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Antimicrobial activity of carbon-based fillers
Stuchlíková, Olga ; Hermanová, Soňa (referee) ; Voběrková, Stanislava (advisor)
Diplomová práce se zabývá vlivem uhlíkatého plniva na životaschopnost a produkci extracelulárních látek vybrané bakterie Bacillus subtilis (CCM 1999) a kvasinky Yarrowia lipolytica (CCY 29-26-52). Antimikrobiální aktivita těchto částic, přítomných v kultivačním mediu, byla sledována pomocí následujících parametrů: růst daného mikroorganismu, produkce extracelulárních proteinů a v poslední řadě byla monitorována produkce extracelulárních polymerních substancí, které mají úzkou souvislost s tvorbou biofilmu. Suspenze materiálů (0,135 mg/mL) byly připraveny ve dvou rozdílných kultivačních mediích; tzn. živné medium s obsahem glukózy pro Bacillus subtilis a bazální medium s přídavkem Tweenu 80 pro Yarrowia lipolytica, a media byla inokulována příslušným typem mikroorganismu. Experimenty probíhaly po dobu 6 dnů při rychlosti třepání 160 rpm a teplotě 30 °C pro Bacillus subtilis a 28 °C pro Yarrowia lipolytica. Testovány byly celkem tři typy uhlíkatého nanomateriálu, získané z Katedry anorganické chemie, Vysoké školy chemicko-technologické v Praze. Tyto materiály specifikované jako materiál “A”, “B” a “C” se navzájem lišily velikostí částic a stupněm oxidace. Na základě skríningových studií byla vybrána koncentrace testovaného materiálu 0,135 mg/mL a rychlost třepání 160 rpm. Metodou měření optické hustoty vzorku při 600 nm byly sestaveny a porovnány růstové křivky obou mikroorganismů v přítomnosti testovaných nanočástic po dobu 5 dní. Tímto způsobem bylo zjištěno, že přítomnost nanočástic v mediu nemá velký vliv na růst zkoumaného mikroorganismu. Tato metoda, je však pouze orientační, protože se nevyhneme chybě díky přítomnosti mrtvých buněk. Dále byla testována produkce celkových a extracelulárních proteinů daným mikroorganismem v přítomnosti testovaných nanočástic. Nebyla však pozorována výrazná odchylka hodnot od hodnot kontrolního vzorku, který neobsahoval testovaný materiál. Na základě metod počítání kolonií (Bacillus subtilis) a buněk (Yarrowia lipolytica) byly určeny ztráty životaschopnosti mikroorganismu ve 3 časech (6, 48 a 144 hodin); v kratším časovém intervalu byl růst spíše podporován. Dále byla monitorována produkce extracelulárních polymerních substancí (EPS), tedy proteinů, redukujících substancí a polysacharidů. Tyto látky byly vylučovány daným mikroorganismem do prostředí v průběhu 24 hodin. Bacillus subtilis produkoval EPS ve větší míře než Yarrowia lipolytica. Předpokládáme, že produkce EPS by mohla souviset s tvorbou biofilmu, který chrání buňky před toxicitou nanočástic.
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Antimicrobial effect of plant extracts
Konderla, Patrik ; Vespalcová, Milena (referee) ; Veselá, Mária (advisor)
The purpose of this bachelor thesis was to research the possible antimicrobial activity of various extracts of rosehip tea and also determine the antioxidant activity and the concentration of biologically active compounds (polyphenols and flavonoids) in these tea. Teoretical part describes basic information about plant Rosa canina and chemical composition of rosehips, summary of the natural biologically active compounds and general classification of tea. The practical part is focused on detection of antimicrobial activity of tea extracts against bacterial strains Serratia marcescens and Bacillus subtilis as well as spectrophotometrical determination of concentration polyphenols, flavonoids and overall antioxidant activity of these extracts. From the results flow the testing aqueous extracts rosehips tea analysed antimicrobial effects. Also was found, that these extracts has high content of polyphenols and flavonoids.
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Characterization of organic nanoparticles with encapsulated antimicrobial peptides
Vejrostová, Petra ; Němcová, Andrea (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on characterization of particles containing encapsulated antimicrobial enzyme lysozyme. The theoretical part deals with characterization of antimicrobial peptides and their description. Further part of review was focused on lysozyme, the selected representative used in this thesis, its structure, mechanism of action and possible usage. In the experimental part the Hartree-Lowry method was used for lysozyme detection, determination of encapsulation efficiency and for detecting the amount of lysozyme released after incubation in model physiological environment and in model foods. In process of encapsulation the highest amount of lysozyme was packed into 1% chitosan particles, manually prepared alginate particles and into liposomes. During study of stability of particles in model foods as the least stable manually prepared chitosan particles were found. The released lysozyme exhibited changes probably caused by its degradation. The highest influence on particles proved 3% acetic acid. During studying the stability of the particles in artificial digestive fluids as the most unstable manually prepared chitosan particles were found, while alginate particles were the most stable. The thesis also deals with changes in antimicrobial activity of encapsulated lysozyme in prepared particles and after its application into the model environments. A gram-positive bacteria Bacillus subtilis was used in order to test the antimicrobial activity. Antimicrobial tests showed that after encapsulation antimicrobial activity of lysozyme was substantially decreased in most samples. Size and stability of prepared particles was tested using dynamic light scattering.
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Preparation and testing of application forms for natural antimicrobial substances
Vajglová, Klára ; Bokrová, Jitka (referee) ; Márová, Ivana (advisor)
The goal of this bachelor thesis was the study of antimicrobial and antioxidant effects of some herbal extracts: cloves, nettle, sage, chamomile, rosemary, elderberry, lavender and also lysozyme. Further, herbal extracts effect on Gram positive and Gram negative bacteria were compared. In the theoretical part were briefly characterized lysozyme, polyphenols, flavonoids and selected strains of microorganisms. In the experimental section characterization of herbs with antimicrobial and antioxidant effect was proved. Particles containing herbal extracts were prepared and encapsulation efficiency was determined. In some of tested herbs encapsulation efficiency of up to 80% was reached. Stability of the prepared liposomes was tested in the model digestive conditions and after 1 week and 1 month incubation period in model foods. Antimicrobial activity was tested on selected representatives of Gram negative and Gram positive bacteria. Gram positive bacteria were more sensitive to herbal extracts and liposomes containing encapsulated herbs, while lysozyme exhibited higher effect to Gram negative bacteria. Prepared particles with encapsulated antimicrobial extracts are especially suitable for use in the food industry.
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In vitro and in vivo antimicrobial effect of lasioglossins on the Candida albicans
Kašperová, A. ; Turánek, J. ; Čeřovský, Václav ; Raška, M.
Lasioglossins represent a new group of amphipathic α-helical peptides with significant antimicrobial effect on the Candida albicans. This study examines the antifungal activity of two peptides LL-III and all D-LL-III as measured by the suppression of Candida proliferation and suppression of induced morphological differentiation both in in vitro and in vivo assays. In the in vitro Candida proliferation assay, the inhibitory effect of lasioglossins LL-III and all D-LL-III was more than 70% within 24 h and more than 84% after 48 h of incubation (final concentration of either peptide was 17.5 .mu.M). Delaying of blastoconidial transition to hyphae in vitro and tendency to suppress vaginal candidiasis in experimental mice were detected.
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Different charged short lipopeptides
Ježek, R. ; Slaninová, Jiřina ; Králová, M. ; Macková, M.
Series of short peptides palmitoylated in different positions was designed, synthesized and tested for antimicrobial activities. The palmitoyl group was situated either on the alpha - amino group in position 1 or on the epsilon - amino group of lysine in position 3. The peptide charge ranged from –3 to +4. The peptide part of the lipopeptides constituted mainly from lysine, arginine and glutamic acid.
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Lucifensin, a peptide behind the maggot therapy
Čeřovský, Václav
The larvae of the green bottle fly (Lucilia sericata) are routinely used as a medication for the treatment of necrotic, non-healing and highly infected wound in many hospitals all over the world. We have identified and determined primary structure of the defensin originated from the immune system of Lucilia sericata larvae and named it lucifensin. This is 40 amino acid residues and three intramolecular disulfide bridges peptide. The synthetic lucifensin was active against Gram-positive bacteria and was not hemolytic. We studied the importance of lucifensin disulfide bridges and the N-terminal part of its molecule for the structure and for antimicrobial activity.
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