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Host-microbe interactions and its consequences for intestinal inflammation and carcinogenesis
Kejzlarová, Leona ; Kverka, Miloslav (advisor) ; Smrž, Daniel (referee)
A number of physiological and pathological processes, including the transition from chronic inflammation to cancer, are affected by commensal microbes. However, abundance of microbes and ability to produce active metabolites in the intestine depend on environmental factors, particularly diet. Microbes can influence this process in two ways, by producing genotoxic substances that directly damage the epithelium or by stimulating the inflammatory response. The aim of my thesis was to study the interaction among gut microbiota, diet and the immune system with the subsequent influence on the development of colorectal cancer (CRC) in an experimental mouse model. Animals were fed synthetic diets containing either normal amounts of animal protein (17%; KD) or elevated amounts of animal protein (51%; HPD) throughout the experiments. Two weeks after the diets were introduced, intestinal tumors were induced by administering azoxymethane (AOM) and inducing acute inflammation with 2% sodium dextran sulfate one week after AOM injection. At the end of the experiment I evaluated the number of tumors in the colon and the status of the immune response in the intestine, mesenteric lymph nodes and spleen. To study the effect of macrophages, a similar experiment was performed in animals with depleted macrophages using...
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PREPARATION AND APPLICATION OF SOME BIOPOLYMERS, NANOPARTICLES AND NANOFIBRES FOR COSMETICS AND FOOD
Bokrová, Jitka ; Pekař, Miloslav (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The presented doctoral thesis is focused on preparation of nanoparticles and nanofibers with natural active ingredient and testing their biological effects. Modern types of application forms were prepared from biomaterials based on one or more natural polymers. Chitosan particles were prepared from cross-linked polymer using ultrasonication. A mixture of soy lecithin and cholesterol was used for preparation of liposomes. Poly-3-hydroxybutyrate was used for preparation of combined liposomes, too. All liposome particles were prepared by ultrasonication. Nanofibers were obtained from polyhydroxybutyrate using electrospinning. Mixtures of low-molecular antioxidants obtained by extraction from natural sources were used as active ingredients. Different types of teas, barks, herbs, spices, fruits and vegetables were selected as sources of natural antioxidants. Total phenolic and flavonoid content and total antioxidant activity of extracts were determined using spectrophotometrical methods. Obtained natural extracts were subsequently used for encapsulation. Prepared application forms were characterized in terms of their physicochemical properties. Particle size was monitored by dynamic light scattering. Colloidal stability of particles in suspension was determined using zeta potential. Spectrophotometry was used to evaluate the efficiency of encapsulation of active compounds into particles. The morphology of the new type of combined PHB liposomes was monitored by electron microscopy. Chromatography was used for quantification of individual components of particles. Morphology of nanofibers and incorporation of active agent into their structure were monitored using FTIR-ATR spectroscopy and electron microscopy. Afterwards, antimicrobial, cytotoxic and genotoxic effects of preparations were evaluated. It was found that the most suitable types of extracts for liposome preparation are aqueous and lipid extracts of natural antioxidants. Prepared particles showed excellent stability and good encapsulation efficiency. The study confirmed that incorporation of polydroxybutyrate into liposome structure does not reduce neither the colloidal stability of the particle, nor the efficiency of encapsulation process. Antimicrobial and antimycotic effect of preparations against model microorganisms Micrococcus lutues, Serratia marcescens and Candida glabrata was detected. It was found that process of encapsulation increases the inhibitory effect of natural extracts of antioxidants. The safety of preparations was assessed using two human cell cultures: epidermal keratinocytes and HaCaT cell line. Assays of cell viability and plasma membrane integrity were used to determine cytotoxicity of preparations. Low toxicity of liposome particles was confirmed by a series of cytotoxic tests. Obtained data showed that association of phospholipid with PHB polymer does not cause a significant increase in cytotoxicity in human skin cells. Genotoxicity testing on model procaryotic organism confirmed zero genotoxic potential of preparations. The new type of combined particles and polymeric fibers cant thus be used as a carrier for active ingredients, complex natural extracts, antimicrobial agents and many others.
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Influence of some super-foods and their active components on human cells
Maslonková, Ivana ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
The presented diploma thesis is focused on the study of composition and biological effects of some super-foods. Theoretical part deals with basic information about chosen superfoods and their bioactive substances. Further, theoretical part describes the overview of vesicular systems used for encapsulation and the most common methods of particle characterization. A brief review of cell cultures and cultivation of human cells is presented as well as methods for cytotoxicity a genotoxicity testing. In the experimental section, aqueous and ethanol extracts of super-foods were prepared. These extracts were then encapsulated into liposomal and combined PHB particles. Super-food extracts were characterized by spectrophotometrical methods in order to determine the content of polyphenols, flavonoids, anthocyanins, carotenes, chlorophyll, tannins, and antioxidant activity. The physico-chemical characteristics of prepared liposomal and combined particles were determined too. The particles with encapsulated extracts were further tested using the MTT assay and SOS chromotest to describe their potential cytotoxic and genotoxic effects.
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Chemical and Physical Transformations of Humic Acids
Vlčková, Zoja ; Pospíšilová, Ľubica (referee) ; Janoš,, Pavel (referee) ; Pekař, Miloslav (advisor)
Tato práce představuje pilotní studii testující souvislosti mezi biologickými vlastnostmi a strukturou huminových kyselin extrahovaných z původního a modifikovaného jihomoravského lignitu, důl Mír, Mikulčice. V první části práce byly testovány metody vhodné ke zvýšení výtěžku huminových kyselin extrahovaných z lignitu. Oxidace lignitu v plynné fázi nepřinesla uspokojivé zvýšení výtěžku a byla instrumentálně poměrně náročná. Dále proto byla zkoumána jen oxidace v kapalné fázi a modifikace nízkomolekulárními organickými kyselinami. Modifikace organickými kyselinami byla inspirována procesy podporujícími biologické funkce v rizosféře, t.j. kořenový systém vylučuje exudáty způsobující změny v supramolekulové struktuře okolní organické hmoty čímž zlepšuje její mobilitu a prostupnost buněčnými stěnami. Primární struktura huminových kyselin připravených v této práci byla zkoumána prostřednictvím elementární analýzy a spektrálních metod (13C CPMAS NMR, EPR a UV-VIS spektroskopie). Navzdory tomu, že primární struktura vykazovala jen malé rozdíly, měření biologické aktivity a genotoxického potenciálu prokázalo, že huminové kyseliny a jejich humáty získané z lignitu s rozdílnou předúpravou vykazují odlišnou bioaktivitu. Proto byla dále zkoumána supramolekulární struktura vzorků ve zředěných roztocích, a to prostřednictvím vysokoúčinné vylučovací chromatografie, měření ultrazvukové rychlosti a hustoty. Testovány byly dva různé protionty – draselný a amonný. Získané výsledky potvrdily předpoklad, že pozorované změny v kvalitě humátů jsou závislé na protiiontu, koncentraci humátu v roztoku a také na metodě předúpravy původního lignitu. Obě zvolené metody předúpravy lignitu prokázaly svůj potenciál produkovat huminové kyseliny s rozmanitými biologickými vlastnostmi, aplikovatelné v zemědělství, životním prostředí a potenciálně i ve farmakologii.
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Use of cell cultures to testing of natural substances of plant origin
Ručková, Michaela ; Kostovová, Iveta (referee) ; Márová, Ivana (advisor)
The presented bachelor thesis is focused on preparing aqueous and oil extracts of plant origin, their characterization and testing of their cytotoxicity and genotoxicity. The theoretical part contains basic information about plants and kinds of spices or tea that were used. Description of used methods of liposome preparation and encapsulation of active substances, measurement of antioxidant activity, particle characterization, cultivation of cell cultures and the principle of cytotoxicity and genotoxicity tests used in this thesis is included. Phenolics and flavonoids content was determined using the spectrophotometry. Antioxidant activity was evaluated spectrophotometrically as well. By ultrasonic homogenization method, liposomes were prepared and active agents were encapsulated into these vesicles. Encapsulation efficiency and stability of active substances were measured by spectrophotometry. By DLS method, size of particles was determined. Particle stability was derived from the zeta potential value. Important part of the bachelor thesis was cultivation of human keratinocytes. The cytotoxicity of extracts and liposomes was assessed by MTT assay on human cell cultures. The genotoxicity of extracts and liposomes was defined using SOS Chromotest on model organism, genetically modified E. coli. In conclusion, the potential use of prepared liposomes in the cosmetic or pharmaceutical industry has been proposed.
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Use of genotoxicity tests to characterization of some natural substances and particles
Tilšarová, Kamila ; Bokrová, Jitka (referee) ; Márová, Ivana (advisor)
In production of drugs, cosmetics, in food industry and other biotechnologies, testing of genotoxicity (that are changes in genetic information which are not inhereted) is one of the common steps in the process before distribution to the market. This bachelor´s thesis is focused on the characterization of extracts from chosen natural substances with respect to the content of polyfenols, flavonoides and antioxidant activity. These extracts were encapsulated into liposomes and chitosan particles. The aim was testing possible genotoxicity of whole extracts and particles on possible genotoxicity on the basis of SOS Chromotest performed on bacteria E. coli. This genotoxic assay did not show genotoxic effect of neither pure extracts nor tested liposomes.
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Spatio-temporal distribution of atmospheric aerosol in urban and rural environment
Bendl, Jan ; Hovorka, Jan (advisor) ; Mikuška, Pavel (referee) ; Vojtíšek, Michal (referee)
Air quality in Europe remains a significant environmental concern, affecting the health and quality of life of its population. While stationary network ambient air quality monitoring allows for the observation of main trends, it is not fully representative of personal exposure of citizens due to high spatio-temporal variability of atmospheric aerosol. Therefore, highly time-and- space resolved measurements with state-of-the-art instruments and methods are needed to observe the aerosol variability, dynamics, identify hot-spots, and pollution sources, which are necessary for successful targeted mitigation measures. This thesis addresses this gap focusing on the characterization of spatio-temporal distribution of atmospheric aerosol in inhabited environments. Novel mobile measurement systems were developed and employed to investigate diverse environments, including rural, urban and suburban area. Aerosol source-apportionment were conducted, and the toxicological effects associated with these environments were also investigated. A novel mobile measurement system was developed for personal exposure measurements and pollution mapping in urban and rural environments. The system was used to measure air quality in the Munich subway, revealing high aerosol dynamics with significantly higher concentrations of...
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The effect of maternal nutrition on the newborn genome methylation
Pavlíková, Jitka ; Rössner, Pavel (advisor) ; Černá, Marie (referee) ; Hlaváč, Viktor (referee)
The maternal diet during pregnancy is an important factor involved in the epigenetic programming of the offspring. In addition to the nutritional aspect, the epigenome is also influenced by possible contaminating substances that may occur in the diet of pregnant women. An important group of these potential contaminants are persistent organic pollutants, which are compounds of mostly anthropogenic origin that persist in the environment for a long time, become part of food chains, and some of them accumulate in living organisms. These substances are being monitored for their adverse effects on organisms, and the use of some of them has already been banned or at least significantly restricted. The aim of this work was to find out whether the quality of the diet of pregnant women in the Czech Republic differs in terms of nutrition and contamination with persistent organic pollutants so much that these differences can be reflected in the methylome of newborns. The diet quality of 49 pregnant women from the Karviná and České Budějovice regions was analyzed. During the last month of pregnancy, these women recorded in detail all the food they ate for one week and at the same time collected a quarter of this food in boxes (one box for one day). Information on the quantity and quality of the diet was...
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Optimization of positive controls and determination of genotoxic potential of the sample using reverse mutation test assays on bacterias
MARVANOVÁ, Lenka
The use of the Ames test to determine the mutagenic and therefore carcinogenic potential of chemicals is currently very popular due to its simplicity, speed and costeffectiveness. The aim of this work is to statistically evaluate the historical data of positive and negative controls obtained in the company MediTox s.r.o., based on this data, to design and execute the optimization of positive controls and to verify and apply the findings from the optimization in practice on several samples. Based on the evaluation of historical data of MediTox s.r.o. I concluded that it is necessary to optimize the work with E. coli. I performed the testing of three batches of positive controls, they were carried out without S9 and two batches were carried out with S9. According to the consistent results provided by the controls, it was possible to evaluate the results of the test. As emerged from three tested samples, it is appropriate to replace the E. coli Combo prepared from two bacteria strains by MediTox s.r.o. by a mixture of the above mentionned strains prepared by Xenometrix. It was not necessary to optimize the work with the other strains and positive controls.
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Ames test in the drug development
Klaučová, Martina ; Pávek, Petr (advisor) ; Konečná, Klára (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Martina Klaučová Supervisor: prof. PharmDr. Petr Pávek, Ph.D. Consultant: PharmDr. Ivona Pávková, Ph.D. Diploma thesis title: Ames test in the drug development Background: Thesis objective is the determination of potential genotoxicity of newly developed drugs within primary testing and the introduction of the Ames microfluctuation test which can be used in common laboratory conditions. Methods: I used commercially supplied kit based on the principles of Ames test which detects reverse mutation through colour changes of the samples using bacterial strains S. typhimurium. At first I had to study literary sources and then I could design the procedures of the Ames microfluctuation test, preparation of the chemicals and storage of the strains which are optimal for all laboratories. Results: The drug samples T6445 and T6447 with 30 µM concentration tested by metabolic activation S9 on bacterial strain ST TA 98 show genotoxicity. The sample UOCHB1 with 30 µM concentration tested without activation shows possible genotoxicity on both strains ST TA 98 and ST TA 100. Other samples do not show any toxicity. I used 3 different procedures during the designation of assay. The most suitable version of the...
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