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Proteins demaged by oxidative stress, their role in physiology and ageing of yest cells
Mikešová, Jana ; Palková, Zdena (advisor) ; Borčin, Kateřina (referee)
Reactive oxygen species (ROS) are regularly produced in cells as a by-product of aerobic metabolism. Hence, organisms developed various defence mechanisms, which are able to avoid molecular damages caused by ROS under physiological conditions. In stress conditions, however, such defence mechanisms are not sufficient to avoid molecular damages. Accumulation of oxidized proteins is supposed to be a reason for ageing and many diseases including Friedreich's ataxia, Amylotrophic lateral sclerosis, Alzheimer's disease and many others. During oxidative stress, reactive oxygen species are reflected in oxidation of cystein residues in transcription factors, regulation proteins and active canters centers of enzymes. Oxidative modifications however could lead also to changes in transcription factor activity and activation of specific pathways, including changes in gene expression, cell cycle and proteolysis. This work shows defence mechanisms, ROS and proteins altered by reactive oxygen species that may function as important signalling molecules, which are essential for many cellular processes.
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Proteins demaged by oxidative stress, their role in physiology and ageing of yest cells
Mikešová, Jana ; Palková, Zdena (advisor) ; Borčin, Kateřina (referee)
Reactive oxygen species (ROS) are regularly produced in cells as a by-product of aerobic metabolism. Hence, organisms developed various defence mechanisms, which are able to avoid molecular damages caused by ROS under physiological conditions. In stress conditions, however, such defence mechanisms are not sufficient to avoid molecular damages. Accumulation of oxidized proteins is supposed to be a reason for ageing and many diseases including Friedreich's ataxia, Amylotrophic lateral sclerosis, Alzheimer's disease and many others. During oxidative stress, reactive oxygen species are reflected in oxidation of cystein residues in transcription factors, regulation proteins and active canters centers of enzymes. Oxidative modifications however could lead also to changes in transcription factor activity and activation of specific pathways, including changes in gene expression, cell cycle and proteolysis. This work shows defence mechanisms, ROS and proteins altered by reactive oxygen species that may function as important signalling molecules, which are essential for many cellular processes.
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Effect of low doses of herbicide paraquat on antioxidant defense in Drosophila
SÁBOVÁ, Michala
Disruption of cell equilibrium between production of free radicals and antioxidant defence is named oxidative stress. The main component of antioxidant mechanism is activity of antioxidant enzymes, which include superoxide dismutase (SOD) and catalase. In this study we evaluated the effect of herbicide paraquat on response of SOD and catalase, their transcription level and locomotion activity in Drosophila melanogaster. We exposed the flies to a wide range of paraquat concentration. Our results revealed that transcript and enzymatic levels of both SOD and catalase have a similar biphasic dose response with the peaks at 2,5 ?M paraquat concentration, resembling hormetic effect. Then, males were more sensitive than females. However, females had an increased locomotion activity. We found that paraquat susceptibility is increased in males and mating flies. Therefore, this study supports hypothesis of stress sensitivity elevation as a physiological cost of reproduction.
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