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Toxic products of cyanobacteria with the focus on endotoxins
Eršilová, Kateřina ; Načeradská, Jana (advisor) ; Semerád, Jaroslav (referee)
Cyanotoxins are toxic products of cyanobacteria that cause problems (e.g. humans can experience unrecognised health effects), especially when they are overgrown. These cyanotoxins include the group of endotoxins, which includes lipopolysaccharides. Based on a literature search, it was found that the structure of these compounds consists of three chemical parts, Lipid A, a central oligosaccharide and O-Antigen. The structure is not the same for all cyanobacterial species and shows considerable variation. As far as the toxicity of lipopolysaccharides is concerned, it appears to be higher in Gram-negative bacteria than in cyanobacteria. The work in section 4.1 on toxicity states that microcystins do not play a major role in toxicity to Daphnia and that other substances from cyanobacteria will be toxic, while lipopolysaccharides are not excreted. In contrast, Chapter 6 states that lipopolysaccharides from Microcystis are not toxic to Daphnia and that other substances will be behind the toxicity. The thesis further considers that a large number of toxic substances coexist in water blooms, thus synergistic effects are at work in water blooms, hence the toxicity of cultures cultivated in laboratories is lower compared to the toxicity of natural cyanobacterial blooms. Water bloom contain many different...
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The effect of sampling point on hygienically significant water indicators in natural bathing establishment
Zelinková, Myra ; Benešová, Libuše (advisor) ; Popovský, Jiří (referee)
In this diploma thesis, I deal with the influence of the sampling site on water quality in natural bathing lakes (Hostivar reservoir, Seberak pond and Vyzlovka pond) in this. I have established that hygienically significant kinds of phytoplankton may differ in terms of water quality especially where there are cyanobacteria constituting water bloom. Surface water bloom may be moved by wind to the lee side of the water body (Microcystis sp.). Aphanizomenon flos-aquae water bloom floating in water column can be affected by wind and by water flow (which may be partly affected by wind as well). With the prevailing fibrous Planktothrix agardhii which does not connstitute water bloom the concentration of chlorophyll-a and cyanobacterial cell abundance in individual sampling sites are similar although the concentration of chlorophyll-a a is about 200 g.l-1 . Microcystis sp. and Scenedesmus sp. survive under eutrophic conditions in competition. From the microbiological perspective, water quality can differ within a single sampling site in places at a distance of less than 100 m. Microbial contamination can be caused by bathers, water birds, farm animals and probably by the removing of microorganisms from sand, mud and sediments on the beach or shore. Rain episodes probably increase the abundance of E.coli...
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The effect of sampling point on hygienically significant water indicators in natural bathing establishment
Zelinková, Myra ; Benešová, Libuše (advisor) ; Popovský, Jiří (referee)
In this diploma thesis, I deal with the influence of the sampling site on water quality in natural bathing lakes (Hostivar reservoir, Seberak pond and Vyzlovka pond) in this. I have established that hygienically significant kinds of phytoplankton may differ in terms of water quality especially where there are cyanobacteria constituting water bloom. Surface water bloom may be moved by wind to the lee side of the water body (Microcystis sp.). Aphanizomenon flos-aquae water bloom floating in water column can be affected by wind and by water flow (which may be partly affected by wind as well). With the prevailing fibrous Planktothrix agardhii which does not connstitute water bloom the concentration of chlorophyll-a and cyanobacterial cell abundance in individual sampling sites are similar although the concentration of chlorophyll-a a is about 200 g.l-1 . Microcystis sp. and Scenedesmus sp. survive under eutrophic conditions in competition. From the microbiological perspective, water quality can differ within a single sampling site in places at a distance of less than 100 m. Microbial contamination can be caused by bathers, water birds, farm animals and probably by the removing of microorganisms from sand, mud and sediments on the beach or shore. Rain episodes probably increase the abundance of E.coli...
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