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Larval Stages of Flukes (Platyhelmintes: Trematoda) in Secondary School Education
Šulcová, Hana ; Říhová, Dagmar (advisor) ; Podroužková, Štěpánka (referee)
The parasites are one of the most important factors that shape relationships in the nature. This thesis deals mainly with developmental stages of trematodes (Platyhelmintes: Trematoda), especially the cercariae of so-called Schistosomes and sporocysts of Leucochloridium paradoxum, as well as with and their intermediate host - freshwater snails. Introductory chapters are focused on general introduction into the topic, such as basic terminology or occurrence issue of trematodes (mainly schistosomes) in the world and in the Czech Republic. In order to determine larval stages of flukes and their morphological types, the research was conducted in four Prague localities with known presence of aquatic snails. Only in one site, Kunratická tůň Pond, the constant presence of echinostomous cercariae (and in lesser extent also furcocercariae) in Radix labiata was recorded during summer season of 2015. In small pond in the Botanical Garden of the Natural Sciences Faculty of Charles University and in Modřanské tůně Ponds, xiphidocercarie in Lymnaea stagnalis were found. No cercarie were detected in the pond in the Genetic garden of Charles University. The presence of Leucochloridium paradoxum in the European Amber Snail Succinea putris was confirmed in the vicinity of Modřanské tůně Ponds. The verified...
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Aporocotyle simplex fluke from the flounder Hippoglossoides platessoides in Svalbard.
HÁJKOVÁ, Šárka
In my bachelor thesis I studied trematodes from plaice Hippoglossoides platessoides obtained during expeditions to Svalbard in 2014 and 2018. My goal was morphological and molecular processing of the obtained material, which allowed me to confirm the identification of the flukes as Aporocotyle simplex Odhner, 1900. Aporocotyle simplex is a common parasite of plaice, ocurring mainly in Hippoglossoides platessoides, but also in Limanda limanda and Pleuronectes platessa. The species A. simplex is geographically distributed in the Gulf of St. Lawrence in Canada, off the west coast of Sweden, in the Barents Sea and Bering Sea, off the coast of Kamchatka and Greenland. My results showed that the species A. simplex is widespread in Svalbard. In the practical part, I dealt with methods that helped me to identify the studied specimens. I observed the trematode tegumental surface with aid of a scanning electrom microscope (JEOL JSM-7401F). The trematode internal organs were stained with Mayer-Schuberg carmine, which allowed me to observe and draw the mounted specimens using a light microscope (Olympus BX51) equipped with a drawing attachment. Furthermore, for molecular analysis, the DNA was isolated using the commercial Exgene Tissue SV mini kit (GeneAll). The isolated DNA (the gene for the large ribosomal subunit, 28S rRNA) was amplified by PCR, the obtained PCR products were sequenced on an automated sequencer (ABI Prism 3130xl or 3730xl, by SEQme). The newly acquired sequences (three in total) were aligned in the program Geneious 8.0.5with sequences available from GenBank (64 sequences). Phylogenetic analysis of the species relationships within the family Aporocotylidae was performed using the Maximum Likelihood method with TPM2u + F + G4 used as the best model. Aporocotyle simplex falls into a separate branch together with A. michaudi, from which however, it differs substantially by its morphology (distribution of tegumental spines on body and their number in the clusters, number of testes, ratio of esophagus length to body length) and geographical distribution (A. michaudi occurs in the South Atlantic Ocean).
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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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Larval Stages of Flukes (Platyhelmintes: Trematoda) in Secondary School Education
Šulcová, Hana ; Říhová, Dagmar (advisor) ; Podroužková, Štěpánka (referee)
The parasites are one of the most important factors that shape relationships in the nature. This thesis deals mainly with developmental stages of trematodes (Platyhelmintes: Trematoda), especially the cercariae of so-called Schistosomes and sporocysts of Leucochloridium paradoxum, as well as with and their intermediate host - freshwater snails. Introductory chapters are focused on general introduction into the topic, such as basic terminology or occurrence issue of trematodes (mainly schistosomes) in the world and in the Czech Republic. In order to determine larval stages of flukes and their morphological types, the research was conducted in four Prague localities with known presence of aquatic snails. Only in one site, Kunratická tůň Pond, the constant presence of echinostomous cercariae (and in lesser extent also furcocercariae) in Radix labiata was recorded during summer season of 2015. In small pond in the Botanical Garden of the Natural Sciences Faculty of Charles University and in Modřanské tůně Ponds, xiphidocercarie in Lymnaea stagnalis were found. No cercarie were detected in the pond in the Genetic garden of Charles University. The presence of Leucochloridium paradoxum in the European Amber Snail Succinea putris was confirmed in the vicinity of Modřanské tůně Ponds. The verified...
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