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Ergothioneine and mycothiol in the biosynthesis of lincosamides
Seidlová, Bára ; Kameník, Zdeněk (advisor) ; Kopecký, Jan (referee)
Specialized microbial metabolites are described as low-molecular-weight bioactive compounds, which are dispensable for the growth, evolution, or reproduction of its producer. This group of substances includes the lincosamides, which are produced mainly by the bacteria of the Streptomyces genera. Apart from other precursors, two low-molecular-weight thiols, ergothioneine and mycothiol, are essential participants of the lincosamide biosynthesis. Mycothiol (MSH) serves in this pathway as a source of sulphur, on the other hand, ergothioneine (ESH) constitutes a conjugate with the aminosugar moiety of lincosamide structure. The conjugate is condensed with an activated amino acid, which is catalyzed by an unusual enzyme to form a core of the lincosamide molecule. The objective of this diploma thesis is to isolate the conjugate of ESH and aminooctose, which serves as a substrate of the LmbD biosynthetic protein. Another aim is to study the links between the thiol metabolism and the biosynthesis of three lincosamides, lincomycin, celesticetin, and intervencin, which are produced by different bacterial strains. Bacterial strains were cultivated under laboratory conditions and methods of liquid chromatography with UV and MS detection were used for the analysis. The parameters of the methods were developed...
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Chromatographic characterization of an ion-exchange column
Seidlová, Bára ; Sobotníková, Jana (advisor) ; Křížek, Tomáš (referee)
The following evaluation procedure was selected for the charterized ion-exchange column Phenosphere™ SCX. First of all, a set of biologically interesting analytes was selected. This set contained several basic drugs, specifically five tricyclic antidepressants (TCA), an anesthetic called procaine and a substance with antimalaric and antiarrythmic effect - quinidine. For this set of basic substances were the separation conditions optimized on a characterized ion-exchange column Phenosphere™ SCX. The effect of the mobile phase composition on chromatographic behaviour of selected drugs was investigated, for instance the effect of used buffer and its concentration, buffer pH and the effect of addition of the organic modifier (in this case methanol). Under optimized chromatographic conditions for basic drugs analysis the ion-exchange column was characterized using LSER (Linear Solvation Energy Relationship). The chromatographic behaviour of the test substances with known molecular descriptors was found and then the multiple linear regression between retention factors of test substances and their molecular descriptors was done. The results of the multiple linear regression were discussed and then the interactions contributing to the analyte retention on the investigated cation-exchange column...
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