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Investigation of HSP70 oligomerization by structural mass spectrometry
Melikov, Aleksandr ; Novák, Petr (advisor) ; Jeřábek, Petr (referee)
Heat shock cognate protein 70 (HSC70) is a 71 kDa chaperone protein belonging to the ubiquitous family of heat shock proteins 70 (Hsp70). The representatives of this protein family are considered as molecular machines with ATP-hydrolase activity facilitating correct folding of spatial protein structure, both in normal and stressful conditions (hypoxia, heat shock, pH fluctuations etc.) In addition, HSC70 was identified as an uncoating enzyme for triskelion meshwork on the surface of clathrin-coated vesicles. Among other roles, HSC70 prevents protein aggregation and assists the polypeptide maturation, it facilitates the protein transport into organelles, such as endoplasmic reticulum and mitochondria. It is involved in targeting proteins for lysosomal degradation and in many other dramatically important cellular processes related to protein homeostasis. Therefore, the regulation of HSC70 and other HSP70 proteins is believed to be dramatically important, especially in a context of cellular stress. Based on the experimental observation, the mechanism of inactivation through oligomerization was hypothesized. The dimer and trimer species of Hsp70 proteins were identified both in case of prokaryotic and eukaryotic homologs. It was also speculated that Hsp40 cofactors promote oligomerization to even...
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Heat-shock proteins and plant tolerance against high temperature stress
Ott, Kristián ; Hála, Michal (advisor) ; Konrádová, Hana (referee)
In context with ongoing climate change, the average temperature is still rising. This is a problem mainly for agriculture and production of groceries, because plants generally have difficulties when coping with ambient temperature higher than 40 řC. If there would be continuing trend in decrease of global food production, it could cause problems with feeding still growing world population. Organisms in general developed many mechanisms of stress adaptation. One of these evolutionary adaptions to high temperature stress is production of heat shock proteins (HSPs). HSPs are very conserved family of proteins present in both prokaryotes and eukaryotes. This thesis summarizes present knowledge about the HSPs and their function (not only) during the high temperature stress in plants, but some of the information presented in this thesis were obtained also from other organisms. The thesis starts with general introduction to the high temperature stress and how plants can sense the ambient temperature. Next is general mechanism of induction of HSPs and their classification, structure, and mechanism of action. The possibility of future use of HSPs in agriculture and medicine is opened in last chapter.
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Use of biochemical methods in the study of plant metabolism with emphasis on the defense system
Bělonožníková, Kateřina ; Ryšlavá, Helena (advisor) ; Luhová, Lenka (referee) ; Plchová, Helena (referee)
As sessile organisms, plants cannot avoid being exposed to various biotic and abiotic stress factors. To defend themselves plants have developed complex and sophisticated defense mechanisms. In agriculture, pesticides are used for plant protection, but they can have undesirable side effects, and therefore attention is being paid to biological control agents. One such agent is Pythium oligandrum, a soil oomycete that has a positive effect on plants at several levels. On the one hand, it secretes elicitins, which stimulate defensive responses and prepare the plant for possible infection (i.e., priming effect), and on the other hand, it produces tryptamine, a precursor of auxin, thus supporting the plant's growth. Furthermore, P. oligandrum directly acts as pathogen mycoparasite or evokes antibiosis, or competition for nutrients and space with other microorganisms. The key research topic of this thesis was the analysis of the biochemical properties of eleven Pythium strains and their impact on plant metabolism. Our results showed that even closely related P. oligandrum strains significantly differ in the content of compounds secreted into the medium, including proteins, amino acids, tryptamine, and hydrolytic enzymes capable of degrading cell walls (endo-β-1,3-glucanase, chitinase, and cellulase),...
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Use of biochemical methods in the study of plant metabolism with emphasis on the defense system
Bělonožníková, Kateřina
As sessile organisms, plants cannot avoid being exposed to various biotic and abiotic stress factors. To defend themselves plants have developed complex and sophisticated defense mechanisms. In agriculture, pesticides are used for plant protection, but they can have undesirable side effects, and therefore attention is being paid to biological control agents. One such agent is Pythium oligandrum, a soil oomycete that has a positive effect on plants at several levels. On the one hand, it secretes elicitins, which stimulate defensive responses and prepare the plant for possible infection (i.e., priming effect), and on the other hand, it produces tryptamine, a precursor of auxin, thus supporting the plant's growth. Furthermore, P. oligandrum directly acts as pathogen mycoparasite or evokes antibiosis, or competition for nutrients and space with other microorganisms. The key research topic of this thesis was the analysis of the biochemical properties of eleven Pythium strains and their impact on plant metabolism. Our results showed that even closely related P. oligandrum strains significantly differ in the content of compounds secreted into the medium, including proteins, amino acids, tryptamine, and hydrolytic enzymes capable of degrading cell walls (endo-β-1,3-glucanase, chitinase, and cellulase),...
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Biological control of plant pathogens
Chudý, Michal ; Ryšlavá, Helena (advisor) ; Müller, Karel (referee)
Heat shock proteins (HSPs) play a major role in protecting cellular proteins, acting as chaperones, preventing aggregation of partially damaged molecules, and help the protein repack, repair and create its right three-dimensional structure. Their synthesis occurs mainly during the stress state of the cell or the whole plant. Biotic forms of stress induce the expression of pathogenesis-related proteins (PRs), which are often characterized by enzyme activity, such as glucanases, chitinases and peroxidases. In this work, the effect of infection with fungal pathogens Alternaria brassicicola and Verticillium longisporum on the content of HSP70, HSP90 and PR-1, PR-2, PR-3 was followed in the tomato plants (Solanum lycopersicum L. cv. Micro-Tom) and rapeseed plants (Brassica napus subsp. oleifera). The seeds were treated with isolates of oomycete Pythium oligandrum, which is one of the unique and commercially available biological control agents. HSPs and PRs proteins were detected immunochemically on a nitrocellulose membrane. Immunochemical analysis showed the interaction of primary antibodies against HSP70 and HSP90 with low relative molecular weight proteins. Infection with Alternaria brassicicola and Verticillium longisporum increased the representation of 33 kDa - 43 kDa proteins. Seed treatment with...
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