|
|
Effect of dihydromyricetin on hepatic ethanol metabolism
Boubínová, Gabriela
Dihydromyricetin (DMH) is a natural flavonoid compound with positive effects on the human organism. In traditional Chinese medicine, plants containing DMH were used to treat liver diseases and to reduce alcohol intoxication. The effects of DHM on ethanol metabolism are not yet completely understood. Effects of DHM during alcohol intoxication were studied on primary hepatocytes of rats. DCFDA and DHR probes were used to prove that DHM (depending on concentration) reduces the number of reactive oxygen and nitrogen species in primary hepatocytes. However, the hepatoprotective effects of DHM were not achieved when presence of the alanine aminotransferase (ALT) was used to measure the damage of cells exposed to alcohol. Further, the effects of DHM on alcohol metabolism were studied in vivo. Rats were administered with single dose of ethanol or ethanol combined with DHM. Measured blood levels of ethanol and acetaldehyde show that DHM has no effects on the rate or levels of alcohol metabolism. The effects of DHM were also studied with repeated alcohol administration. In the group that was administered also DHM, increased blood levels of ethanol were measured. This points that DHM slow down the metabolic rate of ethanol. Obtained results did not prove any positive effects of DHM on alcohol metabolism....
|
|
|
Biological effects of edible algae.
Vaňková, Kateřina
Nutritional factors with antioxidant properties, such as those contained in edible algae or green plants, might be implicated in protection against cancer development. Chlorophyll and other tetrapyrrolic compounds, structurally related to heme and antioxidant bile pigment bilirubin, belong to important candidate molecules, which might be responsible for these effects. Based on our studies demonstrating antiproliferative effects of S. platensis edible alga extract on experimental model of human pancreatic adenocarcinoma we investigated in detail the effect of chlorophyll occurring abundantly in this alga. Since only scarce data exist on the antiproliferative effects of chlorophylls, the aim of our study was to assess these effects. The study was performed on experimental models of human pancreatic and prostate cancer. The inhibitory effects of chlorophylls (chlorophyll a, chlorophyll b, chlorophyllin and pheophytin a) on cell proliferation and cell viability were investigated in in vitro studies. Chlorophylls reduced the mRNA expression as well as activity of hemeoxygenase in tested pancreatic cancer cells. Simultaneously, chlorophylls played an important role in redox environment of studied cancer cell lines including modulation of mitochondrial membrane potential, reactive oxygen species (ROS)...
|
|
|
Myocardial tolerance to ischemia/reperfusion injury - possible protective mechanisms
Alánová, Petra
Ischemic heart disease is the leading cause of death and disability worldwide. The effects of ischemic heart disease are usually attributable to the detrimental effects of acute myocardial ischemia/reperfusion (I/R) injury. The aim of the thesis was to contribute to current effort to clarify the basis of mechanisms that could save the heart from I/R injury. The whole thesis is based on four studies; while the first three are published, the fourth one has been under revision. In the first study, we proved the involvement of nitric oxide (NO) in the cardioprotective mechanism of chronic hypoxia (CH). We described that exogenously increased availability of NO as well as inhibition of phosphodiesterase type 5 led to increased myocardial tolerance of normoxic and chronically hypoxic rats. The effects of both interventions were not additive, suggesting that NO is included in cardioprotective signaling of CH. Second study continued in investigating molecular mechanisms underlying cardioprotection induced by CH. We showed that infarct size-limiting effect of adaptation to CH was accompanied by increased myocardial concentration of tumor-necrosis factor alpha (TNF-α) and TNF-α receptor R2. In the third study, we examined the effect of dexrazoxane (DEX), the only clinically approved drug against...
|
|
|
Changes in anatomy of coniferous needles in response to anthropogenic pollution
Štěpánová, Kristýna ; Albrechtová, Jana (advisor) ; Votrubová, Olga (referee)
The anatomical structure of conifer needles is affected by external enviromental conditions. From abiotic factors, apart of irradiation, main determining factors are drought and extreme temperatures belonging to factors of climate change. Anthropogenic pollution has a significant position among the external abiotic factors that cause changes in the structure of needles. At present, the main polluting compounds are tropospheric ozone, SO2, NOx and PM. Due to the effect of atmospheric pollutants, the proportion of individual tissues in the needle changes, so does the proportion of intercellular spaces and the internal structure of cellular organelles, especially chloroplasts. Mesophyll cells show signs of degradation, especially around the substomatal cavity. There appears a visible damage on the needle surface - chloroses and necroses. The process of senescence speeds up during the activity of stress enviromental factors, such as anthropogenic pollution. The main objective of the present Thesis is to gather knowledge about changes of conifer needle structure, caused by anthropogenic pollution, especially ozone, SO2 and NOx, in combination with climate change factors - drought and extreme temperatures. The review is focused on modifications on various anatomic hierarchical levels, from visible...
|
|
|
Effect of dihydromyricetin on hepatic ethanol metabolism
Boubínová, Gabriela ; Hodek, Petr (advisor) ; Bebová, Michaela (referee)
Dihydromyricetin (DMH) is a natural flavonoid compound with positive effects on the human organism. In traditional Chinese medicine, plants containing DMH were used to treat liver diseases and to reduce alcohol intoxication. The effects of DHM on ethanol metabolism are not yet completely understood. Effects of DHM during alcohol intoxication were studied on primary hepatocytes of rats. DCFDA and DHR probes were used to prove that DHM (depending on concentration) reduces the number of reactive oxygen and nitrogen species in primary hepatocytes. However, the hepatoprotective effects of DHM were not achieved when presence of the alanine aminotransferase (ALT) was used to measure the damage of cells exposed to alcohol. Further, the effects of DHM on alcohol metabolism were studied in vivo. Rats were administered with single dose of ethanol or ethanol combined with DHM. Measured blood levels of ethanol and acetaldehyde show that DHM has no effects on the rate or levels of alcohol metabolism. The effects of DHM were also studied with repeated alcohol administration. In the group that was administered also DHM, increased blood levels of ethanol were measured. This points that DHM slow down the metabolic rate of ethanol. Obtained results did not prove any positive effects of DHM on alcohol metabolism....
|
|
|
The role of NADPH oxidase in architecture and function of β cells and Langerhans Islets
Tučková, Štěpánka ; Plecitá, Lydie (advisor) ; Bardová, Kristina (referee)
Local production of reactive oxygen species (ROS) and changes in the redox environment influence the metabolism and function of β cells of the Langerhans islets (LO). Changing the ratio between NAD(P)H / NAD(P)+ redox partners significantly affects sensitive proteins and ROS production. ROS are able to reversibly modify some amino acid residues (eg Cys, Met) of antioxidant enzymes and their interaction partners. Such a signaling cascade allows the transmission of a signal over longer distances and can also interfere with the influence of gene expression. The unique enzyme NADPH oxidase 4 (NOX4) is present on membranes within β cells and constitutively produces H2O2 depending on the presence of NAD(P)H. After glucose stimulation, both NAD(P)H and Nox4 mRNA levels increase. As previously observed in our laboratory, C57BL/6J mice with a specific Nox4 deletion in β cells have a disrupted biphasic insulin release and exhibit insulin resistance in fat and muscle tissue. We found that the absence of NOX4 in C57BL/6J mice affects LO architecture. Wildtype (WT) mice on a normal, predominantly carbohydrate diet (ND) have the majority of small LO with an area of up to 5 000 μm2 (measured on histological sections). High-fat diet (HFD) feeding of WT for 8 weeks leads to the development of diabetic phenotype and...
|
|
|
Oxidative stress in pathogenic amoebae
Plíva, Jan ; Šuťák, Róbert (advisor) ; Smutná, Tamara (referee)
Reactive oxygen species are substances that contain an atom of oxygen with an unpaired electron. This substance is highly reactive thanks to that unpaired electron. Organisms are capable of utilizing this reactivity in a lot of reactions. Cells can create reactive oxygen species as a by-product of aerobic respiration or by the action of enzymes such as NADPH oxidase. Reactive oxygen species play a crucial role in host defense against parasitic organisms. During host defense, parasitic organisms are destroyed by immune cells utilizing oxygen species. These reactions are in place also in the case of infection caused by pathogenic amoebae. Amoebae are eukaryotic unicellular organisms that are in some cases capable of causing serious illnesses. During the infections, amoebae must be able to bypass the host immune system, thus reactive oxygen species. This is accomplished by parasitic detoxification systems which helps pathogenic amoebae to overcome oxidative stress induced by reactive oxygen species. However, pathogenic amoebae are also capable of using reactive oxygen species to overcome the host immune system. This fact only confirms how tangled and complicated is the effect of reactive oxygen species during an interaction between the host organism and parasite.
|
|
|
Role of carbohydrate metabolism in defence against oxidative stress induced by arsenic
Kofroňová, Monika ; Lipavská, Helena (advisor) ; Száková, Jiřina (referee) ; Kovalíková, Zuzana (referee)
Heavy metal contamination significantly reduces crop yields, causing serious problems in agriculture and having a major impact on human health if these contaminants enter the food chain. Understanding the mechanisms of plant responses could help to increase their resistance to heavy metals as well as their potential use in phytoremediation. Carbohydrates play an important role in plant growth and development as well as in defense reactions. This work summarizes the results of four publications focused on the effects of arsenic and thorium on antioxidant mechanisms in tobacco plants and horseradish root crops. Attention is paid, among other things, to the dynamics of sugar contents, which are potentially important molecules involved in the fight against oxidative stress. The first publication summarizes arsenic effects on plant physiological parameters, focusing on arsenic tolerance-enhancing mechanisms as well as summarizing the ability of plants to cope with arsenic-induced oxidative and nitrosative stress. Emphasis was placed on, among other things, a topic that was unjustly neglected in previous publications - i.e. carbohydrate metabolism. Further work was already experimental and dealt with the study of arsenic as a trigger of oxidative stress in the root culture of horseradish and...
|
|
|
Biological effects of edible algae.
Vaňková, Kateřina
Nutritional factors with antioxidant properties, such as those contained in edible algae or green plants, might be implicated in protection against cancer development. Chlorophyll and other tetrapyrrolic compounds, structurally related to heme and antioxidant bile pigment bilirubin, belong to important candidate molecules, which might be responsible for these effects. Based on our studies demonstrating antiproliferative effects of S. platensis edible alga extract on experimental model of human pancreatic adenocarcinoma we investigated in detail the effect of chlorophyll occurring abundantly in this alga. Since only scarce data exist on the antiproliferative effects of chlorophylls, the aim of our study was to assess these effects. The study was performed on experimental models of human pancreatic and prostate cancer. The inhibitory effects of chlorophylls (chlorophyll a, chlorophyll b, chlorophyllin and pheophytin a) on cell proliferation and cell viability were investigated in in vitro studies. Chlorophylls reduced the mRNA expression as well as activity of hemeoxygenase in tested pancreatic cancer cells. Simultaneously, chlorophylls played an important role in redox environment of studied cancer cell lines including modulation of mitochondrial membrane potential, reactive oxygen species (ROS)...
|
|
|
Přítomnost singletového kyslíku v povrchových vodách
KOVAŘÍKOVÁ, Michaela
This master thesis deals with the methods of measurement of singlet oxygen steady state concentrations in surface water and the factors affecting this concentration. The first part of this work shows theoretical background and an introduction to photochemistry of surface water with respect to the reactive oxygen species. The second part describes the methodology of conducted experiments and discuss its results with respect to current literature.
|
guest ::
