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The role of humoral factors in the snail immune response against schistosomes
Košťáková, Monika ; Horák, Petr (advisor) ; Dvořák, Jiří (referee)
Digenetic trematodes such as Schistosoma mansoni use molluscs, mainly Gastropoda in their life cycle, as their intermediary hosts. e internal defense system (IDS) of snails is composed of immune cells called hemocytes, which are the main effectors and act jointly with soluble components. Humoral factors could in uence directly the parasite's larval stage, the activity of hemocytes and also may serve in recognition of the parasite. Lectins are considered to be the main component of humoral immunity. ey have a primary role in non-self recognition. Other protein group with lectin-like activity called FRePs was found in Biomphalaria glabrata. eir unique structure contains a brinogen and an immunoglobulin-like domain. Cytokine-like molecules may play very important role in defense as well. Many molecules are present in hemolymph and their levels change during infection. e response to parasitosis is therefore very complex and still awaits further clari cation.
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Lymnaeid snails: hemocyte activities and their changes caused by Trichobilharzia infections
Jindrová, Zuzana ; Horák, Petr (advisor) ; Bilej, Martin (referee)
Molluscs as well as all other invertebrates rely on innate immune response only. Their internal defense system is capable of destroying most pathogens. However, there are some exceptions, e.g. some snails serve as intermediate hosts for some trematodes. Trematodes are able to develop inside these snails due to intervention in the snail internal defense system. The submitted thesis describes hemocyte activities of two lymnaeid snails, Lymnaea stagnalis a Radix lagotis, and the influence of Trichobilharzia regenti infection on R. lagotis hemocytes. Hemocytes of both species exposed to various chemicals produced different amounts of H2O2 and NO. The response varied between both lymnaeid species. The amount of circulating hemocytes was elevated in R. lagotis snails due to T. regenti infection. However, the infenction attenuated hemocyte activities monitored by us. Hemocyte basal NO production was decreased as well as phagocytosis of bacteria, cell adherence and pseudopodia formation. Toxicity of L. stagnalis plasma against T. regenti miracidia was also described. Mechanisms used by trematodes to interact with the snail internal defense system will help us to understand why one species is suitable for the develepment of the trematode whereas another closely related species kills it. Powered by TCPDF (www.tcpdf.org)
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The role of humoral factors in the snail immune response against schistosomes
Košťáková, Monika ; Dvořák, Jiří (referee) ; Horák, Petr (advisor)
Digenetic trematodes such as Schistosoma mansoni use molluscs, mainly Gastropoda in their life cycle, as their intermediary hosts. e internal defense system (IDS) of snails is composed of immune cells called hemocytes, which are the main effectors and act jointly with soluble components. Humoral factors could in uence directly the parasite's larval stage, the activity of hemocytes and also may serve in recognition of the parasite. Lectins are considered to be the main component of humoral immunity. ey have a primary role in non-self recognition. Other protein group with lectin-like activity called FRePs was found in Biomphalaria glabrata. eir unique structure contains a brinogen and an immunoglobulin-like domain. Cytokine-like molecules may play very important role in defense as well. Many molecules are present in hemolymph and their levels change during infection. e response to parasitosis is therefore very complex and still awaits further clari cation.
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Species diversity of Plagiorchis Lühe, 1899 (Digenea: Plagiorchiidae) in lymnaeid snails from freshwater ecosystems in central Europe revealed by molecules and morphology
ROHÁČOVÁ, Jana
This study applies molecular and morphological approaches addressing the identification of morphologically similar larval stages (cercariae) of Plagiorchis spp. (Digenea: Plagiorchiidae) parasitising lymnaeid snail populations in the freshwater ecosystems of central Europe. Five morphologically homogeneous and genetically distinct lineages of Plagiorchis spp. were identified via matching molecular data for the mitochondrial cox1 gene with detailed morphometric data. Phylogenetic and comparative sequence analyses using partial 28S rDNA and ITS1-5.8S-ITS2 sequences allowed molecular identification of three species (P. elegans, P. maculosus and P. koreanus) via matching sequences from larval and adult digenean stages. A key for the identification of the cercariae of Plagiorchis spp. parasitising lymnaeid populations in central Europe is provided.
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Molecular and morphological characterisation of species of \kur{Plagiorchis} Lühe, 1899 (Digenea: Plagiorchiidae) in lymnaeid snails from freshwater ecosystems in central Europe
ROHÁČOVÁ, Jana
This study applies molecular and morphological approaches addressing the identification of morphologically similar larval stages (cercariae) of Plagiorchis spp. (Digenea: Plagiorchiidae) parasitising lymnaeid snail populations in the freshwater ecosystems of central Europe. Five morphologically homogeneous and genetically distinct lineages of Plagiorchis spp. were identified via matching molecular data for the mitochondrial cox1 gene with detailed morphometric data. Phylogenetic and comparative sequence analyses using partial 28S rDNA and ITS1-5.8S-ITS2 sequences allowed molecular identification of three species (P. elegans, P. maculosus and P. koreanus) via matching sequences from larval and adult digenean stages. A key for the identification of the cercariae of Plagiorchis spp. parasitising lymnaeid populations in central Europe is provided.
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Effect of temperature on emergence of cercariae
ŠAROUNOVÁ, Petra
The influence of water temperature on cercarial emission of three trematode species parasitising freshwater first intermediate hosts, was studied in laboratory conditions: Echinoparyphium aconiatum from Lymnaea stagnalis; Neoglyphe locellus from Planorbarius corneus; and Echinostoma miyagawai from Planorbis planorbis. The study provided evidence for increase in cercarial emission with temperature increase and revealed both interspecific and intraspecific variations.
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Composition and structure of larval trematode communities in model freshwater pulmonate gastropods in eutrophic environments in Central Europe
SOLDÁNOVÁ, Miroslava
This work applies advanced sampling (mark-release-recapture) and comparative approaches addressing the patterns in composition, structure and variability of larval trematode communities in three species of gastropod molluscs (Lymnaea stagnalis, Planorbarius corneus and Radix auricularia) at two nested scales of community organisation in typical Central European eutrophic environments. Hypothesis-testing with the application of null-model analyses, logistic regression modelling and multivariate randomisation techniques, revealed determinants of transmission rates, levels of infection and community structure in freshwater snail hosts in Central Europe and elucidated the mechanisms linking the spatial and temporal environmental variability with the action of complex community assembly rules in freshwater pulmonate snails.
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