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Influence of avian Plasmodium on their hosts
Dulavová, Kristýna ; Svobodová, Milena (advisor) ; Vinkler, Michal (referee)
Avian malaria parasites of the genus Plasmodium are unicellular (and intracellular) protozoans of the group Haemospororida, using a blood-sucking insect (mosquito) as a vector and a bird as a vertebrate host. The effects of this disease, together with avian pox, have greatly influenced endemic populations of Hawaiian birds after introduction of a suitable vector to the islands by a human hand, leading to a drastic extinction of bird species; most of the remaining Hawaiian endemic species are now endangered. Apart from that, avian malaria is distributed nearly all over the world, infecting a variety of different hosts. This thesis is focused on the influence of avian malaria parasites mainly on their avian hosts. The most severe patologies caused by Plasmodium are associated with blood stages causing serious anemia in birds. More pathologies are connected with exoerythrocytic stages in the endothelial cells in various organs and are accompanied with external signs such as lethargy, respiratory distress, weakness, inappetence, sometimes weight loss and so on; different plasmodium species-bird host combinations have different outcomes. An interesting issue is the emerging tolerance against avian malaria in Hawaii Amakihi (Hemignathus virens), a species occupying low elevation areas of Hawaiian...
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Haemoproteus in passerines: Prevalence and infekction dynamics
Chalupová, Barbora ; Svobodová, Milena (advisor) ; Munclinger, Pavel (referee)
The genera Haemoproteus and Plasmodium are widespread genera of blood parasites from phylum Apicomplexa. Both genera have dixenous life cycle and their definitive hosts belong to the order Diptera. Both parasites can be found in birds where asexual division takes place. The infection with genera Haemoproteus and Plasmodium is usually asymptomatic; during long lasting chronic phase relapses of the infection can occur. We gained 1 092 blood samples from 29 trapped species of passerines in Milovice forest during seasons 2017-2019. Haemosporidians were detected in 48 % of samples. The prevalence of genus Plasmodium was 16 %, the prevalence of genus Haemoproteus was 22 % and 10 % we could not specify the parasite. We have found six new lineages of genus Haemoproteus, provisionally named Haemoproteus lineages coccoc_1, coccoc_2, coccoc_3, coccoc_4, embcit, fricoe which total prevalence was 14 %. Lineage Haemoproteus sp. coccoc_1 was the most noticed one and its prevalence was 12 %. Plasmodium relictum clone Peng14-121Br2AF and isolate Cc_P1 was the second most prevalent (13 %). Infection dynamics was studied in samples gained in years 2014-2019. Forty individuals were examined between years and twenty-seven individuals were examined intraseasonally. Three individuals were trapped both intra- and...
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Invasion of the host cell by the parasitic protist Plasmodium falciparum.
Charvátová, Klára ; Doležal, Pavel (advisor) ; Tůmová, Pavla (referee)
Plasmodium falciparum is an intracellular parasite that causes tropical malaria. Although plasmodium is not a problem in the middle latitudes, in tropical and subtropical regions it poses a great health threat. This specifically concerns little children, which constitute more than a half of the victims. This thesis discusses the invasion of the red blood cell by a merozoite, which is a key step of the parasite life cycle responsible for the disease development. The main part of the thesis deals with proteins secreted by organelles of the invasive apparatus of plasmodium cell. It is preceded by a chapter introducing basic information on P. falciparum and malaria. The end of the thesis contains a chapter on the parasite exit from the red blood cell. Key words Invasion, plasmodium, parasite, merozoite, red blood cell, tight junction, gliding motility, apical complex, micronemes, rhoptries
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Haemoproteus in passerines: Prevalence and infekction dynamics
Chalupová, Barbora ; Svobodová, Milena (advisor) ; Munclinger, Pavel (referee)
The genera Haemoproteus and Plasmodium are widespread genera of blood parasites from phylum Apicomplexa. Both genera have dixenous life cycle and their definitive hosts belong to the order Diptera. Both parasites can be found in birds where asexual division takes place. The infection with genera Haemoproteus and Plasmodium is usually asymptomatic; during long lasting chronic phase relapses of the infection can occur. We gained 1 092 blood samples from 29 trapped species of passerines in Milovice forest during seasons 2017-2019. Haemosporidians were detected in 48 % of samples. The prevalence of genus Plasmodium was 16 %, the prevalence of genus Haemoproteus was 22 % and 10 % we could not specify the parasite. We have found six new lineages of genus Haemoproteus, provisionally named Haemoproteus lineages coccoc_1, coccoc_2, coccoc_3, coccoc_4, embcit, fricoe which total prevalence was 14 %. Lineage Haemoproteus sp. coccoc_1 was the most noticed one and its prevalence was 12 %. Plasmodium relictum clone Peng14-121Br2AF and isolate Cc_P1 was the second most prevalent (13 %). Infection dynamics was studied in samples gained in years 2014-2019. Forty individuals were examined between years and twenty-seven individuals were examined intraseasonally. Three individuals were trapped both intra- and...
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Iron homeostasis in malaria
Wernerová, Klára ; Šuťák, Róbert (advisor) ; Voleman, Luboš (referee)
Although malaria is a well-studied infectious disease, we are still unable to fight it effectively, as evidenced by a large number of infected people. Many drugs are available against malaria. However, because of incessantly emerging resistances, new, more effective antimalarials need to be developed. One possibility is to target the parasite's iron metabolism, the essential element of all organisms. Iron participates in DNA synthesis, respiration, energy production. It acts as a cofactor of ribonucleotide reductase, and metalloproteins with FeS clusters or heme. During the infection, the parasite must compete with the host for nutrients, including iron. The mechanism of iron uptake or excretion in malaria parasite is not completely clear. Only two iron transporters are known, but it is already evident, that there must be more of them. The Plasmodium parasite digests a large amount of hemoglobin, which is degraded into free heme and denatured globin. Free heme is toxic to the cell though. Plasmodium defends itself from the toxicity of free heme by forming chemically inert hemozoin. This unique mechanism of protection against the free heme toxicity is very useful for Plasmodium and other blood parasites, but it also becomes an advantageous target for drugs because the mechanism is present only in...
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The invasion apparatus of protozoan parasites
Novotná, Veronika ; Petrů, Markéta (advisor) ; Štáfková, Jitka (referee)
Protozoa parasitism has evolved many times independently in the history of eukaryotes. Some organelles were reduced, and specific invasion apparatuses were developed by adapting to the host. These apparatuses help to penetrate host cells and escape the immune system. The thesis summarizes the findings of the invasion apparatus and invasion of four selected unicellular protozoan parasites of genus Plasmodium, Microsporidia, Ichthyobodo and Rozella. Each chapter includes general knowledge of the parasite, its structure and life cycle. Keywords: Apicomplexa, Plasmodium, Microsporidia, Ichthyobodo, Rozella, merozoite, glideosom, moving junction, polar tube, germination, cytostome, zoospore, germ tube;
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Avian malaria parasites and their vectors
Synek, Petr ; Munclinger, Pavel (advisor) ; Hypša, Václav (referee) ; Široký, Pavel. (referee)
Parasites causing avian malaria belong to the group Haemosporida, which represents a monophyletic group of dixenic protists within Apicomplexa. Their asexual reproduction takes place in a vertebrate intermediate host, and the formation of gametes and sporogony occur in blood-sucking dipteran insects, which are the definitive hosts of these parasites. Three main genera (Plasmodium, Haemoproteus and Leucocytozoon) are found mostly in their avian hosts. We focused on the Haemosporida of wild birds and their transmission by insect vectors in natural populations, which had previously been a neglected area. Our results were obtained both by traditional methods (investigation of infections by microscopy of blood smears) and mainly by molecular methods (e.g. nested PCR) centered around work with unique haplotypes of the haemosporid lineages. The aim of our work was to determine the range of possible insect vectors of avian haemosporidians in the territory of the Czech Republic, taking into account the specificity of the parasites within these vectors, and to describe the diversity of haemosporidians in the populations of their bird intermediate hosts. We chose four different species of birds from four orders (Passeriformes, Strigiformes, Accipitriformes, and Galliformes). As potential vectors of avian...
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Transgenic mosquitos as a tool for lower incidence of malaria
Čermáková, Eliška ; Schierová, Michaela (advisor) ; Král, Jiří (referee)
Malaria is an infectious disease causing high lethality, mainly in tropic and subtropic Africa. The disease is caused by unicellular Plasmodium and transmitted by infected Anopheles mosquito females. Genetic manipulations in mosquitos are promising approach in malaria vector control. There are two important ways of genetic manipulations in mosquitos: reduction and substitution strategies. In the former one, transgenic male mosquitos are used to achieve long term mosquito population size reduction. The aim of different substitution strategies is the production of transgenic mosquitos refractory to Plasmodium infection, unable to ensure Plasmodium development. These transgenic insects should replace the original mosquito population. Both strategies are under proposals and testing in laboratory conditions. Key words: Transgenic mosquitos, vector, Plasmodium, malaria
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Use of RNAi and CRISPR systems in genetic modifications of parasitic protists
Kaiserová, Veronika ; Votýpka, Jan (advisor) ; Stojanovová, Darja (referee)
In organisms, RNA interference serves as a defence mechanism against foreign nucleic acids. RNAi has a negative effect on translation, via the binding of small non-coding molecules to the complementary region of mRNA, resulting in its degradation. CRISPR, a new method of genetic engineering, is based upon modulating genetic expression via creating double-stranded breaks in target DNA, aided by a ribonucleoprotein complex, consisting of the prokaryotic endonuclease Cas9 and sgRNA. Both of the aforementioned methods can be utilised in functional analysis of proteins and the characterisation of metabolic pathways in organisms of interest. This work summarises the current state of knowledge regarding RNAi and CRISPR and their use in genome editing of parasitic protists.
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Mosquitoes as hosts and vectors of protozoa transmitted to birds
Fialová, Magdaléna ; Svobodová, Milena (advisor) ; Munclinger, Pavel (referee)
Mosquitoes belong to significant representatives of inscet which are particularly studied due to their ability to transmit pathogens (viruses, bacteria, protozoa, worms) in many cases causing serious illnesses. The hosts of these pathogens can be various animals including birds. In this study I have focused on protozoa (especially Plasmodium and Trypanosoma) transmitted by a mosquito. Concerning trypanosomes the mosquito is one of several possible vectors and up to now there have been named two trypanosomes transmitted by birds, namely Trypanosoma culicavium and Trypanosoma thomasbancrofti. In the case of the genus Plasmodium the mosquito is the only vector and there are many more species of the genus Plasmodium, which mosquito transmits between birds. Key words: vector, mosquito, host, bird, Trypanosoma, Plasmodium, infection
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