National Repository of Grey Literature 14 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
The role of protein phosphorylation during progamic phase of tobacco male gametophyte development
Fíla, Jan ; Honys, David (advisor) ; Paleček, Jan (referee) ; Smýkal, Petr (referee)
v angličtině (English abstract) Tobacco male gametophyte has a strongly dehydrated cytoplasm and represents a metabolically inactive stage. Upon cytoplasm rehydration, pollen grain becomes metabolically active and after the activation is finished, the pollen tube growth through a selected pollen aperture starts. The rehydration together with metabolic activation are accompanied by the regulation of translation and post-translational modifications (mainly phosphorylation) of the existing proteins. In this Ph.D. thesis, there were identified phosphopeptides from tobacco (Nicotiana tabacum) mature pollen, pollen activated in vitro 5 min and pollen activated in vitro 30 min. The total proteins from the above male gametophyte stages were extracted. The protein extract was trypsinized and the acquired peptide mixture was enriched by MOAC (metal oxide/hydroxide affinity chromatography) with titanium dioxide matrix. The enriched fraction was subjected to liquid chromatography coupled with tandem mass spectrometry (LC- MS/MS). Totally, there were identified 471 phosphopeptides, carrying 432 exactly localized phosphorylation sites. The acquired peptide identifications were mapped to 301 phosphoproteins that were placed into 13 functional categories, dominant of which were transcription, protein synthesis,...
Role of TCTP1 in plant reproduction
Pitoňak, Oliver ; Hafidh, Said (advisor) ; Lafon Placette, Clément (referee)
TCTP is a conserved eukaryotic protein involved in regulation of multiple cellular processes, such as translation, cell cycle and cell death. Apart from its intracellular functions, TCTP is secreted and participates in human immune response. Dimerization via a terminal cysteine residue is critical for its extracellular function. Multiple sequence alignment of eukaryotic TCTPs revealed that terminal cysteine residue is conserved not only in animals but also in green plant lineage. In contrast to animal model organisms, knowledge about TCTP in plants is limited. Arabidopsis thaliana genome harbors two TCTP paralogs, TCTP1 and TCTP2. TCTP1 expression is highly upregulated in pollen. Previously published studies pointed to its role in embryo development, pollen tube growth and targeting. Using mutant characterization and analysis of subcellular localization, the role of TCTP1 in plant reproduction was investigated in this thesis. Recombinant Arabidopsis thaliana TCTP1 protein was produced along with its potential interacting partners BRL2 and TTL3 in heterologous Escherichia coli system. tctp-1 T- DNA line characterization pointed to TCTP1 role in pollen tube growth. It was expressed in mature pollen and pollen tube under native promoter and localized to the cytoplasm. Recombinant AtTCTP1 formed dimers...
It takes two to tango; signal perception during male-female interaction in flowering plants
Vlasák, Jonáš ; Honys, David (advisor) ; Vaňková, Radomíra (referee)
This thesis summarizes the current understanding of the communication between partners during the progamic phase of pollen with focus on the cruciferous family After attachment of conspecific pollen to stigma, pollen coat peptides (PCP) competitively inhibit the signaling perceived by the FERONIA receptor in the papillary cell and thus allow pollen acceptance. Contrary, the interaction of pollen protein SCR (S-LOCUS CYSTEIN RICH PROTEIN) with SRK receptor (S-LOCUS RECEPTOR KINASE) determines pollen incompatibility. The regulation of oriented secretion is essential for pollen tube (PT) growth. During the growth of the PT, the components of the extracellular matrix as well as stiffness and preassure are perceived. On its way to the egg, the PT matures and acquires the competence to perceive signals. The PT exits the transmitting tract thanks to the ovular signalisation. The PT is accepted by synergids, communication takes place involving RALF peptides (RAPID ALKALIZATION FACTOR) and the FERONIA receptor. The signaling results in the rupture of the PT and the transport of sperm cells to the female gametes. Sperm cells bind to the egg cell and the central cell and after confirmation, fuse with the female gametes. After fertilization, the egg cell degrades signaling molecules and the persistent synergid also...
Revealing phosphoproteins playing role in tobacco pollen activated in vitro
Fíla, Jan ; Honys, David (advisor) ; Fischer, Lukáš (referee)
5 Abstract Tobacco mature pollen rehydrates in vivo on a stigma tissue, and develops into the rapidly-growing pollen tube. This rehydration process is accompanied by the de-repression of stored mRNA transcripts, resulting in the synthesis of novel proteins. Furthermore, such metabolic switch is also likely to be regulated on the level of post-translational modifications of the already-present proteins, namely via phosphorylation, since it was shown to play a significant regulatory role in numerous cellular processes. Since only a minor part of proteins is phosphorylated in a cell at a time, the employment of various enrichment techniques is usually of key importance. In this diploma project, metal oxide/hydroxide affinity chromatography (MOAC) with aluminium hydroxide matrix was applied in order to enrich phosphoproteins from the mature pollen and the 30-minute in vitro activated pollen crude protein extracts. The enriched fraction was separated by both 2D-GE and gel-free liquid chromatography (LC) approaches with subsequent mass spectrometric analyses. Collectively, 139 phosphoprotein candidates were identified. Additionally, to broaden the number of phosphorylation sites identified, titanium dioxide phosphopeptide enrichment of trypsin-digested mature pollen crude extract was performed. Thanks to the...
Dynamics of ALBA proteins in Arabidopsis thaliana evaluated by fluorescence microscopy
Popelářová, Anna ; Honys, David (advisor) ; Vosolsobě, Stanislav (referee)
ALBA proteins were discovered in Archaea more than 30 years ago. They were gradually identified to be well conserved in Eucaryotes as well. A functional dimeric form of these proteins with DNA and RNA-binding capability was claimed in both mentioned domains of organisms. However, their roles diversified during evolution and vary in between organisms. In Archaea, ALBAs are involved in the genome organization and RNA-protein interactions. In Eukaryotes, there are presented two different subfamilies of ALBA proteins - Rpp20 and Rpp25 subfamily. A sole protein from each subfamily was identified in some organisms though they were multiplied in plants, respectively. These proteins can interact with each other and participate in ontogenetic development and stress responses. According to several studies, ALBA proteins were found to be involved in DNA stability maintenance or pre-rRNA splicing in the nucleus of Arabidopsis thaliana. However, they have been shown to play a role in the cellular metabolism and stress responses in cytoplasm. Six ALBA proteins were identified in the genome of A. thaliana, three from each subfamily. In this study, all heterodimeric protein- protein interactions were investigated by the bimolecular fluorescence complementation (BiFC) assay which revealed positive results in...
The role of protein phosphorylation during progamic phase of tobacco male gametophyte development
Fíla, Jan
v angličtině (English abstract) Tobacco male gametophyte has a strongly dehydrated cytoplasm and represents a metabolically inactive stage. Upon cytoplasm rehydration, pollen grain becomes metabolically active and after the activation is finished, the pollen tube growth through a selected pollen aperture starts. The rehydration together with metabolic activation are accompanied by the regulation of translation and post-translational modifications (mainly phosphorylation) of the existing proteins. In this Ph.D. thesis, there were identified phosphopeptides from tobacco (Nicotiana tabacum) mature pollen, pollen activated in vitro 5 min and pollen activated in vitro 30 min. The total proteins from the above male gametophyte stages were extracted. The protein extract was trypsinized and the acquired peptide mixture was enriched by MOAC (metal oxide/hydroxide affinity chromatography) with titanium dioxide matrix. The enriched fraction was subjected to liquid chromatography coupled with tandem mass spectrometry (LC- MS/MS). Totally, there were identified 471 phosphopeptides, carrying 432 exactly localized phosphorylation sites. The acquired peptide identifications were mapped to 301 phosphoproteins that were placed into 13 functional categories, dominant of which were transcription, protein synthesis,...
Functional characterization of Alba-family genes in Arabidopsis thaliana
Kočová, Helena ; Honys, David (advisor) ; Fischer, Lukáš (referee)
(anglicky) Alba-family proteins were identified in Archaea and Eucarya and are classified among the oldest and the most conserved nucleic acid-binding proteins. The binding preferences and roles differ among certain evolution clades. In Crenarchaea they represent chromatin-binding proteins, while their role in RNA metabolism is suggested in Euryarchaea and Eukaryotes. ALBA proteins are well characterized in human, where they play a role in the RNAse P/MRP complex and in unicellular parasites, such as Plasmodium and Trypanosoma, where an involvement in the life cycle regulation is confirmed. In plants, their role is not yet well understood. The aim of this thesis is to increase a knowledge about the Alba-family proteins in the model plant Arabidopsis thaliana. Based on a minimal changes to development and reproduction in single mutants and high sequence similarity, a functional redundancy of the proteins was assumed. For better understanding of the ALBA proteins function, three smaller members of the family were edited by the same metod. The obtained triple mutant showed delay in flowering. ALBA dimer formation was confirmed in many organisms. BiFC method was used to determine Arabidopsis ALBA homodimerization. The data analysis showed potential homodimerization in most of them.
Reproduction of flowering plants and heat stress
Nedvědová, Kateřina ; Honys, David (advisor) ; Vítámvás, Pavel (referee)
This bachelor's thesis is a review summarizing the effects of heat stress on the reproductive development of flowering plants and their tolerance mechanisms. Plants are continuously exposed to changing environmental conditions and ever-increasing temperatures. Reproduction, especially the development of the male gametophyte, is particularly sensitive to these changes. This leads to defective development, sterile pollen, and fewer seeds, which affects crop productivity and yield. Therefore, it is essential to understand these changes, and especially the tolerance mechanisms. Keywords: reproduction, flowering plants, heat stress, tolerance, male gametophyte, female gametophyte
Androgenesis
Kočová, Helena ; Honys, David (advisor) ; Kocábek, Tomáš (referee)
(anglicky) Androgenesis in the plant kingdom is an interesting phenomenon, in which a new individual is regenerated from male gametophyte. Having gametophytic, i.e. haploid number of chromosomes, these plants are potentially useful in research as well as for the generation of new genotypes. Duplication of their genetic information then results in fully homozygous plants, that can be used for breeding. At the same time, microspores represent a unique system for studying totipotency, cell proliferation, differentiation and embryogenesis. However, in many important crops as well as in some model species, such technology has not yet been efficiently managed. The aim of this thesis is to summarize the knowledge about androgenesis, from the historical context to the latest discoveries, including methods, development, complications and at the end also the possible use of obtained doubled haploid plants. Keywords: androgenesis, male gametophyte, microspore embryogenesis, pollen, totipotency, cell differentiation, stress, organogenesis, haploid
Characterization of eukaryotic translation initiation factor 3 subunits (eIF3) in A. thaliana male gametophyte
Linhart, Filip ; Hafidh, Said (advisor) ; Retzer, Katarzyna (referee)
From RNA-to-protein, translation initiation and protein synthesis is mediated by trans-acting factors that recognize mRNA features common to almost all eukaryotes. Eukaryotic translation initiation factor 3 complex (eIF3) is a highly conserved protein complex that recognizes 5'-CAP elements of the mRNA to initiate translation. eIF3 consists of nine subunits, three of them having two isoforms: eIF3A, eIF2B1, eIF3B2, eIF3C1, eIF3C2, eIF3D, eIF3E, eIF3F, eIF3G1, eIF3G2, eIF3H and eIF3K. This work deals with functional characterization, expression and subcellular localization of eIF3B1, eIF3B2 and eIF3E in Arabidopsis thaliana male gametophyte and interaction of eIF3E with the Constitutive photomorphogenesis 9 (COP9) complex as a regulatory complex of eIF3E post-translational control. Here we show that depletion of eif3b1 or eif3b2 is not gametophytic lethal and that the two protein might function redundantly, whereas, knockout of eIF3E causes male gametophyte lethality. Interestingly, eif3b1 show post-fertilization defects during embryogenesis, suggesting that its redundancy with eIF3B2 is restricted to the gametophyte. Gene expression studies revealed high expression of eIF3 subunits in actively dividing zones of leaf primordia, root meristem and root elongation zones as well as in the vegetative...

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