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Bee trypanosomatids and their interactions with pollutants
Pařízková, Kamila ; Votýpka, Jan (advisor) ; Krejčí Bruce, Alena (referee)
Honeybees (Apis mellifera) are highly valued worldwide for their products, but also as pollinators of crops and wild plants. Due to the close proximity of bees in the beehive and their foraging habits, a large number of pathogens that weaken the bee colonies are spread both inside and between colonies. In recent decades, high annual losses of bees have been recorded, which still do not have a clear explanation. The sudden loss of bees (known as colony collapse disorder) is likely due to the interaction of multiple factors at once. A large part of the problem is attributed to viral diseases and some parasitic organisms; parasites of the Trypanosomatida group play an uncertain role. A member of this group, Crithidia bombi, is considered a problematic inhabitant of the digestive tract of bumblebees, which can cause serious complications. Close relatives, C. mellificae and Lotmaria passim, parasites of honeybees, are sometimes associated with their higher mortality. Pesticides, whose effects can be very toxic, have also come to the forefront in assessing bee losses, and most pesticides have therefore been banned in the EU. This thesis examines the prevalence, infection development, and host specificity of monoxenous trypanosomatids in bees and their pesticide interactions. A total of 26 species of...
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Genomics of Blastocrithidia, a trypanosomatid with all three stop codons reassigned
NENAROKOVA, Anna
This work describes genomic studies of Blastocrithidia, the trypanosomatid with all three stop codons encoding amino acids and the only known euglenozoan with non-standard nuclear genetic code. We describe unique genomic features of Blastocrithidia and the sister clade "Jaculum", and discuss possible mechanisms of translation termination with ambiguous stop codons and the evolutionary path that may have established this system.
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Molekulární epidemiologie druhů Crithidia mellificae a Lotmaria passim v populaci včelstev
VOČADLOVÁ, Kateřina
The increased honey bee colony losses in the last decade gain a considerable attention of scientists and public. The causes of these losses include a wide range of biotic and abiotic factors, but pathogens and parasites are probably the main ones. Monoxenous trypanosomatids in honey bee gut Lotmaria passim and Crithidia mellificae were neglected for a long time but according to recent studies they seem to participate in those colony declines. Trypanosomatids are widespread parasites, including also the causes of some human illnesses, such as sleeping sickness, Chagas disease and leishmaniasis. The mechanism of the effect on honey bee health is not well understood so far. The aim of this thesis was to verify the occurrence of the trypanosomatids in honey bee samples from two regions in Czech Republic. The methods, based on detection of specific DNA loci, confirm the high prevalence of L. passim, which was founded in majority (71 %) of the samples. On the contrary, no samples were positive to C. mellificae.
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Attachment of trypanosomatids in the insect vector.
Tichá, Lucie ; Myšková, Jitka (advisor) ; Leštinová, Tereza (referee)
Trypanosomatids are protozoan parasites known for its medical and economical significance. Leishmania, Trypanosoma, Endotrypanum and Phytomonas genera are dixenous parasites. Part of the life cycle takes place in the insect vector, where the parasites are attached using their flagella. Supraplyarian Leishmania differs in the binding method depending on the type of vector it uses for its transmission. The attachment is dependent on lipophosphoglycan (LPG) in a specific vector while in a permissive vector, the interaction is based on a different mechanism (LPG-independent). Attachment of T. cruzi in the posterior part of a digestive system of a hemipterous bugs appears to be necessary for metacyclogenesis. Similar strategy seems to be used by T. brucei which is attached in the salivary glands. The genera Endotrypanum and Phytomonas are not medically significant pathogens, thus their life cycles have not been profoundly researched. Endotrypanum, as well as Leishmania, develops in the digestive system of sand flies, thus the binding mechanism could be analogous. Phytomonas develops in the salivary glands of hemipterous bugs which denotes similarity with T. brucei. Based on the collected data, it is assumed that the binding mechanism of the Trypanosmonatids is generally based on the lectin-like protein...
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Biting midges and their patogens
Mračková, Marie ; Votýpka, Jan (advisor) ; Modrý, David (referee)
This thesis deals with biting midges of the genus Culicoides, which are tiny nematoceran insects belonging to the Diptera, and their parasites. Biting midges partake in transmissions of several parasitical organisms of various groups. Most notably, they are the vectors of several pathogenic viruses which might have a serious impact on livestock. However, the thesis deals with detection of parasites belonging to Trypanosomatids and Filarioids related to two independent biting midges collections - from the Czech Republic and from the Central African region. Apart from testing biting midges, there were carried out the tests on the occurrence of the same group of parasites within ruminant hoofed games in the Czech Republic. Our goal was to find out whether the same parasites occur with biting midges and their hosts (hoofed games) and whether biting midges could play a role as vectors. Biting midges are relatively overlooked group of haematophagous insects. Until recently, they had not been paid much attention, which changed with the spread of Bluetongue virus over Europe. This stimulated a widespread monitoring of biting midges in several European countries, including the Czech Republic. This helped to gain a large amount of data about the occurrence of biting midges near livestock. Nevertheless, there is no...
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Kinetoplastids biology, from the group phylogeny and evolution into the secrets of the mitochondrion of one representative: \kur{Trypanosoma brucei}, the model organism in which new roles of the evolutionary conserved genes can be explored
TÝČ, Jiří
This thesis is composed of two topics, for which trypanosomatids and evolution are common denominators. First part deals with phylogenetic relationships among monoxenous trypanosomatids, with emphasis on flagellates parasitizing dipteran hosts, analyzed mainly from biogeographical and evolutionary perspectives. Second part focuses on the trypanosomatid Trypanosoma brucei, causative agent of severe diseases, which serves as a model organism for functional studies of evolutionary conserved mitochondrial proteins, in particular those involved in replication, maintenance and expression of the mitochondrial genome, also termed the kinetoplast. This thesis identified the mtHsp70/mtHsp40 chaperone machinery as an essential component of replication and maintenance of the kinetoplast, and also identified numerous conditions under which mtHsp70 has a tendency to aggregate. Moreover, several conserved proteins, previously identified to be part of the mitochondrial ribosome, were shown to be important for translation of the mitochondrial transcripts.
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