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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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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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Leishmaniases and their vectors in the Middle East
Zelenková, Natálie ; Dvořák, Vít (advisor) ; Votýpka, Jan (referee)
Leishmaniases are vector-borne parasitic diseases that remain major neglected tropical diseases of the world. Both cutaneous and visceral leishmaniasis is endemic in the Middle East, with several countries reporting increasing incidence in recent years. The Middle East is a region of great political instability and the escalating conflicts in Syria, Yemen and Iraq have led to collapses of local healthcare systems. These countries have consequently seen many outbreaks of leishmaniasis. War is associated with refugee crisis that enables further spread of the disease to previously non-endemic areas. L. major and L. tropica are the main causative agents of cutaneous leishmaniasis and species of the L. donovani complex are the causative agents of visceral leishmaniasis in this region. Many species of the genus Phlebotomus occur here, with P. papatasi and P. sergenti being among the most abundant proven local vectors. Rodents and dogs are considered to be the main reservoir hosts of the infection. The aim of this bachelor thesis is to summarize the occurence of leishmaniases in the Middle Eastern countries in the context of the current situation in this region.
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Critical factors affecting pathogen development in sand flies
Jančářová, Magdaléna
This thesis deals with barriers and factors critical for development of viruses, leishmania and gregarines in sand flies. First, we focused on life cycle of sand fly-borne phleboviruses, especially possible routes of sand fly infection. As a laboratory model we chose Massilia virus (MASV), species closely related to Toscana virus, which is main causative agent of summer meningitis in Mediterranean area. We tested different ways of infection by MASV in various developmental stages of Phlebotomus perniciosus; infection of (i) first (L1) and fourth (L4) instar larvae through larval food, (ii) females by blood meal, (iii) both sexes by sugar meal. Infection of L1 and L4 by larval food and subsequent transstadial MASV transmission to adults were not efficient; from 875 adults only three were MASV-positive. Infection through bloodmeal led to high infection rate before defecation, nevertheless, post defecation the infection rate declined and only 5 out of 27 females were MASV-positive. The most efficient infection way was through the sugar meal: 72% of females (88 out of 122) and 51% of males (58 out of 113) were detected as MASV-positive. Moreover, both males and females infected by this way released MASV particles into the drop of sugar which stayed infectious for next 24 hours for other naïve sand...
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Genotype influence on development of infections caused by Trypanosomatidae in mouse
Šíma, Matyáš
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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Development of a new sand fly exposure test to evaluate vector control tools
Willen, Laura Adrienne André ; Volf, Petr (advisor) ; Kopecký, Jan (referee) ; Valenzuela, Jesus G. (referee)
In the Mediterranean basin, human visceral leishmaniasis caused by the protozoan parasite Leishmania infantum is a zoonotic disease that gives rise to 1,200 to 2,000 new cases annually. The domestic dog constitutes its main reservoir, of which some may suffer from a severe chronic disease, canine leishmaniasis (CanL). The sand fly Phlebotomus perniciosus is considered to be the principle vector. Saliva of bloodfeeding vectors of diseases has been used in the past to assess host exposure to vector bites and to evaluate vector control tools. This Ph.D. focused on saliva of P. perniciosus to identify exposure markers that could be used in the preparation of a new vector exposure tool. The first part of this Ph.D. aimed at validating the use of a recombinant salivary protein of P. perniciosus - rSP03B - in endemic settings of CanL. During a cross-sectional study, no significant differences between the antibody (Ab) response against whole saliva or the rSP03B were observed between different regions across the Mediterranean basin. Furthermore, the rSP03B was shown to resemble the native protein. During a subsequent study this protein was used to assess the seasonal dynamics of the canine Ab response to P. perniciosus in an endemic area of L. infantum. This study elucidated that also in a heterogeneous...
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Critical factors affecting pathogen development in sand flies
Jančářová, Magdaléna ; Volf, Petr (advisor) ; Ratinier, Maxime (referee) ; Bilej, Martin (referee)
This thesis deals with barriers and factors critical for development of viruses, leishmania and gregarines in sand flies. First, we focused on life cycle of sand fly-borne phleboviruses, especially possible routes of sand fly infection. As a laboratory model we chose Massilia virus (MASV), species closely related to Toscana virus, which is main causative agent of summer meningitis in Mediterranean area. We tested different ways of infection by MASV in various developmental stages of Phlebotomus perniciosus; infection of (i) first (L1) and fourth (L4) instar larvae through larval food, (ii) females by blood meal, (iii) both sexes by sugar meal. Infection of L1 and L4 by larval food and subsequent transstadial MASV transmission to adults were not efficient; from 875 adults only three were MASV-positive. Infection through bloodmeal led to high infection rate before defecation, nevertheless, post defecation the infection rate declined and only 5 out of 27 females were MASV-positive. The most efficient infection way was through the sugar meal: 72% of females (88 out of 122) and 51% of males (58 out of 113) were detected as MASV-positive. Moreover, both males and females infected by this way released MASV particles into the drop of sugar which stayed infectious for next 24 hours for other naïve sand...
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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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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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Mitochondrial gene expression in trypanosomatids
PROCHÁZKOVÁ, Michaela
This thesis comprises of diverse projects all focused towards analysis of mitochondrial translation in unicellular parasites. As only two mitochondrially encoded genes are required during the life cycle stage when Trypanosoma brucei resides in the bloodstream of a mammalian host, this protist provides a simplified background in which to study mitochondrial translation termination phase. The leading project utilizes T. brucei to examine mitochondrial translation termination factor TbMrf1 by gene knockout. Subsequently, it is suggested that the peptidyl-tRNA hydrolase TbPth4 is able to abate the TbMrf1 knockout phenotype by its ability to rescue mitoribosomes that become stalled when TbMrf1 is absent. Additionally, modifying methyltransferase of TbMrf1, the TbMTQ1, was characterized. And finally, this work contributed to the development of the protein expression regulation method in Leishmania parasites, a protocol for measurement of proton pumping activity of FoF1 ATPase complex in native mitochondria, and optimization of purification protocol for hydrophobic recombinant proteins.
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