilharzia
Vaščiková, Michaela ; Horák, Petr (advisor) ; Ditrich, Oleg (referee)
Cercariae of the genus Trichobilharzia can penetrate not only the skin of definitive hosts (ducks), but they are also able to penetrate the skin of accidental hosts (mammals). As a result of the penetration, the inflammatory response known as cercarial dermatitis appears. The goal of our thesis is to detect parasite DNA in the serum and cerebrospinal fluid of infected ducks, and also in the serum of infected mice. By using PCR with primers designed for a tandem repeated sequence, we were able to detect 1 femtograms of parasite DNA isolated from sera of infected ducks. We were able to amplify parasite DNA only from 16 samples of sera and cerebrospinal fluid of the infected ducks, but we were not able to do so with the serum of mice. Sera of infected mice were also tested by ELISA and Western blot. The homogenates of T. regenti (TRhc), T. szidati (TShc) and S. mansoni (SMhc) cercariae were selected as an antigen. The results showed progressive increase in the level of IgM antibody from 10 days after 1st infection and also increase of the level of IgG from the 2nd infection. 10 days after the 4th infection, the level of IgM and IgG gradually declined, but the level of antibodies 100 days after the 4th infection was still higher if compared to uninfected mice. Results from Western blot analysis...
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Differentiation of totipotent germinal cells in larvae of bird schistosomes
Peštová, Jitka ; Horák, Petr (advisor) ; Chanová, Marta (referee)
This thesis aims to explore the larval development of a bird fluke Trichobilharzia regenti in its intermediate hosts, as well as the processes of differentiation of its embryonal cells and the differentiation between sporocystogenesis and cercariogenesis in sporocysts, with the ultimate goal to find out whether it is possible to find multiple generations of daughter sporocysts throughout the development of avian schistosomes in the intermediate hosts, just like in the case of human schistosomes of genus Schistosoma. Five developmental stages of daughter sporocysts, and ten developmental stages of cercariae have been defined. The first developmental stage in both larvae is the germinal cell. It divides and gives rise to a cell agregate. Afterwards an envelope (primitive epithelium) is formed around the embryo and subsequently, the embryo elongates. At this stage, the development of the two larvae undergoes different pathways. We can distinguish daughter sporocyst from cercaria in the phase, when the tegument is completed. The daughter sporocyst acquires characteristic vermiform appearance, and its body cavity contains plenty of germinal cells. For cercariae with an developed tegument, presence of the penetration glands is characteristic. Key words: Trichobilharzia regenti, germinal cells, mother...
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Application of mass spectrometry methods for identification and localization of important molecules from parasitic helminths
Siegel, Tomáš ; Kašný, Martin (advisor) ; Harant, Karel (referee)
The thesis summarises the fundamental technological solutions, processes and principles of mass spectrometry with special focus on their use in parasitology. In the first part, the particular phases of processing of the biological sample by using mass spectrometry are defined - from ionisation to the evaluation of results. In the text, the various methodological approaches are presented mainly on the published examples concerning the identification of molecules from parasitic helminths, especially proteins of fasciolid flukes (e.g. Fasciola hepatica). The second part of the thesis comprises the methods of identification and localization of molecules by using mass spectrometry imaging and the use of this combined technique in experimental biology, parasitology, is discussed. There is also proposed the procedure including the combination of laser microdissection and mass spectrometry techniques which could be applied for identification and localisation of important proteins of the fluke Fascioloides magna.
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