|
|
Adenosine metabolism and its role in cell physiology
Neumannová, Kateřina ; Novotný, Jiří (advisor) ; Hansíková, Jana (referee)
Adenosine is not just a major component of important molecules such as ATP, RNA or cAMP, but also has its own signaling function. Therefore, its extracellular level is strictly maintained by balance in its formation, degradation and transport. Both inside and outside the cell adenosine is formed mainly through degradation of ATP and is eliminated by two enzymes, adenosine kinase and adenosine deaminase. Transport of adenosine through the cell membrane is provided by nucleoside transporters, which are either equilibrative or concentrative according to the mechanism of transfer. All three processes described above contribute to maintaining adenosine level under normal conditions and its increase in pathological situations. Extracellular adenosine as a signal molecule binds to adenosine receptors (subtypes A1, A2A, A2B, A3) that affect many cellular signaling pathways via G-proteins. By these pathways adenosine regulates energy homeostasis, controls the function of various organs and also modulates the nervous and immune system and thus it may participate in a number of pathological processes. Pharmacological affecting of specific adenosine receptors or enzymes involved in its metabolism can serve as an effective therapy. Some drugs based on this system are already in use, others are being tested, and many...
|
|
|
The influence of perinatal hypoxia on motoric development on laboratory rat and means of therapy
Vachovcová, Sylva ; Mareš, Pavel (advisor) ; Stuchlík, Aleš (referee)
Severe perinatal hypoxia represents a substantial brain injury in human newborns. This Diploma thesis is focused on long-term motor outcome of laboratory rat after moderate perinatal hypoxia. We described some behavioral test for detection motor development and presented the influence of perinatal hypoxia on central nervous system. We also discussed an effect of agonists and antagonists of adenosine A1 receptor in brain. The aim of an experimental part was an evaluation of long-term motor behavior in rats affected by perinatal hypoxia. To cause perinatal hypoxia we put pregnant female rats to a hypoxic (10% O2) normobaric room in 11th day of their gestation. The pregnant female rats stayed in hypoxic room until they gave a birth and 6 more days after birth with their litters. For classification of motor development we used battery of tests of motor coordination. These tests correspond to the level of development of the rat. Then a group of rats with perinatal hypoxia was treated by a single administration of an agonist of adenosine A1 receptor 2-chloro-N(6)- cyclopentyladenosin (CCPA) in postnatal day 14. The animals affected by perinatal hypoxia show motor deficits in 3 from 4 selected behavioral tests. Otherwise, this motor behavior was no longer detected in young adults. The rats affected by...
|
|
| |
|
|
Anti-oxidative stress response in Drosophila melanogaster - The role of adipokinetic hormone and adenosine
ZEMANOVÁ, Milada
In this thesis, the phenomena of the oxidative stress (OS) and anti oxidative stress responses in insects are described in a comprehensive review, and the outcomes of the experimental work are presented. The focus of the work was on defence reactions and their putative control by the adipokinetic hormone (AKH) and adenosine in the Drosophila melanogaster model. For this purpose, we studied the effect of the paraquat (oxidative stressor) treatment on adult flies and larvae carrying mutations in Akh (Akh1) and adenosine receptor (AdoR1) genes, and in both these genes together (Akh1 AdoR1 double mutant). The initial mortality tests revealed the double mutant Akh1 AdoR1 was more sensitive to OS than either of the single mutants. The AKH synthesis under the OS condition seems to be out of the gene expression control, since the increase of an AKH amount in CNS was not linked with the stimulation of Akh gene expression after a paraquat treatment. Further, the gene expression of the antioxidant enzyme glutathione S transferase D1 (GstD1) increased rapidly with OS, though the enzyme activity increased negligibly regardless of both the OS and mutations. Interestingly, the relative expression of GstD1 gene was minimal in the double Akh1 AdoR1 mutant; thus, it was concluded that both AKH and adenosine are employed in the GstD1 gene expression control. Similarly, AKH and adenosine seem to act in tandem in glutathione (GSH) regeneration, since the GSH level was significantly lower in all untreated deficient flies with the maximal effect in the Akh1 AdoR1 double mutant; accordingly, the reduction in the GSH level was enhanced by paraquat treatment. Altogether, the important roles of both AKH and adenosine in the anti oxidative stress response in D. melanogaster were demonstrated.
|
|
|
Efekt ADGF-A RNAi na imunitní odpověď \kur{Drosophily melanogaster} po infekci parazitickou vosou
ŠNEBERGEROVÁ, Pavla
In previous studies the extracellular adenosine has been proved as an important signaling molecule controlling dynamics of the immune response in Drosophila melanogaster. In mammals the adenosine signaling and control is more complex process. Since there is a certain genetic and evolutionary conservation between mammals and invertebrates, Drosophila represents simple system how to study such a complex regulation in vivo. Mutations of adenosine receptor in all cells as well as downregulation of ENT2 in immune cells caused decrease of resistance of the immune system against Drosophila parazitoid. The aim of the thesis is to determine whether RNAi targeted against mRNA of adenosine deaminase ADGF-A, which degrades e-Ado under natural conditions, would have any effect on immune response.
|
|
| |
|
|
Effect of adenosine on Salvador/Warts/Hippo signaling pathway in \kur{Drosophila melanogaster}
FILIP, Tomáš
Adenosine is a ubiquitous metabolite that has various functions in organisms. We examined in this thesis possible interactions between adenosine and Salvador/Warts/Hippo signaling pathways. The results suggest that Adenosin may influences the expression of four important Salvador/Warts/Hippo signaling pathway genes. Our results also suggest strong effect of nutritional diet composition on the expression of these genes.
|
|
|
Role of extracellular adenosine in Drosophila
FENCKOVÁ, Michaela
This thesis describes several aspects of the role for extracellular adenosine in Drosophila. Reverse genetic, molecular and microscopic methods together with the most forefront Drosophila research techniques have been applied to elucidate the role of adenosine signaling in the regulation of development, physiology and metabolism of Drosophila larvae. The thesis helps to establish the model for extracellular adenosine as a stress-signal for the release of energy stores. It also describes the elucidation of Drosophila extracellular adenosine production pathway by functional characterization of extracellular ATP/adenosine converting enzymes. Further, this thesis describes the attempt to study adenosine signaling by creation of tissue specific knock-down mutation of Drosophila adenosine receptor. Finally, it provides results of the utilization of in vivo fluorescent reporters for studying of the localization, function and interaction of enzymes implicated in adenosine signaling pathway.
|
|
|
Genetic screening for the dominant suppressors of adgf-a mutant phenotype in Drosophila
HARTMANN, David
Extracellular adenosine is an important signaling molecule in various physiological processes. When not regulated properly it can cause various pathologies such as Severe Combined Immunodeficiency. To study the effects of increased extracellular adenosine level a Drosophila model has been established. This model is based on mutation in the main adenosine deaminase gene in Drosophila (ADGF-A, Adenosine Deaminase-related Growth Factor A). This work is a consequence of large screening for the suppressors of adgf-a mutant phenotype and presents a more detailed study of 3 previously identified regions containing dominant suppressors.
|
|
|
Effect of Extracellular Adenosine on \kur{Drosophila melanogaster} Cells
HOLÁ, Hana
The effects of extracellular adenosine on Drosophila melanogaster cell lines Cl.8+, Mbn-2, S2 were examined. The cells were grown in the complete medium and tested for growth rate with in presence or absence of adenosine, dipyridamole, uridine and deoxycoformycin. The S2 cells were tested for cAMP production in presence or absence of adenosine.
|
guest ::
