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Influence of PHA accumulation on resistance of bacteria against selected antibacterial drugs
Hrabalová, Vendula ; Kučera, Dan (referee) ; Obruča, Stanislav (advisor)
The aim of this bachelor thesis was to study the effect of bactericidal drugs on bacteria from the genus C. necator H16 and its mutant genus PHB-4. The genus H16 shows ability to accumulate polyhydroxyalkanoates (PHA) in the form of granules while the genus PHB-4 lacks to show this ability. The theoretical part of the bachelor thesis is focused on the effect of antibiotics on bacteria in general and the determination of susceptibility of bacteria to antimicrobial substances. The effect of three specific antibiotics (nisine, streptomycin and penicillin) on both bacterial strains was tested in the experimental part. The viability of bacteria was determined by the spread plate method and flow cytometry. Agar diffusion test and broth microdilution test were used to test the susceptibility of bacteria. It was concluded that the accumulation of PHA decreases the tolerance of bacteria to antimicrobial substances because the genus C. necator H16 is more susceptible to streptomycin and penicillin then the strain C. necator PHB-4.
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Antimicrobial materials based on nanostructures with enzymes
Jurová, Bronislava ; Vysoká, Marie (referee) ; Skoumalová, Petra (advisor)
This bachelor thesis is focused on the preparation and characterization of antimicrobial gels and coatings containing antimicrobial components and enzymes. The theoretical part deals with a brief description of antimicrobial substances, their structure and mainly enzymes with antimicrobial effect. The methods used in the testing are also listed here. The practical part deals with testing the antimicrobial effects of extracts from cinnamon and cloves, clove essential oil, lysozyme and bromelain against Micrococcus luteus, Serratia marcescens and Candida glabrata. Various types of extracts were prepared from the selected spices, namely aqueous and ethanol extracts in different percentages. The individual extracts were characterized and, according to the total proportion of phenolic substances, the best ones were selected for encapsulation in liposome particles and gels. Extracts and enzymes were also added to the hydrogel and non-fibrous covers. A solution of sodium alginate and chitosan was used to prepare non-fibrous covers. A broth dilution method was used to test the antimicrobial effects on the given microorganisms. Furthermore, nanofibers based on PHB were prepared using the forcespinning method. These nanofibers were enriched with clove essential oil and their antioxidant activity was monitored.
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Screening of biotechnological potential of selected members of the genus Geobacillus and other related genuses
Kouřilová, Xenie ; Brázda, Václav (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with selected thermophilic representatives of genera Geobacillus, Saccharococcus and Bacillus, taking screening of its biotechnological potential into account. Bacteria from the first two genera came from Czech and German collection of microorganisms, while bacteria of genus Bacillus were natural isolates. Researched strains were examined from a viewpoint of carbon source utilization and furthermore, production of biosurfactants, extracellular hydrolytic enzymes (protease, amylase, lipase, cellulase, xylanase), organic acids, antimicrobial agents and microbial plastics – polyhydroxyalkanoates was also tested. Bacteria S. thermophilus, G. uzenensis and G. zalihae evinced a substantial ability of biosurfactant production. Strains G. jurassicus, G. uzenensis, G. gargensis and G. lituanicus were capable of intensive production of all tested, technologically significant enzymes. Highest antimicrobial effects were reached with bacteria G. stearothermophilus and G. thermocatenulatus. Largest production of acetic acid was achieved with G. jurassicus and lactic acid with G. thermodenitrificans. Ability to produce polyhydroxyalkanoates was proved at genotype level by some cultures only, however at fenotype level, response was negative. On the contrary, bacteria genus Bacillus were able to produce polyhydroxyalkanoates, although in small amounts under given circumstances. With remaining researched metabolites, production ability was considerably lower, compared to genera Geobacillus and Saccharococcus.
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Testing of lactic acid bacteria Lactobacillus genus for bacteriocins production
Volecová, Veronika ; Němcová, Andrea (referee) ; Trachtová, Štěpánka (advisor)
Antimicrobial substances, or bacteriocins are substances produced by probiotic lactic acid bacteria. They have a positive effect on the gastrointestinal tract of humans and are especially suitable for the food, but also the pharmaceutical industry. The aim of the thesis was the molecular identification of lactic acid bacteria of the Lactobacillus genus, species and their subsequent inclusion PCR method. Using the PCR method were tested also genes responsible for the production of bacteriocins. To confirm the production of bacteriocins has been selected the microbiological method, agarose droplet spot-test. In the present study also included the bioinformatics part to assess the specificity and non-specificity of the primers using in Primer-BLAST program.
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Methods for detection of antimicrobial properties of lactic acid bacteria
Vránová, Petra ; Němcová, Andrea (referee) ; Trachtová, Štěpánka (advisor)
Lactic acid bacteria are classified as probiotics producing substances that act against microorganisms. These antimicrobial substances include organic acids, carbon dioxide, hydrogen peroxide and bacteriocins. Currently, the focus is on bacteriocins, which are used in the food and pharmaceutical industries. The aim of this thesis is creating an overview of antimicrobial properties of lactic acid bacteria, methods of their determination and their applications in the food industry. The experimental part deals with identification of lactic acid bacteria present in selected samples of bacterial DNA. In addition, we tested for bacteriocin Gassericin K7A-producing gene. Molecular diagnostic methods such as real-time polymerase chain reaction (qPCR) and conventional polymerase chain reaction were used to distinguish bacterial DNA as well as the bacteriocin.
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Use of cell cultures to test cytotoxicity of natural substances
Blažková, Veronika ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
This thesis is aimed on study of cell cultures, primarily on introduction of techniques for cultivation of human cells and optimization of their usage in cytotoxicity tests. The thesis is aimed preferably on natural substances and liposomes that are suitable to be used in cosmetics. Theoretical part contains literature review focused on overview of cell cultures, appropriate cultivation conditions for in vitro testing and summary of cytotoxicity tests. Experimental part contains characteristics of natural extracts with antimicrobial effect in terms of content of polyphenols, flavonoids and antioxidant activity. Further, these extracts were encapsulated into the liposomes. Encapsulation effectivity was determined. Distribution of particles size by dynamic light scattering and finally also stability of prepared particles were also determined. Long-term stability in water and gel environment was tested too. This thesis also contains study of optimization of cell culture of human skin keratinocytes cultivation and use of those cells for testing cytotoxicity of selected natural substances by MTT method.
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Study of Probiotic Lactic Acid Bacteria Producing Antimicrobial Compounds
Turková, Kristýna ; Doležal, Petr (referee) ; Rada,, Vojtěch (referee) ; Španová, Alena (advisor)
The sixty-eight strains isolated from breastfed full-term infant feces and from another sources were identified using genus-specific polymerase chain reaction (PCR) for Lactobacillus, species-specific PCRs, multiplex PCR, pheS PCR, rep-PCR, RAPD-PCR and 16S rDNA sequencing into Lactobacillus species or group of species. Seven strains produced antimicrobial proteinaceous substances in the supernatants. Antimicrobial proteinaceous substances of three strains were tested on temperature, pH a detergent stability. All tested strains produced temperature-stable antimicrobial proteinaceous substances. Antimicrobial activity was not influenced by detergents with exception of SDS. Presence of genes for production of bacteriocins (acidocin B, gassericin A, gassericin T, gassericin K7A and gassericin K7B) were detected in DNA of fourteen strains using PCR and DNA/DNA hybridization. Selected PCR products were sequenced and analyzed using BLAST algorithm and CLUSTAL W2 programme. The sequences of specific PCR products in DNA of two strains had 100% similarity with the sequences from the database GeneBank. Selected strains of Lactobacillus acidophilus group were tested for the surveillance in gastrointestinal tract, for the production of antimicrobial substances, for the adhesion on Caco-2 cells and for the presence of genes of antibiotic resistance. DNA of strains was tested using specific primers on the presence of genes for histidine-decarboxylase, tyrosine-decyrboxylase and linoleate isomerase. The gene for histidine-decarboxylase production was detected in DNA of seven strains, for tyrosine-decarboxylase production in DNA of one strain and for linoleate isomerase in DNA of four strains. Imunomagnetic separation of the cells was optimized. Magnetic particles functionalized with streptavidin and the anti-Lactobacillus antidote was used for the separation of the cells of Lactobacillus rhamnosus LOCK 0900 from MRS medium, UHT milk and from the yogurt. The IMS-PCR was used for detection of imunomagnetic separated bacterial cells.
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Antimicrobial substances from plants and their application in acne preparations
Alexová, Adéla ; Byrtusová, Dana (referee) ; Němcová, Andrea (advisor)
The aim of the bachelor thesis is a determination of selected active substances of various plants and their possible application in cosmetic products for acne. In the theoretical part, an inventory of active substances including their effects in cosmetic products has been developed. Furthermore, the work is focused on characteristics of certain types of plants, mechanisms of antimicrobial effects and the emergence and treatment of acne. In the experimental part of this work the contents of biologically active substances, antioxidant and antimicrobial activity in extracts from selected plant species are characterized, namely from flowers of Levandula angustifolia, Matricaria chamomilla, Calendula officinalis, Syzygium aromaticum, leaves of Salvia officinalis and leaves of Rosmarinus officinalis. The plant extracts are also tested in different mixtures. Plant extracts and mixtures are incorporated into a recipe of acne cosmetic products. Their inhibitory effect against Propionibacterium acnes which causes acne and against representatives G+, G- and yeast Micrococcus luteus, Escherichia coli and Candida glabrata is observed. From the results it is clear that the best products against acne are micellar water and possibly skin lotion. The biggest amount of active substances is in cosmetic products which contain Matricaria, Syzygium and Rosmarinus. Overall effect of active substances is lower in cosmetic products than in 100% extracts.
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Toxicity study of antimicrobial wound dressings and perspective novel nanomaterials
Kozlíčková, Hana ; Vojtová, Lucy (referee) ; Zajíčková, Lenka (advisor)
This bachelor thesis deals with the study of toxicity of selected commercial antimicrobial wound dressings (StopBac STERILE, containing silver ions and Traumacel Biodress Disinfect, containing chlorhexidine) and antimicrobial nanomaterial, provided by CEITEC BUT laboratories. The experimental part of the work describes the preparation of this polycaprolactone nanomaterial, on which a layer of copper was subsequently deposited by the magnetron sputtering system BESTEC (MAGNETRON). Furthermore, a method was designed to study the cytotoxicity of individual shelters with antimicrobial additives. These tests were performed in vitro on cell cultures by leaching the materials in the laboratories of the Faculty of Science, Masaryk University in Brno. We found that, with the exception of chlorhexidine, low concentrations of active substances extracted from the materials promoted the proliferation of the studied cells, while at high concentrations there were also cytotoxic effects. The analysis of individual materials was also performed using scanning electron microscopy and energy dispersive X-ray spectroscopy.
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Bakteriociny a jejich aplikace v potravinářském a farmaceutickém průmyslu
Tesarčík, David
This bachelor thesis deals with bacteriocins, their current utilisation and potential use in the future at food industry and pharmacy. The first part of the thesis focuses on their general description, their chemical and biological properties,as well as on their ecological importance and synthesis. Than it summarises their distribution to individual classes and subclasses. There are briefly mentioned some representatives of certain classes, together with germs, which produce them,as well as their properties. The second part of thesis deals with utilisation of bacteriosins in the food industy and pharmacy. There are par-ticular examples of bacteriosins yet utilised. Especially in case of food preservation. Next there is a summary of the potential utilisations of these agents in the future. Which are either in the stage of research, testing or theory.
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