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Taxonomic classification of yeasts associated with meadow plants
Čurillová, Natália ; Ing.Hana Dudášová, Ph.D. (oponent) ; Horváthová, Ágnes (vedoucí práce)
In total 60 yeast strains isolated from meadow flowers were selected for identification using MALDI-TOF biotyping. Selected yeast strains were prepared according to standard (Bruker) method and method developed at Institute of Chemistry SAS in Bratislava for MALDI-TOF yeast identification. To acquire valuable data two cultivating media were used. The principle of identification embody in comparing obtained mass spectra according to the score of selected yeast strain isolated from meadow plants, formerly identified by physicobiochemical properties (verification of their taxonomic classification) or the new isolates (their identification) with mass spectra of the reference yeast cultures. Reference yeast cultures were identified by sequencing the D1/D2 of 26S rRNA domain. In total 53 yeast strains were identified by biotyping at species level. The remaining 7 yeast strains were designed to be identified by sequencing the D1/D2 26S rRNA domain as the reference mass spectra were not available. The highest abundance of yeast species was as follows Metschnikowia pulcherrima (12 %), Rhodotorula spp. (12 %), Cystofilobasidium infirmominiatum (10 %), Metschnikowia reukaufii (7 %), Metschnikowia fructicola (7 %), Sporobolomyces metaroseus (7 %), Hanseniospora uvarum (5 %), Rhodotorula mucilaginosa (5 %), Meyerozyma guillermondii (5 %), Cystofilobasidium macerans (3 %) a Rhodotorula dairenensis (3 %), and yeast strains of species Candida bombi, Pichia kudravzievii, Cystofilobasidium capitatum, Cystofilobasidium macerans, Solicoccozyma aeria, Sporidiobolus salmonicolor, Papiliotrema flavescens, Sporidiobolus metaroseus, Sporidiobolus pararoseus and Cryptococcus wieringae were identified as well. In general, the most diverse abundance of yeast species were isolated from meadow plants comparing to the older studies.
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Study of yeasts transglycosylases
Čurillová, Natália ; Ing.Hana Schusterová, Ph.D. (oponent) ; Stratilová, Eva (vedoucí práce)
This study is interested in properties of fungal transglycosylases, specifically Phr1, Phr2 and Crh2. These enzymes are involved in the remodelling of yeast cell walls due to their cleavage of structural donor polysaccharides and transfer of their fragments to the other acceptor (poly)saccharide molecules. The mammalian cells do not contain cell walls, nor cell wall transglycosylases, that´s why these enzymes are possible targets for antifungal agents. In this diploma thesis the effect of 67 commercially available inhibitors on Phr1 and Phr2 enzymes was studied by rapid screening. In the case of the Phr1 enzyme, two inhibitors showed a potential effect which was subsequently tested by size exclusion chromatography column incorporated into HPLC device. None of the inhibitors were found to have an inhibitory effect on Phr1 or Phr2 enzymes in contrast to DMSO in which all inhibitors were dissolved. The mode of action of Phr enzymes was also studied by thin layer chromatography and high performance liquid chromatography. The first method allowed to monitor the formation of products only in the later stages of the reaction, but more sensitive size exclusion chromatography showed the product formation at the beginning of the reaction. Phr1 cleaved the donor substrate near the non-reducing end and forms small fragments that are transfered to labeled acceptors during the whole reaction. Phr2 utilized random action pattern, thus creating products with higher molecular weight from the beginning of reaction. The effect of the polymerization degree of acceptor on it´s affinity with the Crh2 was also studied. The Michaelis-Menten constants showed no effect of acceptor lenght on the affinity between enzyme and substrate.
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Study of yeasts transglycosylases
Čurillová, Natália ; Ing.Hana Schusterová, Ph.D. (oponent) ; Stratilová, Eva (vedoucí práce)
This study is interested in properties of fungal transglycosylases, specifically Phr1, Phr2 and Crh2. These enzymes are involved in the remodelling of yeast cell walls due to their cleavage of structural donor polysaccharides and transfer of their fragments to the other acceptor (poly)saccharide molecules. The mammalian cells do not contain cell walls, nor cell wall transglycosylases, that´s why these enzymes are possible targets for antifungal agents. In this diploma thesis the effect of 67 commercially available inhibitors on Phr1 and Phr2 enzymes was studied by rapid screening. In the case of the Phr1 enzyme, two inhibitors showed a potential effect which was subsequently tested by size exclusion chromatography column incorporated into HPLC device. None of the inhibitors were found to have an inhibitory effect on Phr1 or Phr2 enzymes in contrast to DMSO in which all inhibitors were dissolved. The mode of action of Phr enzymes was also studied by thin layer chromatography and high performance liquid chromatography. The first method allowed to monitor the formation of products only in the later stages of the reaction, but more sensitive size exclusion chromatography showed the product formation at the beginning of the reaction. Phr1 cleaved the donor substrate near the non-reducing end and forms small fragments that are transfered to labeled acceptors during the whole reaction. Phr2 utilized random action pattern, thus creating products with higher molecular weight from the beginning of reaction. The effect of the polymerization degree of acceptor on it´s affinity with the Crh2 was also studied. The Michaelis-Menten constants showed no effect of acceptor lenght on the affinity between enzyme and substrate.
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Taxonomic classification of yeasts associated with meadow plants
Čurillová, Natália ; Ing.Hana Dudášová, Ph.D. (oponent) ; Horváthová, Ágnes (vedoucí práce)
In total 60 yeast strains isolated from meadow flowers were selected for identification using MALDI-TOF biotyping. Selected yeast strains were prepared according to standard (Bruker) method and method developed at Institute of Chemistry SAS in Bratislava for MALDI-TOF yeast identification. To acquire valuable data two cultivating media were used. The principle of identification embody in comparing obtained mass spectra according to the score of selected yeast strain isolated from meadow plants, formerly identified by physicobiochemical properties (verification of their taxonomic classification) or the new isolates (their identification) with mass spectra of the reference yeast cultures. Reference yeast cultures were identified by sequencing the D1/D2 of 26S rRNA domain. In total 53 yeast strains were identified by biotyping at species level. The remaining 7 yeast strains were designed to be identified by sequencing the D1/D2 26S rRNA domain as the reference mass spectra were not available. The highest abundance of yeast species was as follows Metschnikowia pulcherrima (12 %), Rhodotorula spp. (12 %), Cystofilobasidium infirmominiatum (10 %), Metschnikowia reukaufii (7 %), Metschnikowia fructicola (7 %), Sporobolomyces metaroseus (7 %), Hanseniospora uvarum (5 %), Rhodotorula mucilaginosa (5 %), Meyerozyma guillermondii (5 %), Cystofilobasidium macerans (3 %) a Rhodotorula dairenensis (3 %), and yeast strains of species Candida bombi, Pichia kudravzievii, Cystofilobasidium capitatum, Cystofilobasidium macerans, Solicoccozyma aeria, Sporidiobolus salmonicolor, Papiliotrema flavescens, Sporidiobolus metaroseus, Sporidiobolus pararoseus and Cryptococcus wieringae were identified as well. In general, the most diverse abundance of yeast species were isolated from meadow plants comparing to the older studies.
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