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With a little help from my friends: "understanding the roles and importance of the millipede gut microbiome"
NWEZE, Julius Eyiuche
This research aimed to elucidate the role and importance of the millipede gut microbiome in cellulose digestion by using inhibitors to disrupt potential host-symbiosis and assessing their effects on millipede digestion and overall health. It involved the first comprehensive profiling of microbial communities within the hindgut and faeces of two distinct millipede species: Epibolus pulchripes, a tropical species found on the East African coast, and Glomeris connexa, a temperate species native to Central Europe. Although both species share a similar detritivorous lifestyle, they differ in size and gut redox conditions, with G. connexa being smaller (10-17 mm) than E. pulchripes (130-160 mm). The study also revealed the potential of the hindgut bacterial community in breaking down complex polysaccharides and recycling nutrients. It described the active bacterial community vital for certain processes and the extent of the millipedes' dependence on them. Additionally, the research provided a comprehensive investigation of viral communities in the hindguts of the two millipedes and their role in enhancing metabolism and modulating microbial composition. Furthermore, it introduced a new perspective that millipedes primarily ingest litter to gain access to microbial biomass (primarily fungal), which they and their gut microbiota consume.
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Cell inclusions in microscopic eukaryotes
Pilátová, Jana
This thesis reports, for the first time, a systematic study identifying various cell inclusions across the broad diversity of all major eukaryotic supergroups. Raman microspectroscopy technique was employed as a powerful technique, which is becoming the method of the first choice for such studies. In Chapter 1, the spatial reconstruction of chloroplasts of the unicellular zygnematophyte Cylindrocystis sp. (Streptophyta) revealed "empty spaces" inside. Subsequent analysis showed massive accumulations of polyphosphate, which is not located in the cytoplasm as in other species, but inside the chloroplasts. This newly discovered ability of the zygnematophytes, a sister group of terrestrial plants, to accumulate polyphosphate leads us to speculate about a possible adaptation to extreme Arctic conditions or even a preadaptation leading to plant terrestrialization. Chapter 2 summarizes the serendipitous discovery of purine crystalline inclusions in dinoflagellates and other microalgae. Investigated dinoflagellate species comprised zooxanthellae, the endosymbionts of reef-building corals, and the species causing toxic algal blooms. Purine crystals were further shown to act as dynamic high-capacity nitrogen storage. To show how widespread purine inclusions are, a revision of crystalline inclusions in all...
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Interactions among free-living prokaryotes and protists in microbial communities
Jirouchová, Kateřina ; Pánek, Tomáš (advisor) ; Fiala, Ivan (referee)
Protists and prokaryotes live in the natural environment in complex microbial communities whose members interact with each other. These communities consist of a few to many species that interact with each other in many ways such as predation/prey, ecto/endosymbiosis, parasitism, modulation of development or behaviour and harmful algicidal/bactericidal interactions, resulting in a complex network of interactions that influence structure of the microbial community as well as metabolism and behaviour of present species. This bachelor thesis is an overview of the interactions between free-living protists and prokaryotes within microbial communities, excluding well-studied interactions such as predation, parasitism, and ecto/endosymbiosis, while focusing on the diversity of lesser- known interactions, highlighting their importance and future research opportunities.
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Cell inclusions in microscopic eukaryotes
Pilátová, Jana ; Schwarzerová, Kateřina (advisor) ; Gierlinger, Notburga (referee) ; Prášil, Ondřej (referee)
This thesis reports, for the first time, a systematic study identifying various cell inclusions across the broad diversity of all major eukaryotic supergroups. Raman microspectroscopy technique was employed as a powerful technique, which is becoming the method of the first choice for such studies. In Chapter 1, the spatial reconstruction of chloroplasts of the unicellular zygnematophyte Cylindrocystis sp. (Streptophyta) revealed "empty spaces" inside. Subsequent analysis showed massive accumulations of polyphosphate, which is not located in the cytoplasm as in other species, but inside the chloroplasts. This newly discovered ability of the zygnematophytes, a sister group of terrestrial plants, to accumulate polyphosphate leads us to speculate about a possible adaptation to extreme Arctic conditions or even a preadaptation leading to plant terrestrialization. Chapter 2 summarizes the serendipitous discovery of purine crystalline inclusions in dinoflagellates and other microalgae. Investigated dinoflagellate species comprised zooxanthellae, the endosymbionts of reef-building corals, and the species causing toxic algal blooms. Purine crystals were further shown to act as dynamic high-capacity nitrogen storage. To show how widespread purine inclusions are, a revision of crystalline inclusions in all...
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Biogenesis and function of peroxisomes in parasitic protists
Nguyen, Thu Duong ; Tachezy, Jan (advisor) ; Verner, Zdeněk (referee)
Peroxisomes are found in majority of eukaryotes and possibly originate from the last eukaryotic common ancestor, as the proteins involved in their biogenesis are highly conserved. Enzymatic content of peroxisomes is highly diverse and their metabolic activity may vary depending on the cell type. Metabolically, peroxisomes interact with mitochondria and these organelles are functionally linked. Peroxisomes in unicellular eukaryotes are very diverse. The peroxisomes in kinetoplastids are named glycosomes because they contain several glycolic enzymes. The loss of peroxisomes occurs in certain representatives of Alveolata, and peroxisomes are entirely absent in Metamonada group. Anaerobic peroxisomes were found in Archamoebidae. They are metabolically quite distinct from their aerobic counterparts. The properties of these peroxisomes are related to the lifestyle of these protists. This work briefly summarizes information regarding the biogenesis of peroxisomes and their functions, their functional connection with mitochondria and then provide characteristics of peroxisomes in selected protists.
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Communities of protists and invertebrate animals in freshwater aquaria and possibilities of their use in teaching
Hásková, Barbora ; Mourek, Jan (advisor) ; Hanel, Lubomír (referee)
This bachelor thesis focuses on the hidden but very diverse community of protists and microscopic invertebrates in freshwater aquaria. Samples of these micro-organisms were obtained from microscopic slides submerged in aquaria for several weeks. The main output of this thesis is a multimedia didactical atlas of characteristic protists and invertebrates inhabiting freshwater aquaria. In total, eleven members from two phyla of protists and six phyla of invertebrate animals are presented using own original micrographs and short videosequences. The atlas was prepared in two forms - a text document and a web page. Potential of the atlas for use in biology teaching and extracurricular education is discussed. Key words: zoology, protists, invertebrates, teaching, didactics, communities
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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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Diversity and biogeography of protists
Ryšánek, David ; Škaloud, Pavel (advisor) ; Kulichová, Jana (referee)
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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Evolution of silica structures in SAR protists
Čížková, Natálie ; Čertnerová, Dora (advisor) ; Kulichová, Jana (referee)
Silicon is an important element in the earth's crust. In nature it mainly occurs in the form of silicic acid. This element is used by marine and freshwater organisms to form their siliceous structures. The organisms that make up these structures are located throughout the phylogenetic tree and are not limited just to protist groups. The SAR line includes Stramenopila, Alveolata and Rhizaria. The main protist taxa forming the mentioned siliceous structures are in these groups. These are mainly diatoms, silicoflagellates, radiolarians and the group chrysophyceae. The formation of siliceous structures usually provides evolutionary benefits to organisms, such as protection of the cell from actions of biotic and abiotic factors. The availability of dissolved silicon changed during evolution, thus affecting the appearance and functionality of the structures of individual species. Structural changes were manifested by thinning of the shells, change of cell size, enlargement or decrease of pores, increase of the number of thorns or, conversely, their loss. The individual lines thus had to choose the best possible strategies in response to the decreasing availability of silicic acid. Therefore, there was frequent competition between the groups for the remaining dissolved silicon. The current diversity of...
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