National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Factors contributing to stress adaptation of human pathogen Bordetella pertussis
Hejnarová, Václava ; Večerek, Branislav (advisor) ; Černý, Ondřej (referee)
The role of bivalent metals as cofactors in various enzymes is essential for all domains of life. Their importance can be seen in interactions of hosts with patogens such as Bor- detella pertussis. This bacterium has several mechanisms that protect it from oxidative stress in phagosomes of immune cells. One example is Mn-dependent enzyme superoxide dismutase. Phagosome itself is an environment with limiting concentrations of several key bivalent metals. Thus, the transport of these metals must be controlled to ensure sufficent concentration for enzymatic activity and prevent from toxic cumulation and mismetallation. This study focuses on a particular locus BP3083-BP3077 that is highly expressed in B. pertussis surviving after internalization by THP-1 macrophages. The locus consists of two transporters, one of which shares homology with SitABCD Mn2` impor- ter of Salmonella enterica and is regulated by Fur family repressor. Bacterial cells were exposed to toxic concentrations of several bivalent metals and the level of gene expres- sion was studied by RT-qPCR. Deletion mutants were used for examination of bacterial phenotype. Results of the study show that the locus encodes Mn2` and Co2` transporters and becomes negatively regulated by Fur family repressor in toxic concentration of Co2` . The...
Regulatory mechanisms governing the virulence of the human pathogen Bordetella pertussis
Hejnarová, Václava ; Večerek, Branislav (advisor) ; Jurnečka, David (referee)
Bordetella pertussis is human pathogen, which causes severe respiratory disease called per- tussis or whooping cough. Pathogenicity of B. pertussis is mediated by a wide variety of vi- rulence factors including pertussis toxin, adenylate cyclase toxin, pertactin and filamentous haemagglutinin. Successful infection and colonization of the host depend on the precise timing of virulence factors production. For this purpose bacteria developed miscellaneous mechanisms of gene regulation. Two-component phosphotransferase systems, such as BvgAS, RisAK and PlrSR are involved in response to external stimuli. These systems of signal transduction modu- late bacterial gene expression profiles and establish consecutive phases of infection. Non-coding RNAs, particularly sRNAs and RNA chaperone Hfq provide additional level of regulation. Hfq is a post-transcriptional regulator, which mediates interaction of sRNA with target mRNA and thereby modulates their translation. Hfq affects approximately 10% of all B. pertussis genes including virulence factors such as type III secretion system, adenylate cyclase toxin, pertussis toxin and filamentous haemagglutinin. Knowledge of these regulatory mechanisms plays a key role in understanding of the pathogenesis of whooping cough and can lead to improved control over the spread...

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