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The use of algal test in ecotoxicology
Hájková, Tereza ; Zlámalová Gargošová, Helena (referee) ; Doležalová Weissmannová, Helena (advisor)
This diploma thesis deals with a use of algal test in ecotoxicology. A freshwater algae, Desmodesmus subspicatus, was used to asses the ecotoxicity of selected chemical substances. A spectrophotometry method, of VIS spectrum, was used in evaluation of the EC50. A correlation, between a number of algal cells and the wavelength absorbance at 683 nm, has been determined for this purpose. Following chemicals were tested, 2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetic acid, (RS)-2-[4-(2-methylpropyl)phenyl]propanoic acid and N-(4-hydro-xyphenyl)acetamide. An EC50 value was determined for all these substances and also their ecotoxicity has been evaluated.
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Role of variable chains at the interface between subunits in forming ATP-binding pocket and function of P2X4 receptor
Tvrdoňová, Vendula ; Zemková, Hana (advisor) ; Novotný, Jiří (referee) ; Vlachová, Viktorie (referee)
7 ABSTRACT Crystallization of the zebrafish P2X4 receptor in both open and closed states revealed conformational differences in the ectodomain structures, including the dorsal fin and left flipper domains. The role of these domains in forming of ATP-binding pocket and receptor function was investigated by using alanine scanning mutagenesis of the R203- L214 (dorsal fin) and the D280-N293 (left flipper) sequences of the rat P2X4 receptor and by examination of the responsiveness to ATP and orthosteric analog agonists 2- (methylthio)adenosine 5'-triphosphate, adenosine 5'-(γ-thio)triphosphate, 2'(3'-O-(4- benzoylbenzoyl)adenosine 5'-triphosphate, and α,β-methyleneadenosine 5'- triphosphate. ATP potency/efficacy was reduced in 15 out of 26 alanine mutants. The R203A, N204A, and N293A mutants were essentially non-functional, but receptor function was restored by ivermectin, an allosteric modulator. The I205A, T210A, L214A, P290A, G291A, and Y292A mutants exhibited significant changes in the responsiveness to orthosteric analog agonists. In contrast, the responsiveness of L206A, N208A, D280A, T281A, R282A, and H286A mutants to analog agonists was comparable to that of the wild type receptor. These experiments, together with homology modeling, indicate that residues of the first group located in the upper part of...
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The use of algal test in ecotoxicology
Hájková, Tereza ; Zlámalová Gargošová, Helena (referee) ; Doležalová Weissmannová, Helena (advisor)
This diploma thesis deals with a use of algal test in ecotoxicology. A freshwater algae, Desmodesmus subspicatus, was used to asses the ecotoxicity of selected chemical substances. A spectrophotometry method, of VIS spectrum, was used in evaluation of the EC50. A correlation, between a number of algal cells and the wavelength absorbance at 683 nm, has been determined for this purpose. Following chemicals were tested, 2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetic acid, (RS)-2-[4-(2-methylpropyl)phenyl]propanoic acid and N-(4-hydro-xyphenyl)acetamide. An EC50 value was determined for all these substances and also their ecotoxicity has been evaluated.
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Biosensors for Environmental Monitoring and Biomedical Applications
ŠTOFIK, Marcel
Study of biosensors has become an essential part of research in biotechnology. Biosensors as fast, portable, highly sensitive, and low-cost bioanalytical detection devices have been utilized in many fields of human activity. The first part of the presented work focuses on electrochemical biosensors for rapid environmental screening of herbicides as water pollutants. A sol-gel immobilization method for a photosystem II (PSII) complex is studied in order to enhance the sensitivity and the signal strength and stability of a PSII-based biosensor. Computer simulations of a PSII biosensor are employed with the aim to find out how the immobilization membrane properties influence the biosensor parameters. Newly developed immobilization by a thin-layer membrane based on the results of computer simulations and revised measurement protocols are presented. The second part of the work is devoted to synthesis and electrochemical detection of newly developed metal labels for electrochemical immunosensors. The synthesis of dendrimer-encapsulated silver nanoparticles and biorecognition properties of biotin-nanocomposite conjugates are discussed. For detection of synthesized labels, a microfluidic detector was manufactured and tested and different approaches to packing of a microfluidic chip employing polydimethylsiloxane (PDMS) were investigated. Newly designed microstructures for a microfluidic separator of magnetic beads (MBs) were studied by computer simulations. The separator was made and trapping of MBs for the further employment in MBs-based immunoassays are presented
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