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Influence of ionic strength on the properties of ionic amphiphilic pairs
Filipová, Lenka ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
The Bachelor thesis studies catanionic vesicle systems consisting of ion pair amphiphile (IPA) and their properties in the presence of ionic strength. Ion pair amphiphile was prepared from single-chained surfactants: cationic surfactant HTMAB (hexadecyltrimethylammonium bromide) and anionic surfactant SDS (sodium lauryl sulfate). Cationic double-chained surfactant DDAC (dimethyldioctadecylammonium chloride) was added in order to stabilize the vesicle system and make it positively charged. Cholesterol was also added to further stabilize the vesicle system. The system is considered to be relatively stable when consisting of 90 % IPA and 10 % DDAC with 43 mol.% cholesterol in a membrane. The stability of the system can be disrupted by external factors such as ionic strength. The Ionic strength was induced by NaCl solutions of varying concentrations (0.0, 0.5, 1.0, 2.0, 50.0, 100.0, 150.0 and 300.0 mM). The change of properties of a vesicle system, which was induced by ionic strength, was analyzed by electrophoretic and dynamic light scattering, fluorescence anisotropy, and generalized polarization. –potential was obtained by electrophoretic light scattering analysis which determines the stability of the system. Dynamic light scattering measurement resulted in the determination of the size of vesicles. The fluidity of vesicles’ membranes was examined by fluorescence anisotropy with DPH (1,6-diphenyl-1,3,5-hexatriene) as a probe. The hydration shell of vesicles was observed by generalized polarization with Laurdan (2-(dimethylamino)-6-dodecanoylnaphthalene) as a probe. As a result, it was found out that low ionic strength (0.5 to 2.0 mM) causes a decrease in the size of vesicles and high ionic strength (50.0 to 300.0 mM) causes vesicles to grow in size. –potential showed a consistent trend for the whole concentration series – its value rapidly decreasing with increasing ionic strength. The samples with the concentrations of salt 50.0 to 300.0 mM were considered unstable according to the –potential data. Fluorescence anisotropy decreases with increasing temperature and increasing ionic strength. The value of generalized polarization decreases with increasing temperature; hence there is more solvation of a vesicle membrane. The highest value of generalized polarization was measured when the concentration of sodium chloride was relatively high (from 50.0 to 300.0 mM), as a result of which the membrane was less hydrated and therefore, more organized.
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Effect of changing ionic strength on the properties of catanionic vesicles from HTMA-DS
Filipová, Lenka ; Klučáková, Martina (referee) ; Mravec, Filip (advisor)
This diploma thesis is focused on evaluating the influence of ionic strength on catanionic vesicules made of ion pair amphiphile (IPA) in the form of HTMA-DS (hexadecyltrimethylammonium-dodecyl sulphate). Catanionic vesicles were stabilized by the addition of cationic surfactant dioctadecyldimethylammonium chloride (DODAC) and cholesterol. The ionic strength was attained by adding CaCl2 and Na2SO4 salts in the concentrations 0–300 mM. The changes influenced by ionic strength were studied by dynamic and electrophoretic light scattering (DLS and ELS), fluorescence anisotropy, generalized polarization (GP), pH measurement, and visual observation. During this experiment, the temperature was set both constant and altering in time. The measurement was performed shortly after adding salts to the catanionic vesicles and in-time measurement was performed as well. This thesis follows a bachelor thesis, where the influence of NaCl on the same type of catanionic vesicles in the same range of ionic strength was studied. The CaCl2 and Na2SO4 influences were then compared to the NaCl according to Hofmeister series. By the DLS and ELS method it was found that the size of vesicles with added CaCl2 and Na2SO4 was decreasing at first and then increasing whereas the -potential was exponentially decreasing with increasing ionic strength. The vesicle size, when the ionic strength was applied, was increasing in time while -potential was almost constant in time. The addition of both salts caused slight dehydration of the external part of the membrane which was examined by the fluorescent probe Laurdan (6-dodecanoyl-2-dimethylamino-naphthalene) and generalized polarization. By fluorescence anisotropy with the probe DPH (1,6-diphenyl-1,3,5-hexatriene), it was detected that both salts caused an increase of the fluidity of an inner part of a membrane. By both of the fluorescent techniques, it was confirmed that the increase in temperature caused a phase transition of the membrane from the solid ordered through the liquid ordered phase to the liquid disordered phase. The pH values also did not show any change with the addition of salts. When comparing the salts’ influence (CaCl2 and Na2SO4 versus NaCl) on catanionic vesicles it was found that in most cases NaCl influenced the observed properties the most. The addition of NaCl caused the largest increase in vesicle size, highest -potential values, initial dehydration of the external part of the membrane, and increased fluidity of the inner part of the membrane at I > 15 mM. These results are in agreement with the Hofmeister series. Based on the visual observation, the samples with ionic strength of more than 150 mM for CaCl2 and 75 mM for Na2SO4 were said to be unstable. This fact is in agreement with the result of ELS. The rest of the samples did not show any visual changes in time (28 days). Additionally, the influence of PBS buffer on catanionic vesicles at the same ionic strength values was studied. PBS buffer simulates the ionic environment of living organisms. Its' influence was characterized by the same methods under the same conditions as mentioned above. The effect of PBS on catanionic vesicles displayed almost the same behaviour in the observed properties. During this experiment, it was also found that the PBS influence on the studied properties was more significant than the influence of CaCl2, Na2SO4, and NaCl salts. Influence of PBS was most similar to the effect of NaCl on catanionic vesicles.
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Rozdílné mikrobiální aktivity v rhizosféře trav Festuca ovina a Calamagrostis epigejos
Filipová, Lenka
The diploma thesis "Different microbial activity in the rhizosphere of grasses Festuca ovina and Calamagrostis epigejos" deals with the issue of climate change and eutrophication and their impact on the stability of rare habitats, specifically dry acidophilous grasslands in the Podyjí national park. The aim of the thesis is to study and collect the available sources about the issue of the interaction of soil microorganisms and plant roots in exceptional and protected dry grassland ecosystems, which are colonized by aggressive expansion of Calamagrostis epigejos, thereby compromising their integrity and stability. This issue is still not fully understood. Review of literature in the thesis describes the explanation of the most significant part of the issue - the nutrient cycling in ecosystems, C: N ratio, the role of microorganisms in the soil, and the importance of microbial processes in the rhizosphere and in grassland ecosystems generally. In the experimental part the hypothesis - that drought stress and eutrophication causes changes in the plant - microorganisms - soil system, which result in destabilization of the system, by an increase in leakage of nitrate and ammonium ions from the soil, and in changes in the quantity and quality of underground and aboveground biomass of Festuca ovina -- was confirmed.
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MOBILE MARKETING IN MARKETING MANAGEMENT OF NON-PROFIT ASSOCIATION
FILIPOVÁ, Lenka
Mobile marketing is one of the youngest marketing branch. It was found out that mobile marketing was not used in any publication yet, but it can be very usefull for non profit association. For this purpose was used marketing research. 85 % of all informants knew what is DMS, 46 % have already send DMS and 65 % of all informants would be willing to download logo, wallpapers or animation in case that the fee would be used for charitable purposes . We found out other instruments of mobile marketing that can be used in non profit organization's fundraising and merchandising.
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Distribution and genetic variation of invasive crayfish of the genus Orconectes
Filipová, Lenka ; Petrusek, Adam (advisor) ; Kozák, Pavel (referee)
Crayfish are an important part of European fauna, but since the 19th century native crayfish species have been largely influenced by biological invasions, when large number of their populations was dramatically reduced due to the introduction of the pathogen of the crayfish plague (oomycete Aphanomyces astaci) to Europe. Several North American crayfish species were then brought to the European continent to substitute lost populations of native crayfish, the most widespread being the spiny-cheek crayfish (Orconectes limosus), the signal crayfish (Pacifastacus leniusculus) and the red swamp crayfish (Procambarus clarkii). However, these crayfish can carry pathogen of the crayfish plague and therefore represent a serious threat to the native species. My work focused mostly on the spiny-cheek crayfish (O. limosus). Available literature data suggest that the species was brought to Europe only once, and all European individuals may be descendants of the founder population. However, other cases of introduction may not have been documented, and cannot be ruled out. The first aim of my thesis was to evaluate the haplotype variation of the spiny-cheek crayfish populations from Europe and North America. Mitochondrial gene for cytochrome c oxidase subunit 1 (COI) of selected O. limosus individuals from several...
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Influence of ionic strength on the properties of ionic amphiphilic pairs
Filipová, Lenka ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
The Bachelor thesis studies catanionic vesicle systems consisting of ion pair amphiphile (IPA) and their properties in the presence of ionic strength. Ion pair amphiphile was prepared from single-chained surfactants: cationic surfactant HTMAB (hexadecyltrimethylammonium bromide) and anionic surfactant SDS (sodium lauryl sulfate). Cationic double-chained surfactant DDAC (dimethyldioctadecylammonium chloride) was added in order to stabilize the vesicle system and make it positively charged. Cholesterol was also added to further stabilize the vesicle system. The system is considered to be relatively stable when consisting of 90 % IPA and 10 % DDAC with 43 mol.% cholesterol in a membrane. The stability of the system can be disrupted by external factors such as ionic strength. The Ionic strength was induced by NaCl solutions of varying concentrations (0.0, 0.5, 1.0, 2.0, 50.0, 100.0, 150.0 and 300.0 mM). The change of properties of a vesicle system, which was induced by ionic strength, was analyzed by electrophoretic and dynamic light scattering, fluorescence anisotropy, and generalized polarization. –potential was obtained by electrophoretic light scattering analysis which determines the stability of the system. Dynamic light scattering measurement resulted in the determination of the size of vesicles. The fluidity of vesicles’ membranes was examined by fluorescence anisotropy with DPH (1,6-diphenyl-1,3,5-hexatriene) as a probe. The hydration shell of vesicles was observed by generalized polarization with Laurdan (2-(dimethylamino)-6-dodecanoylnaphthalene) as a probe. As a result, it was found out that low ionic strength (0.5 to 2.0 mM) causes a decrease in the size of vesicles and high ionic strength (50.0 to 300.0 mM) causes vesicles to grow in size. –potential showed a consistent trend for the whole concentration series – its value rapidly decreasing with increasing ionic strength. The samples with the concentrations of salt 50.0 to 300.0 mM were considered unstable according to the –potential data. Fluorescence anisotropy decreases with increasing temperature and increasing ionic strength. The value of generalized polarization decreases with increasing temperature; hence there is more solvation of a vesicle membrane. The highest value of generalized polarization was measured when the concentration of sodium chloride was relatively high (from 50.0 to 300.0 mM), as a result of which the membrane was less hydrated and therefore, more organized.
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Genetic variation in North American crayfish species introduced to Europe and the prevalence of the crayfish plague pathogen in their populations
Filipová, Lenka
- ABSTRACT (IN ENGLISH) - Biological invasions by crustaceans represent a serious threat for native species in Europe. In my thesis I focus on non-indigenous freshwater crayfish introduced to Europe and their parasite Aphanomyces astaci, the pathogen of the crayfish plague. The thesis consists of four already published first-author papers (chapters I, II, IV and V), two first-author manuscripts (chapters III and VI), and one paper which I co-authored (chapter VII). The first part (chapters I-V) focuses on genetic variation in North American crayfish introduced to Europe. We showed that in two crayfish species, both successful invaders in Europe, genetic variation differs significantly, reflecting their different colonization histories on the continent. The spiny-cheek crayfish Orconectes limosus was likely introduced to Europe just once, in small numbers (90 individuals). Variation at the mitochondrial DNA (mtDNA) level in the spiny-cheek crayfish in Europe is much lower compared to North America (chapter I), although some variation was revealed by nuclear markers in its Central European populations (chapter II). In contrast, the signal crayfish Pacifastacus leniusculus was introduced to Europe several times, in large numbers. Its European populations are highly diverse genetically and belong to a single...
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