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The effect of cold adaptation on the immune system
Vašek, Daniel ; Krulová, Magdaléna (advisor) ; Filipp, Dominik (referee)
Maintaining energy homeostasis at reduced temperatures is essential for the survival of the organisms. In this diploma thesis, we determined the impact of cold stress and cold adaptation on the rat immune system. A number of different factors participate at the process of thermoregulation, but the adrenergic signalling plays a crucial role. The binding of norepinephrine to β-adrenergic receptors leads to the formation of brown adipose tissue, which is necessary for non-shivering thermogenesis, as well as for energy balance. Bioactive products of adipocytes subsequently modulate the immune system, this process is significantly influenced by signalling of nerve cells. In order to understand neuro-immune interaction during the cold adaptation, we monitored changes in immune cell populations and the production of soluble products in rats treated with specific inhibitors of β-adrenergic receptors. Relationship between the immune and nervous system seems to be very important in many biological processes. Deciphering basic mechanisms of the influence of cold adaptation on immune cells can therefore explain other clinically relevant topics, such as treatment of obesity. Key words: immune system, cold adaptation, norepinephrine, adrenergic receptor, cytokines, brown adipose tissue, non-shivering thermogenesis
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Energy metabolism and apoptotsis markers in cold heart aclimated rat.
Pospíšilová, Barbora ; Horníková, Daniela (advisor) ; Knytl, Martin (referee)
Cold adaptation and her effects has been known for many decates. Positive or negative impact depends especially on its length and strength. The lower temperature can very often cause the stress for organism. On the other hand in expreriment with long-term adapatation were found positive consequences on cardiovascular system. We found the lack of studies devoted to the energy metabolism and apoptosis in heart tissue during long-term cold adaptation. In this work we used a model with milder conditions of the adaptation (10žC±1), so there wouldn't be damage of the experimental animals. We compared the resuls betwen control, cold and regressive group of rats. In this expreriment we used methods of electrophoresis and Western blot. The target of the work was found if we can find any differences betwen chosen HIF targeted genes. The next goal was to detect the differences betwen chosen pro-apoptotic and anti-apoptotic markers. Keywords: cold adaptation, heart, energetic metabolism, HIF, apoptosis
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The effect of cold exposure on beta-adrenegic signaling in the rat myocardium
Podojilová, Anna ; Novotný, Jiří (advisor) ; Ujčíková, Hana (referee)
and keywords The aim of this work was to evaluate the effect on rat myocardial β-adrenergic system of short-term (10 hours and 3 days) and long-term (5 weeks) cold exposure of rats with possible subsequent two-week recovery at normal temperature. The subtypes of β-adrenergic receptors (β-AR), their cognate G-proteins and adenylate cyclase have been characterized. β-AR are important components of cardiac regulatory mechanisms. They are involved in stimulating G-protein (Gs) and adenylate cyclase to increase cardiac contractility and frequency during stressful situations, including cold exposure. Heart tissue contains all three β-AR subtypes (β1-AR, β2-AR, β3-AR). While β1-AR couples with only Gs, β2-AR and β3-AR interact with the inhibitory G-protein (Gi). Electrophoresis and Western blotting showed a significant increase in β1-AR after a three-day exposure to cold. There was also a significant increase in β3-AR concentrations after a five-week cold exposure and this increase lasted for two weeks. There were no significant changes in the amnounts of β-AR cognate G-proteins (Gαs, Gβ, Gαi1/2 a Gαi3). In contrast, expression of adenylyl cyclase isoform V and VI significantly decreased during short-term exposure to cold. Using the saturation experiment with the β-antagonist [3H]CGP 12177, β-AR were...
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Mitochondrial respiration at cold acclimated rats. Comparison of tissues.
Flégrová, Eliška ; Žurmanová, Jitka (advisor) ; Nováková, Olga (referee)
Acclimation to cold or hardening is known for many decades through its beneficial effects on human health. In contrast, sudden exposure to cold, cold shock, is a great risk of cerebral and cardiac injury, especially in the elderly. There is very little published data on the cellular and molecular mechanisms induced by cold adaptation in heart and brain. The aim of this work was to describe and compare different properties heart, liver, brain and brown adipose tissue mitochondria of rats housed at 25 ± 1 řC and at mild cold (9 ± 1 řC, 5 weeks). The high-resolution oxygraphy, spectrophotometry and Western blotting analyses were used. We found differences in the respiratory control between the heart and liver. Cold acclimation decreased activity of the Krebs cycle enzymes. Fatty acid contribution to the respiration reached the maximum in brown fat and the minimum in the hippocampus. However, further study is necessary.
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Cold adaptation of snow algae: the role of changes in the composition of fatty acids
Dřízhalová, Marie ; Nedbalová, Linda (advisor) ; Němcová, Yvonne (referee)
Snow algae as typical extremophiles are good model organisms for study of adaptation for life on the boundary of physiological possibilities. So far, it is not clear, how these microorganisms ensure on the molecular level the optimization of photosynthetic processes in conditions around 0 řC, often with very high light intensity. The aim of this work was to find out light and temperature growth optima of two less studied strains and to assess the composition of fatty acids in selected psychrophilic and psychrotrophic strains from the genera Chloromonas and Chlamydomonas (Chlamydomonadales, Chlorophyta) from culture collections UTEX and CCCryo and collections in Europe including the Czech Republic and Slovakia. Using crossed gradients method, this thesis describes optimal temperature and light conditions of two strains of snow algae isolated from sites in the Krkonoše Mountains that are characterized by different ecological conditions. The strain Chloromonas reticulata Luční originates from alpine zone and according to its growth characteristics, it can be classified as psychrotrophic alga requiring high light. The second tested strain was Chloromonas pichinchae Meandry from forest environment, which is also characterized as psychrotrophic, In contrast to previous strain, it grows in a wide range of...
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Ischemia-reperfusion injury in cold acclimated rats
Vebr, Pavel ; Žurmanová, Jitka (advisor) ; Alánová, Petra (referee)
The effect of cold acclimation on body of mammals has been studied for many decades by using relatively low temperatures for acclimation (6-10 řC). The results of these experiments have shown the important role of the adrenergic and thyroid system during acclimation and negative impact on renal system at the same time. In contrast, a recent study on winter swimmers suggests a possibility of positive influence of hardening on cardiovascular system. There is no available study investigating a relationship between cold adaptation and ischemia-reperfusion injury. The aim of this study was to establish a protocol of isolated rat heart and its fixation at our workplace. Furthermore, to find the impact of mild cold acclimation on the ischemia-reperfusion injury of rat. Methods of ex vivo heart perfusion and fixation were successfully established. The effect of 5 weeks long cold acclimation in 10 ± 2 řC on left ventricle ischemia-reperfusion injury was observed. Powered by TCPDF (www.tcpdf.org)
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The role of the adrenergic system in the process of cold acclimation
Dynybylová, Anna ; Novotný, Jiří (advisor) ; Brabcová, Iveta (referee)
The ability to keep constant body temperature is necessary for mammals. There are effective strategies developed during the evolution - shivering and nonshivering thermogenesis, which start during cold exposure. This thesis is focused on the nonshivering thermogenesis which occurs in brown adipose tissue and is controlled by norepinephrine released from the sympathetic nerves if the cold stress persists for a long time. The principle of the heat production is based on function of the uncoupling protein 1 which disrupts the proton gradient in mitochondria thereby releasing heat the waste product. Similar mechanism of energy dissipation is used not only during cold exposure but also after digestion of high fat diet, which may provide clues for potential therapeutic treatment of obesity and associated metabolic diseases. This study summarizes current knowledge about the role of adrenergic signalling in the process of cold acclimation. Key words: cold acclimation, nonshivering thermogenesis, brown adipose tissue, sympathetic nerve system, uncoupling protein 1 (UCP1), obesity
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Cardioprotection induced by changes in abiotic environmental factors
Kubátová, Hana ; Vybíral, Stanislav (advisor) ; Žurmanová, Jitka (referee)
Cardiovascular diseases are one of the most frequent causes of death worldwide. Methods of limiting the ischemia-reperfusion injury, which occurs as a result of acute myocardial infarction (MI), have therefore been receiving significant attention. Preconditioning through ischemia application, cold exposure or physical exercise reduces the size of an infarction and the occurrence of ventricular arrhythmias. The exact mechanism behind this process has not yet been fully comprehended; nevertheless important roles are played by factors such as the maintenance of calcium homeostasis, the opening of ATP-dependent potassium channels (KATP) and the prevention of the Mitochondrial Permeability Transition pore (MPTP) opening. Chronic hypoxia and exercise have also been proven to have a cardioprotective effect, which is to be at least partially attributed to the intensified activity of antioxidant enzymes and the opening of KATP. During winter the risk of MI is increased for a wide range of patients. In winter swimmers, the stress caused by a cold stimulus is reduced. However, a mild stress is necessary to initiating cardioprotection. At present, there is unfortunately insufficient information available regarding the effects of long term cold adaptation on the size reduction of MI. Some studies suggest,...
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Cold adaptation mechanisms in microorganisms
Dřízhalová, Marie ; Nedbalová, Linda (advisor) ; Kvíderová, Jana (referee)
On our planet there are vast areas, where the average temperature does not exceed 5 řC. They are also many places, where the temperature often drops below zero. Not every living organism is able to live in these conditions. The ability to survive in cold region and succefully colonize, such presumably adverse environment requires particular evolutionary adaptation. Adaptation to cold environments has evolved independently in different phylogenetic groups. In low temperature environments, organisms has to adapt in a complex way to be able to permanently inhabit these habitats. Since the analysis of cold adaptation in all organisms is a very complex topic, this thesis is focused on microorganisms. Within this group, it is possible to find certain, which are repeated also in unrelated taxa. The general mechanisms include changes in membrane composition, shifts of enzyme temperature optima, production of compounds that prevent the negative effects of low temperature or the formation of resting stages. This thesis summarizes the mechanisms of cold adaptation which have evolved in microorganisms as response to a long-term or temporary survival at low temperatures. Their potential biotechnological applications are also mentioned. keywords: psychrophilic, psychrotolerant, cold adaptation, enzymes,...
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