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PREPARATION AND CHARACTERIZATION OF NATURAL EXTRACTS WITH ANTIMICROBIAL EFFECT
Vysoká, Marie ; Obruča, Stanislav (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
Celosvětová spotřeba antibiotik v posledních několika desetiletích významně vzrostla, což vedlo ke zvýšenému výskytu genů antibiotické rezistence (ARG), které představují rostoucí vážnou hrozbu pro lidské zdraví na celém světě. Používání přírodních nebo alternativních léčivých přípravků tudíž v posledních několika letech výrazně vzrostlo. Velká pozornost je nyní věnována přírodním extraktům, které by mohly být v jisté formě použity jako jedna z možností léčby bakteriálního onemocnění, a to s vysokou účinností proti patogenům a se zanedbatelnými vedlejšími účinky. Biomasa kvasinek, která obsahuje cenné mastné kyseliny, sacharidy, nukleové kyseliny, vitamíny a minerály, byla testována jako možná alternativa, a to samotná i v kombinaci s rostlinnými extrakty ve formě doplňku stravy. Tato disertační práce je zaměřena na studium antimikrobiální aktivity a nutriční přínosy vybraných rostlinných extraktů, jako je acai, hřebíček, kurkuma, zázvor, ženšen a oregano. Následně byly testovány biologické účinky kvasinkové biomasy rodu Metschnikowia pulcherrima CCY 029-002-145, Cystofilobasidium infirmominiatum CCY 17-18-4, Phaffia rhodozyma CCY 77-1, Rhodotorula kratochvilovae CCY 20-2-26. Tyto kvasinky byly vybrány zejména pro vysoký obsah aktivních látek v produkované biomase. Na závěr byl posouzen potenciální synergický efekt rostlinných extraktů ve spojení s kvasinkovou biomasou ke zvýšení celkového antimikrobiálního účinku, antioxidační aktivity a vlivu na růst buněčných linií Caco-2, B16F1 a HaCaT. Vzhledem k dosaženým výsledkům lze konstatovat, že zařazení imortalizované kvasinkové biomasy v kombinaci s přírodními extrakty do doplňků stravy ve vhodné formě může být prospěšné lidskému zdraví. Existuje přímý vztah mezi životaschopností buněk a apoptózou. Všechny mikrobiální extrakty vykazovaly určité pozitivní výsledky na apoptózu u rakovinných buněčných linií a současně nevykazovaly žádné cytotoxické účinky na nezhoubné buněčné linie při stejných koncentracích.
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Production and application of antimicrobial substances produced by lactic acid bacteria
Utíkalová, Kristýna ; Dzurická, Lucia (referee) ; Márová, Ivana (advisor)
The bachelor’s thesis deals with the production of antimicrobial substances by selected lactic acid bacteria of the genera Lactobacillus, Pediococcus and Bifidobacterium, in which the production of bacteriocins was assumed based on the conducted research. Bacteriocins are peptide-based antimicrobial substances with the potential to be widely used primarily as biopreservatives in the food industry. The theoretical part of the bachelor’s thesis focuses on antimicrobial substances produced by probiotic bacteria with a further concentration on bacteriocins produced by selected bacterial species and their current research and application in the industry. In the experimental part, the antimicrobial activity of prepared isolates from probiotic bacteria was tested on selected gram-negative and gram-positive bacteria. Specifically, this was done by the agar diffusion method, the broth dilution method and the cell viability test using resazurin. The amount of lactic acid and acetic acid in the individual isolates was determined using high performance reverse-phase liquid chromatography, which made it possible to further discuss their influence on the antimicrobial activity of the isolates. Strong antimicrobial activity against indicator bacteria was found in all isolates. For some isolates, it was higher than the antimicrobial activity of lactic acid itself together with its concentration which is found in the isolate according to the measurements. That is a significant stimulus for further research of these probiotic isolates, especially the L. acidophilus and L. plantarum isolates. For example, it was found that the tested isolate from L. acidophilus showed an inhibitory activity against S. epidermidis of 90,76 % and 81,62 % against E. coli at a concentration of 20,47 mg/ml. The isolate from L. acidophilus was subsequently applied to plant packaging with the potential of usage in the food industry, and the inhibitory activity of this isolate against contaminating microorganisms was observed.
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Production and characterization of antimicrobial substances from lactic acid bacteria
Franeková, Eliška ; Smetana, Jan (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on the production of antimicrobial compounds using lactic acid bacteria, their characterization and testing of their antimicrobial activity. The theoretical part of this work deals with the characteristics of lactic acid bacteria and the bacteriocins they produce, the possibilities of bacteriocin production and the factors that influence it. In the experimental part of this work, lactic acid bacteria Lactococcus lactis subsp. lactis, Lactobacillus helveticus and Bifidobacterium bifidum were cultivated, their growth curves and total protein content in supernatants after cultivation were measured. Cell-free culture supernatants were prepared by lyophilization and their antimicrobial activity against gram-positive and gram-negative bacteria was determined. The antimicrobial activity of commercial antimicrobial peptide nisin and a commercial preservative obtained using lactic acid bacteria was also measured. The sample obtained from Bifidobacterium bifidum was selected as the most effective of the isolates. Its antimicrobial activity was further tested on polymeric sausage packaging materials. Antimicrobial substances produced by lactic acid bacteria can be used in the food industry as preservatives or as a part of antimicrobial packaging, and in the pharmaceutical industry in materials for antimicrobial wound dressings.
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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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Testing of the sensitivity of bacteria on selected substances in school environment
Švehlová, Vendula ; Pavlasová, Lenka (advisor) ; Skýbová, Jana (referee)
The aim of this bachelor thesis lies in describing and executing of methods which are determining the resistance of various types of bacteria to antibiotics and selected common household disinfectants and also selected products for oral hygiene. Due to the structure of these methods they can be used f.e. in practical classes in grammar or high schools. Antibiotic discs and other supplies are used when examining resistence of bacteria towards antibiotics which are affordable for aforementioned schools. We can see the efficiency of various antibiotics and disinfectants and we can easily decide which ones are worth of purchase and which ones are not very functional alltogether. Last items tested are samples of mouthwashes and toothpastes. The mechanisms behind the efficiency of all these substances and the sensitivity of bacteries will be described either in practical and theoretical part of this thesis. Key words: Antimicrobials substances, resistance, inhibition, agar soil, bacteria
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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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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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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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Characterization of antiobiotic activity of nonpathogenic streptomyces isolated from human tissue.
ŽLÁBKOVÁ, Zuzana
The bachelor thesis is focused on characterization of ten strains of streptomycetes isolated from human clinical samples. Streptomycetes are soil bacteria known for their production of secondary metabolites with characteristic antibiotic, antihelmitic, anti-cancerous and antiviral effects. The objective of my work is to characterise microbiologically the antibacterial and antifungal action of these circa ten taxonomically classified isolates on strains of typical human pathogens from the group of Gram-positive and Gram-negative bacteria, yeast and fungi.
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