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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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Diversity, ecology and ecophysiology of snow algae
Mikešová, Lenka ; Nedbalová, Linda (advisor) ; Kvíderová, Jana (referee)
Permanent and temporary snow cover in polar and mountain areas is a very extreme habitat. However, there are organisms that inhabit this environment. Green algae of the order Chlamydomonadales (Chlorophyta) belong among the important representatives of cryoseston, which are known from polar and mountain regions around the world. These organisms, which occupied the snow environment probably secondarily, developed different ecophysiological adaptations required for the successful survival in extreme conditions. Low temperatures and high levels of radiation are the main extreme factors that organisms must cope with. The most important survival mechanisms include the adaptation of life cycles (such as of the shifts between resistant stages and moving vegetative stages), accumulation of secondary carotenoids, changes in fatty acid composition of membranes and lowering of growth temperature optima in some species. These adaptations together with the study of diversity represent at present the main subjects of research of snow algae.
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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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|
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Diversity, ecology and ecophysiology of snow algae
Mikešová, Lenka ; Nedbalová, Linda (advisor) ; Kvíderová, Jana (referee)
Permanent and temporary snow cover in polar and mountain areas is a very extreme habitat. However, there are organisms that inhabit this environment. Green algae of the order Chlamydomonadales (Chlorophyta) belong among the important representatives of cryoseston, which are known from polar and mountain regions around the world. These organisms, which occupied the snow environment probably secondarily, developed different ecophysiological adaptations required for the successful survival in extreme conditions. Low temperatures and high levels of radiation are the main extreme factors that organisms must cope with. The most important survival mechanisms include the adaptation of life cycles (such as of the shifts between resistant stages and moving vegetative stages), accumulation of secondary carotenoids, changes in fatty acid composition of membranes and lowering of growth temperature optima in some species. These adaptations together with the study of diversity represent at present the main subjects of research of snow algae.
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