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Research of vertebrate-microbiota relationship using germ-free organisms
Kubovčiak, Jan ; Kreisinger, Jakub (advisor) ; Hájková, Petra (referee)
Germ free (axenic) animals are individuals reared under specific conditions preventing their contact with surrounding microorganisms. Some of the features observed in these individuals vary from those observed in naturally colonized counterparts. These differences probably reflect the influence of presence of a complex intestinal microbial population in the intestine, which influences important physiological functions of the host body by various mechanisms. Thus, nature of these differences allows to study relationship of the host, vertebrate in this case and its microbiota, which evolved into a complicated system of interactions providing relatively stable coexistence. Germ free research of this relationship is focused on interactions between microbiota and host's immune system, metabolism, morphology of digestive tract and behavior. This thesis provides summary of research outcomes on previously mentioned topics. Powered by TCPDF (www.tcpdf.org)
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Adaptation mechanism of nematodes for harsh condition survival
Čermáková, Petra ; Vadlejch, Jaroslav (advisor) ; Kyriánová, Iveta Angela (referee)
Adaptation is a complex of mechanisms, thanks to which nematodes can endure unfavourable conditions. These can come from either external or internal environment. Which one would be dominating, depends on the exact lifestyle of a certain nematode e.g. nematodes living in free nature must deal with environmental changes, parasitic ones are influenced by viability of the host, but even in this case we cannot dismiss the role of environment. There is always a mutual bond between the parasite, host, and the environment. Nematodes usually resolve emergency situations in two ways. One way is to adapt to the new conditions so they can grow and reproduce. The other way is to choose an adaptation mechanism thanks to which nematodes will survive a threat temporarily. Adaptation mechanisms can vary between individual species or various stages of the same kind of nematodes. Universal adaptation behaviour among nematodes does not exist. Adaptation mechanisms of nematodes cause changes in their physiology, metabolism, morphology, development or growth, but also in their behaviour. The aim of this thesis is to gather information from academic literature and scientific articles and provide a closer description of nematodes and their most usual and important adaptation mechanisms. This is preceded by a general description of nematode biology for better understanding of the issue. Based on this information we can comprehend why nematodes are such a successful phylum. Nematodes can be also considered as pests having a negative impact on the economic and social sphere. Further knowledge of nematodes and their mechanisms of adaptation and exploration of their surprisingly resistant forms can lead to control their regulation.
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Transfer of genetic information between parasite and its host
Soukal, Petr ; Hampl, Vladimír (advisor) ; Votýpka, Jan (referee)
Horizontal gene transfer (HGT) is considered a rare evolutionary event. It can take place between unrelated organisms that coexist in an intimate symbiotic relationship. Such relationship have some parasites with its host. HGT between eukaryotic parasite and its host was identified in some holoparazitic and hemiparazitic plants, the most important human protozoan parasites, microsporidias, human blood-flukes, parasitoids and fruit flies.
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Evolution of molecular interaction between host and parasite
Bílková, Barbora ; Vinkler, Michal (advisor) ; Synek, Petr (referee)
Coevolution between host and parasite is a long-term object of scientific interest, mostly because of negative influence of parasites and human need to defend against it., The evidence concerning host-parasite coevolution mechanisms is, however, still incomplete and various models and theories are considered separately, out of the general concept. Beside generally well-known theories such as the "Red queen" theory or the coevolution "arms race" theory, several other models were proposed, e.g. the "gene for gene" model or the "matching allele" model, which describe detailed aspects of host-parasite coevolution and principles of genetic variability maintenance in their interaction. Although there are many studies mapping reciprocal evolution of hosts and parasites, the connection between empirical evidence and theoretical models is often missing. Therefore, this thesis covers theory on host-parasite evolutionary interactions and provides examples of host-parasite systems and molecules, which correspond to behavior of described models.
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Parasitic diseases of Australian parrot species
Rasochová, Karolína ; Jankovská, Ivana (advisor) ; Husák, Tomáš (referee)
Australian parrot species can host many species of parasites. Parasitic diseases affects both parrots kept in captivity and living wild. This work is compiled as a literary review and provides a summary of most parasites with confirmed presence at the Australian species of parrots. Many parasites species have been detected recently. The presence of new species is confirmed also for parrots kept in Central Europe (coccidia Sarcocystis
calchasi) including the Czech Republic (parasitic protozoa Leucocytozoon spp., roundworm Ascaridia platyceri).
Parasitic infections may be detected trough examining samples from living parrots (feces, blood, tissues) or trough necropsy of died individuals (histopatology). In psittacines, protozal infections have been described (phylum Metamonada and Apicomplexa). Giardiasis, coccidiosis, cryptosporidiosis and blood parasites (Plasmodium spp., Leucocytozoon spp., Haemoproteus spp.) are among the most frequent. Australian parrot species are among the most frequent hosts of nematodes roundworms (Ascaridia spp.) and capillaries (Capillaria spp.). Regarding the strain Fungi, presence of Encephalitozoon hellem which causes microsporidiosis which primarily occurs in humans with acquired immunodeficiency has also been identified in psittacines. This makes it a potentially zoonotic disease. As of the ectoparasites, those most important representatives from the variety of species of parasitic mites and insects are mentioned. The life cycle of the parasites, their pathogenicity, ways of transmission, clinical signs in affected individuals, diagnosis and treatment options have been described.
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Early trichinosis disease – characteristics and evaluation of known available detection methods.
Janáček, Martin ; Farkač, Jan (advisor) ; Nakládal, Oto (referee)
Trichinellosis is a worldwide serious disease transmittable from animals to humans. The disease agent is Trichinella spp., which belongs to the phylum of parasitic nematoda called Nematodes. There are 12 genotypes of Trichinella currently known but the most important for the Czech Republic and neighboring countries are T. spiralis, T. britovi and T. pseudospiralis.
Man can be infected by ingestion of raw or undercooked meat of infected animals. Treatment is very expensive and can be fatal, therefore a great emphasis is placed on prevention, especially control of animal carcasses which are intended for human consumption. The most famous method, also approved by law, is the digestive method, however there are many other methods for testing the presence of a parasite or for specification of genotype.
This paper mainly deals with comparison of known and available methods of detection of trichinosis originators. Furthermore this paper gives character description of majorgenotypes of Trichinella.
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Detection of cryptosporidia by means of molecular methods in clinical samples:infection or the transit of oocyst through the host gastrointestinal tract?
MUNZAROVÁ, Lucie
Representatives of the Cryptosporidium family are, from a medical and veterinary aspect, designated as important unicellular parasitic protozoa infecting all classes of vertebrates including humans. Their development cycle is monoxene, which means that its life cycle is completed uniquely in one host. Their exogenous stages of infection development ? oocysts ? are mostly secreted in faeces causing a parasitic disease called Cryptosporidiosis. Generally, it is assumed that isolated cryptosporidia from one class of vertebrates are not contagious for other hosts from different classes, and also, that the majority of cryptosporidia types and genotypes have low host specifity. However, there are many cases where the presence of oocysts was proved, or the presence of specific cryptosporidium DNA in faeces of atypical hosts. With regard to the fact that the majority of genotypes and their potential hosts were described only on the basis of the presence of the specific cryptosporidium DNA in faeces, the question arises as to whether the aforementioned hosts are in all cases perceptive to the given infection, or it was only contamination in a sample or the transit of oocysts through the host gastrointestinal tract. This issue is also characterised as being the main objective of this thesis. The study gives an appropriate answer to this question by a series of experiments. Different isolations of cryptosporidia were used for experimental infection of rodents which were per orally infected and put down after reaching the specified patent period. By means of the combination of standard parasitological and molecular methods, the presence of oocysts and specific DNA of cryptosporidia in faeces and in mucous membrane of the gastrointestinal tract of infected hosts was observed. The results of this study prove that the transit of oocysts through the gastrointestinal tract can be detected in the interval between 6 and 24 hours after infection, yet not in every case. On the basis of this finding, the first hypothesis which stated that it is not possible to qualify explicitly by detection of a specific cryptosporidium DNA in faeces whether the infection has begun in the host or it is the transit of oocysts through the host gastrointestinal tract, was thus partially proved. On the other hand the second hypothesis stating that the specific cryptosporidium DNA in clinical samples of faeces can be detected only in cases of the host´s successful infection, was rejected.
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[Population ecology of annual hemiparasitic species \kur{Melampyrum pratense.}
PRŮŠOVÁ, Monika
The thesis deals with the hemiparasitic species Melampyrum pratense. This species was monitored during the growing season 2009 and the relationship between morphological characteristics and reproductive success of plant individuals was assessed. The relationships between population density, the vegetative biomass and the investments in generative reproduction were investigated. Identity of the host species was determined using the DNA barcoding method.
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