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Study of effect of Bacillus subtilis yxkO gene on motility during stress response to osmotic upshift.
Streitová, Eliška ; Lichá, Irena (advisor) ; Krásný, Libor (referee)
Bacillus subtilis is gram-positive soil bacteria. In its natural environment it is constantly exposed to changes of chemical and physical conditons, including changes of osmolality. It responds to high osmolality by transporting of potassium ions and afterthat transporting and/or synthetising of compatible solutes. In last years the mutant strain Bacillus subtilis L-42 was isolated with non-specific insertional mutagenesis (mini Tn10) in our laboratory. This strain displays limited growth and inability to cope with hyperosmotic shock in a defined medium with potassium concentration of < 1 mmol/l. Insertion of transposon was located in yxkO gene which encodes a protein of unknown biological function. Some other data also indicate a possible role of disruption of yxkO gene in regulation of expression of hag gene, which encodes flagelin - a pivotal protein of bacterial flagellum. The goal of this thesis was to clarify if the disruption of yxkO gene influences motility and whether is affected the transcription of hag gene. With integrative vector pMUTIN4 a mutant strain with specific mutation of yxkO gene was prepared. Vector was pasted into chromosome of Bacillus subtilis strain 1A839 - genotype of this strain allows to extrude the known transcriptional regulation of hag gene. Cell's motility was...
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delta subunit of bacterial RNA pol and its role in regulation of gene expression in B. subtilis
Dvořáček, Lukáš ; Krásný, Libor (advisor) ; Vopálenský, Václav (referee)
Delta subunit of bacterial RNA pol and its role in regulation of gene expression in B. subtilis. In this work I focus on regulation of eubacterial gene expression. First, I describe recent knowledge about a key stage of gene expression - transcription, focusing on regulation of trancription iniciation via small effector molecules (guanosine tetraphosphate, initiating nucleoside triphosphate) that are important for the regulation of ribosomal RNA. Second, in the experimental part of my work, I focus on the role of the _ protein, a subunit of RNA polymarase in gram positive bacteria, in transcription iniciation and its effects on regulation of RNA polymerase by the concentration of initiating nucleoside triphosphates.
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The delta subunit of RNA polymerase from gram positive bacteria
Matějčková, Jitka ; Beranová, Jana (referee) ; Krásný, Libor (advisor)
1 Abstrakt Aby bakteriální buňka přežila neustále se měnící podmínky, musí se na ně adaptovat. Tato adaptace je podmíněna změnou genové exprese. Klíčovým krokem genové exprese je transkripce. Hlavním enzymem bakteriální transkripce je RNA polymerasa (RNAP), což je esenciální vícepodjednotkový enzym. RNAP je nejvíce prostudována u Escherichia coli, modelového organismu gram negativních bakterií. Porovnala jsem E. coli a Bacillus subtilis (zástupce gram pozitivních bakterií) a shrnula jsem rozdíly v RNAP a transkripci. Jejich RNA polymerasy se liší přítomností podjednotky δ u gram pozitivních bakterií. Tato podjednotka zvyšuje promotorovou selektivitu, recykluje jádro RNAP a celkově stimuluje syntézu RNA. Podjednotka δ ovlivňuje sporulaci a virulenci některých bakterií. V této práci jsem shromáždila současné poznatky o jednotlivých částech genové exprese, zejména o regulaci iniciace transkripce a o podjednotce δ RNAP.
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Insights into the mechanism of action of bactericidal lipophosphonoxins
Panova, Natalya ; Zborníková, Eva ; Šimák, Ondřej ; Krásný, Libor ; Kolář, M. ; Látal, T. ; Seydlová, G. ; Rejman, Dominik
The advantages offered by antibiotics in the treatment of infectious diseases are endangered due to the increase in the number of antibiotic-resistant bacterial strains. This reduces the efficiency of antibiotic treatments and poses a serious health and economical problem. Currently, the need for novel antibiotics is becoming increasingly apparent. Recently, we discovered a series of compounds termed lipophosphonoxins exhibiting selective cytotoxicity towards gram-positive bacterial cells. The attempt to elucidate the mode of action of lipophosphonoxins is presented here.
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Regulace syntézy ribozomů v bakteriích
Krásný, Libor
Rapidly growing bacteria need a high number of ribosomes to satisly the cells need for increased translation. Starving bacteria need a low number of ribosomes to limit energy expenditure.The number of ribosomes is regulated at the level of ribosomal RNA (rRNA) transcription.
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