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Preparation of edible antimicrobial packaging
Kozubová, Petra ; Dzurická, Lucia (referee) ; Skoumalová, Petra (advisor)
This bachelor’s thesis is focused on preparation and characterization of eatable packaging. Eatable packaging consists of two components, antimicrobial component and base of packaging. The task of eatable packaging is to protect product against antimicrobial attack and to extend durability of the product. As antimicrobial components were used water and oil extracts of several herbs (mint, nettle, lavender, cinnamon, cloves, vanilla, ginger and rhinoceros). Oil extracts were also encapsulated into liposomes for better application. Firstly, concentrations of polyphenoles and antioxidants of extracts were determined. Oil extract of clove contained the highest concentration of both determined substances. Encapsulation efficiency, stability and size of liposomes were tested too. All prepared liposomes were stable and relatively of the same size. Also high encapsulation efficiency was observed. Next, antimicrobial activity of prepared extracts and liposome particles against yeast Candida glabrata and two bacteria strains Escherichia coli and Staphycococcus epidermidis was tested and the high antimicrobial activity reported mainly all tested liposomes. Then alginate, chitosan and carboxymethylcellulose and their combinations respectively were used as bases of packaging. Created film had to meet several parameters, especially suitable sensory properties such as pleasant taste and smell, as well as invisibility, gloss, affordability and suitable manipulability. Combination of 2% carboxymethylcellulose and 1% alginate in a ration of 2:1 with liposomes of mint as antimicrobial component achieved the best results.
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Study of plasma interaction with bacteria for wound healing
Šrámková, Sarah ; Krčma, František (referee) ; Kozáková, Zdenka (advisor)
This thesis focuses on the study of the interaction of plasma with bacteria to enhance the promotion of wound healing. Firstly, the wound healing process is described, followed by low temperature plasma, its effect on bacterial cells and its use in biomedicine. The experimental part deals with the application of low-temperature plasma generated by microwave jet on selected microorganisms and the influence of experimental conditions on the antimicrobial effect of the plasma. One representative of the microorganisms occurring in the wounds was selected as representatives of Gram-positive bacteria and Gram-negative bacteria, namely Staphylococcus epidermidis and Escherichia coli. Using the results obtained, the antimicrobial effect of plasma generated by microwave jet in argon was confirmed. The degree of antimicrobial effect is related to the concentration of the microorganisms, the time of treatment and whether the bacteria are Gram-positive or Gram-negative.
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Engineering of microbial glycosidases for modifying synthetic potential
Hovorková, Michaela ; Bojarová, Pavla (advisor) ; Lichá, Irena (referee)
Glycosidases (EC 3.2.1.) alias glycoside hydrolases are enzymes that catalyze the cleavage of a glycosidic bond between two carbohydrates or between a carbohydrate and an aglycone. Under suitable conditions (especially reduction of water activity in the reaction mixture), these enzymes are also able to synthesize a glycosidic bond. By targeted mutagenesis of the catalytic centre of the enzymes, it is possible to suppress or completely abolish their hydrolytic activity. Enzyme synthesis using glycosidases makes it possible to prepare bioactive galactosides, for example galectin ligands. The present work deals mainly with β-galactosidase from Bacillus circulans, its recombinant expression and mutagenesis. In the first part of the work, the commercially prepared plasmid of -galactosidase from B. circulans isoform A that I designed was used for recombinant expression in E. coli. It was necessary to optimize the conditions of the enzyme production. As it is a large protein (189 kDa), the expression vector pCOLD II and cold production at 15 ř C were used. The enzyme is specific for the formation of the β-1,4 glycosidic bond and has been used to synthesize complex tri- and tetrasaccharide ligands that cannot be prepared with a crude commercial preparation containing undesirable enzyme activities....
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Influence of antibacterial nanomaterials on the development of bacterial resistance
Bábíková, Daniela ; Lucie,, Bozděchová (referee) ; Šmerková, Kristýna (advisor)
Bacterial resistance to antibiotics is a long-discussed problem. The use of antibiotics in primary agricultural production, especially in pig breeding. High levels of zinc subsequently seeps into the soil in the form of secondary agricultural products. Doses of effect the intestinal bacteria of pigs, but also the microorganisms in the environment which can subsequently lead to the development of resistance to metals also antibiotics. This thesis deals with the effect of ZnO and newly used nanoparticles (ZnO NPs) on bacteria S. aureus, methicilin-rezistant S. aureus and E. coli. Acquired data point to the effect of ZnO on minimal inhibition concentration of antibiotics and the development of resistance in E. coli. Based on biochemical tests, the change of metabolic pathways reacting with selected substrates was confirmed. Repeated subcultur of bacteria with tested ZnO and ZnO NPs has on the susceptibility of bacteria to antibiotics and changes their biochemical pathways. Studies dealing with the issue of long-term effect on medicinal substances are essential for the development of modern antibacterial components.
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Antimicrobial activity of selected natural extracts
Šandová, Lucie ; Veselá, Mária (referee) ; Zemanová, Jana (advisor)
The aim of the bachelor thesis was to determine antimicrobial activity of selected natural extracts, specifically three model extracts made from purple coneflower (Echinacea purpurea) and four commercial extracts – true lavender (Lavandula angustifolia), lemon balm (Melissa oficinalis), echinacea herbal drops (Echinacea purpurea) and echinacea extract (Echinacea purpurea) with ginger, against selected microorganisms. Theoretical part is focused on description of bioactive substances that are found in plants. It also describes extraction methods used for obtaining extracts from plant materials, methods for determining antimicrobial activity and then the use of natural extracts in food and cosmetic industry. In experimental part, antimicrobial effect of the extracts was tested against gram-negative bacteria Escherichia coli, gram-positive bacteria Bacillus cereus and yeast Candida glabrata. For determination of the antimicrobial activity, two methods (hole method and disc diffusion method) were used and compared. The highest antimicrobial activity against selected microorganisms was showed by commercial extract of lemon balm, which contains lot of geraniol and citroneloll. Significant antimicrobial activity had also been shown by commercial extract of true lavender. On the contrary, extracts from Echinacea had not shown any antimicrobial activity against selected microorganisms.
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Výskum funkcie rastlinného hormonálného receptoru CRE1/AHK4 za použitia automatizovanej metódy pre vysokoúčinný skríning
Kopecká, Romana
The bachelor thesis is focused on the possibilities of using high-throughput screening (HTS) for the research of plant hormone receptor AHK4 functions. For the study of AHK4 receptor signaling was used Escherichia coli (strain KMI001) which express beta-galactosidase as a reporter enzyme based on the receptor-ligand interaction. The main advantages of used HTS method include the identification of agonists, antagonists and non-receptor interacting agents in one experiment and the possibility of identifying false-positive results (predominantly fluorescence determination of the enzyme product, 4-metylumbelliferon). The effects of 279 unknown substances on the AHK4 receptor were studied in the experimental part. A part of the experiment was also a closer characterization of selected substances with agonist effect on the AHK4 receptor. Within this section, a method has been developed that has allowed the dilution of selected 12 substances using Nanodrop II. On the basis of data analysis, it was found that selected substances with a statistically significant agonist or antagonist effect in the selected part of the substance library did not achieve the effects of the control substances (tZ, ZOGA). In a more detailed characterization of the screening agents, the agonist effect was suppressed in some cases. This phenomenon was probably caused by the absence of tZ, which was present in the primary screening.
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Mikrobiologie koření - stanovení a porovnání výskytu významných skupin mikroorganismů ve vzorcích koření - pepře černého celého a pepře černého mletého
Procházková, Marcela
The dissertation is occupy with microbial settlement of black pepper, which is one of the world's most widely used spices. Characterizes each kind of pepper, discribe microorganisms occurring in spices and spice treatments. It also state legislative limits of microorganism occurrence. The practical part of this work deals with experimental determination of selected groups of microorganisms in black pepper. Analyzed samples of black pepper were purchased in business chains, sold under a known brand and private label and also in shops dealing only with spices and herbs. The results of the work shows that microbial contamination of spices is constantly decreasing and in most cases doesn’t exceed the allowed limits. The most contaminated sample belonged to private label samples, and the least contaminated sample belonged to wholesale spice distributors.
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Mikrobiální kvalita kozího mleziva na různých farmách
Hallová, Tereza
This diploma thesis contains a brief history of goat breeding and its numbers in the world and in the Czech Republic. It also deals with the importance of colostrum for kids, its structure and the factors that in uence it. The aim of this thesis was to analyze the microbiological quality of goat colostrum from the individual sample collections realized on seven farms in February 2017 and to assess the in uence of the farm, breed and freezing. At the time of sample collection, the animals were housed in a stable in an individual birth box and were fed an intensive diet. The individual samples of colostrum were chilled or frozen and then transported for laboratory tests at the Veterinary and Pharmaceutical University in Brno. The microbiological analysis was focused on the total plate count (TPC), the presence and amount of Escherichia coli, verotoxigenic Escherichia coli (VTEC), Staphylococcus aureus and its genes encoding staphylococcal enterotoxins. Data analysis suggests that the most common pathogenic microorganism on farms is Escherichia coli, while VTEC has not been detected in any sample. Among the observed indicators, the Staphylococcus aureus was found most often. For the total number of microorganisms and pathogenic microorganisms, the lowest incidence was observed in farm no.5 with an average TPC of 162,250 CFU/ml and Escherichia coli in a single sample of 20 CFU/ml. The farm with the lowest microbial quality of colostrum was identi ed as a farm no.1 whose TPC was not the most numerous: 130 166.7 CFU/ml, but the incidence of pathogenic microorganisms was the highest out of all samples: Escherichia coli 250 CFU/ml and Staphylococcus aureus 780,000 CFU/ml. Based on the results, Farm no.1 was adviset with the possibilities of how to improve the animal hygiene to raise the microbial quality of colostrum. The in uence of the breed was not explicitly determined, however, the highest quality colostrum was obtained from the crossbreeds of the following breeds: white shorthair goat, short-haired goat and Anglonubian goat.
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Mechanism of action of bacterial toxins elevating the cAMP in host cells
Lepesheva, Anna ; Mašín, Jiří (advisor) ; Petráčková, Denisa (referee)
Cyclic adenosine monophosphate (cAMP) is an universal second messenger that regulates a large number of molecular mechanisms inside the eukaryotic cell. The level of synthesized cAMP is tightly regulated by endogenous adenylatecyclase (AC), and therefore this enzyme is often a target for various bacterial toxins. To manipulate intracellular cAMP levels in a target cell, bacteria have developed two different strategies for their toxins. Bordetella pertussis adenylate cyclase toxin (CyaA), Bacillus anthracis edema factor (EF) and Pseudomonas aeruginosa exotoxinY have in their structure an enzymatic AC domain which is activated by an intracellular cofactor and has several times higher activity than the eukaryotic AC enzyme itself. Other toxins, such as Bordetella pertussis pertussis toxin (PT), Vibrio cholerae cholera toxin (CT), and Escherichia coli heat labile toxin use ADP-ribosylation reaction of AC-coupled heterotrimeric G proteins to increase its activity and uncontrolled cAMP production. This work presents a literature search with accent on the molecular mechanism of interaction of these toxins with the target cell. Keywords: bacterial pathogens, virulence factors, intracellular cAMP elevation, bacterial toxins, adenylatecyclase (adenylylcyclase), Bordetella pertussis, Vibrio cholerae,...
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Monitoring and detection of Escherichia coli and Klebsiella pneumoniae strains with Extended Spectrum Beta-Lactamase (ESBL) production in Hospital Prachatice, a. s. in 2014-2018.
TVRDKOVÁ, Pavla
The ever increasing resistance of bacteria is a grave issue world-wide. Some bacteria are resistant naturally but for other resistance is acquired. As a result, we can encounter bacterium that would formerly be quite easily killed by administering antibiotics but, in the course of time, as a result of, for example, communication between various bacteria species and strains in the form of various mutations and, frequently, after the administration of incorrect antibiotic and the effects of selective antibiotic pressure, the same bacterium becomes resistant to antibiotics. One of the types of such acquired resistance is the production of broad-spectrum beta-lactamases ESBL. The objective of this thesis is to establish the representation and development of ESBL production in Escherichia coli strains and Klebsiella pneumoniae strains as these make the most frequent producers of these broad-spectrum beta-lactamases, in certain hospital departments and in various types of clinical materials over the period of 5 years. In addition, the thesis focuses on the development of antibiotic resistance, accordingly, over the 5 year period. Data gathering and utilization of methods took place at the Medical Microbiology Department of the Prachatice Hospital (Nemocnice Prachatice, a.s.). To identify microbes to a more precise level, the commercial set ENTEROtest 24 N and INDOL test were used. The disk diffusion method and method for determining the minimum inhibitory concentration were used to determine sensitivity to antimicrobial agents. The commercial set MASTDISC AmpC and ESBL (D68C) were used to detect ESBL. The outcomes indicated that the number of Escherichia coli strains producing ESBL and Klebsiella pneumoniae strains producing ESBL grew almost each year (with the exception of 2016). The outcomes also indicated that the greatest number of ESBL producers were found with Klebsiella pneumoniae strains. Furthermore, the ESBL producers were grouped depending on hospital departments in which most frequent occurrences were found; the most frequent ESBL occurrence of both producers was found in the department of internal medicine. Additionally, the ESBL producers were grouped based on capture in various types of clinical materials; the greatest quantities of both microbes were found in urine. Based on these findings, the development of antibiotic resistance for both microbes over the period of 5 years was analyzed on samples of urine. When monitoring antibiotic resistance development, no considerable growths in bacterial strains resistant to individual anti-microbial agents was found over the 5 year period. Only for 3rd generation cephalosporins, there was a certain growth in resistance detected almost every year for both microbes. Namely, Escherichia coli isolates showed a growth from 6 % to 9 % and Klebsiella pneumoniae isolates showed a growth from 29 % to 33 % in the percentual quantity of strains resistant to these antibiotics.
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