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Use of animal models in Leishmania research
Pekařová, Julie ; Vojtková, Barbora (advisor) ; Pacáková, Lenka (referee)
Leishmaniasis is a disease caused by parasitic protozoa of the genus Leishmania, whose life cycle includes a mammalian host and an insect vector, typically of the genus Phlebotomus or Lutzomyia. While the number of vectors is limited, the spectrum of hosts is wide. Therefore, there are also many animal models that can be used for the study of different aspects of leishmaniasis. These include the study of the host's immune response, pathological manifestations of diseases, virulence factors or testing drugs and vaccines. Commonly used animal models are mainly rodents, which make up a large part of reservoir hosts of leishmaniasis. Examples of standard rodent models are the laboratory mouse (Mus musculus) and the golden hamster (Mesocricetus auratus), however, higher models such as non-human primates or dogs are also being used. Animals that are relatively new to leishmaniasis research are wild rodents, which appear to be ideal experimental models for studying the natural dynamics of infections. Key words: animal models, laboratory animals, rodents, Leishmania, leishmaniasis
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Host immune response in cutaneous versus visceral form of leishmaniasis
Matějková, Barbora ; Leštinová, Tereza (advisor) ; Jelínková, Kristýna (referee)
Parasitic protozoans of the genus Leishmania circulate between vectors and hosts during their life cycle, in which they come into contact with the immune system. In the host body, infection can lead to the development of a disease called leishmaniasis. This can manifest itself in a number of ways, with the best known forms being referred to as visceral, mucocutaneous and cutaneous leishmaniasis. This thesis focuses on the host immune response during the cutaneous and visceral forms of leishmaniasis. In addition, attention has been given to host, vector and parasite factors that differ between cutaneous and visceral leishmaniasis forms and that may influence the different clinical manifestations. Attention is paid not only to factors related to immunity, but also to factors such as parasite inoculum dose sizes, temperature differences between skin and internal organs, parasite genetics, and others. Keywords - Leishmania, visceral leishmaniasis, cutaneous leishmaniasis, immune response, parasite, immunity
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Development of flagellates of the genus Porcisia and subgenus Mundinia in phlebotomine sand flies (Diptera: Psychodidae) and ceratopogonid midges (Diptera: Ceratopogonidae)
Bačíková, Dominika ; Sádlová, Jovana (advisor) ; Modrý, David (referee)
The main part of the thesis is focused on flagellates of the genus Porcisia, parasitizing Neotropical porcupines with unknown vectors. The development of two known species of this genus (P. deanei and P. hertigi) in two sand fly species (Lu. migonei, Lu. longipalpis) and biting midges C. sonorensis was studied using experimental infections. While P. hertigi did not survive defecation in females of either vector, P. deanei formed strong mature infections in 51-61% of Lu. longipalpis and in a smaller percentage in Lu. migonei (7 %) and C. sonorensis (7 %). Porcisia showed significantly smaller size than the control species L. infantum but formed the same morphological forms. The localization of P. deanei was exceptional; infections were detected predominantly in Malpighian tubules. Further experiments demonstrated the presence of P. deanei in the urine of Lu. longipalpis excreted during prediuresis and successful transmission of parasites to BALB/c mice by this unique route. Thus, Lu. longipalpis is a competent vector of P. deanei, but other vector species may be involved in transmission at endemic localities. A minor part is focused on the comparison of the morphology of two Mundinia species - L. martiniquensis and L. orientalis - during development in biting midges C. sonorensis and sand flies Ph....
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Factors affecting the protective effect provided by sand fly saliva immunization on the outcome of Leishmania infection
Jelínková, Kristýna ; Kolářová, Iva (advisor) ; Lipoldová, Marie (referee)
ENGLISH VERSION Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania, transmitted by its vector - female sand flies during the process of blood feeding. Preexposure to sand fly saliva prior to Leishmania infection affects the host immune system, leading to possible establishment of protective effect on the disease outcome. This effect is based on the delayed type hypersensitivity reaction to sand fly saliva which has been shown to peak about 48 hours after antigen encounter, leading to the more effective host immune response towards the Leishmania parasites. In this project, we found this protective effect as species-specific, additionally dependent also on the timing of the infection post last immunization. Results of presented experiments showed that infection of BALB/c mice with Leishmania major performed after 48 hours post last Phlebotomus duboscqi sand fly saliva immunization, did not confer protection in comparison to infection performed at one-week after the last exposure. Moreover, the effect of the sand fly saliva pre-exposure was at this shorter timing of infection rather diminished, supported by insignificant differences in the measured parameters compared to the unpre-exposed infected control group. Additionally, immunization with sand fly Sergentomyia...
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Genetic regulation of Leishmania infection
Sohrabi, Yahya ; Lipoldová, Marie (advisor) ; Krulová, Magdaléna (referee) ; Kolářová, Iva (referee)
6 Abstract Leishmaniasis is a neglected tropical disease, which belongs to the top health problems because it is endemic in 98 countries in Asia, Africa, the Americas and the Mediterranean region, and is gradually expanding to new areas, including Central Europe and USA. Clinical manifestations of leishmaniasis include a diverse range of forms, ranging from non-lethal cutaneous leishmaniasis to potentially lethal visceral leishmaniasis. Asymptomatic cases are known to exist in endemic areas. Different species of Leishmania induce distinct symptoms, but even the patients infected by the same species develop different symptoms and may respond differently to the treatment. Thus, one of the challenges is to explain the observed variability of leishmaniasis that cannot be attributed to the currently known factors. To find novel regulatory factors of the disease we tested molecules that were shown to play role in other infections and mapped loci controlling parasite load after L. major infection. We also determined genetic control of survival after infection with tick-borne encephalitis virus (TBEV) in order to establish whether there are common elements in response to L. major and TBEV. Interferon-induced GTPases (guanylate-binding proteins, GBPs) play an important role in inflammasome activation and mediate...
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Gene engineering methods in Leishmania research
Kriegová, Gabriela ; Bečvář, Tomáš (advisor) ; Arbonová, Lenka (referee)
Gene engineering methods are now increasingly used in the study of leishmania. These modern DNA technologies make it possible to manipulate with the genome of organisms, allowing it to be altered and repaired. The most important methods include CRISPR/Cas9, RNA interference (RNAi), dimerizable Cre recombinase (DiCre), plasmid shuffle and gene tagging. The choice of method depends on whether essential or non-essential genes are being studied as well as the reason of the study. These methods investigate leishmania using a reverse genetics approach that allows the phenotype to be studied. This work summarizes the current knowledge on the use of gene engineering methods in Leishmania, the necessary modifications of the procedures and discusses their limitations and advantages.
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Leishmaniases and their vectors in western Africa
Hošková, Anna ; Dvořák, Vít (advisor) ; Sádlová, Jovana (referee)
Leishmaniasis is a parasitic disease transmitted by sand flies. In West Africa, leishmaniasis is endemic and we distinguish cutaneous, visceral and mucocutaneous form of the disease. The most common form in this area is cutaneous leishmaniasis, which is caused by Leishmania major, Leishmania tropica and a new, as yet undescribed species Leishmania sp. from Ghana. The causative agents of visceral leishmaniasis are Leishmania donovani and Leishmania infantum. Phlebotomus duboscqi is a confirmed vector of L. major in this region. Vectors of Leishmania sp. from Ghana and vectors of visceral leishmaniasis remain unknown in West Africa. Sand flies of the genus Sergentomyia or Culicoides biting midges are considered as potential alternative vectors in this area. The confirmed reservoir hosts of L. major in some countries are the rodents Tatera gambiana, Arvicanthis niloticus and Mastomys erythroleucus, but in most states they are not confirmed. The reservoir hosts of visceral leishmaniasis are mainly dogs. Some West African states used to be French colonies, and there are many people of African descent in France who come to visit their relatives in West Africa. This poses a risk of import of leishmaniasis to non-endemic areas. The aim of this bachelor thesis is to summarize the current knowledge about the...
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Macrophages and nitric oxide in leishmania - sandfly - host interactions
Kratochvílová, Tereza ; Kolářová, Iva (advisor) ; Fialová, Anna (referee)
Leishmania reside fagolysosome of macrophages immediately after their entry to host where they multiply and consequently infect other macrophages or eventually other cells. A synthesis of a reactive reactant of oxygen and nitrogen is one of the mechanisms that some mammal cells are equipped with and that also contributes to eradication of leishmania. Nitric oxide rising during a metabolic change of L-arginine under the catalysis of NO synthase is of a large importance. Beyond cytotoxic function, nitric oxide is involved in signalling pathways for a neurotransmission (nNOS) and vasorelaxation (eNOS). Not all types of macrophages have ability to produce NO (iNOS). It is a heterogeneous group differing in immunological function and also in physiology. A group of classical activated macrophages represents an effective APC capable of efficient killing of intracellular pathogens. In addition to NO, they also secrete an inflammatory cytokines, which evolve an immune reaction towards to Th1. Contrary to this, a group of alternative activated macrophages is not capable of any efficient antigen presentation and nitric oxide production but produces L-ornithine, which is a precursor of polyamines, which leishmania utilizes for its own intracellular growth. For the mouse model, status of resistance and/or...
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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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