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Structure and properties of bacterial biofilms
Mrázová, Kateřina ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This thesis deals with the study of basic properties of cells of bacterial biofilm produced by PHA producing bacteria, specifically Burkholderia cepacia and Burkholderia sacchari. Two cultivation approaches were used to compare different types of cells: at first, the cells were cultivated in bioreactor providing both planktonic and biofilm attached cells, secondly, cells grown on Petri dishes were also included in the study. In experimental part the affinity of each type of cells to hydrophobic phase was studied using BATH method. It was found that sessile cells, either biofilm associated cells as well as cells taken from Petri dishes, prefer hydrophobic phases more than planktonic cells. Also size and Zeta potential were measured using Dynamic Light Scattering (DLS). It was found for studied samples that, cells in these samples tend to aggregate and the difference of size between both types of cells occurs only for biofilm of the strain Burkholderia cepacia. Finally the impact of presence various bacterial cells types on surface tension of water as well as amount of PHA cumulated in different types of cells were observed.
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Adsorption of microbial cells on model biological surfaces
Mikušová, Janka ; Krouská, Jitka (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis is creating sorption surface suitable for studying adsorption bacterial strain Lactobacillus rhamnosus, as representative probiotic bacterial strain. Included in the experimental part of this thesis was the process of creating sorption surface, according to the designed and especially optimized method. Optimization method comprised of preparing sorbent with sorption surface including mucin, on which was the bacterial strain Lactobacillus rhamnosus bound to, using specific interaction. UV-VIS spectrophotometry was utilized in the optimization of the sorption surface preparation for monitoring losses of mucin in solution that happens during the bondation on used substrate. Designed sorption surfaces were subjected to various physical-chemical analyses, which roles were displaying and characterisation of surface and confirming the presence of mucin. One of the major components, in the process of observing and characterization of changes in surface structure of the sorption surface, was infrared spectroscopy with Fourier transformation. Scanning electron microscopy was used for more detailed observation of the surface structure, created by adhesive interactions, which participate in probiotic bacteria adhesion. Finally, the created surfaces were used in pilot experiment, during which, the kinetics in growing bacterial culture with and without the presence of sorbent using microcalorimetry were observed. Designed sorbent appears to be a suitable mediator for detailed characterisation of bacterial adhesion, which is the first step in creating bacterial biofilm.
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Polyhydroxyalkanoates and their role in bacterial biofilms
Rucká, Markéta ; Samek,, Ota (referee) ; Obruča, Stanislav (advisor)
This master thesis deals with polyhydroxyalkanoates (PHA) and their role in bacterial biofilms. In the theoretical part the polyhydroxyalkanoates, bacterial biofilm and the relationship between them were reviewed. The experimental part focused on differences in PHA production by planktonic and biofilm cells. In order to study selected topic, bacterial strains of Burkholderia cepacia and Burkholderia sacchari were cultivated using a CDC biofilm reactor. The attention was paid to quantity and especially to the form in which PHA occurs in planktonic and biofilm cells. Results of Raman spectroscopy have shown that PHA exists exclusively in native amorphous form in planktonic bacterial cells. On the other hand, in biofilm PHA occurs also in a partially crystalline form. In addition, the resistance of planktonic and biofilm cells against various stress factors and the effect of osmotic stress on PHA production was tested too. According to the results of the experiment, when the bacteria were exposed to different stress factors (high temperature, low temperature, presence of detergent and so forth) biofilm cells showed a higher stress resistance than planktonic cells. Apart from slowing cell growth and reproduction, increased osmotic pressure in the culture medium also caused decrease of PHA production. In addition, planktonic cells responded to external stimuli more sensitively than biofilm ones.
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Experimental study on the adsorption of bacterial cells on solid surfaces
Kahanovská, Kristína ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This diploma thesis focuses on an optimalization of simple laboratory model systems which serve as an innovative tool for an experimental study on the adsorption of bacterial cells on solid surfaces. In the description of living biological systems, an adsorption is labelled as an adhesion. Designed model systems were validated with a physical-chemical analysis. Various techniques were used to determine bacteria properties, more specifically Burkholderia cepacia and Bacillus megaterium. The solid surfaces after sorption of bacterial cells of Bacillus megaterium were subjected to a structural and visual analysis. Applying the theoretical approach (e.g. using different physical-chemical models) to study the adhesion of microorganisms to a particular surface allows a prediction of the conditions for a successful adhesion. The results will give us a better understanding of a formation and development of a biofilm.
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Selection of suitable disinfections to prevent the spread of Corynebacterium pseudotuberculosis in farms focused on the production of milk products and meat
Liová, Alexandra ; Pořízka, Jaromír (referee) ; Marková,, Jiřina (advisor)
This diploma thesis deals with the selection of suitable disinfectants and their effective concentrations for the prevention of the spread of the causative agent of caseous lymphadenitis in sheep and goat farms with a focus on milk processing, dairy and cheese production or meat production. For these purposes, disinfectants were selected from the group of quaternary ammonium compounds, oxidizing compounds, biguanides and alcohols, which were tested according to the ČSN EN 1656 standard on Corynebacterium pseudotuberculosis isolates forming a biofilm. The theoretical part first deals with the general characterization of the bacterial species Corynebacterium pseudotuberculosis and caseous lymphadenitis. In other chapters, the bacterial biofilm, its formation and the factors that influence it are described. Last but not least, the theoretical part is focused not only on the legislative treatment of the use or testing of disinfectants, but also on the closer characterization of their individual groups. In the experimental part, the procedure for determining the sensitivity of Corynebacterium pseudotuberculosis biofilms to selected disinfectants (benzalkonium chloride, chlorhexidine digluconate, ethanol, iodinated povidone, sodium hypochlorite and peracetic acid) was first optimized according to the ČSN EN 1656 standard. The optimization was followed by the cultivation and formation of biofilms of Corynebacterium pseudotuberculosis and the evaluation of their intensity by spectrophotometric determination of optical density. Subsequently, tested disinfectants were applied to the obtained biofilms, and after 24 hours of incubation from the end of the disinfection process, the effectiveness of the tested disinfectants was visually evaluated. At the end of the research, the minimum bactericidal concentrations for individual disinfectants were determined and the concentrations of these substances suitable for preventing and preventing the spread of the bacterium Corynebacterium pseudotuberculosis in small ruminant farms were also selected.
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Evaluation of the effectiveness of selected methodical approaches for disagregation of staphylococcal biofilm biomass
Nosková, Martina ; Konečná, Klára (advisor) ; Jílek, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Subject of study: Bioanalytical laboratory diagnostics in healtcare Student: Bc. Martina Nosková Supervisor: RNDr. Klára Konečná, Ph.D. Title: Evalution of the effectiveness of selected methodical approaches for disagregation of staphylococcal biofilm biomass Background: Evaluation of the impact of selected biochemical and physical approaches on the disaggregation of the biofilm community formed by the bacterium Staphylococcus aureus. For the biochemical approach was chosen enzyme proteinase K, the impact of sonication, shaking with/without glass beads was studied within the physical approaches. Methods: Staphylococcal biofilm was formed in vitro in two methodical configurations - in the wells of a microtiter plate and on pegs (analogy to the Calgary Biofilm Device). To evaluate the degree of consistency of the obtained data, which reflects the homogenity of the biofilm biomass disaggeragation, the "recovery" method, and the method of metabolic activity evaluation, using the Alamar Blue indicator. To express the degree of effectiveness of the chosen approaches on the overall disaggregation of the biofilm community, the method of quantification of biofilm biomass by crystal violet staining was...
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Evaluation of the effectiveness of selected methodical approaches for disagregation of staphylococcal biofilm biomass
Nosková, Martina ; Konečná, Klára (advisor) ; Jílek, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Subject of study: Bioanalytical laboratory diagnostics in healtcare Student: Bc. Martina Nosková Supervisor: RNDr. Klára Konečná, Ph.D. Title: Evalution of the effectiveness of selected methodical approaches for disagregation of staphylococcal biofilm biomass Background: Evaluation of the impact of selected biochemical and physical approaches on the disaggregation of the biofilm community formed by the bacterium Staphylococcus aureus. For the biochemical approach was chosen enzyme proteinase K, the impact of sonication, shaking with/without glass beads was studied within the physical approaches. Methods: Staphylococcal biofilm was formed in vitro in two methodical configurations - in the wells of a microtiter plate and on pegs (analogy to the Calgary Biofilm Device). To evaluate the degree of consistency of the obtained data, which reflects the homogenity of the biofilm biomass disaggeragation, the "recovery" method, and the method of metabolic activity evaluation, using the Alamar Blue indicator. To express the degree of effectiveness of the chosen approaches on the overall disaggregation of the biofilm community, the method of quantification of biofilm biomass by crystal violet staining was...
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Adsorption of microbial cells on model biological surfaces
Mikušová, Janka ; Krouská, Jitka (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis is creating sorption surface suitable for studying adsorption bacterial strain Lactobacillus rhamnosus, as representative probiotic bacterial strain. Included in the experimental part of this thesis was the process of creating sorption surface, according to the designed and especially optimized method. Optimization method comprised of preparing sorbent with sorption surface including mucin, on which was the bacterial strain Lactobacillus rhamnosus bound to, using specific interaction. UV-VIS spectrophotometry was utilized in the optimization of the sorption surface preparation for monitoring losses of mucin in solution that happens during the bondation on used substrate. Designed sorption surfaces were subjected to various physical-chemical analyses, which roles were displaying and characterisation of surface and confirming the presence of mucin. One of the major components, in the process of observing and characterization of changes in surface structure of the sorption surface, was infrared spectroscopy with Fourier transformation. Scanning electron microscopy was used for more detailed observation of the surface structure, created by adhesive interactions, which participate in probiotic bacteria adhesion. Finally, the created surfaces were used in pilot experiment, during which, the kinetics in growing bacterial culture with and without the presence of sorbent using microcalorimetry were observed. Designed sorbent appears to be a suitable mediator for detailed characterisation of bacterial adhesion, which is the first step in creating bacterial biofilm.
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Experimental study on the adsorption of bacterial cells on solid surfaces
Kahanovská, Kristína ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This diploma thesis focuses on an optimalization of simple laboratory model systems which serve as an innovative tool for an experimental study on the adsorption of bacterial cells on solid surfaces. In the description of living biological systems, an adsorption is labelled as an adhesion. Designed model systems were validated with a physical-chemical analysis. Various techniques were used to determine bacteria properties, more specifically Burkholderia cepacia and Bacillus megaterium. The solid surfaces after sorption of bacterial cells of Bacillus megaterium were subjected to a structural and visual analysis. Applying the theoretical approach (e.g. using different physical-chemical models) to study the adhesion of microorganisms to a particular surface allows a prediction of the conditions for a successful adhesion. The results will give us a better understanding of a formation and development of a biofilm.
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Structure and properties of bacterial biofilms
Mrázová, Kateřina ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This thesis deals with the study of basic properties of cells of bacterial biofilm produced by PHA producing bacteria, specifically Burkholderia cepacia and Burkholderia sacchari. Two cultivation approaches were used to compare different types of cells: at first, the cells were cultivated in bioreactor providing both planktonic and biofilm attached cells, secondly, cells grown on Petri dishes were also included in the study. In experimental part the affinity of each type of cells to hydrophobic phase was studied using BATH method. It was found that sessile cells, either biofilm associated cells as well as cells taken from Petri dishes, prefer hydrophobic phases more than planktonic cells. Also size and Zeta potential were measured using Dynamic Light Scattering (DLS). It was found for studied samples that, cells in these samples tend to aggregate and the difference of size between both types of cells occurs only for biofilm of the strain Burkholderia cepacia. Finally the impact of presence various bacterial cells types on surface tension of water as well as amount of PHA cumulated in different types of cells were observed.
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