National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Vliv kovů v potravinářství na bakteriální virulenci
Pavezka, Pavel
The bachelor's thesis deals with the issue of gene transfer of resistance of β-lactam antibiotics by means of horizontal gene transfer, specifically transformation. It deals with the transfer of resistance genes through the food chain, when Escherichia coli can subsequently cause foodborne illness. It also points to the current risks of resistance to β-lactam antibiotics and an alternative method of replacing antibiotics with an iron complex together with an antibiotic. The experimental part is demonstrating the antibacterial effect of the Fe16+AMP complex on the ampicillin-resistant bacterial strain E. coli CCM 4225 and the sensitive strain E. coli CCM 3953. The minimum inhibitory concentration was experimentally determined for these samples. Morphological changes upon exposure of the Fe16+AMP complex to E. coli CCM 3953 were also observed using a cryo-SEM scanning electron microscope. The development of resistance to the model bacterium E. coli TOP10 by transformation was also investigated and verified by polymerase chain reaction PCR and gel electrophoresis. Based on the results, it was proven that the Fe16+AMP complex has an inhibitory effect on the bacterium E. coli CCM 3953 and does not have a significant effect on the resistance spreading via transformation mechanism.
Photodissociation studies of xanthene dyes, iron(III) azido complexes and hemithioindigo molecular switches in the gas phase
Navrátil, Rafael ; Roithová, Jana (advisor) ; Žabka, Ján (referee) ; Volný, Michael (referee)
Electronic excitation triggered by the absorption of light enables numerous chemical, physical and biological processes and transformations. Accordingly, full control over the processes involving excited molecules requires an in-depth knowledge of electronic UV/vis spectra and potential energy surfaces. Unsurprisingly, most electronic spectra are acquired in the condensed phase in which molecules are dissolved and most transformations occur. However, our knowledge of excitation, transformations and processes at the level of isolated molecules is still limited, partly because such studies require unconventional experimental approaches and equipment. This Thesis describes experimental methods for recording electronic spectra of isolated molecules in the gas phase by ion spectroscopy, which combines mass spectrometry with optical spectroscopy. Using these methods, experimental factors which affect the electronic excitation and therefore the electronic spectra of ions were determined and evaluated for various fluorescent xanthene dyes, iron-containing complexes and molecular pho- toswitches. Furthermore, factors which govern photochemical processes, such as photo- oxidation, photoreduction and photoisomerization, were also analyzed in detail, with surprisingly different outcomes from previous studies...

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