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Genome sequences of two Antarctic strains of Pseudomonas prosekii: insights into adaptation to extreme conditions
SNOPKOVÁ, Kateřina
Pseudomonas is ubiquitous bacterial genus with the high biotechnological potential. Pseudomonas prosekii is species recently described from James Ross Island (Antarctica). Although its endemic lifestyle could be assumed, its low-temperature adaptation mechanisms have not yet been described and understood. Therefore, we sequenced two P. prosekii strains and performed deep genome analysis with a special respect to the genes related to cold adaptation. We identified and analyzed the genes responsible for cold shock and oxidative stress response, osmoregulation, exopolysaccharide and siderophores production, and biofilm formation. Comparative genome analysis of P. prosekii and P. aeruginosa PAO1 highlighted differences in genome content between extremophile species and a mesophilic opportunistic pathogen.
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The role of cold acclimation in activation of adrenegic and thyrode signalling pathway in rat myocardium
Tibenská, Veronika
Despite advances in research and therapy, cardiovascular diseases are still the leading cause of death worldwide. A closer understanding of the endogenous protective mechanism may improve pharmacological interventions for the treatment of heart diseases. Cold acclimation or hardening has strong potential for reducing cardiovascular risk and the literature shows that it stimulates the β-adrenergic and thyroid systems in tissues. At the same time, the adrenergic system in the heart is one of the main regulators of cardiac activity. However, these signaling pathways have surprisingly not been studied at the protein level in the heart yet, and no studies can be found on the subject matter in current literature. Our results show a reduced infarct size induced by ischemic injury in cold-acclimated rats (CA) at 8 ř C for 5 weeks and then returning to normothermic conditions for 2 weeks (CAR). The aim of this dissertation is to determine, the degree of involvement of the adrenergic system in the myocardium during acclimation after 3 days, 10 days, 5 weeks of CA and subsequent CAR at the level of all three β-adrenergic receptor isoforms (β-ARs) and their signaling pathways. The results show unchanged signaling of β1-AR-Gs-adenylyl cyclase-protein kinase A in the cardioprotective regimes CA and CAR, whose...
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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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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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The role of cold acclimation in activation of adrenegic and thyrode signalling pathway in rat myocardium
Tibenská, Veronika ; Žurmanová, Jitka (advisor) ; Babula, Petr (referee) ; Tribulová, Narcisa (referee)
Despite advances in research and therapy, cardiovascular diseases are still the leading cause of death worldwide. A closer understanding of the endogenous protective mechanism may improve pharmacological interventions for the treatment of heart diseases. Cold acclimation or hardening has strong potential for reducing cardiovascular risk and the literature shows that it stimulates the β-adrenergic and thyroid systems in tissues. At the same time, the adrenergic system in the heart is one of the main regulators of cardiac activity. However, these signaling pathways have surprisingly not been studied at the protein level in the heart yet, and no studies can be found on the subject matter in current literature. Our results show a reduced infarct size induced by ischemic injury in cold-acclimated rats (CA) at 8 ř C for 5 weeks and then returning to normothermic conditions for 2 weeks (CAR). The aim of this dissertation is to determine, the degree of involvement of the adrenergic system in the myocardium during acclimation after 3 days, 10 days, 5 weeks of CA and subsequent CAR at the level of all three β-adrenergic receptor isoforms (β-ARs) and their signaling pathways. The results show unchanged signaling of β1-AR-Gs-adenylyl cyclase-protein kinase A in the cardioprotective regimes CA and CAR, whose...
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The effect of cold stress on the immune system in the presence of infection
Kratochvílová, Anna ; Krulová, Magdaléna (advisor) ; Filipp, Dominik (referee)
Although the relationship between the effects of cold and infection has been studied for a long time, the mechanisms contributing to this phenomenon have not yet been discovered. While short-term exposure to cold triggers a stress response and the production of proinflammatory cytokines, long-term cold exposure induces adaptation and anti- inflammatory shift. The role of cold adaptation in the development and the process of the organism's response to infection remains an unresolved issue. In this diploma thesis, we focused on determining the effect of cold stress or cold adaptation on the immune system of rats which was stimulated by ligands of Toll-like receptors (TLRs). The obtained results showed the importance of γδT lymphocytes and their cytokine production in the process of cold adaptation. To determine how cold adaptation affects the response to infectious agents, we studied changes in the proportion of different immune cell populations in rats treated with the TLR2/6 ligand Pam2CSK4. We determined significant changes in the activation of myeloid cells and B lymphocytes, but also in the population of γδT lymphocytes. Our obtained results suggested the importance of γδT lymphocytes and the protective effect of cold adaptation. Key words: immune system, cold stress, cold adaptation, infection,...
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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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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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Gene expression of selected genes in heart of long-term cold acclimated rat under mild conditions
Marvanová, Aneta ; Žurmanová, Jitka (advisor) ; Nováková, Olga (referee)
Beneficial effect of hardening or cold adaptation for human health has been known for many decades. Beneficial or detrimental effect depends on the regimen and intensity of the adaptation and thus it is very important to pay attention to them. It has been shown in previous studies that cold adaptation of animals at a low temperature 0-4 žC is accompanied by dehydration and the damage of kidneys. As our best knowledge, the effect of mild cold adaptation on the molecular mechanisms in the heart has not been studied until now. The first aim of this study was to set up a new model of cold adaptation without any negative effects on the organism. The second aim was to assess mRNA levels of selected genes related to the important mechanisms associated with energy metabolism and cardio-protective signaling pathways in the left ventricle. Results obtained using the new model for cold adaptation at 102 řC did not show any negative changes in the blood or urine parameters and body fluid balance was maintained. Screening of mRNAs showed that chronic adaptation might affect the phenotype of the heart, transcriptional activity of the antioxidant system and of the pro-apoptotic genes, lowers adrenergic signaling and moderate glucose metabolism in cardiomyocytes. Key words: cold adaptation, heart, gene...
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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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