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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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Influence of competition to structure of protist communities
Škvorová, Marie ; Bestová, Helena (advisor) ; Svoboda, Pavel (referee)
This work deals with competition as well as mechanisms of coexistence of species. The introduction presents comtemporary coexistence theory. There are two types of differences - niche and relative fitness differences. Fitness differences increase inter-species competition. This is a novell result, current theory expected differences decrease competition in any case. This work summarized results of experimental works that have investigated various aspects of co- existence theory, with special focus on protists. Competition was found to be an important mechanism in creating patterns of community assembly, unfortunately drawing common results is complicated. According to competition-relatedness hypotheses, within some competition lines competition decreased with relatedness. This relation however does not hold always. There are two conditions: functional traits must bear a phylogenetic signal and must be evolutionally conserved. Studies on protists imply that higher number of species should be included instead of pairwise combination tests in order to get valid information on relation of species. This could be similar for traits. Plants experiments have shown that competition may be affected by traits only in complex systems with a number of traits included. Such experiment involving protists have...
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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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The method of DNA barcoding and its use in protists
Rotterová, Johana ; Čepička, Ivan (advisor) ; Fiala, Ivan (referee)
DNA barcoding is a molecular method of species identification based on short regions of DNA sequences. These DNA barcodes should be unique for each species. The sequences within species should be identical or very much alike, while between species they should display a significant amount of differences. The sequences of an undetermined specimen can be compared with sequences vouchered to a particular species in a global DNA barcode database. The database was developed with the aim to simplify traditional taxonomy, eliminate its problems and accelerate its approaches. However, DNA barcoding has its own limitations that may hinder achieving its original goals and a compliance with the concept. The aim of this bachelor thesis consists of explaning the evolution of DNA barcoding through time and assessing the importance of this method at present, particularly in protists. Species identification may be very difficult in many protist groups, which can be explained by several reasons. To appraise this method completely is a hard task, because creation of the database has not yet been finished and official DNA barcodes have not been chosed for many groups. We can only find out in the future, therefore i will only focus on factors that influence the success of DNA barcoding at present.
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Protein import into mitochondria and peroxisomes of parasitic protists
Žárský, Vojtěch ; Tachezy, Jan (advisor) ; Hampl, Vladimír (referee)
The presented thesis includes three related projects, that are linked by a common interest in the evolution of eukaryotic organelles and machineries that import proteins into these compartments. The first project considers the possibility of peroxisomes (eukaryotic organelles known in aerobic organisms) being conserved in two related anaerobic protists: a free-living amoeba Mastigamoeba balamuthi and a parasite Entamoeba histolytica. The most important hint for the presence of peroxisomes was the discovery of proteins that are homologous to known components of the peroxisomal protein import machinery. The second project aims to characterize the unknown protein translocase of the inner membrane (TIM) in the mitosomes (extremely reduced mitochondria) of an anaerobic protozoan Giardia intestinalis. We have discovered an important subunit of the mitosomal translocase (Tim44), which usually tethers the Hsp70/PAM (presequence translocase-associated motor) complex to the TIM translocon. The last project shows that the protein translocase of the outer mitochondrial membrane in trypanosomatids is related to a typical eukaryotic channel Tom40. This finding is important because the absence of Tom40 was previously considered an ancestral feature of trypanosomatids.
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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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Seasonal dynamics and diversity of protist organisms in peat bog microhabitats.
Mutinová, Petra ; Kulichová, Jana (advisor) ; Šťastný, Jan (referee)
This bachelor thesis summarizes the literature dealing with diversity of protist organisms in peatlands. First part presents brief general characteristics of peatlands for the acquisition of basic knowledge about this ecosystem. Further, this work concerns closely with spatial dynamics of protists in peatlands, with emphasis on microbiotops. The final part reviews available information on seasonal dynamics of protist organisms in peatlands and also on the factors that have an influence on seasonality. This work concludes that the community of protist organisms in peatlands is different from those observed in other ecosystems. The composition of the community of protists in peatlands is very heterogeneous, because it depends on the type of microbiotop and prevailing physicochemical conditions. The communities of protist organisms are subject to seasonal dynamics as well. Nonetheless, this issue is largely unexplored so far, because there are substantially less recent studies concerning peatlands than for example other aquatic ecosystems that are frequently used for water quality monitoring.
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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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Diversity and biogeography of protists
Ryšánek, David ; Kulichová, Jana (referee) ; Škaloud, Pavel (advisor)
My bachelor thesis consists of two parts. The first part is a literature review, the second part is a practical one, which contains the results of my own research. The first part of my thesis is devoted to the literature review, dealing with two current views on biodiversity and biogeography of protists. The first theory, model of protist ubiquity is described in a few points and illustrated by several examples. Likewise is presented the second hypothesis of moderate endemicity model. In conclusion, both models are compared and advantages and disadvantages of each theory are pointed out. In the second part of this thesis I briefly describe the genus Klebsormidium, which is followed by an optimization of molecular methods to study biodiversity and biogeography of this genus.
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