National Repository of Grey Literature 8 records found  Search took 0.00 seconds. 
The effect of antibiotics on human gut microbiome and the influence of probiotics on its restoration
Hloucalová, Nikola ; Lichá, Irena (advisor) ; Ulrych, Aleš (referee)
Antibiotics are used for treatment of bacterial infections. They negatively affect not only the pathogens, but also other microorganisms in the gut, including the beneficial bacteria. Antibiotic treatment changes the proportion of good versus bad bacteria in the gut, causes a decrease in the number of commensal bacteria and leads to the overgrowth of opportunistic pathogens. We should consume probiotics during and after the antibiotic treatment, otherwise it results in an unhealthy stool and moreover it affects the immune system which then leads to physical and mental illnesses. This thesis summarizes the influence of probiotics on human gut during dysbiosis caused mainly by antibiotics.
The cell wall biosynthesis in gram-positive bacteria and inhibitory effect of antibiotics.
Mašková, Kateřina ; Ulrych, Aleš (advisor) ; Lichá, Irena (referee)
The cell wall of Gram-positive bacteria includes, in addition to the core peptidoglycan molecule, unique polysaccharides such as teichoic acids, capsular polysaccharides and exopolysaccharides, and covalently bound surface proteins. Together, they create a strong and durable layer that provides protection but also communication with the external environment. Peptidoglycan biosynthesis in Gram-positive bacteria can be divided into three phases: cytoplasmic, membrane and extracytoplasmic phase. The individual phases consist of specific reactions that are catalyzed by often conserved bacterial enzymes, which are potential targets for antibiotic molecules. Most known antibiotics effective against Gram-positive bacteria are aimed at inhibiting the process of cell wall synthesis. The mechanisms of action of individual antibiotics are described with varying degrees of detail. Some are known and widely used in medicine or veterinary practice, and some have so far only shown the potential to become drugs. Another use of antibiotics is in the basic research itself, especially in the study of cell wall biosynthesis and bacterial division. In this work, I have compiled a summary of knowledge about cell wall biosynthesis of Gram-positive bacteria and a list of antibiotics and a description of the mechanisms of...
Identification of new substrates of Ser/Thr protein kinase StkP
Kleinová, Simona ; Ulrych, Aleš (advisor) ; Konopásek, Ivo (referee)
Streptococcus pneumoniae encodes single serine/threonine protein kinase StkP and its cognate protein phosphatase PhpP. This signalling couple phosphorylates/dephosphorylates many target proteins involved in various cellular processes. So far, only few ot them was characterized in detail. Global phosphoproteomic analysis in the ∆stkP mutant strain background resulted in the identification of protein Spr0175 as phosphorylated on threonine 7. The main aim of this work was to characterize this new substrate. The ∆spr0175 mutant strains were prepared in the wild type genetic background Rx and R6 and then monitored for their growth and cell morphology. Mutant strains exhibited morphological defects revealing potential involvement of Spr0175 in the process of cell division. In the wild type D39 the deletion was unsuccesful, which may entail possible essentiality of Spr0175 in D39 strain. The results obtained also confirmed that the Spr0175 is modified in in vitro and in vivo conditions at threonine 7. In vitro study also confirmed minor phosphorylation at T4 residue. By using co-immunoprecipitation assay we demonstrated that Spr0175 protein can form oligomeric structures. Another aim of this work was cellular localization of Spr0175. By using fluorescent microscopy we showed that GFP-Spr0175 fusion...
Functional analysis of phosphoglucosamine mutase GlmM in Streptococcus pneumoniae
Mühldorfová, Tereza ; Ulrych, Aleš (advisor) ; Lišková, Petra (referee)
Phosphoglucosamine mutase (GlmM), an enzyme taking part in biosynthesis of cell wall, has been recently proven to be essential for Streptococcus pneumoniae. The main goal of this thesis was to prove in vivo that GlmM serine residues S99 and S101 phosphorylation is essential while the necessity of it was already proven indirectly based on transformation efficiency. For this purpose we have prepared a strain with two copies of the glmM gene - the first one with amino acid changes on monitored serine residues located at native locus; and the second ectopic copy of the wild allele of glmM gene under control of inducible zinc promoter. We have observed morphology, growth, and GlmM expression with and without the presence of an inductor. All the observed parameters show that the cells are not viable without ectopic glmM expression, thus the essential protein GlmM is functional only when phosphorylated on S99 and S101 residues. Further, we have attempted to localize the enzyme in the S. pneumoniae cell. We have fused GlmM with fluorescent marker GFP and by using the florescent microscopy we have proved that GlmM is cytoplasmic protein. Another goal of this thesis was to find an unknown third phosforylation site of the GlmM protein which is dependent on the protein kinase StkP. From in vitro kinase assay and...
The mechanism of action of phage tail-like bacteriocins on target cells and artificial membrane systems.
Hryzáková, Klára ; Fišer, Radovan (advisor) ; Ulrych, Aleš (referee)
Fonticins are phage tail-like bacteriocins produced by gram-negative bacterium Pragia fontium from the family Enterobacteriaceae. Phage tail-like bacteriocins can be divided into two different families: flexible ones (F-type) and contractile particles (R-type). Pragia fontium produces R-type particles that adsorb on the surface of sensitive bacterial cell and form pores probably during the contraction using mechanism similar to Type VI Secretion System. The pore-forming activity of fonticins was tested in vivo using bacterial cells. It was also characterized in vitro on artificial lipid membranes. On Black Lipid Membranes fonticins create large channels into the membranes; single channel conductance (G) is about two times higher than single channel conductance of well known α-hemolysine produced by Staphylococcus aureus. Further, we tested the voltage-dependent blocking of fonticin pores by native and unfolded proteins, dsDNA, ssDNA, polyethylene glycol and diamond nanoparticles. The rigid structure of fonticin nanotube in combination with constant conductivity makes it a promising device for analysing the size and shape of nanoparticles and large macromolecules. Key words: fonticin, bacteriocine, nanopore, Pragia fontium, blocking, pore-forming activity, black lipid membranes.
The role of Spr1851 protein Streptococcus pneumoniae in cell division
Jarošová, Václava ; Ulrych, Aleš (advisor) ; Seydlová, Gabriela (referee)
The role of Spr1851 protein Streptococcus pneumoniae in cell division Human extracellular pathogen S. pneumoniae encodes unique serin/threonine protein kinase of Eucaryotic type StkP and its cognate phosphatase PhpP. This kinase affects number of cellular processes including virulence, competence, cell division and cell wall synthesis by phosphorylating its substrates. Hypothetical protein Spr1851 named Jag was identified as a new StkP substrate in the membrane fraction by comparing the wild-type phosphoproteomes with StkP deleted strain. This protein consists of three domains and an interdomain region that contains T89 phosphorylation site. There is a Jag_N domain with an unknown function at the N-terminus. The C-terminus contains two domains - KH and R3H, which are highly conserved and their expected function is binding of nucleic acid. The main aim of this work is to explain the function of Jag protein, to determine the effect of individual domains on the phenotype and the localization of the protein and to determine the role of phosphorylation on T89. The results confirm that Jag protein could play a role in cell division or cell wall synthesis. Furthermore, the results indicate that the Jag_N domain is essential for the localization of the protein into the membrane, whereas the KH and R3H domains are...
The pleiotropic effect of WD-40 domain containing proteins on cellular differentiation and production of secondary metabolites in Streptomyces coelicolor
Ulrych, Aleš
The pleiotropic effect of WD-40 domain containing proteins on cellular differentiation and production of secondary metabolites in Streptomyces coelicolor WD-40 domains, also known as beta-transducin repeats, are highly conserved repeating amino acid units, which are found in a wide variety of eukaryotic proteins that have a range of different functions. In the late 1990s, the first WD-40 containing proteins were identified in prokaryotes, however the knowledge about their function is scarce. Streptomyces coelicolor is a gram-positive bacterium with complicated morphological and physiological differentiation in the course of its life cycle. The genome of Streptomyces coelicolor encodes 6 potential genes encoding proteins with WD-repeat motifs. To determine the function of two of these WD-40 genes (wdpB and wdpC), the deletion replacement mutants in both genes were prepared. Both mutants exhibited medium-dependent phenotypes, which are markedly evident on modified R3 plates. Phenotypic studies revealed that deletion of wdpB gene resulted in substantial reduction of aerial hyphae formation and reduced production of undecylprodigiosin. In addition, the hyphae of ΔwdpB mutant were unusually branched and showed the signs of precocious lysis. Delayed spore-containing hyphae were irregularly septated....
The pleiotropic effect of WD-40 domain containing proteins on cellular differentiation and production of secondary metabolites in Streptomyces coelicolor
Ulrych, Aleš ; Branny, Pavel (advisor) ; Pátek, Miroslav (referee) ; Španová, Alena (referee)
The pleiotropic effect of WD-40 domain containing proteins on cellular differentiation and production of secondary metabolites in Streptomyces coelicolor WD-40 domains, also known as beta-transducin repeats, are highly conserved repeating amino acid units, which are found in a wide variety of eukaryotic proteins that have a range of different functions. In the late 1990s, the first WD-40 containing proteins were identified in prokaryotes, however the knowledge about their function is scarce. Streptomyces coelicolor is a gram-positive bacterium with complicated morphological and physiological differentiation in the course of its life cycle. The genome of Streptomyces coelicolor encodes 6 potential genes encoding proteins with WD-repeat motifs. To determine the function of two of these WD-40 genes (wdpB and wdpC), the deletion replacement mutants in both genes were prepared. Both mutants exhibited medium-dependent phenotypes, which are markedly evident on modified R3 plates. Phenotypic studies revealed that deletion of wdpB gene resulted in substantial reduction of aerial hyphae formation and reduced production of undecylprodigiosin. In addition, the hyphae of ΔwdpB mutant were unusually branched and showed the signs of precocious lysis. Delayed spore-containing hyphae were irregularly septated....

Interested in being notified about new results for this query?
Subscribe to the RSS feed.