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Cytotoxicity and secondary metabolites of cyanobacteria
HROUZEK, Pavel
Cyanobacteria are well-known producers of secondary metabolites of different chemical structures and a wide range of biological functions. In the present thesis, the cytotoxic activity of cyanobacteria, originating from different habitats, was studied in order to reveal whether cytotoxicity is an environmentally dependent characteristic. In addition, the data were compared with the toxicity of these extracts to the model invertebrate Artemia salina. The obtained data suggest that cytotoxic cyanobacteria are favoured under some conditions and thus more frequent in particular localities. The majority of the studied extracts and fractions exhibited cytotoxitity to the Sp/2 cell line not accompanied by toxicity to A. salina. Moreover, in most of the strains with both activities to A. salina and Sp/2 cells the toxic effect was caused by an identical fraction. This result suggests that the toxic effect of the cyanobacterial secondary metabolites is mostly affecting basal cell metabolism rather than targeting specific organisms. In one of studied strains, Cylindrospermum sp. C24/1989, novel lipopeptides puwainaphycin F and G have been detected, isolated and their structure and biological effect have been characterized. Both of these structures interfere with eucaryotic membranes and cause a Ca2+ leakage into the cell. Subsequently, an enhanced tyrosine phosohorylation and relocalization of f-actin in the cell was observed. Lastly, the correlation between metabolite production and the reconstructed phylogeny was studied in planktonic Dolichospermopsis strains. Most of the detected compounds were found to be randomly disspersed across the reconstructed phylogeny and thus cannot be considered as good chemotaxonomic markers. This result also hampers the possible detection of toxic cyanobacteria by morphological methods or molecular detection based on the 16SrDNA gene.
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Cladocerans and copepodans biodiversity in Naděje fishponds systém.
KOSÍK, Miroslav
Biodiversity of planktonic crustaceans, cladocerans and copepodans in southbohemian Naděje fishponds system were studied. Both fishpond and non-fishpond (pools, canals, sand-pits, river) localities were observed. Samples were taken from pelagic and littoral zones. Total of 21 species of copepodans and 44 species of cladocerans were recorded over whole area. Hypothesis {\clq}qA higher fish management intensity and higher fish stock cause a lower diversity of zooplankton in a pelagic zone`` was proven. Suppressed species are able to survive in a smaller space (littoral zones, pools, canals, fishponds with a lower fish stock and other non-fishpond localities), where predation pressure is not so strong. None or mild decline of a species diversity can be observed in large areas rich in different water ecosystems, with a reasonable management and production intensity. Different methods of sampling were also compared, those of {\clq}qprolovení litorálních partií`` proved good with the view of effectiveness.
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Macrozoobenthos of the Pohořský and Dobechovský brooks in the Novohradské hory Mts.
KLOUDOVÁ, Jana
The presented thesis deals with the structure and composition of macrozoobenthos of Pohořský and Dobechovský brooks in the Novohradské Mountains. The evaluation was based on the collections from 10 localities carried out in July 2001, March 2002 and July 2002/2003. In addition to determination and classification of the species found, the collections have also been qualitatively evaluated with the use of the diversity index (saprobic index, Belgian Biotic index) and the similarity index. It has been found that the zoobenthos population of Pohořský and Dobechovský brooks encompasses the species of both trout and grayling zones. In most taxa it concerns characteristic representatives of clear, flowing and adequately aerated water. Mutual species similarity of macrozoobenthos population of Pohořský and Dobechovský brooks is approximately 40%. The comparison of macrozoobenthos population diversity indices of Pohořský and Dobechovský brooks has shown that the Pohořský brook bentic fauna is, according to the obtained data, richer and better balanced. From the saprobity point of view, the Pohořský brook can mainly be placed into oligosaprobic stream class. The water of Dobechovský brook oscillates between oligosaprobic and {$\beta$}-mesosaprobic level.
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SEASONAL DEVELOPMENT OF ZOOPLANKTON - COMPARISON OF DIFFERENT WATER BODIES
KOSÍK, Miroslav
Structure and seasonal dynamic of zooplankton and hydrochemical and limnological parameters were studied in different type of small water bodies. Twelve localities of shallow standing waters were selected from four varied biotopes - pools, ponds, sink, surface depression, mining potholes and larger reservoirs like flooded excavated hollow. Zooplankton was primarily determinated by external factors influencing the overall character of water ecosystem and internal factors like fish stock and content of organic matter. Zooplankton species composition exhibits distinctive differences in the individual types of localities as well as in the season. Higher species diversity was recorded in pools, mesotrofic water bodies were considered as localities with lower species diversity. Results of this observation should be useful for water locality planning and management in restoration process in post-mining landscape.
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Village{\crq}s places as biocentre. Improvement mapping plants to evaluation biodiversity.
RÁDR, Jiří
The main aim of graduation theses was today{\crq}s loom of species distribution, which were in former times surely ample in integral area Blatensko. On the basis of it to rewiev the diversity. With village{\crq}s alternation the diversity changed, too. The 22 villages scattered in the whole area phytogeografically subregion Blatensko and the 59 plant species from archeofyts, apofyts and neofyts were selected. My objective was to note, if these species are still occurred in Blatensko region or not. The number of monitored plant species decreases and every year are more and more abundant.
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