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Biochemical aspect of investigation of the natural-origin binders and varnishes in the paint layer of old paintings
Pecháčková, Soňa ; Hudeček, Jiří (advisor) ; Kubíčková, Božena (referee)
The subject of this work are choosen bioanalytical methods, used for the identification of organic binders and varnishes in coloured layer of ancient paintings. In the past, the plant and animal substances were used as a binders and varnishes. To those materials belong proteins, oils, polysacharide gums and resins. Succesful analysis in the history of using binders and varnishes demands a good knowledge of their chemical qualities and reactivity during the process of aging. Nowadays are prefered the methods and technics, which don?t destruct the sample and which are non-invasive towards the whole artwork. Recently, the imunofluorescence technics have been started to use as the alternative methods of classical and easier microchemical tests. The spectroscopic methods are widely used in material investigation of ancient artworks. The main is infrared spectometry (FTIR) and Raman spectroscopy. The methods of nuclear magnetic resonance are significant mainly for studying changes of connective and isolating material during the process of aging. To indentify mainly protein binders, the technic of mass spectrometry (MALDI-TOF) is widely used. Due to the progress of technic the paper and thin-layer chromatography were replaced by very effective high performance liquid chromatography (HPLC), gas chromatography (GC)...
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Potenciální využití WIP1 fosfatasy v terapii nádorového onemocnění prsu
Pecháčková, Soňa ; Macůrek, Libor (advisor) ; Souček, Pavel (referee) ; Krejčí, Lumír (referee)
Cells in our body respond to genotoxic stress by activation of a conserved DNA damage response pathway (DDR). Depending on the level DNA damage, DDR signaling promotes temporary cell cycle arrest (checkpoint), permanent growth arrest (senescence) or programmed cell death (apoptosis). Checkpoints prevent progression through the cell cycle and facilitate repair of damaged DNA. DDR represents an intrinsic barrier preventing genome instability to protect cells against cancer development. WIP1 (encoded by PPM1D) phosphatase is a major negative regulator of DDR pathway and is essential for checkpoint recovery. This thesis contributed to the understanding of molecular mechanisms of WIP1 function and revealed how WIP1 can be involved in tumorigenesis. Firstly, we described that WIP1 protein levels decline during mitosis by APC-Cdc20 dependent proteasomal degradation. WIP1 is phosphorylated at multiple residues which inhibit its enzymatic activity. We propose that inhibition of WIP1 in mitosis allows sensing of low levels of DNA damage that appear during unperturbed mitosis. Further, we identified novel gain-of-function mutations of PPM1D which result in expression of C-terminally truncated WIP1. These truncated WIP1 variants are enzymatically active and exhibit increased protein stability. As result, cells...
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Potenciální využití WIP1 fosfatasy v terapii nádorového onemocnění prsu
Pecháčková, Soňa ; Macůrek, Libor (advisor) ; Souček, Pavel (referee) ; Krejčí, Lumír (referee)
Cells in our body respond to genotoxic stress by activation of a conserved DNA damage response pathway (DDR). Depending on the level DNA damage, DDR signaling promotes temporary cell cycle arrest (checkpoint), permanent growth arrest (senescence) or programmed cell death (apoptosis). Checkpoints prevent progression through the cell cycle and facilitate repair of damaged DNA. DDR represents an intrinsic barrier preventing genome instability to protect cells against cancer development. WIP1 (encoded by PPM1D) phosphatase is a major negative regulator of DDR pathway and is essential for checkpoint recovery. This thesis contributed to the understanding of molecular mechanisms of WIP1 function and revealed how WIP1 can be involved in tumorigenesis. Firstly, we described that WIP1 protein levels decline during mitosis by APC-Cdc20 dependent proteasomal degradation. WIP1 is phosphorylated at multiple residues which inhibit its enzymatic activity. We propose that inhibition of WIP1 in mitosis allows sensing of low levels of DNA damage that appear during unperturbed mitosis. Further, we identified novel gain-of-function mutations of PPM1D which result in expression of C-terminally truncated WIP1. These truncated WIP1 variants are enzymatically active and exhibit increased protein stability. As result, cells...
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Lipidic binders in artworks: possible identification of the used drying oils by liquid chromatography
Pecháčková, Soňa ; Hudeček, Jiří (advisor) ; Kubíčková, Božena (referee)
This work is concerned with lipidic substances, in particular vegetable oils, used as pigment binders or as a protective varnishes for finishing artwork. The introduction reviews the recent knowledge of this subject, in particular with respect to the identification of the most used drying oils, and of the methods to study their changes in the course of time. Both can be achieved using determination of the relative representation of fatty acids, most characteristic being the ratio of stearic/palmitic a oleic/palmitic acids. This parameter is changing as the artwork is getting older and the oils are drying. Because of the availability of the instrumentation needed, we have chosen the high- performance liquid chromatography method for further experimental work. The first step was optimalization of the analytical method by standards of fatty acids. For derivatization of fatty acids, reagents 2,4-dinitrophenylhydrazine and 2-nitrophenylhydrazine were examined. Whereas we were unable to get any results with the first one (the method based on the article: Bravo, B. et al., Talanta 64, 1329-1334, 2004) for unknown reasons, good results were obtained with the second one. Derivates of fatty acids have been analyzed by high performance liquid chromatography (HPLC) on column with revesed phase (C18). The...
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Biochemical aspect of investigation of the natural-origin binders and varnishes in the paint layer of old paintings
Pecháčková, Soňa ; Kubíčková, Božena (referee) ; Hudeček, Jiří (advisor)
The subject of this work are choosen bioanalytical methods, used for the identification of organic binders and varnishes in coloured layer of ancient paintings. In the past, the plant and animal substances were used as a binders and varnishes. To those materials belong proteins, oils, polysacharide gums and resins. Succesful analysis in the history of using binders and varnishes demands a good knowledge of their chemical qualities and reactivity during the process of aging. Nowadays are prefered the methods and technics, which don?t destruct the sample and which are non-invasive towards the whole artwork. Recently, the imunofluorescence technics have been started to use as the alternative methods of classical and easier microchemical tests. The spectroscopic methods are widely used in material investigation of ancient artworks. The main is infrared spectometry (FTIR) and Raman spectroscopy. The methods of nuclear magnetic resonance are significant mainly for studying changes of connective and isolating material during the process of aging. To indentify mainly protein binders, the technic of mass spectrometry (MALDI-TOF) is widely used. Due to the progress of technic the paper and thin-layer chromatography were replaced by very effective high performance liquid chromatography (HPLC), gas chromatography (GC)...
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