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Regulation of VLDL production in the liver
Jirátová, Markéta ; Kovář, Jan (advisor) ; Cahová, Monika (referee)
The aim of this thesis is to summarize current knowledge about VLDL (very low density lipoprotein) assembly. In the first part of this thesis basic characteristics of lipids and lipoproteins are described. Lipids are the most favourable source of energy for animals. Lipoproteins are the macromolecular complexes that transport hydrofobic lipids in plasma. According to their density, they are classified to five groups: chylomicrons, VLDL, IDL, LDL, HDL. Second part of this thesis is focused on the apolipoproteins - structural peptide components of lipoproteins. The characteristics and functions of major apolipoprotein classes are explained with the main focus on apolipoproteins B that have an important role in VLDL assembly. The process of VLDL assembly is described in detail in the third part of the thesis. VLDL assembly consists of two steps. Pre-VLDL and lipid droplet are synthetized independently in the first step, for which apolipoprotein B-100 and microsomal triglyceride transfer protein (MTP) are essential. Second step is the fusion of pre-VLDL with the lipid droplet. ADP-ribosylation factor 1 (ARF1) and phospholipase D (PLD) are the essential components in the second step. Also apolipoprotein E, apolipoprotein A-V and acyl-coenzym A:cholesterol acyl transferasa 2 (ACAT2) are important. VLDL...
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Function of phospholipases D and lipid phosphate phosphatases in the regulation of plant cell morphogenesis
Bezvoda, Radek ; Žárský, Viktor (advisor) ; Hašek, Jiří (referee) ; Vaňková, Radomíra (referee)
of the thesis The presented work explores the function and regulation of intracellular signaling that utilizes phospholipase D (PLD) and phosphatidic acid (PA), especially in the context of cellular morphogenesis of plants. PLDs cleave membrane phospholipids to phosphatidic acid, which has important biophysical and signaling role in many contexts, such as stress response, regulation of cytoskeletal dynamics and vesicular transport. Vesicular transport is essential in focused tip growth of plant pollen tubes and root hairs. Part of the work deals with NADPH oxidases, that are an emerging counterpart of PLD/PA signaling. Tobacco pollen tubes served as the main experimental model, as it enables assessing of changes in secretory pathway after pharmacological or genetic treatments. A technique utilizing antisense oligonucleotides was used for selective knock-down of PLD isoforms, NADPH oxidase and newly studied family of lipid phosphate phosphatases (LPPs) in pollen tubes. This enabled to assess functions of individual isoforms. For studying of selected gene families, various bioinformatic tool were utilized, such as dendrogram construction, analysis of available expression data and creating of virtual proteome. These tools together enabled to select potentially important genes for further experimental...
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Function of phospholipases D and lipid phosphate phosphatases in the regulation of plant cell morphogenesis
Bezvoda, Radek ; Žárský, Viktor (advisor) ; Hašek, Jiří (referee) ; Vaňková, Radomíra (referee)
of the thesis The presented work explores the function and regulation of intracellular signaling that utilizes phospholipase D (PLD) and phosphatidic acid (PA), especially in the context of cellular morphogenesis of plants. PLDs cleave membrane phospholipids to phosphatidic acid, which has important biophysical and signaling role in many contexts, such as stress response, regulation of cytoskeletal dynamics and vesicular transport. Vesicular transport is essential in focused tip growth of plant pollen tubes and root hairs. Part of the work deals with NADPH oxidases, that are an emerging counterpart of PLD/PA signaling. Tobacco pollen tubes served as the main experimental model, as it enables assessing of changes in secretory pathway after pharmacological or genetic treatments. A technique utilizing antisense oligonucleotides was used for selective knock-down of PLD isoforms, NADPH oxidase and newly studied family of lipid phosphate phosphatases (LPPs) in pollen tubes. This enabled to assess functions of individual isoforms. For studying of selected gene families, various bioinformatic tool were utilized, such as dendrogram construction, analysis of available expression data and creating of virtual proteome. These tools together enabled to select potentially important genes for further experimental...
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The role of PLD in early phases of aluminium toxicity
Poláková, Lucie ; Schwarzerová, Kateřina (advisor) ; Malínská, Kateřina (referee)
Aluminium toxicity is the main limiting factor in crop production on acid soils. The main symptom of aluminium toxicity is a rapid inhibition of root growth, but the mechanism of root growth cessation remains unclear. In this diploma thesis we deal with the question of whether phospholipases PLDα1 and PLDδ may play a role in the mechanism of aluminium toxicity. We compared the responses of plants lacking PLDα and PLDδ with WT plants. Growth analysis of roots was performed in hydroponic conditions. The most sensitive part of roots was transient zone in which cells were dying earlier. It was further found that pldα1 plants were less sensitive on aluminium toxicity because their roots showed less growth inhibition than WT. Pldδ plants did not differ from WT plants in their response to aluminum. During further analysis of the pldα1 reactions, it was found that the root cells were capable of cell expansion during aluminum toxicity, and the cellular malformations were formed on the roots. This phenomenon was associated with faster reorientation and even depolymerization of cortical microtubules in response to toxic aluminium in pldα plants compared to WT plants. The results indicated that PLDα1 molecule affects the stability of cortical microtubules. Microtubules were less stable and they depolymerized...
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Regulation of VLDL production in the liver
Jirátová, Markéta ; Kovář, Jan (advisor) ; Cahová, Monika (referee)
The aim of this thesis is to summarize current knowledge about VLDL (very low density lipoprotein) assembly. In the first part of this thesis basic characteristics of lipids and lipoproteins are described. Lipids are the most favourable source of energy for animals. Lipoproteins are the macromolecular complexes that transport hydrofobic lipids in plasma. According to their density, they are classified to five groups: chylomicrons, VLDL, IDL, LDL, HDL. Second part of this thesis is focused on the apolipoproteins - structural peptide components of lipoproteins. The characteristics and functions of major apolipoprotein classes are explained with the main focus on apolipoproteins B that have an important role in VLDL assembly. The process of VLDL assembly is described in detail in the third part of the thesis. VLDL assembly consists of two steps. Pre-VLDL and lipid droplet are synthetized independently in the first step, for which apolipoprotein B-100 and microsomal triglyceride transfer protein (MTP) are essential. Second step is the fusion of pre-VLDL with the lipid droplet. ADP-ribosylation factor 1 (ARF1) and phospholipase D (PLD) are the essential components in the second step. Also apolipoprotein E, apolipoprotein A-V and acyl-coenzym A:cholesterol acyl transferasa 2 (ACAT2) are important. VLDL...
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