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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...
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Effect of increased temperature on fungal necromass decomposition in tundra
Moravcová, Andrea ; Kohout, Petr (advisor) ; Kolaříková, Zuzana (referee)
This diploma thesis deals with the decomposition of fungal necromass in the Arctic tundra (Svalbard archipelago) under the factor of climate change (simulated by an increased temperature inside the Open Top Chamber). The dynamics of fungal necromass decomposition of two selected fungi, which differ in the level of melanin content and in C:N ratio - Laccaria laccata (hyaline, lower C:N ratio) and Phialocephala fortinii (melanized, higher C:N ratio), was compared. The aim of the work was to evaluate the influence of melanization level of fungal necromass and elevated temperature on the dynamics of fungal necromass decomposition and on the community composition of the decomposers (fungi, bacteria). The experiment focused on monitoring the dynamics of fungal necromass decomposition, changes in enzyme activity, changes in melanin content and C:N ratio during decomposition, as well as on the analysis of the microbial community composition on decomposing mycelium. Throughout the whole incubation, the necromass of P. fortinii decomposed more slowly than the necromass of L. laccata. The differences in the dynamics of decomposition were mainly due to the biochemical composition of the fungal necromass (C:N ratio and melanin content). The melanin content increased in both types of mycelium during...
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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...
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