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Storage cells and their role in tardigrade physiology.
Czerneková, Michaela ; Svoboda, Petr (advisor) ; Delagoutte, Emmanuelle (referee) ; Weyda, František (referee)
STORAGE CELLS AND THEIR ROLE IN TARDIGRADE PHYSIOLOGY Abstract Tardigrades possess remarkable tolerance to numerous stress conditions (e.g. almost complete desiccation, exposure to very low sub-zero temperature, heat stress and even exposure to space in low Earth orbit). Indeed, they are among the most radiation-resistant multi-cellular organisms. The body cavity of tardigrades is filled with the storage cells (SC). Their role in anhydrobiosis has been discussed. The main objectives of this work were to analyse (i) the occurrence of mitosis in SC, (ii) the factors constraining anhydrobiotic survival, and (iii) the general ultrastructure of SC and their ultrastructure concerning the stress conditions. Our model species, R. cf. coronifer is one of the most extensively studied tardigrades concerning anhydrobiosis. Comprehensive histochemical techniques were used in combination with SEM, TEM, and confocal microscopy. First, mitotic divisions of tardigrade SC occur with a higher frequency in juveniles than in adults and correlate with animal growth. Mitosis is more frequent in moulting tardigrades, but the overall mitotic index is low. Furthermore, tardigrades of R. cf. coronifer can survive the maximum of 6 repeated desiccation cycles with significantly declining survival rate with repeated desiccations and...
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Water Bears (Tardigrada) In Teaching
Gruntová, Zuzana ; Říhová, Dagmar (advisor) ; Mourek, Jan (referee)
This thesis is focused on the phylum Tardigrada. The main goal is to implement this topic into the curriculum of primary and secondary education. The thesis is divided in two parts - theoretical and empirical. The theoretical part comprises five basic topics: the general introduction to phylum Tardigrada and other moss fauna; extraction methods; analysis of textbooks for primary and secondary schools; and application of obtained knowledge about phylum Tardigrada in education. In this thesis, water bears are used as model organisms for creating practical suggestions for teaching methods and forms that can be used when implementing this theme into a teaching process. The empirical part presents the results of extensive study focused on the occurrence of Tardigrada in moss from variety of habitats in the Czech Republic and its implication for practical use. Keywords: moss fauna, cryptobiosis, education, teaching methods, research, analysis of textbooks
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