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Structure-function relationships and use of RTX proteins of Gram-negative bacteria
Sadílková, Lenka
RTX (Repeat in ToXin) superfamily consists of many proteins divided into several groups according to their different functions and characteristics: toxins, metalloproteases, lipases, proteins of the S-layer, bacteriocins and proteins with unknown function. However, all of them can be characterized by the following features: i) they contain tandemly repeated (6-50) nonapeptide glycine-rich calcium-binding consensus sequences GGXGXDX[L/I/V/W/Y/F]X (where X is any amino acid residue) in the C-terminal part of the protein. The presence of these repeats is a sine qua non condition for RTX protein family membership; ii) secretion from the cell occurs without a periplasmic intermediate by a mechanism which involves recognition of a signal sequence at the C-terminus of the protein by membrane-associated proteins that export the toxin across a channel spanning the entire bacterial envelope directly to the outside of the cell (Type I Secretion System); iii) the genes for protein synthesis, activation and secretion are mostly grouped together on the chromosome and form rtx operons. RTX toxins are the largest protein group of the RTX family. To this group belong mostly the proteins with molecular weight ranging from 100 to 200 kDa, with posttranslational fatty acid acylation mediated by a specific activating...
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Meningococcal infection
Malá, Markéta ; Vejsová, Marcela (advisor) ; Konečná, Klára (referee)
7 2. ABSTRACT Title of Bachelor thesis: Meningococcal infections Student: Markéta Malá Supervisor: Mgr. Marcela Vejsová, Ph.D. Charles University, Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Backround: The aim of this bachelor thesis was to summarize the findings about meningococcal infections and their originator - Neisseria meningitidis. Further this bachelor thesis should provide infomation about progression in meningococcal vaccines development, treatment and diagnostics. Main findings: N. meningitidis spreads into the human body from nasopharynx, through the epithelium it travels into the bloodstream. Severity of meningococcal infection depends on a strain of meningococcus and on strenght of immune system on the side of a host. Meningococcus has got efective tools for invading human body, they are called virulence factors. Quick recognition of clinical signs and rapid confirmation of infection originator are important when the infection breaks out. Nowadays we can prevent meningococcal infection by effective vaccination - combining meningococcal tetravalent conjugate vaccine and meningococcal serogroup B vaccine. Conclusions: Infections caused by N. meningitidis varies from ordinary nasopharyngitis to bacteremia and severe acute meningitis. N. meningitidis...
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Structure-function relationships and use of RTX proteins of Gram-negative bacteria
Sadílková, Lenka
RTX (Repeat in ToXin) superfamily consists of many proteins divided into several groups according to their different functions and characteristics: toxins, metalloproteases, lipases, proteins of the S-layer, bacteriocins and proteins with unknown function. However, all of them can be characterized by the following features: i) they contain tandemly repeated (6-50) nonapeptide glycine-rich calcium-binding consensus sequences GGXGXDX[L/I/V/W/Y/F]X (where X is any amino acid residue) in the C-terminal part of the protein. The presence of these repeats is a sine qua non condition for RTX protein family membership; ii) secretion from the cell occurs without a periplasmic intermediate by a mechanism which involves recognition of a signal sequence at the C-terminus of the protein by membrane-associated proteins that export the toxin across a channel spanning the entire bacterial envelope directly to the outside of the cell (Type I Secretion System); iii) the genes for protein synthesis, activation and secretion are mostly grouped together on the chromosome and form rtx operons. RTX toxins are the largest protein group of the RTX family. To this group belong mostly the proteins with molecular weight ranging from 100 to 200 kDa, with posttranslational fatty acid acylation mediated by a specific activating...
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Structure-function relationships and use of RTX proteins of Gram-negative bacteria
Sadílková, Lenka ; Šebo, Peter (advisor) ; Stulík, Jiří (referee) ; Weiser, Jaroslav (referee)
RTX (Repeat in ToXin) superfamily consists of many proteins divided into several groups according to their different functions and characteristics: toxins, metalloproteases, lipases, proteins of the S-layer, bacteriocins and proteins with unknown function. However, all of them can be characterized by the following features: i) they contain tandemly repeated (6-50) nonapeptide glycine-rich calcium-binding consensus sequences GGXGXDX[L/I/V/W/Y/F]X (where X is any amino acid residue) in the C-terminal part of the protein. The presence of these repeats is a sine qua non condition for RTX protein family membership; ii) secretion from the cell occurs without a periplasmic intermediate by a mechanism which involves recognition of a signal sequence at the C-terminus of the protein by membrane-associated proteins that export the toxin across a channel spanning the entire bacterial envelope directly to the outside of the cell (Type I Secretion System); iii) the genes for protein synthesis, activation and secretion are mostly grouped together on the chromosome and form rtx operons. RTX toxins are the largest protein group of the RTX family. To this group belong mostly the proteins with molecular weight ranging from 100 to 200 kDa, with posttranslational fatty acid acylation mediated by a specific activating...
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Crystallographic study of the iron-regulated outer membrane lipoprotein (FrpD) from Neisseria meningitidis
SVIRIDOVA, Ekaterina
Neisseria meningitidis (N. meningitidis) is a Gram-negative commensal bacterium colonizing nasopharynx of about 10 % of healthy individuals, which can cause invasive diseases, such sepsis and meningitis, upon occasional penetration into bloodstream. Pathogenesis of N. meningitidis appears to be directly related to conditions of limited iron availability. Under these conditions two proteins of unknown function: FrpC and FrpD, are synthesized. FrpD is a highly conserved lipoprotein of N. meningitidis anchored to the bacterial outer membrane. It is known that FrpD tightly binds the FrpC protein, which belongs to the Repeat-in-Toxin (RTX) protein family and may act as bacterial exotoxin. However, the mechanism of FrpD-FrpC interaction and the exact function of this complex are unknown due to the absence of structural information on these proteins. Therefore, we set out to determine the structure of FrpD and provide insights into its interaction mechanism with FrpC and structure-functional relationships of these two proteins. We determined the first crystal and solution structures of the FrpD protein. We found that atomic structures of FrpD reveal a novel protein fold. We uncovered the structure-function relationships underlying the mechanism of interaction between the FrpD and FrpC proteins and tested the putative function of the FrpD-FrpC1-414 complex in vitro. Finally, we proposed the putative function of the FrpD-FrpC1-414 complex as a new minor adhesin of N. meningitidis, which mediates the bacterial adhesion to the host epithelial cells and facilitate the colonization. Our work constitutes the first step in clarifying the molecular basis of the FrpD-FrpC interaction and sets the base for further investigation of the role of FrpD and FrpC in the virulence mechanism of N. meningitidis.
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Invasive meningococcal disease in terms of pre-hospital care
MASOPUSTOVÁ, Jana
Invasive meningococcal disease is one of the most feared infectious diseases in the Czech Republic. It is the condition where a person is infected with any serotype of the bacteria Neisseria meningitidis, which causes a life-threatening meningococcal sepsis. Unfortunately, meningococcal infections belong, even in today's advanced medicine, to the world´s health problems. The life-threatening form of meningococcal invasive disease leads to death when left without treatment. The aim of this thesis was to survey the paramedics´ knowledge of procedures and practices in connection with invasive meningococcal disease in conditions of pre-hospital emergency care, because paramedics usually come into contact with the disease in the first line. In its quantitative investigation the thesis is focused on staff members of the Medical Rescue Service of the South Bohemian region. The questionnaire technique was used to meet the objective to survey the paramedics´ knowledge of procedures and practices in connection with invasive meningococcal disease. The research has proved that paramedics are truly knowledgeable about procedures in pre-hospital emergency care. Most questions in the survey were answered correctly, better than average. By using control questions, only minor shortcomings were detected, such as insufficient training of the issue by the employer and a limited possibility of monitoring the further life story of the patients with this disease after their transfer for further care. In my opinion this specific disease with its rapid invasiveness in the organism requires a thorough knowledge by medical staff, which has been verified. It has been confirmed that the Medical Rescue Service personnel of the South Bohemian region are ready to provide expert medical care to our patients with the utmost expertise and professionalism.
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Comparison of methods for determination of Neisseria meningitidis in Nemocnice ČB a.s.
SKOŘEPOVÁ, Lucie
Molecular biology methods are of great importance for routine diagnostics of infections diseases. In this work two such methods were compared for the case of diagnostics of Neisseria meningitides in Nemocnice ČB a.s. Nemocnice ČB a.s. is a municipal hospital owned by South Bohemia Region. I hypothesised that real-time polymerase chain reaction provides lower analysis time compared to nested polymerase chain reaction. These two methods are routinely used in Central Laboratories of the hospital and it is feasible to use both of them for the diagnostics of Neisseria meningitides. During the investigation I have found another method useful for the diagnostics of this pathogen. Latex agglutination test is an immunological reaction used to detect antibodies which appear as an immune response to infection. In spite of very quick output, the immunological origin of the latex agglutination test brings serious limitations: any suppression of the immune response or degradation of the antibodies leads to false negative results of the test. Lower reliability of the latex agglutination test compared to various polymerase chain reactions based on the detection of bacterial DNA strengthen my devotion to compare the two methodologies of reliable polymerase chain reaction and led to a decision not to include the latex agglutination test into the original research plane. In good agreement with the original expectation, practical evaluation of tests based on real-time polymerase chain reaction and on nested polymerase chain reaction displayed significant differences in the analysis time (3 h 40 min versus 7 h 30 min respectively). Another advantage of the test based on real-time polymerase chain reaction is its higher sensitivity of one order of magnitude more than in the test based on nested polymerase chain.
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