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Resistance to macrolides, lincosamides and streptogramins in coagulase-negative staphylococci in ČR
Novotná, Gabriela ; Janata, Jiří (advisor) ; Petráš, Petr (referee) ; Sigler, Karel (referee)
VÝSLEDKY Analýza okolí genu msr(A) 45 součástí kompletního transpozonu Tn552 a s rekombinačním místem resbinR je identická až k místu rekombinace (resbinR site I). Druhá, v pozici JCSC1435 261884-2618311, je součástí sekvence transpozonu Tn5404. Kompletní transpozon Tn5404 je na vnějších okrajích ohraničen 7 bp dlouhou přímou repeticí (AGTAACT), jež vznikla zdvojením místa inzerce transpozonu (Obr. 5.3.), stejné inzerční místo pro Tn552 bylo pozorováno v chromozómu Entereococcus faecalis CH116 (146, 155). Shrnutí výsledků: Gen msr(A) byl u 41 izolátů lokalizován na chromozómu ve společném místě, pouze u dvou izolátů byl gen lokalizován na plazmidu. Oblast chromozomálně kódovaného genu msr(A) je u všech patnácti podrobněji studovaných izolátů (Tab. 5.1.) vysoce homologní s plazmidem πSh1, integrovaným v genomu S. haemolyticus JCSC1435 izolovaného v Japonsku (179). Uspořádání genů na tomto plazmidu je konzervovaným souborem jednotlivých genových motivů, jehož menší fragmenty byly odděleně popsány v několika dřívějších studiích. Rozdíly v msr(A) hybridizačních profilech jsou dány výhradně variabilitou v úseku kódujícím resolvasu Bin a rekombinasu Sin. Nalezli jsme pět různých typů uspořádání msr(A) oblastí, které se liší od JCSC1435 tímto: i) vložením části transpozonu Tn552 (typ KM50; 7,2kb msr(A)...
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The analysis of membrane potential recovery in yeast under CCCP-induced stress
Babuka, David ; Plášek, Jaromír (advisor) ; Sigler, Karel (referee)
The master's thesis is focused on the study of response of the intracellular pH of the yeast cells on various external environments, primarily in a relation to the protonophore carbonyl cyanide m-chlorophenylhydrazone, CCCP. To measure the intracellular pH of the yeast cells we used a genetically coded fluorescent probe the ratiometric pHluorin. Using the method of synchronously scanned fluorescent spectra we were able to measure the intracellular pH of the cells with high precision. As a part of these experiments we also studied the influence of ionic strength of the cell suspensions buffers on the surface potential as well as the influence of the mineral salt KCl on the depolarization of the yeast membranes and cytosolic acidification induced by the protonophore CCCP. We examined the changes of cytosolic pH as such but we also used the measured pH as an indicator of the processes and the state of environment outside the cell. One of the most notable outcomes of this thesis is a new method of monitoring the value of the surface potential of the yeast cells by measuring the titration curves of cytosolic acidification induced by the protonophore CCCP.
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Study of thermal and photodegradation of beer and other fermented beverages
Škoda, Jakub ; Gabriel, Petr (advisor) ; Sigler, Karel (referee)
In this thesis the optical changes of beers and model beer solutions during their photodegradation were studied. The optical changes - change of absorbance - were measured on the prototype of apparatus COLORTURB and were correlated with sensory tested intensity of the lightstruck flavour of beer and with riboflavin content in samples. High correlation between the lightstruck flavour intensity, the loss of absorbance at the wavelength of 450 nm and the riboflavin content loss was found. The partial recovery of the absorbance for both beers and model beer solutions was found and was attributed to the riboflavin photoproducts transformation. Powered by TCPDF (www.tcpdf.org)
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Monitoring the effect of medically important drugs on activity of human P-glycoprotein using fluorescent probes
Veľas, Lukáš ; Gášková, Dana (advisor) ; Sigler, Karel (referee)
One of the main causes of failure in cancer treatment when using chemotherapy is the phenomenon of multidrug resistance - MDR. The most important protein mediating MDR in human cells is P-glycoprotein. The main goal of this thesis was the modification of fluorescent method - developed for studying yeast MDR pumps at the Department of Biophysics at the Institute of Physics of Charles University - to study the activity of P-glycoprotein in human tumor cells. The fluorescent method is based on the use of redistribution potentiometric probe diS-C3(3) which we found to be a substrate of P-glycoprotein. The optimalization of the method (experimental window) allowed sensitive monitoring of changes in the activity of P-glycoprotein caused by the effect of its several known inhibitors/substrates: oligomycin, amiodarone, verapamil, vinblastine, ketoconazole, itraconazole and FK506. New important results regarding the effect of these medically significant drugs on human cells were obtained. The developed method will undoubtedly be of great benefit in the search for new effective inhibitors and the study of their mechanisms in the future.
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Measurement of the membrane potential using ion-selective electrode sensitive to tetraphenylphosphonium
Lábajová, Anna ; Kofránek, Jiří (advisor) ; Sigler, Karel (referee) ; Plášek, Jaromír (referee)
103 ABSTRACT The computerized device for membrane potential measurement using the tetraphenylphosphonium-selective electrode was constructed. Signal acquisition, processing and data storage were realized by MATLAB/Simulink software. The selective membrane was optimized incorporating TPP+ TPB- precipitate into the membrane. The electrode had a Nernstian response from 3.10-6 M TPP+ . The TPP+ TPB- precipitate was later replaced by sodium tetrakis[3,5-bis(1,1,1,3,3,3-hexafluoro-2- methoxy-2-propyl)phenyl]borate (NaHFPB). The electrode with incorporated NaHFPB had a Nernstian response from 1.10-6 M TPP+ and had better sensitivity than commercially available electrodes. The values of selectivity coefficients for K+ , Na+ , Ca2+ and Mg2+ were calculated. The device was used for mitochondrial membrane potential measurement of isolated mitochondria and for evaluating the respiratory chain function of digitonin- permeabilized cells (hepatocytes, HeLa G, BSC-40 and control transmitochondrial cybrids). This method was used also for monitoring the mitochondrial permeability transition pore (MPTP) function of isolated mitochondria and permeabilized hepatocytes. MPTP opening was induced by high calcium concentration and the action of calcium was enhanced by pro-oxidant tert-butyl hydroperoxide (t-BHP). This...
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