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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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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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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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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.
|
|
|
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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