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New antimcrobial peptides isolated from the bee venom and the study of their action mechanism
Čujová, Sabína ; Čeřovský, Václav (advisor) ; Fusek, Martin (referee) ; Hlaváček, Jan (referee)
EN The growing emergence of bacteria resistant to conventional antibiotics is very alarming. This has prompted an intensive search for alternative antimicrobial agents which kill bacteria with different modes of action than do traditional antibiotics and do not develop drug resistance. Among these, antimicrobial peptides (AMPs) are considered as promising compounds against resistant pathogens. These positively charged peptides permeabilize or disrupt bacterial cell envelope which leads to leakage of cytoplasmic components and cell death. The aim of my dissertation thesis was the study of the action mechanism of novel antimicrobial peptides which I have isolated from the venom of different wild bees. I identified six novel AMPs which were named panurgines (PNG), codesane (COD) and antapines (ANTPs). These peptides were isolated from the venom of three different bee species (Panurgus calcaratus, Collete daviesanus and Anthophora plumipes). I was also involved in the structural studies of lasiocepsin (Las), the antimicrobial peptide identified in the venom earlier in our laboratory. All studied peptides possess activity against various strains of bacteria and low or moderate hemolytic activity. We prepared series of PNG, COD and ANTP analogs in order to study the effect of physicochemical properties...
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Glutamatergic synaptic transmission, targeting and distribution of metabotropic glutamate receptor in neuronal cells
Techlovská, Šárka ; Blahoš, Jaroslav (advisor) ; Vyklický, Ladislav (referee) ; Fusek, Martin (referee)
Stránka 7│146 ABSTRACT An evolutionary developed eukaryotic proteins for transformation of extracellular signal into intracellular targets are receptors. There are known receptors integrated to intracellular organelle membranes e.g. inositol-3-phosphate receptor (Inositol-3-phoshpate receptor; IP3R) specific for endoplasmic reticulum or nuclear receptors e.g. receptors for gonad hormones transforming the intracellular signals, however the vast majority of receptors are present on plasmatic membrane and recognize an extracellular signals. High percentage of these receptors are included in family of proteins called G-protein coupled receptors, (G-protein coupled receptors, GPCRs) due to their signal mediators heterotrimeric G-proteins. Each receptor of this family has the preference to specific type of G-protein influencing the intracellular concentrations of Ca2+ , cyclic adenosinmonophosphate or inositol-3- phosphate. Some of them are able to signalise by dual manner or through G-protein independent pathways. Independently on cellular target membrane, GPCRs integration into membranes is enables by the content of GPRCs-specific 7-transmembrane domain (7-transmembrane domain, 7TM) which is consist of hydrophobic amino acids. The relation between the structure and functionality is very tightly related. Many...
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Peptide inhibitors immobilized on magnetic particles and Sepharose used for separation of stomach aspartate proteinases
Rajčanová, Michaela ; Kučerová, Zdenka (advisor) ; Fusek, Martin (referee) ; Pacáková, Věra (referee)
IN ENGLISH Human gastric juice contains mainly aspartate proteinases: pepsin A and pepsin C. Both pepsins are produced by gastric mucosa as inactive pepsinogens and they are activated to the corresponding pepsins in the acidic environment of the gastric lumen. The levels of pepsinogens in serum reflect the morphological and functional status of gastric mucosa. A subject of this thesis is a part of a long-term investigation that focuses on the elaboration of methods for separation gastric aspartate proteainases that would be suitable for diagnostic purposes. The preparation of new type ligands was a concrete subject of PhD. thesis that after their immobilization they can enable the separation of aspartate proteinases. Four heptapeptides containing D-leucinyl residue were synthetized (Val-D-Leu-Pro-Phe-Phe-Val- D-Leu, Val-D-Leu-Pro-Tyr-Phe-Val-D-Leu, Val-D-Leu-Pro-Tyr-Tyr-Val-D-Leu and Val-D- Leu-Pro-Phe-Tyr-Val-D-Leu. The prepared heptapeptides immobilized on agarose magnetic particles were used for the study of their interaction with porcine pepsin A and rat pepsin C. While porcine pepsin A was adsorbed to all heptapeptides immobilized to magnetic particles, rat pepsin C was not retarded. Similar results were obtained using heptapeptides immobilized to Sepharose. The situation was more complicated...
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Antimicrobial peptides isolated from the venom of hymenopterous insect
Monincová, Lenka ; Čeřovský, Václav (advisor) ; Macek, Tomáš (referee) ; Fusek, Martin (referee)
Rapid development of bacterial resistance and multiresitance to conventional antibiotics has resulted in an intensive search for alternative antimicrobial agents. Antimicrobial peptides (AMPs) belong to promising anti-infective candidates since they do not development bacterial resistance. They kill microbes by disturbing or permeabilizing the cytoplasmic membrane, or may target putative key intracellular compartments. Their advantages include fast action and selectivity between prokaryotic and eukaryotic cells. We have isolated several novel AMPs from the venom of wild bees: halictines (HAL-1 and HAL-2) from Halictus sexcinctus, lasiocepsin (Las) from Lasioglossum laticeps and macropin (MAC-1) from Macropis fulvipes. They are active against Gram-positive and Gram- negative bacteria and against yeast Candida albicans. While halictines and macropin have moderate hemolytic activity, Las shows no hemolytic activity. A novel AMP was isolated also from the mucus of Xiphydria camelus. This AMP belongs to the category of insect defensins. It contains 55 amino acid residues, three disulphide bridges and its C-terminus is amidated. CD and NMR studies of HAL-1, HAL-2 and MAC-1 revealed propensity to form amphipathic α-helical structure in the presence of sodium dodecyl sulfate or trifluoroethanol. For the...
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Peptide inhibitors immobilized on magnetic particles and Sepharose used for separation of stomach aspartate proteinases
Rajčanová, Michaela ; Kučerová, Zdenka (advisor) ; Fusek, Martin (referee) ; Pacáková, Věra (referee)
IN ENGLISH Human gastric juice contains mainly aspartate proteinases: pepsin A and pepsin C. Both pepsins are produced by gastric mucosa as inactive pepsinogens and they are activated to the corresponding pepsins in the acidic environment of the gastric lumen. The levels of pepsinogens in serum reflect the morphological and functional status of gastric mucosa. A subject of this thesis is a part of a long-term investigation that focuses on the elaboration of methods for separation gastric aspartate proteainases that would be suitable for diagnostic purposes. The preparation of new type ligands was a concrete subject of PhD. thesis that after their immobilization they can enable the separation of aspartate proteinases. Four heptapeptides containing D-leucinyl residue were synthetized (Val-D-Leu-Pro-Phe-Phe-Val- D-Leu, Val-D-Leu-Pro-Tyr-Phe-Val-D-Leu, Val-D-Leu-Pro-Tyr-Tyr-Val-D-Leu and Val-D- Leu-Pro-Phe-Tyr-Val-D-Leu. The prepared heptapeptides immobilized on agarose magnetic particles were used for the study of their interaction with porcine pepsin A and rat pepsin C. While porcine pepsin A was adsorbed to all heptapeptides immobilized to magnetic particles, rat pepsin C was not retarded. Similar results were obtained using heptapeptides immobilized to Sepharose. The situation was more complicated...
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New antimcrobial peptides isolated from the bee venom and the study of their action mechanism
Čujová, Sabína ; Čeřovský, Václav (advisor) ; Fusek, Martin (referee) ; Hlaváček, Jan (referee)
EN The growing emergence of bacteria resistant to conventional antibiotics is very alarming. This has prompted an intensive search for alternative antimicrobial agents which kill bacteria with different modes of action than do traditional antibiotics and do not develop drug resistance. Among these, antimicrobial peptides (AMPs) are considered as promising compounds against resistant pathogens. These positively charged peptides permeabilize or disrupt bacterial cell envelope which leads to leakage of cytoplasmic components and cell death. The aim of my dissertation thesis was the study of the action mechanism of novel antimicrobial peptides which I have isolated from the venom of different wild bees. I identified six novel AMPs which were named panurgines (PNG), codesane (COD) and antapines (ANTPs). These peptides were isolated from the venom of three different bee species (Panurgus calcaratus, Collete daviesanus and Anthophora plumipes). I was also involved in the structural studies of lasiocepsin (Las), the antimicrobial peptide identified in the venom earlier in our laboratory. All studied peptides possess activity against various strains of bacteria and low or moderate hemolytic activity. We prepared series of PNG, COD and ANTP analogs in order to study the effect of physicochemical properties...
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