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Trypanosomes transmitted by mosquitoes: occurrence in hosts, transmission, and specificity
Kulich Fialová, Magdaléna ; Svobodová, Milena (advisor) ; Bernotienė, Rasa (referee) ; Modrý, David (referee)
7 Abstract Trypanosomes (Trypanosoma, Kinetoplastea) are dixenous blood protists that require not only a vertebrate host but also a blood-feeding invertebrate to complete their life cycle. Infection of vertebrates can be asymptomatic, but on the other hand can cause serious diseases affecting lives of humans and animals. Thus, researchers usually focus on Trypanosoma species causing Chagas disease and sleeping sickness in humans or nagana and surra in animals, and on their vectors: tsetse flies and kissing bugs. However, mosquitoes are able to transmit trypanosomes as well, specifically, avian trypanosomes and probably mammalian trypanosomes from the T. theileri group. Nevertheless, the role of mosquitoes in the life cycle of trypanosomes has substantial gaps, which are focused in this dissertation. Within the experimental work, it has been demonstrated that mosquitoes of the genus Culex are susceptible hosts of two species of avian trypanosomes: T. thomasbancrofti and T. tertium n. sp. On the other hand, Culex mosquitoes were unsuitable hosts for T. theileri, while the genus Aedes and surprisingly even sand flies (Phlebotomus perniciosus) turned up to be competent vectors. All investigated trypanosomes were able to develop within the guts of mosquitoes and were also found in their prediuretic liquid. This...
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Identification and characterization of flagellar tip proteins in Trypanosoma brucei
Pavlisková, Hana ; Varga, Vladimír (advisor) ; Čajánek, Lukáš (referee) ; Hashimi, Hassan (referee)
The tip of the eukaryotic flagellum is one of the most important regions of the flagellum in many eukaryotic cells. Several important functions have been associated with the flagellar tip. However, its protein composition remains largely unknown. The main aim of this thesis was to identify flagellar tip proteins and characterize them. Using the parasitic model organism Trypanosoma brucei and the TrypTag.org project, a unique resource localizing every protein encoded in the trypanosome's genome, we were able to identify, for the first time, the complete catalog of flagellar tip proteins in a eukaryotic organism. In T. brucei the full complement comprises 78 proteins localizing exclusively to the flagellar tip or being highly enriched there. To characterize these proteins, we established new reagents and approaches. First, we developed antibody markers labeling the tip of an assembling trypanosome flagellum via recognizing the flagella connector. This enabled us to study the tip-specific processes. Second, we developed a rapid and cloning-free approach for tagging and inducible overexpression of trypanosome proteins. We demonstrated that the approach is well suited for overexpression of large proteins, such as some of the flagellum tip proteins. This enables the study of overexpression phenotypes and...
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Trypanosomes of green frogs (genus Pelophylax)
Poloprutská, Klára ; Votýpka, Jan (advisor) ; Modrý, David (referee)
Anuran trypanosomes are the first ever observed and described trypanosomes and Trypanosoma rotatorium from frogs of the genus Pelophylax is a type species of the genus Trypanosoma. Despite the early discovery, they are being neglected in terms of current descriptive studies when compared to other trypanosomes, although their diversity and prevalence in anurans are quite high. Anuran trypanosomes, which are significantly larger than their mammal relatives, display a high rate of polymorphism and pleiomorphism; however, without any explanations. Because of the amphibious nature of frogs, the vectors of anuran trypanosomes are both aquatic leeches and terrestrial bloodsucking insects. This thesis which aims at widening the scope of knowledge about this neglected group of trypanosomes focuses on trypanosomes from frogs of the genus Pelophylax found in Central Europe and the Balkan Peninsula. An overall prevalence of 71% was found in 981 individuals and a total of thirteen trypanosome species were detected, eight of which are new to science. Significantly higher diversity was found in frogs originating from the Balkan Peninsula; however, no host specificity of trypanosomes was detected. It was not possible to unambiguously prove the relationship between morphospecies and genospecies. On the contrary, I...
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Genotype influence on development of infections caused by Trypanosomatidae in mouse
Šíma, Matyáš ; Lipoldová, Marie (advisor) ; Krulová, Magdaléna (referee) ; Kolářová, Iva (referee)
Parasitic protists of genera Trypanosoma and Leishmania are members of Trypanosomatidae family. In our studies, we investigated genetic influence on infections caused by these parasites in a mouse model. These diseases are on genetic level controlled by quantitative trait loci (QTLs), when the resulting phenotype is controlled by set of genes with small individual effect. As a mouse model for mapping of QTLs controlling these infections, we used recombinant congenic strains (RCS). Each RCS carry unique set of 12.5% of the genome from donor parental strain on genetic background of other parental strain. For mapping of QTLs controlling infections caused by Trypanosoma brucei brucei (T. b. brucei) and Leishmania tropica (L. tropica) and eosinophil infiltration into inguinal lymph nodes after Leishmania major (L. major) infection, we used RCS from CcS/Dem series, where STS is donor strain and BALB/cHeA is strain of genetic background. First, it was necessary to find suitable model strains for mapping. In all three studies, we selected RCS, which exceeded range of monitored phenotype parameters in comparison with any other tested RCS or parental strains. Mice of RCS CcS-11 showed shorter survival after T. b. brucei infection and strain CcS-9 exhibited higher eosinophil infiltration after L. major infection. For...
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Sex in Trypanosomatids
Kvapilová, Kateřina ; Volf, Petr (advisor) ; Čepička, Ivan (referee)
3 Abstrakt Rody Leishmania a Trypanosoma jsou původci vážných lidských onemocnění: leishmaniózy a trypanosomózy. Dlouhá léta nebyly u těchto parazitů nalezeny přesvědčivé důkazy o genetické výměně, a proto byly rody Trypanosoma a Leishmania považovány za klonálně se rozmnožující, a to binárním štěpením jako většina prvoků. Výzkum ztěžovaly i skutečnosti, že pohlavní dimorfismus není patrný a chromosomy nekondenzují, tudíž nejsou viditelné. Nicméně klonální model začaly zpochybňovat pozorování přirozeně se vyskytujících hybridních druhů. Nejdříve byla existence sexu popsána u trypanosom a to prvním přímým důkazem hybridů T. brucei, získaných po společném přenosu rodičů mouchou tsetse. U leishmanii byl důkaz poskytnut na základě dvojitě rezistentních hybridů a sexuální výměna podstupovala stejný meiotický proces jako T. brucei. Byli pozorovaní přirozeně se vyskytující hybridi Nového i Starého světa jak u rodu Viannia, tak i u rodu Leishmania. Otázkou dalších výzkumů bylo, jaký je mechanismus genetické výměny, ale odpověď dodnes není jasná. Klíčová slova: genetická výměna, Trypanosoma, Leishmania, klonalita, meióza, GFP, přenašeč Abstract Genera Leishmania and Trypanosoma are agents of serious human diseases: leishmaniasis and trypanosomózy. For many years these parasites were considered clone-replicating by...
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Advances in treatment of human trypanosomiasis
Novotná, Kristýna Klára ; Mach, Jan (advisor) ; Grekov, Igor (referee)
Sleeping sickness is a human disease found in sub-saharan Africa, and is caused by a parasitic protozoan Trypanosoma brucei. Trypanosoma brucei species infects various mammals, however, only Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense subspecies are resistant to trypanolytic factors found in human blood serum. This work briefly summarizes known operating mechanisms of trypanolytic factors and resistance mechanisms of trypanosomes to these factors. The work covers mainly description and summarization of current diagnostic methods of sleeping sickness and used trypanocidal drugs. Majority of introduced methods shows high levels of sensitivity and specificity, however, for poor, disease affected areas they are often way too expensive. Prescribed drugs are expensive as well, and what's more, they are often ineffective against both subspecies and have severe side effects. Last part of the work is dedicated to potential development of new medicaments.
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The role of biting midges in avian blood parasites transmission
Chobotová, Kristýna ; Brzoňová, Jana (advisor) ; Kočišová, Alica (referee)
Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are hematophagous in- sects mainly important as vectors of viral diseases of farm animals. They have shifted to the forefront of scientific interest in the Czech Republic primarily in relation to the Bluetongue Virus spread since 2007. However, they have been often ignored as vectors of parasitic infec- tions, especially if these are not pathogens of economic importance. In birds, which are the focus of this bachelor's thesis, biting midges are the most significant vector mainly for the genus Haemoproteus, they transmit at least 24 species of these protozoa. On the other hand, they are proven vectors for only one species of the genus Leucocytozoon - L. caulleryi. Trans- mission has been proven for three species of the genus Trypanosoma - T. avium, T. bennetti and T. everetti. Biting midges also transmit helminths of the family Onchocercidae, they play a role as vectors for the genera Eufilaria, Chandlerella and Splendidofilaria. The goal of this bachelor's thesis is to gather information about biting midges as vectors of avian blood parasites - protozoa of the genera Haemoproteus, Leucocytozoon and Trypanosoma and helminths of the family Onchocercidae. Key words: biting midges, parasite, vector, host, bird, Haemoproteus,...
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Current options of treatment for parasitic kinetoplastids
Čadková, Aneta ; Mach, Jan (advisor) ; Richterová, Lenka (referee)
Chagas disease, sleeping sickness and leishmaniasis are diseases occurring mainly in developing areas of Africa, America and Asia. They are caused by parasitic kinetoplastids from the genus Trypanosoma and Leishmania. These protozoans undergo morphologic transformations during their development leading to changes of their properties. They are characterized by complex mechanisms that allow them to evade the host's immunity. At the same time, because of these mechanisms and selection pressures, they are able to subsequently develop resistance to used drugs. The diseases caused by protozoa are classified as "neglected tropical diseases". The research and development of drugs against them is heavily underfunded. Currently used drugs are expensive, have a number of side effects, and due to lack of usage regulation develop resistance. The work first generally presents human parasites of the class Kinetoplastida. It further describes the treatment of diseases caused by the characterized species and focuses on a summary of currently used drugs, their mechanism, resistance and potential new drugs in clinical phases. Key words: kinetoplastids, Trypanosoma, Leishmania, treatment, disease, mechanism of action, resistance, nitroreductase
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