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Mechanisms of iron-sulfur cluster biogenesis in eukaryotes
Temešinko, Tomáš ; Doležal, Pavel (advisor) ; Malych, Ronald (referee)
Many essential cellular proteins use iron-sulfur (Fe-S) clusters as cofactors. These proteins often serve as enzymes, components of the electron-transport chain or as intracellular sensors. Prior to the use of the cluster in a protein, it needs to be formed or created de novo. In total, four different mechanisms of Fe-S cluster biogenesis can be used by the eukaryotic cell - ISC, CIA, SUF and NIF. All of these pathways include a specific targeting system for delivering the cluster to its acceptor protein. Errors in biosynthesis ofFe-Sclustersaremostlylethalandcanleadtofailureindevelopmentofmulticellularorganisms.Despite this a better characterization of these mechanisms is needed as research is currently still in progress. This bachelor's thesis provides current information regarding the mechanisms of Fe-S clusters biogenesis in eukaryotes acquired mostly from mammalian cells, including humans, and from well-known model organisms such as Saccharomyces cerevisiae, Arabidopsis thaliana, and parasitic protist Giardia intestinalis.
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Quantitative Analysis of Gene Ancestry in Euglenoidea
Soukal, Petr ; Hampl, Vladimír (advisor) ; Burki, Fabien (referee) ; Horák, Aleš (referee)
Genes, units of genetic information, are passed from one individual to another, typically within the same species from parents to offspring. Occasionally, genes can be transferred to different species through a process called horizontal gene transfer (HGT). Endosymbiosis is a process in which one organism engulfs another organism and the genes flow between the two symbionts in a process called endosymbiotic gene transfer (EGT), which is a subtype of HGT. Eventually, the endosymbiont may become an organelle such as a mitochondrion or a plastid. Euglenids (Euglenoidea) are unicellular eukaryotes with diverse modes of nutrition - phagotro- phy (e. g., Peranema), osmotrophy (e. g., Rhabdomonas), mixotrophy (phagotrophy and phototrophy in Rapaza), and phototrophy (possessing plastids; e. g., Eutreptiella). The history of endosymbioses of green algae (especially Chlorophyta) and ancestors of Euglenophyceae (including Rapaza) is complex. In my thesis, I performed the quantitative analysis of gene ancestry (QAGA) based on transcripto- mic data of Euglena gracilis showing contribution of closely related Kinetoplastea (1,420 genes, 3.88 % of transcripts inherited vertically), and contribution of multiple "unrelated" (mainly) phototrophic organisms, e. g. Viridiplantae (572, 1.57 %), or Haptophyta (234, 0.64...
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Evolution of euglenid plastid proteome
Novák Vanclová, Anna ; Hampl, Vladimír (advisor) ; Gruber, Ansgar (referee) ; Maier, Uwe (referee)
Endosymbiotic gain and transfer of plastids is a widespread evolutionary phenomenon and a major driving force of eukaryotic evolution. The integration of a new organelle is accompanied by changes in its structure, gene content, molecular mechanisms for biogenesis and transport, and re-wiring of the host and organelle metabolic pathways. To understand the course and underlying mechanisms of plastid evolution, it is important to study these processes in variety of secondary algae and notice their differences and similarities. Euglenophytes gained their plastids from green eukaryotic algae after a long history of heterotrophic lifestyle. In my thesis, I participated in analyses of newly generated sequence datasets: transcriptomes of Euglena gracilis and Euglena longa and mass spectrometry-determined proteome of E. gracilis plastid with especial regard to the potential novelties associated with plastid gain and incorporation. In the resulting publications we particularly focus on plastid protein import machinery and targeting signals and report extremely reduced TIC and completely absent TOC in euglenophyte plastid. Using the proteomic dataset, we predict potential novel plastid protein translocases recruited from ER/Golgi and re-analyze plastid signal domains, characterizing previously overlooked...
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Losses of mitochondria and plastids in the evolution of eukaryotes
Trokšiar, David ; Hampl, Vladimír (advisor) ; Hadariová, Lucia (referee)
- 5 - Abstract: Mitochondria and plastids were acquired by endosymbiotic event, where prokaryotic organism was engulfed by ancestors of extant eukaryotes. There are more known endosymbiotic events in plastid evolution. In primary endosymbiosis cyanobacterium cell was engulfed by heterotrophic eukaryotic organism. In following secondary, tertiary and quaternary endosymbiotic events eukaryotic cell was engulfed by another eukaryote. Mitochondria originated by engulfment of α-proteobacteria. In the evolution of eukaryotes, reduction of mitochondria occurred in many lineages, making living under anaerobic conditions possible. The least reduced form is anaerobic mitochondria, which together with aerobic mitochondria and hydrogen producing mitochondria, possess genome. Hydrogenosomes and the most reduced form mitosomes, does not possess genome. Plastid reductions led to loss of photosynthetic ability. In last years, more examples of organisms that lost entirely their semi- autonomous organelle, are coming. Loss occur at two parasitic representatives of the Alveolata group, and one endobiotic oxymonad. Parasites Cryptosporidium parvum and Hematodinium lost nonphotosyntetic plastid, whereas Monocercomoides lost its mitochondria. Semi-autonomous organelles were dispensable, because all representatives have access to...
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Diversity of prasinophyte algae related to the euglenid plastid
Lukešová, Soňa ; Hampl, Vladimír (advisor) ; Horák, Aleš (referee)
Euglenophyceae represent a group of unicellular eukaryotic organisms that have gained during their evolution the ability to photosynthesize. They aquired plastids via secondary endosymbiosis with a green alga as the plastid donor. Phylogenetic studies searching for the origin of this organelle revealed the green alga Pyramimonas parkeae from Prasinophytes as the closest known relative to euglenid plastids. Pyramimonas parkeae and Euglena share several genes clusters with unique order of genes in their plastid genomes, which also point to the Pyramimonadales as the donor of the plastids. However, it is posible, that organisms more closely related to euglenid plastids than P. parkeae, occur in the environment. In my diploma thesis I focused on the exploration of diversity of Pyramimonadales and Euglenophyceae in environmental samples. I used several approaches to perform this task. I amplified parts of the plastid genomes in environmental samples by using specific PCR and determined their position in the phylogenetic tree. I also made large-scale phylogenetic analyses based on 16S rRNA and 18S rRNA sequences from representatives of the groups Euglenophyceae, Prasinophytes and environmental samples. The results revealed the presence of a large number of environmental sequences relative to the...
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Membrane proteome of euglenid plastid
Vanclová, Anna ; Hampl, Vladimír (advisor) ; Füssy, Zoltán (referee)
Euglenophyta are monophyletic group of euglenids defined by presence of green, three membrane- bound plastid which has been aquired via secondary endosymbiosis with chlorophyte alga. Mechanism of transport of nuclear-encoded proteins into this plastid is not yet completely understood. It was observed that the proteins are transported to the outermost plastid membrane in vesicles passing through ER and Golgi, but the mechanism of their recognition and fusion with the target membrane remains unclear. Translocation system of inner two membranes is still completely unknown, regarding the situation in other plastids, it has been proposed that homologues of TOC and TIC complexes are present. In this work we analyzed sequence data from proteome of isolated plastid membranes of model organism Euglena gracilis and transcriptome of E. gracilis and its distant relative Eutreptiella gymnastica. We studied whether they contain proteins potentially involved in transport and homologues of proteins of transport systems known from plastids in other organisms (TOC/TIC, ERAD-like transport, SNARE). However, all our results are negative. It is hard to determine whether these findings indicate the possible absence of TOC and TIC complexes in euglenid plastid, or rather the insufficiency of our data. Powered by TCPDF (www.tcpdf.org)
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Analýza vývoje klíčních transgenních rostlin Arabidopsis thaliana nadprodukující cytokinin-glukosid specifické ß-glukosidasy Zm-p60.1
Štuříková, Helena
In this bachelor thesis the localization of the maize beta-glukosidase Zm-p60.1 was studied in transgenic Arabidopsis plants using histochemical staining and confocal microscopy. Zm-p60.1 plays an important role in cytokinin metabolism, where it participates in the reversible activation of zeatin from its inactive storage form - zeatin-O-glucoside. Histochemical staining confirmed the expression of Zm-p60.1 in root tips, leaf tissues and vasculature. Subsequent, confocal microscopy using a fluorescently (GFP)-labeled version of Zm-p60.1 revealed localization in chloroplasts, plastids (in root tips) and in xylem of vasculature. Localization of Zm-p60.1 in chloroplasts and plastids in Arabidopsis correlates with previous studies in maize (Kristoffersen et al., 2000) and tobacco (Kiran et al., 2006), which indicates the stability of Zm-p60.1 targeting. The expression of Zm-p60.1 in the vasculature is an unexpected finding and needs to be clarified in future research.
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