|
|
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...
|
|
|
Changes of the intracellular redox state during virus infections
Kompas, Maroš ; Mělková, Zora (advisor) ; Trejbalová, Kateřina (referee)
Viruses are infectious agens, which cause disruption of a host cellular redox homeostasis. This effect is mediated by cellular defense machinery or via viral gene products. In order to restore cellular redox enviroment, activation of cellular adaptive response takes place. That is mediated by transcription factor Nrf2, which leads to upregulation of gene expression of antioxidant enzymes. Under suboptimal redox condition, or by detecting foreign nucleic acid, redox sensitive transcription factor Nf-κB is also being activated, what leads to expresion of proteins mediating cellular imunne responses. It is important to remember that these proteins might show malignant effects to surrounding tissues during long term inflammations. With respect to that, viruses have evolved mechanisms, through which they are able to overcome or hijack these pathways, in order to propagate the infection. Key words: intracellular redox state, ROS, RNS, oxidative stress, antioxidant enzymes, regulation of gene expression, virus infections
|
|
|
The role of oxidative stress in etiology of Alzheimer's disease
Šuláková, Anna ; Novotný, Jiří (advisor) ; Randáková, Alena (referee)
Oxidative stress is the result of an imbalance between the formation of reactive oxygen species and the ability of the body to detoxify these free radicals. As a result of this disbalance, harmful substances, especially peroxides and free radicals, accumulate in the body, resulting in damage of proteins, lipids and DNA leading to total cell destruction and necrosis. For this reason, oxidative stress contributes to the development of many serious diseases including atherosclerosis, many types of cancer, heart failure or neurodegenerative diseases such as Parkinson's disease, multiple sclerosis and Alzheimer's disease. Alzheimer's disease is a chronic neurodegenerative disease whose risk increases with age. It is an incurable disease affecting an ever increasing number of patient. Early AD symptoms include disorientation, loss of short-term memory, mood swings and problems with expression of thoughts. The causes of AD have not yet been fully clarified but there are speculations about importance of the role of tau-proteins and -amyloid plaques that form in AD progression. Oxidative stress can also play an important role, and may participate in the development of this disease. This work focuses mainly on the role of oxidative stress in pathophysiology and progression of AD. Key words:...
|
|
|
Vliv oxidačního stresu na telomery u \kur{Drosophila melanogaster}
HEROUTOVÁ, Barbora
There is a balance between production of free radicals and their degredation by antioxidation mechanisms. Free radicals play roles in numerous fyziological functions like immune reactions or detoxification processes. However, overabundance of free radicals, may causes a significant damage of cell structures, including telomeres. Telomeres are terminal sections of eukaryote chromosomes with a number of vital cellular functions. Telomeres are damaged and shortened by free radicals.
|
|
|
Analysis of oxidative stress markers in rat brain: the effect of maternal separation
Pallag, Gergely ; Novotný, Jiří (advisor) ; Vodička, Martin (referee)
Adverse events that cause stress during the early stages of life may alter the normal development of the brain and neuroendocrine system and increase the vulnerability of the individual to various disorders. Chronic stress and subsequent releasing of stress mediators can lead to oxidative stress and cell damage. The first aim of this work was to determine selected oxidative stress markers in the cerebral cortex, hippocampus, and cerebellum after the exposure of rats to early life stress. To model the stressful situation, we used maternal separation of the offspring for three hours a day during the first three weeks of life. We choose reduced glutathione, protein carbonyls, lipid peroxides and hydroperoxides as typical markers. These markers were determined in the brains of rats aged 22 days. Any significant changes were found in the levels of the studied markers after maternal separation. Damage to brain cells may also be reflected in behavior. Studies of numerous neuropsychiatric and neurodegenerative diseases have indicated that oxidative stress is a promising candidate for inducing changes at the cellular level. The second aim of this work was to monitor the behavior of rats by the light/dark box test after maternal separation along with administration of N-acetylcysteine (NAC), a drug with...
|
|
|
Vliv triazinových pesticidů a jejich metabolitů na necílové vodní organizmy
KOUTNIK, Dalibor
Pesticides used in agro-ecosystems and forests enter aquatic environments such as streams, rivers, and lakes if applied in adjacent areas or if an accidental spill occurs. For the studies, we chose the early life stages of common carp (Cyprinus carpio L.) and marbled crayfish (Procambarus fallax f. virginalis). In selected organisms, we observed long-term effect of triazine herbicides (prometryne, terbuthylazine, metribuzine) and their metabolites (terbuthylazine-desethyl and tebuthylazine-2-hydroxy) in concentrations commonly occurring in Czech rivers. The first part is about monitoring the effects of triazines (prometryne, terbuthylazine) on the early development stages of carp and marble crayfish. Subchronic prometryne exposure of early-life stages of common carp at concentrations of 1 200 and 4 000 ?g/L affected their survival, growth rate, early ontogeny, and histology. Terbuthylazine in concentration 1 400 and 3 000 ?g/L caused significant decrease of mass, total length, delayed in development and cause of alternation of tubular system of caudal kidney of carp. Prometryne in concentration 144, 1 444 and 4 320 ?g/L caused decrease of weight, specific growth rates and caused histopathological changes in gill of crayfish. Moreover concentration 4 320 ?g/L of prometryne caused delay in ontogenetic development of crayfish. Second part of the work has included effects of low concentrations of metabolites (terbuthylazine-desethyl and tebuthylazine-2-hydroxy) on the early development stages of carp and marble crayfish. Chronic terbuthylazine-desethyl exposure in concentrations 180, 900, and 1 800 ?g/L affected growth, ontogenetic development, and the antioxidant system and caused pathological changes in the caudal kidney of early life stages of carp. Chronic terbuthylazine-2-hydroxy exposure in concentrations 2.9, 70, 1 400 and 3 500 ?g/L caused decreased of total superoxide dismutase activity of early life stages of carp. Moreover concentration 1 400 and 3 500 ?g/L of terbuthylazine-2-hydroxy caused delay in ontogenetic development and pathological changes in the caudal kidney of carp. Chronic terbuthylazine-2-hydroxy exposure in concentrations up 75 ?g/l affected growth, ontogenetic development, antioxidant system, caused oxidative stress and pathological changes in hepatopancreas of early life stages of marbled crayfish. The last part of our study examined the effect of metribuzine on signal crayfish (Pacifastacus leniusculus Dana). Crayfish were exposed to metribuzine concentrations of 0.52 ?g/L and 3.06 mg/L for 30 days and a 30-day depuration period. In the thiobarbituric acid reactive substances, superoxide dismutase, and catalase were observed differences in all examined tissues (gill, muscle, hepatopancreas) compared to the control group. Differences from control were observed in glutathione reductase activity in hepatopancreas after 10 days for both exposure concentrations and after 30 days at 3.06 mg/L. Histological examination revealed extensive focal autolytic disintegration of tubular epithelium in hepatopancreas of crayfish exposed to metribuzin. These studies provided important results for the evaluation of long-term impact and effect of (prometryne, terbuthylazine and metribuzine) and their metabolites (terbuthylazine-desethyl and tebuthylazine-2-hydroxy) on the water non-target organisms, even in real concentrations founded in surface waters.
|
|
|
The effect of acute cold and permanent light to left ventricular of the rat heart
Vítková, Ivana ; Žurmanová, Jitka (advisor) ; Bendová, Zdeňka (referee)
Acute cold exposure increases the risk of sudden cardiac events, similarly exposure to constant light negatively affects the cardiovascular system. However, the individual effects of these factors and the effect of their combination on cardiomyocytes are not yet known. The thesis deals with the influence of a 3 day cold exposure and constant light on the expression of β-adrenergic receptors and associated G-proteins in association with apoptotic signals in the left ventricle of the Wistar rat heart. In this work apoptotic proteins BAX, BCL2, caspase 8 and important components of β-adrenergic signalization - β1, β2, G-proteins, Gas, Gi1/2 and Gi3 were determined. The relative expression of the proteins was analyzed by Western blotting. The results confirm the detrimental effect of cold and light exposure. However, the synergistic effect of these two stressors shows surprising results.
|
|
|
Effect of chronic morphine on cell survival after oxidative stress in the SH-SY5Y neuroblastoma cell line
Moutelíková, Karolína ; Hejnová, Lucie (advisor) ; Musílková, Jana (referee)
Morphine is a natural opioid which is used in medicine due to his potent analgesic and sedative effects. In the forefront of scientific interest is a chronic usage of opioids which can lead to a development of drug addiction. Morphine role in oxidative stress was described in last years. It was revealed its protective potencial by many studies. However, some studies described its pro-oxidative effect. The aim of this study was to determinate effect of chronic morphine on cell survival after oxidative stress caused by H202 analog - tBHP in the SH-SY5Y neuroblastoma cell line. The results verified morphine protective effect against oxidative stress. The highest protective effect of morphine was achieved in a concetration of 10 µM. It was desribed that morphine can induce activation of mu-opioid (MOR) and Toll-like 4 (TLR4) receptors signalling pathway on molecular level. The aim of this thesis was to evaluate the role of MOR a TLR4 in protective effect of morphine against oxidative stress by two methods. Firstly, it was used tests of oxidative stress on cell viability. The obtained results demonstrated majority role of TLR4 and minory role of MOR. Afterwards, we assesed changes in the expression of MOR a TLR4 after chronic morphine by SDS-PAGE electrophoresis. Results of these experiments did not...
|
|
|
Oxidative stress in bacteria - with an emphasis on the model organism of Escherichia coli
Moravcová, Andrea ; Lichá, Irena (advisor) ; Čáp, Michal (referee)
Most bacterial species encounter aerobic conditions during their life, which can be toxic. This leads to a state of oxidative stress. Toxicity of aerobic environment results from the chemical properties of molecular oxygen and its reactive species (ROS). Bacteria had to adapt to these conditions in the past to ensure preservation and prosperity. This thesis is preferably focused on oxidative stress adaptations in the most elaborated bacterial model - Escherichia coli. Regulation of adaptations at the regulation of transcription, translation and metabolism level are described with emphasis on molecular mechanisms. The main adaptation mechanism against oxidative stress is the deactivation of ROS, as well as the repair of damaged cell structures (macromolecules). These enzyme activities are regulated by several transcriptional regulators. The transcriptional regulators OxyR and SoxRS have been well studied in E. coli. Even though these regulators are conserved across the bacterial spectrum, they may not have the same function in all organisms. For this reason, also other, more or less studied bacterial species - Bacillus subtilis, Streptomyces coelicolor, Pseudomonas putida, Pseudomonas aeruginosa - were included in this thesis. The various strategies of how these bacteria use not only OxyR and SoxRS...
|
|
|
Leaf structural changes induced by tropospheric ozone.
Češpírová, Zdeňka ; Lhotáková, Zuzana (advisor) ; Hála, Michal (referee)
Tropospheric ozone is an important pollutant formed by the photochemical reactions of ultraviolet radiation and nitrogenous. Recently, its concentration in the air is increasing due to the promoting climate change and antropogenic activities, mainly because of combustion of the fossil fuels. The ozone is highly reactive molecule degrading to the reactive oxygen species having negative effects on the leaf physiological functions and structure. Ozone penetrates the leaf through the stomata, thereafter it reacts with the cells and their singular compartments. The products formed due to ozone degradation are able to cause the disintegration of plasma membranes and other oxidative damage, for example accumulation of plastoglobuli inside the chloroplasts, changes in the shape of chloroplasts, mitochondria or peroxisomes. At the macroscopic level the visible lesions, chloroses and necroses are observed. In addition, the faster senescence of leaves is observed under the effect of ozone. The main aim of present thesis is to review knowledge of the ozone-induced changes in the leaf structure beginning on the cell structure level and ending at the whole plant body level and to explain physiological mechanisms leading to these damages. Key words: ozone, oxidative stress, leaf structure, mesophyll, reactive...
|
guest ::
