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Characterization of bacterial genes encoding DbtC-like extradiol dioxygenase with bioremediation potential for aromatic compounds in locality Hradčany
Šnajdrová, Renata ; Bořek Dohalská, Lucie (advisor) ; Nešvera, Jan (referee)
Aromatic pollutants pose a serious environmental problem. Petroleum and its derivates belong to the most abundant contaminants in the Czech Republic and their sanation is a priority objective for improving the life quality of the population. Bioremediation is a technology taking advantage of the natural capacity of soil and water microbial community to degrade environmental pollutants. Deeper understanding and detailed knowledge on specialized bacterial species, pathways and genes is required for selection, optimization and application of targeted bioremediation approach and for monitoring of its results. Recent analysis of a metagenomic library constructed from highly contaminated soil of the former military air-base Hradčany has identified a novel group of catabolic genes encoding extradiol dioxygenase similar to DbtC of Burkholderia sp. DBT1. The DbtC-like enzymes are among the three priority groups of extradiol dioxygenases with biodegradation relevance for the locality. The present study of soil bacterial isolates and metagenomic fosmid clones harboring the genes of interest gained evidence about the dbtC-like genes as a part of highly mobile gene cassette. Transposon insertion mutagenesis identified the genes joined with the expression of the extradiol dioxygenase activity. The dbtC-like genes were...
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Sampling of persistent organic compounds using SPMDs: Advantages and disadvantages
Čáslavský, Josef ; Kotlaříková, Pavla ; Benešová, Karolína ; Doškářová, Š. ; Hamrusová, M.
Passive sampling methods gain more and more popularity for the sampling of persistent organic pollutants in the environment, including air. These passive samplers are substantially cheaper than standard active sampling methods, their deployment is simpler, they don't need electricity, thus they can be deployed even in very distant regions. They offer an itegrative response, therefore these samplers are especially suitable for monitoriong purposes. For quantitative evaluation it is necessary to establish the values of sampling rates for individual compounds. In the presented study these values for polycyclic aromatic hydrocarbons were evaluated from the comparison of the results of passive sampling using SPMDs and standard active sampling method.
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Magnetic properties of Ce compounds studied by specific heat
Čermák, Petr ; Javorský, Pavel (advisor) ; Havela, Ladislav (referee)
Materials containing the 4f (rare earth) or 5f (actinides) exhibit a large variety of interesting physical properties. The Ce-based compounds have a special place among the rare-earth compounds. The Ce atom contains only a single f-electron that is responsible for the magnetic behavior. The 4f states in compounds with the heavy rare earths have a well localized character, whereas many Ce-based compounds are on the borderline between the localized and itinerant behavior. These compounds show large variety of the magnetic ground states what is a result of the competition between the long-range order of the RKKY type and the screening of the localized moments by conduction electrons. We observe nonmagnetic states with a mixed valence (between Ce3+ and Ce4+), metallic systems with a long-range order of the Ce moments (ferromagnetic, antiferromagnetic or more complex structures). To analyze the electronic properties, the heat capacity data, and namely their low-temperature part, play an indispensable role. This diploma work comprise the sample preparation of selected cerium compounds, their phase characteristics and the heat capacity measurements at low temperatures (0.4 - 300 K). The main part is focused on the data analysis and comparison with theoretical models.
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Assessment of aroma active compounds in chosen fruit types
Rodzíková, Martina ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the assessment of aroma active compounds in less known berries, gooseberries. In the theoretical part the general characteristics, biological signs and properties of selected varieties, chemical composition and structure of the components, drug effects, the possibility of processing and use of gooseberries are mainly described. The main aim of this thesis was to determine aroma active substances in selected varieties of gooseberry fruits using SPME-GC method. Aroma active compounds were first extracted by solid-phase microextraction and then assessed by gas chromatography.
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Assessment of aroma active compounds in unconventional fruit types
Melikantová, Marcela ; Pšenáková, Ivana (referee) ; Vítová, Eva (advisor)
The aim of this bachelor thesis is the assessment of aroma active compounds in unconventional fruit types, sea buckthorn (Hippopha rhamnoides L.) was chosen as a model sample. The first part is focused on the description of these plants, their chemical composition and use. The experimental part is focused on identification and quantification of aroma compounds in chosen cultivars of sea buckthorn using SPME-GC-FID method. In total, eleven cultivars were analysed. The cultivar Krasna was found as having the most aromatical profile (the highest content of aroma compounds identified). Ethanol, 3-hydroxy-2-butanone, ethanal, butyl acetate and acetic acid were the most often occuring compounds.
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Assessment of aromatic compounds with allergenic effect
Obrdlíková, Blanka ; Sůkalová, Kateřina (referee) ; Vítová, Eva (advisor)
The thesis deals with the determination of allergenic fragrances in cosmetics. The theoretical part is focused on the description of cosmetic products, the use of fragrances in the preparation of cosmetics, obtaining fragrances and their allergenic effects on the human body. In the practical part the SPME-GC-FID method is used for the determination of aromatic substances with allergenic potential in selected cosmetic products (natural creams and toilet water).
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Assessment of aroma active compounds in elderberries
Kaňová, Kateřina ; Divišová, Radka (referee) ; Vítová, Eva (advisor)
This work is focused on determination of aroma compounds of elderberries (Sambucus nigra L.). The theoretical part provides an overview of the properties, occurrence, other varieties and composition of elder berries and their use particular in the production of juices. The possibilities of assessment of aroma compounds are also briefly discussed. In the experimental part, the identification and quantification of aroma compounds in samples of mixed juices (elder with grape) and comparison of the content of aroma compounds in different types of juices, was made. Solid Phase Microextraction in conjunction with gas chromatography (SPME-GC) was used for analysis. Totally 51 different volatile aroma compounds were identified. They were 19 alcohols, 10 aldehydes, 8 esters, 7 ketones, 6 fatty acids and an oxide. As expected, the largest amount of aroma compounds was found in sample of pure elderberry juice.
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Aroma profile of cheese analogues
Součková, Šárka ; Pšenáková, Ivana (referee) ; Vítová, Eva (advisor)
This Bachelor’s thesis deals with the issue of processed cheese analogues. It will explain what they are, their chemical composition and properties. The aim is to examine a number of cheese analogue samples with added various types of vegetable fats and identify and quantify the volatile aroma active substances present. Aroma compounds were isolated from samples using the Solid Phase Microextraction (SPME), a fiber with polar stationary phase (CARTM/PDMS) was used and the captured substances were then determined by gas chromatography. The evaluated cheese analogues varied in the type of the contained fat. In total 27 aroma active compounds in different amounts were identified. Cheese analogue with sunflower oil contained the most compounds (24) and the smallest number of aroma substances (16) has been detected in the cheese analogue with coconut fat. The highest concentration of aromatic compounds was found in the analogue with coconut fat and lowest in the cheese analogue with palm fat. Ethanol occurred in all types of analogues in the largest concentration. In conclusion it can be argued that the various analogues varied in the type and the amount of aromatic compounds, depending on the type of fat used.
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Heterocyclic Compounds with Antimycobacterial Activity
Herzigová, Petra ; Klimešová, Věra (advisor) ; Potáček, Milan (referee) ; Pytela, Oldřich (referee)
The dissertation thesis belongs to the conception of the research of potential antimycobacterial compounds. The aim of this work is synthesis of sulphide pyridine derivatives and the relationship between structure and antimycobacterial activity. Within the framework of this Thesis, the 112 substituted derivates of 4-(subst. fenylalkylsulfanyl)pyridine-2-carboxylic acid were synthesized. Antimycobacterial activity of prepared substances has been tested under in vitro conditions against M. tuberculosis, and non-tuberculous mycobacteria M. avium and M. kansasii. The series of 4-(subst. phenethylsulfanyl)pyridine-2-carbothioamide (MIC 1-32 µmol/L) represents the most active substances (MIC 1-32 µmol/L). These derivates don't reach the activity used antituberculosis drugs against M. tuberculosis, but their activities against M. avium exceed that of isoniazid. The synthesis of new structures as potential antimycobacterial compounds forms the second part of Thesis. All synthesis is based on the use of bis- arylimidoyl chlorides of oxalic acid of as starting material. None of prepared new compounds don't display an interesting antimycobacterial activity.
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Structure-Antifungal Activity Relationships in Substituted Butenolides
Šenel, Petr ; Pour, Milan (advisor) ; Hampl, František (referee) ; Doležal, Martin (referee)
Within the framework of this Thesis, several series of 3-(4-bromophenyl)-2,5- -dihydrofuran-2-ones with various substituents at C(5) derived from in vitro antifungally active 3-(4-bromophenyl)-5-acetyloxymethyl-2,5-dihydrofuran-2-one were prepared with the aim of further development of potential antifungals based on this lead. Primarily, we focused on the synthesis of furanones bearing alkylidene or alkoxymethyl/aryloxymethyl moiety in position 5. We found that 5-acyloxymethyl and 5-aryloxymethyl furanone derivatives undergo elimination leading to 3-(4-bromophenyl)-5-methylene-2,5-dihydrofuran-2-one under the antifungal screening conditions. This compound initiates fungal cell membrane disruption and is responsible for the antifungal activity of the former. The 5-alkoxymethyl analogues are unable to undergo the elimination process and are therefore inactive. The antifungal activity of 5- alkylidene furanones depends on the substitution of alkylidene side chain. Some of the target compounds displayed interesting cytostatic activities against HeLa S3 and CCRF-CEM cells (IC50 < 5 µmol.L-1 ). Furthermore, syntheses of 4-substituted or 4,5-disubstituted-3-(4-bromophenyl)-2,5- -dihydrofuran-2-ones were carried out. Some of the prepared derivatives possessed notable antifungal or antimicrobial activity.
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