National Repository of Grey Literature 21 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Výskyt střevního prvoka, \kur{Dientamoeba fragilis}, u primátů v zajetí
KOUTENSKÁ, Monika
The main aim of this thesis was to summarize all available information on the occurrence of intestinal protist Dientamoeba fragilis in non-human primates kept in captivity. The partial objectives were to describe all available facts about the biology of D. fragilis, such as about its life cycle, host specificity, genetic diversity and the role of D. fragilis in the intestinal microbiome. In addition, I also addressed the issue of diagnosis of D. fragilis, which until recently was relatively difficult, and I summarized the available diagnostic molecular approaches and their benefits.
Molecular mechanisms of predation of planktonic protist \kur{Hemistasia phaeocysticola}
KNOBLOCH, Tomáš
In this thesis growth curves under specific conditions, fluorescence microscopy, and transcriptomic analyses were used to investigate whether the marine protist Hemistasia phaeocysticola is able to prey on bacteria and the determination of its molecular mechanisms of predation.
Diversity and function of pattern structures in the microworld
Hirnerová, Anna ; Škaloud, Pavel (advisor) ; Němcová, Yvonne (referee)
This thesis summarizes current knowledge of patterns and structures at various scales, with an emphasis on the use of these patterns in the microworld and also on the materials that are most often used. Patterns are applied in all areas of natural processes and human activity. There are many analogous models at different scales, but we do not know if they have the same self-organizing mechanisms. Many patterns formed by microorganisms can be prepared without their presence, on the basis of physical and chemical methods, so they are probably created under certain parameters that can be influenced by a given protist. These patterns are evolutionarily advantageous for microorganisms, because they provide them with a number of functional adaptations, mainly in connection with defense against predators and movement in the water column, which is based on the organism's life strategy. The mathematical description of the pattern is extremely important for its further research and for determining the laws that have allowed the organism to benefit from its parameters. Keywords: pattern, structure, convection, reaction - diffusion model, geometry, protist, microorganism, skeletons, shells, scales
Protists in oral cavity of humans and animals.
Brixí, Kateřina ; Tachezy, Jan (advisor) ; Rada, Petr (referee)
Trichomonas tenax, Trichomonas gallinae, Trichomonas gypaetinii, Trichomonas stableri, Trichomonas equibuccalis, Trichomonas brixi, Tetratrichomonas canistomae, Tetratrichomonas felistomae and Tetratrichomonas empyemagena are unicellular eukaryotes (protists) that may occur in oral cavity of humans and domestic animals. These protozoans are mostly referred as commensals and relatively low attention is paid to them, since they usually are not primary cause of serious health problems. However, based on current knowledge, it can be concluded that more appropriate term for Entamoeba gingivalis and Trichomonas tenax would be an opportunistic pathogen, while Trichomonas gallinae is a primary pathogen. There are very little studies and findings about the rest of oral protozoans and their pathogenicity, therefore it is not possible to assess their significance for a host. Nevertheless, the oral protozoans should not be neglected, as in some cases they can cause serious health complications in their host.
Sexual reproduction of ochrophyte algae
Procházková, Kateřina ; Eliáš, Marek (advisor) ; Kulichová, Jana (referee)
Sexual reproduction is one of the specific features of eukaryotes. Almost all the knowledge that we have about the sexual process is based on studies conducted on animals and plants. In fact, we know only a tiny fraction of what protist organisms could reveal about distribution and other aspects of the sexual process. For the vast majority of them we miss any evidence that the sexual process actually occurs. However, it is conceivable that the putative protist asexuality is only a human artifact. Likewise, for most ochrophyte algae, which are the main subject of this thesis, the sexual process is unknown. It has been observed only in individuals belonging to six of the sixteen hitherto described classes of Ochrophyta. In some cases, an enviromnental factor that stimulates the formation of gametes was also found. The gradual clarification of the phylogeny that we can expect in the years coming, along with knowledge of biology of ochrophyte algae, can provide more information about sexuality in this group.
Sexual incompatibility of protist cryptic species
Jelínková, Lucie ; Škaloud, Pavel (advisor) ; Urbánková, Pavla (referee)
The systematic and the evolutionary biology attempt to define a species category or a species taxon from the beginning of their existence. Specific taxons are considered species on the base of different criteria, so on the base of different species concepts. Most of these concepts emerged previous century. The biological species concept has been assumed to be most important species concept for dozens of times. It was based on a presence of the reproduction isolation of two species. However, its applicability was questioned by the existence of many asexual lineages and also the lineages with a large degree of hybridization between an approved species. This thesis is trying to give a description of the biological species concept and its changes during the time. And it is also trying to answer the question of its simultaneous usability for protist.
Role of exosomes and ectosomes in Trichomonas vaginalis virulence
Göblová, Rebeka ; Tachezy, Jan (advisor) ; Ditrich, Oleg (referee)
Trichomonas vaginalis is a causative agent of the most common non-viral sexually transmitted disease with approximately 275 mil new cases annually. Virulence of this parasitic depends on at least four factors: cell shape transformation, cytoadherence, secretion of cysteine proteases, and presence of endosymbionts. Over the past decades, extracellular vesicles appeared being another important player in the host-parasite interaction. It was discovered that T. vaginalis is one of the protists that can shed the extracellular vesicles such as exosomes and ectosomes. These vesicles are possibly involved in host-parasite communications, however limited information is available about their function. To investigate a possible role of exosomes in T. vaginalis virulence, we first selected suitable strain, which is free of endosymbionts (TV 17-2MI). Next we prepared six clones of TV 17-2MI strain to test whether the strain is homogenous concerning the virulence, or there are differences in virulence among individual cells. Mouse intraperitoneal virulence tests revealed that the clones displayed significant differences in virulence level, particularly in abscess formation and mortality of infected animals. Thus, for the first time we demonstrated heterogeneity of cells derived from a single T. vaginalis strain...
Analysis of the genome of a free-living amoeba Mastigamoeba balamuthi and its comparison with pathogenic Entamoeba histolytica
Žárský, Vojtěch ; Tachezy, Jan (advisor) ; Bruchhaus, Iris (referee) ; Beneš, Vladimír (referee)
Charles University, Faculty of Science Department of parasitology Doctoral study programme: Parasitology Abstract (en) Analysis of the genome of a free-living amoeba Mastigamoeba balamuthi and its comparison with pathogenic Entamoeba histolytica Mgr. Vojtěch Žárský Supervisor: prof. RNDr. Jan Tachezy, Ph.D. Praha, 2020 Abstract Examination and comparison of organisms have been tremendously important for the study of life's history on earth. The progress of our understanding of the genetic basis of heredity and the recent boom of sequencing technologies allows us to continue in this exciting field of research from the perspective of genes and genomes. In this work, I focus on the study of an anaerobic amoeba Mastigamoeba balamuthi, which is related to an important human pathogen Entamoeba histolytica. Comparative analysis allows us to draw some conclusions about the nature of the common ancestor of Mastigamoeba and E. histolytica, how it adapted to the anaerobic lifestyle, and about the way the Entamoeba lineage evolved to become a successful parasite. Surprisingly we also noticed that besides hydrogenosomes (hydrogen-producing organelles related to mitochondria), M. balamuthi also harbors peroxisomes - organelles thought to be absent in anaerobic organisms. This finding motivated us to inquire more about...
Maintenance of chromosomes integrity in Giardia intestinails as a model organism.
Uzlíková, Magdalena ; Nohýnková, Eva (advisor) ; Lalle, Marco (referee) ; Stejskal, František (referee)
Giardia intestinalis is a protozoan causing diarrhea worldwide. Beside its medical importance, it is evolutionary distant protist with two nuclei within a cell adapted for parasitic life in the environment poor of oxygen. Its genome is small and compact in term of gene content and size. It is therefore an attractive model organism for studies of minimal requirements for cellular processes. Present work brings new partial information on different levels of chromosome integrity maintenance of this parasite. Our study presents characteristics of chromosome termini and their protection. We localized telomeres during all stages of the trophozoite cell cycle and determined the length of Giardia telomeres ranging from 0.5 to 2.5 kb, we proved an existence of an active telomerase enzyme synthesizing telomeric repeats in in this parasite, despite the fact that giardial telomerase is structurally divergent. Present data support the view that the chromosomal termini in Giardia are maintained in a conservative manner that is common to other eukaryotes. We described effects of commonly used drug for treatment of anaerobic infections, metronidazole, on DNA and cell cycle progression in susceptible and resistant cell lines. Incubation of cells with this drug causes phosphorylation of histone H2A in cell nuclei...
Interaction between hydrogenosomes and endoplasmic reticulum in Trichomonas vaginalis
Kučerová, Jitka ; Tachezy, Jan (advisor) ; Černý, Jan (referee)
Endoplasmic reticulum-mitochondria encounter structure (ERMES) is a protein complex tethering ER and mitochondria. ERMES consists of four core subunits - Mmm1, Mmm2 (Mdm34), Mdm10 and Mdm12. It was first discovered in Saccharomyces cerevisiae and most functional information is based on studies of this organism. ERMES affects mitochondrial distribution and morphology, participates in lipid trafficking and is important for homeostasis of the cell. In Trichomonas vaginalis, the human urogenital parasite, three genes for putative, highly divergent components of ERMES complex were predicted. However, the cell localization of these proteins and their function is unknown. This thesis is focused on investigation of ERMES components in T. vaginalis, their cellular localization, interactions between components and identification of their possible interacting partners.

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