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Conformation of the adenylate cyclase toxin of Bordetella pertussis.
Motlová, Lucia
This work is focused on the RTX (Repeats in ToXin) domains structure of selected RTX toxins and its impact on secretion and protein folding. The structural analysis included RTX domains of ApxI (Actinobacillus pleuropneumoniae-RTX-toxin I) from Actinobacillus pleuropneumoniae, HlyA (Alfa-hemolysin) from Escherichia coli and LtxA (Leukotoxin A) from Aggregatibacter actinomycetemcomitans and blocs 4 a 5 RTX domain CyaA (adenylate cyclase toxin) from Bordetella pertussis. The structures of LtxA RTX domain and CyaA RTX blocs 4 and 5 were obtained and characterized. Two models of CyaA RTX domain were built based on SAXS (Small Angle X-ray Scattering) model, previously solved RTX structures and RTX structures presented here.
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Adenylate cyclase toxin of Bordetella pertussis, its conformation and ion balance in host cell.
Motlová, Lucia ; Konopásek, Ivo (advisor) ; Krůšek, Jan (referee)
Adenylate cyclase (CyaA, ACT) toxin is one of the major virulence factors of Bordetella pertussis. Although CyaA binds to many types of membranes, it is assumed that the integrin CD11b/CD18 is its receptor which is expressed on the surface of myeloid cells. CyaA belongs to the family of RTX toxin-hemolysins. CyaA acts on the host cells by two independent activities. One of them is the conversion of ATP to cyclic AMP, which is catalyzed by adenylate cyclase (AC) domain after its translocation into the cytosol of the host cell, which leads to the entry of calcium cations into the host cell. Translocation is probably initiated by interaction of CyaA monomer with the target membrane. The second activity is the formation of CyaA channel selective for cations, which probably causes colloid osmotic lysis of target cells. The channel forming activity is provided by RTX hemolysin domain which most probably forms oligomers, although it was found that CyaA as a monomer causes leakage of potassium cations from the host cell. It is also not clear whether the oligomerization of CyaA would occur in solution, or after interaction with the host membrane. The aim of this study was to examine the flow of sodium ions on the membrane of murine macrophages J774A.1, which express integrin CD11b/CD18 on their surface....
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Regulation of yeast chronological ageing
Némethová, Ema ; Palková, Zdena (advisor) ; Motlová, Lucia (referee)
Yeast cells are able to differentiate during chronological aging and form different cell- types which acquire different viability. Chronological aging cells do not divide and thus mimic the aging of cells within multicellular organisms, such as mammals. Understanding of mechanisms of chronological aging of yeasts thus could help to understand similar processes of more complex organisms. Two types of cells, called "quiescent" and "non- quiescent" cells, are formed when yeast are grown in liquid medium. These cells have different morphology and gene expression and also differ in their metabolism. Yeast cells within agar-plate-grown colonies can sense different gradients of nutrients and signaling compounds and diversify to different cell types such as U and L cells, located in different colony regions. Both the "quiescent" and U cells are more vital and able to proliferate, whereas "non-quiescent" and L cells are less viable and exhibit stress features. Chronological aging involves many cellular processes including accumulation of storage compounds, mitochondrial activity, functions of specific genes and can be affected by calorie restriction and mild stress. Key words: chronological aging, yeast, differenciation of cell populations, metabolic change
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Inovation in influenza vaccines
Satoriová, Martina ; Drda Morávková, Alena (advisor) ; Motlová, Lucia (referee)
Influenza viruses annually infect 3 to 5 millions of people worldwide, cause annually many hospitalizations, 250 000-500 000 deaths and significant economical losses. The vaccines still remain the most efficient way of prevention of this infectious disease. Conventional egg- based vaccines are used for more than 60 years. Although they are safe, they have many disadvantages. Their main disadvantage is the relatively low effectiveness and time-limited induced immunity. The need for annually updates of their composition due to an antigenic variability of viral surface proteins can be considered a disadvantage as well. What is more, the dependence on an egg suply and a way too long time of preparation might be limiting in the case of pandemic. The development of an universal vaccine that would induce a broad imunne response against different strains of Influenza and longlasting protection is a worldwide priority.
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Antibiotic resistance in clinically important strains of Enterococcus spp.
Kozická, Barbora ; Petráčková, Denisa (advisor) ; Motlová, Lucia (referee)
The Enterococcus spp. is a common part of microflora in the digestive tract; it is used in the food industry and added to probiotics. However, in the last few decades it comes to the fore particularly as a cause of nosocomial diseases. Its importance grows with its increasing resistance to antibiotics. The Enterococcus is intrinsically resistant to many types of antibiotics. In addition to that it may acquire additional resistance determinants by mutations or horizontal gene transfer. This work focuses on the Enterococcus faecium and the Enterococcus faecalis intrinsic and acquired resistances, as these two strains have the major clinical importance. In this work, the most attention is dedicated to the antibiotics vancomycin and linezolid. For several decades, vancomycin was the last treatment option in the case of a failure of commonly used antibiotics. The fact that the resistance to this antibiotic was spreading rapidly became a significant problem in these cases of treatment. Hence the antibiotic linezolid was developed as a response to the growing resistance of gram-positive bacteria to available antibiotics. It is also proved to be effective against the vancomycin- resistant strains E. faecium and E. faecalis.
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Conformation of the adenylate cyclase toxin of Bordetella pertussis.
Motlová, Lucia ; Fišer, Radovan (advisor) ; Obšil, Tomáš (referee) ; Holoubek, Aleš (referee)
This work is focused on the RTX (Repeats in ToXin) domains structure of selected RTX toxins and its impact on secretion and protein folding. The structural analysis included RTX domains of ApxI (Actinobacillus pleuropneumoniae-RTX-toxin I) from Actinobacillus pleuropneumoniae, HlyA (Alfa-hemolysin) from Escherichia coli and LtxA (Leukotoxin A) from Aggregatibacter actinomycetemcomitans and blocs 4 a 5 RTX domain CyaA (adenylate cyclase toxin) from Bordetella pertussis. The structures of LtxA RTX domain and CyaA RTX blocs 4 and 5 were obtained and characterized. Two models of CyaA RTX domain were built based on SAXS (Small Angle X-ray Scattering) model, previously solved RTX structures and RTX structures presented here.
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Regulation of yeast chronological ageing
Némethová, Ema ; Palková, Zdena (advisor) ; Motlová, Lucia (referee)
Yeast cells are able to differentiate during chronological aging and form different cell- types which acquire different viability. Chronological aging cells do not divide and thus mimic the aging of cells within multicellular organisms, such as mammals. Understanding of mechanisms of chronological aging of yeasts thus could help to understand similar processes of more complex organisms. Two types of cells, called "quiescent" and "non- quiescent" cells, are formed when yeast are grown in liquid medium. These cells have different morphology and gene expression and also differ in their metabolism. Yeast cells within agar-plate-grown colonies can sense different gradients of nutrients and signaling compounds and diversify to different cell types such as U and L cells, located in different colony regions. Both the "quiescent" and U cells are more vital and able to proliferate, whereas "non-quiescent" and L cells are less viable and exhibit stress features. Chronological aging involves many cellular processes including accumulation of storage compounds, mitochondrial activity, functions of specific genes and can be affected by calorie restriction and mild stress. Key words: chronological aging, yeast, differenciation of cell populations, metabolic change
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Exosomes, their biogenesis, composition and role
Hyka, Lukáš ; Forstová, Jitka (advisor) ; Motlová, Lucia (referee)
Exosomes are a subtype of extracellular vesicles. Exosomes are distinguishable from other extracellular vesicles by their endosomal origin and their typical cup-shaped morphology. The biogenesis of exosomes begins in the early endosomes by inward budding. The endosomal sorting complex required for transport sorts ubiquitinylated proteins into the vesicles. The small volume of cytosol is also encapsulated during budding. These vesicles are called intraluminal vesicles and the whole body is called multivesicular body. Multivesicular body fuses with the plasma membrane and vesicles are released as exosomes into the extracellular space. Exosomes are present in all bodily fluids and are secreted by a high number of cells. Exosomes present antigens on their surface to trigger immunity or serve in the cellular communication by the transfer of small RNAs.
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Inovation in influenza vaccines
Satoriová, Martina ; Drda Morávková, Alena (advisor) ; Motlová, Lucia (referee)
Influenza viruses annually infect 3 to 5 millions of people worldwide, cause annually many hospitalizations, 250 000-500 000 deaths and significant economical losses. The vaccines still remain the most efficient way of prevention of this infectious disease. Conventional egg- based vaccines are used for more than 60 years. Although they are safe, they have many disadvantages. Their main disadvantage is the relatively low effectiveness and time-limited induced immunity. The need for annually updates of their composition due to an antigenic variability of viral surface proteins can be considered a disadvantage as well. What is more, the dependence on an egg suply and a way too long time of preparation might be limiting in the case of pandemic. The development of an universal vaccine that would induce a broad imunne response against different strains of Influenza and longlasting protection is a worldwide priority.
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