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Virulence factors of Entamoeba histolytica
Novotná, Monika ; Tachezy, Jan (advisor) ; Tůmová, Pavla (referee)
The parasitic protist Entamoeba histolytica causes intestinal disease called amoebiasis (amoebic dysentery), which is one of the most significant diseases worldwide, mainly in developing countries. The goal of this bachelor thesis is to summarize current knowledge about virulence factors of E. histolytica. It is primarly focused on adhesive lectin Gal/GalNAc, cysteine proteases, phagocytosis of apoptotic cells, amoebapore forming pores in the membranes of the target cells and trogocytosis. Keywords: virulence factors, Entamoeba histolytica, parasite, protist, amoebiasis, lectin Gal/GalNAc, cysteine proteinase, phagocytosis, trogocytosis, amoebapore
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Diversity and host specificity of intestinal protists of cockroaches and termites (Blattodea)
Soviš, Matyáš ; Čepička, Ivan (advisor) ; Kolísko, Martin (referee)
The cockroaches (Blattodea) are morphologically and ecologically diverse group of insects living in manifold habitats. Some of them including many termites (Isoptera) feed on wood in various stages of decay. This is however difficult to metabolise for the vast majority of cockroaches and termites and this is why they harbour in their hindguts symbiotic protists belonging mostly to the excavate lineages Parabasalia and Preaxostyla. In this thesis I sum up the knowledge on the diversity of organisms living in the hindgut of cockroaches and termites and on the host specificity of the most important groups of symbiotic protists. Keywords: Blattodea, Isoptera, hindgut, host specificity, diversity, protist, Parabasalia, Oxymonadida
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Alcohol dehydrogenases in parasitic protists
Šipková, Anna ; Mach, Jan (advisor) ; Smutná, Tamara (referee)
Bachelor's thesis summarizes alcohol dehydrogenases mainly in parasitic protists. These widespread enzymes have been identified in several organisms ranging from bacteria to human. Thanks to the diversity of the enzyme's structure and substrate specificity is its function variable. Structure of the model zinc-containing Adh1 Saccharomyces cerevisiae is tetrameric. Enzymes are responsible for reversible oxidation of alcohols to aldehydes or ketones with concomitant reduction of NAD(P)+ as a cofactor. In most organisms, Adh appears in several types. Classification of Adhs is quite difficult and incomplete due to the investigation progress. The current classification includes three groups: MDR ("medium chain" Adh), SDR ("small chain" Adh) and iron-containing Adh. Adhs in parasitic protists have a specific role in the flexibility of metabolism and the adaptability to environmental changes in the host. This thesis deals especially with anaerobic parasites, where Adh is important in fermentation metabolism. Adh also figures in the resistance to drugs like in Trypanosoma cruzi or Tritrichomonas foetus. Recently, Adh has become a promising enzyme for a biotechnological application like in pharmaceutical or chemical industry. Keywords: Alcohol dehydrogenases, classification, parasitic protists, resistance
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Utilization of cellulose and hemicellulose as a source of energy by symbiotic protists and other organisms
Hammerbauerová, Iva ; Tachezy, Jan (advisor) ; Hrdý, Ivan (referee)
In this thesis I focus on the enzymatic degradation of plant structural polysaccharides cellulose and hemicellulose. I describe the enzymes involved in their lysis and their breakdown and their function and occurence among organisms. I also pay attention to the mechanisms of xylose and arabinose catabolism as pentoses found in hemicellulose. I describe some niches where cellulose and hemicellulose degradation takes place and organisms that take part in it. Finally I shortly point out the biotechnological importance of these organisms in the production of bioethanol.
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The metabolism of amino acids in parasitic and anaerobic protists
Jakubec, Dávid ; Šuťák, Róbert (advisor) ; Hrdý, Ivan (referee)
Parasitic protists are the cause of countless pathological conditions and economic issues in many parts of the world. While being phylogenetically unrelated, they share many similarities in their approach to satisfying the essential needs. Unlike the much studied energy metabolism, amino acids utilisation pathways are rather unexplored areas. This review shows that in many cases, the parasitic life style has not had the same impact on the amino acid metabolism as it did on the energy metabolism of the protists, which is often severely reduced. Novel pathways have been found in many of the organisms in question, for the biosynthesis of amino acids deemed both essential and non-essential in humans. The arginine dihydrolase pathway found in Trichomonas and Giardia represents a complely new way of utilising the said amino acid. The metabolism of sulfur-containing amino acid has been a matter of intensive research for their non-proteogenic roles. Polyamines are organic nitrogenous compounds involved in many vital processes in the cells, including DNA replication and protein translation. The synthesis of polyamines and their derivatives is elucidated, as it is directly connected to the amino acid metabolism. Finally, the exploitation of the unique pathways described integrates the previous research with the aim...
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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.
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Reductive Evolution of Mitochondria - Related Organelles in Anaerobic Protist
Rada, Petr ; Tachezy, Jan (advisor) ; Embley, Martin (referee) ; Eliáš, Marek (referee)
Charles University in Prague, Faculty of Science Department of Parasitology Ph.D. study program: Parasitology Abstract of the Ph.D. Thesis Reductive Evolution of Mitochondria - Related Organelles in Anaerobic Protist Petr Rada Supervisor: Prof. RNDr. Jan Tachezy,Ph.D. Advisor: Doc. RNDr. Ivan Hrdý, Ph.D. Praha, 2011 1 ABSTRACT Trichomonas vaginalis and Giardia intestinalis are parasitic protists of the Excavata group. Both contain anaerobic forms of mitochondria called hydrogenosomes (Trichomonas) and mitosomes (Giardia). Hydrogenosomes produce hydrogen and ATP by substarte level phosphorylation and mitosomes represent the highly-reduced form of mitochondria that do not participate in cellular energy metabolism and ATP generation. Both types of organelles lost the majority of mitochondrial pathways and their genomes during the mitochondrion to hydrogenosome transition. Consequently, hydrogenosomes and mitosomes facilitate translocation of nuclearly encoded proteins into the matrix of the organelle as well as exchange of metabolites and ions across their membranes. Little is known about the membrane machineries required for the biogenesis of the organelle and metabolite exchange and the limited knowledge of mitosomal proteomes has been mostly gained from genomic analysis and localization studies of a few...
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Morphological strategies of photoautotrophic protists under various environmental conditions.
Ševčíková, Tereza ; Kulichová, Jana (advisor) ; Pichrtová, Martina (referee)
The aim of this thesis is to provide a comprehensive overview of morphological adaptation of photoautotrophic protists to various environmental conditions and to describe the influence of their shape and size for different life strategies. Thesis summarizes overview of the main factors affecting the natural mikroalgal community and shows their relevance for life of photoautotrophic protists. These factors include availability of nutrients, pH, temperature, penetration of light and predation. Next part focuses on different methodological approaches and attitudes, how to investigate, measure and explain morphological features.
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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.
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