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Role of catalase and chitinase in the life cycle of Leishmania parasites
Glanzová, Kristýna ; Sádlová, Jovana (advisor) ; Kodym, Petr (referee)
Leishmaniasis is an infectious disease caused by protozoa of the genus Leishmania (Kinetoplastida: Trypanosomatidae) which are transmitted by phlebotomine sand flies (Diptera: Phlebotominae). For the dixenous life cycle, leishmania parasites are equipped with enzymes that facilitate survival in both insect vectors and mammalian hosts. Gene for the enzyme catalase which protects cells from reactive oxygen species by the elimination of H2O2 and is present in related monoxenous trypanosomatids is, however, missing in Leishmania genome. Chitinase can be involved in the interaction of leishmania parasites with chitin-containing structures in sand flies (peritrophic matrix, stomodeal valve). The expression of the enzyme in amastigotes suggests its significant function also in the mammalian host. I tested the role of these enzymes in the life cycle of leishmania by direct comparison of L. mexicana mutants (i) with inserted catalase gene and (ii) with deleted chitinase gene with control groups. I conducted experimental infections of Lu. longipalpis including transmission of leishmania to the hosts by bite, tested the survival of leishmania in macrophages and performed experimental infections of BALB/c mice followed by xenodiagnoses. The experiments confirmed that the presence of catalase in leishmania does...
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Trypanosomes of Rodents and Lagomorphs
Valsová, Iveta ; Votýpka, Jan (advisor) ; Sádlová, Jovana (referee)
Trypanosomes (Kinetoplastea) are widespread endoparasitic protozoa commonly found in all vertebrate groups. Some species cause serious diseases in humans and livestock, while non- pathogenic species cause little or no apparent negative effects on the host and are mostly host- specific. The high host specificity of mammalian trypanosomes is found in the rodent- associated subgenus Herpetosoma. This study is focused on trypanosomes of rodents and rabbits. Experimental infections of rodents have shown that some trypanosomes are only able to infect their natural hosts. However, an exception to these highly host-specific species of the subgenus Herpetosoma is T. lewisi, which has been demonstrated not only in rodents but also in primates, including humans. Rodent trypanosomes, like rodents themselves, are cosmopolitan and their vectors are fleas. More than 50 species of trypanosomes have been gradually included into the subgenus Herpetosoma, mainly based on blood-stage morphology and their host specificity. However, with the development of biochemical and molecular methods, this number may change significantly. Key words: Trypanosoma, Herpetosoma, rodents, lagomorphs, morphology, development cycle, vectors
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Leishmania of the subgenus Mundinia: genetical analysis and experimental infections of rodents and vectors.
Bečvář, Tomáš ; Sádlová, Jovana (advisor) ; Modrý, David (referee)
Leishmaniasis is a human and animal disease caused by digenetic parasites of the genus Leishmania, which is now divided into 4 subgenera - L. (Leishmania), L. (Viannia), L. (Sauroleishmania) and L. (Mundinia). Subgenus Mundinia was established in 2016 and consists of 5 species - L. enriettii and L. macropodum are parasites of wild mammals and L. martiniquensis, L. orientalis and unnamed L. sp. from Ghana are infectious to humans. Mundinia are geographically widely dispersed, their distribution covers all continents, except of Antarctica. Despite phlebotomine sand flies (Diptera: Psychodidae) also biting midges (Diptera: Ceratopogonidae) are supposed to be involved in transmission of these species, which is a unique feature for this subgenus. But there is little to no current information on natural reservoir hosts and vector species for any Mundinia species. In this thesis we tested possible vectors and potential model organisms (Guinea-pigs) and reservoir hosts of Mundinia species by experimental infections. We used 3 sand fly species sharing geographical distribution with respective Mundinia species and available in our laboratory for experimental infections. Sand flies from Australia had never been colonised so we used the permissive vector Lu. migonei for testing development of L. macropodum....
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Blood parasites (namely genus Plasmodium) of game ungulates
Pařízková, Kamila ; Votýpka, Jan (advisor) ; Sádlová, Jovana (referee)
Haematozoa is a group of protozoa parasitizing in mammals, birds and reptiles that are characterized by development in blood cells. Some representatives of the Haematozoa class may cause serious human illnesses and losses in livestock and domestic animals. In ungulates there are three genera of blood parasites - Theileria, Babesia and Plasmodium. This thesis is focused mainly on the genus Plasmodium in forest ungulates. The vectors of these parasites in ungulates are mosquitoes of the genus Anopheles. Until recently, the area of Plasmodium in ungulates only reached the Old World, where P. cephalophi, P. bubalis and P. caprae were described. These species have traditionally been described on the basis of their morphology under a light microscope. The discovery of molecular methods has allowed a more detailed description and discovery of a new species of P. odocoilei in cervids in North and South America. The paper summarizes the present information related to the occurrence of blood parasites in forest ungulates. Key words: Plasmodium, Babesia, Theileria, ungulates
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Leishmaniases of northern Africa and their vectors
Hanušniaková, Ida ; Dvořák, Vít (advisor) ; Sádlová, Jovana (referee)
Leishmaniasis belongs to the most important world human as well as animal diseases. It occurs in almost all continents. Its nearest area of occurrence from our point of view is the Mediterranean, including the states of North Africa. A significant portion of all registered cases occurs here and the prevalence has been increasing in last decades. Algeria is the second in the world in number of cases of cutaneous leishmaniasis and in the other countries the situation is quite similar. Two major forms of the disease occur in the region: visceral and cutaneous leishmaniasis. Leishmania major is the most abundant species in the are, followed by L. infantum and L. tropica. In the Old World, leishmanises are transmitted by sand flies of the genus Phlebotomus. The most important proven vectors are Phlebotomus papatasi, P. sergenti, P. perfiliewi or P. perniciosus. Rodents are considered to be main reservoir organisms (Psammomys obesus, Meriones shawi), together with dogs in which canine leishmaniasis may occur with clinical symptoms; at the same time they serve as reservoirs of the disease. This bachelor thesis summarizes occurrence of individual Leishmania species, clinical symptoms they cause in the hosts and their vectors in North Africa. Key words: leishmaniasis, phlebotomus, North Africa, Leishmania,...
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African rodents as reservoirs of Leishmania parasites.
Glanzová, Kristýna ; Sádlová, Jovana (advisor) ; Votýpka, Jan (referee)
Leishmania spp. (Kinetoplastida: Trypanosomatidae) are protozoa related to the Trypanosoma genus that are causative agents of leishmaniasis. Their life cycle alternates between mammalian hosts and insect vectors. The principal vectors are phlebotomine sand flies (Diptera: Phlebotominae) that occur mostly in the tropics, however, several species range to the temperate regions. Various species of rodents serve as reservoir hosts of leishmania. In endemic localities, they represent most abundant mammals and their burrows are used as breeding sites of larval stages of sand flies. In this bachelor thesis I summarize available literature about rodents that serve as reservoir hosts of six human pathogenic leishmania species present in Africa. Several species of African rodents are regarded as reservoir host of L. major and one species (Ctenodactylus gundi) as a suspected reservoir host L. tropica. On the other hand, rodent infections caused by L. aethiopica, L. infantum and L. donovani should be still considered as accidental. In the case of Leishmania sp. from Ghana, reservoir hosts are still entirely unknown. All species of proven African rodent reservoir hosts share clustered distribution in colonies where animals live in high population densities.
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Role of rodents of the genus Arvicanthis in Leishmania major maintenance: xenodiagnosis and experimental transmission of infections.
Hrnčířová, Kateřina ; Sádlová, Jovana (advisor) ; Kodym, Petr (referee)
A cutaneous leishmaniasis is the most common clinical form of human disease caused by parasite of the genus Leishmania. They are transmitted between the hosts by haematophagous females of dipteran sand flies of the genus Phlebotomus in the Old World and Lutzomyia in the New World. One of the major agents of cutaneous leishmaniasis in the Old World is Leishmania major. The disease caused by this species is a zoonosis where rodents act as reservoir host. The parasite long time circulates between reservoir rodents and sand flies, while humans are infected only accidentaly in the focus of infection. Rodents of the genus Arvicanthis belongs to the most abundant in the African continent. The genus has evolved in Ethiopia from where it expanded to a major part of Sub - Saharan Africa and the delta of the river Nile. These rodents are very abundant in endemic locations of cutaneous and visceral leishmanias and fulfil many reservoir host criterias including repeated field findings of individuals infected by L. major and another Leishmania species in nature. However, their role in the disease cycle remains to be confirmed. A. neumanni used in this study is an East African species spread from Ethiopia and Somalia to Kenya and Tanzania. Animals were experimentally infected with three different L. major...
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Biology of Leishmania enriettii species complex.
Bečvář, Tomáš ; Sádlová, Jovana (advisor) ; Spitzová, Tatiana (referee)
vytvořený v roce 2016, ve kterém je zařazeno 5 druhů leishmanií - pouze divokých druhů savců, zatímco druhy "L. siamensis" . izolovaná v Ghaně mají potenciál infikovat i člověka. Areál rozšíření těchto druhů je velmi široký a zasahuje do všech kontinentů světa kromě Antarktidy, čemuž odpovídá i neobvyklá hostitelů a přenašečů onemocnění. Mezi vektory patří nejen flebotomové dvoukřídlý krevsající hmyz čele i tiplíci (Diptera: což je v rámci rodu zcela unikátní Škála zvířat, ze kterých byli zástupci podrodu izolováni je široká, od ů í či dobytka po hlodavce, ale skutečné doklady o jejich rezervoárové roli chybí. Mnohé otázky, zejména přesná identita rezervoárových zvířat a přenašečů, musí být zodpovězeny, než pochopíme unikátního Klíčová slova: leishmanióza, "Leishmania siamensis" , leishmanióza koní, fylogeneze, agbamekanu
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Alternative vectors of Leishmania (Kinetoplastida: Trypanosomatidae)
Jursová, Klára ; Sádlová, Jovana (advisor) ; Dvořák, Vít (referee)
The life cycle of Leishmania (Kinetoplastida: Tripanosomatidae) alternates between vertebrate hosts and insect vectors. Phlebotomine sand flies (Diptera: Psychodidae) were supposed to be the only arthropod vectors supporting morphological and functional development of the parasite including production of infective metacyclic forms capable to infect the vertebrate host. Recently also other bloodsucking arthropods have been suggested for possible transmission of some Leishmania species. The bachelor thesis summarizes the recent knowledge about these alternative vectors of Leishmania.
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A comparison of the peritrophic matrix in four sand fly species (Diptera: Psychodidae) and its role in the Leishmania development (Kinetoplastida: Trypanosomatidae).
Homola, Miroslav ; Sádlová, Jovana (advisor) ; Hypša, Václav (referee)
anglický Phlebotomine sand flies (Diptera: Psychodidae) are the only proven vectors of Leishmania parasites (Kinetoplastida: Trypanosomatidae). In Nematoceran Diptera, including sand flies, adults produce a type 1 peritrophic matrix (PM) which is secreted in response to the distension of the midgut caused by blood meal. The PM is an acellular envelope composed of chitin fibres and proteins, which protects the midgut epithelium against abrasion and pathogens and improves digestion. In hematophagous insects, the PM also plays a central role in heme detoxification. Female sand flies acquire Leishmania with a bloodmeal and the parasites undergo complicated development in their gut finished by the colonization of the stomodeal valve. The PM is one of the most important barriers in Leishmania development and its role in the vector competence of the S. schwetzi is the main topic of this master thesis. The PM's kinetic and morfology in the S. schwetzi is compared with other three sand fly species which differ in susceptibility to L. donovani. The key role of the PM in S. schwetzi vector competence is finally proved by disrupting the PM using the exogenous chitinase from Beauveria bassiana. Under these artificial conditions, the Leishmania parasites (L. donovani and L. major) are able to exit the PM,...
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