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Microbial communities of soils affected by long-term heavy metal contamination
Průchová, Pavla ; Kopecký, Jan (advisor) ; Matyska Lišková, Petra (referee)
This work is focused on microbial communities living in the soil affected by long-term exposure to heavy metals. The soil was sampled at two sites with different levels of contamination near Příbram. In the samples, respiration rate was measured in vitro after addition of carbon sources and at different levels of cadmium, one of the contaminating metals found in the soil. After the incubation with carbon sources, soil samples were collected for environmental DNA isolation. Gene coding for 16S rRNA in Actinobacteria was amplified from the environmental DNA samples and the amplicon composition was assessed by terminal restriction fragment length polymorphism analysis. The resulting profiles were used to compare actinobacterial communities in both groups of soil samples and in individual treatments. The analysis showed a clear distinction between the two sites differing in the contamination level and shifts in the community composition of various intesity depending on the added substrate.
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Structure and evolution of efflux pump in gramnegative bacteria.
Gálová, Diana ; Lichá, Irena (advisor) ; Matyska Lišková, Petra (referee)
Drug resistence in microorganisms is of major concern and there is an increasing number of pathogenic bacteria resistent to clinically used antibiotics. The major mechanism of resistence in Gram-negative is active efflux that prevent the intracellular accumulation of antibiotics to toxic levels. We recognise five families of efflux pumps, mainly using proton motive force to translocate the substrate, less common driven by ATP hydrolysis. The multidrug pumps with broad substrate specifity are of a key role in drug resistance of pathogens, typically represented by RND superfamily. The source of efflux pumps are probably the producers of antibiotics and organisms exposed to toxic compounds in their natural habitat. The genes for resistance can then spread out via horizontal gene transfer to other bacteria. It is presumed that eflux pumps have developed from transporters serving physiological functions like transport of endogenous substrates.
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Biofilm formation in Streptococcus pneumoniae
Jarošová, Václava ; Petráčková, Denisa (advisor) ; Matyska Lišková, Petra (referee)
Biofilm is a structured community of cells adhered to the surface or to each other and surrounded by extracellular matrix. Biofilm is fomed in several steps starting from single cells adhered to the surface up to microcolonies linked by channels. Because of a higher resistance to antibiotics the current hot topics in the biofilm research are formation of biofilms on medical materials and treatment of bacterial infections associated with biofilms. This work is focused on a biofilm forming bacteria Streptococcus pneumoniae. It is a potentially pathogenic bacterium which colonizes the upper respiratory tract and causes a number of diseases. Biofilms formed by S. pneumoniae exhibit increased resistance to antibiotics, therefore, alternative antimicrobial agents have been recently studied. For biofilm formation studies both open and closed systems are used. The flow cell and biofilm reactors represent commonly used open systems. Closed cultivation systems are for example a Calgary biofilm device and a micro titer plate-system developed by Christensen et al.
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The relation between microbial diversity and biodegradation of organic pollutants in soils
Adámek, Michael ; Svobodová, Kateřina (advisor) ; Matyska Lišková, Petra (referee)
This work sums up the knowledge of the currently studied microorganisms capable of degradation of organic compounds contaminating soil and of the impact of biodiversity on biodegradation efficiency. As documented in many studies effective soil remediation can be achieved by mixed-species consortia isolated from polluted soils. However, use of these cultures for bioaugumentation requires further research on their influence on the biodiversity of autochthonic soil microflora. Though bioaugumentation provably affects bioremediation effectivity no ideal carrier for microbes has been found yet that would provide survival of the introduced organisms in the competitive soil environment. Next, selection of suitable bioaugumentation agents should be based on previous analyses of autochthonic microbes in the targeted contaminated soils. Further, this work shows that the presence of key species might be more important for the biodegradation efficiency than biodiversity of soil microflora. Biodiversity is more related to the functionality of soil ecosystems which can be affected by the presence of contaminants leading to positive selection of taxa capable of pollutant degradation. However, there are just a few studies on the relationship between biodiversity and degradation of pollutants. Its further research...
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Therapeutic approaches to Ebola virus infections
Tomanová, Tereza ; Drda Morávková, Alena (advisor) ; Matyska Lišková, Petra (referee)
Ebola virus is a very dangerous virus because of its high mortality rate and unavailability of an approved vaccine or medicament. There was more than 31 000 infected people since the first epidemic in 1976 and almost 13 000 of them died (cdc.gov). Ebola virus usually occures in the west Africa, its occure on the other continents was rare in the past and it was always just one case. There is one exception though, strain Reston of Ebola virus. Strain Reston was spread from Philippines to the USA while deporting macaques. Strain Reston is able to infect people, but there is no case of death after being infected with this strain (who.int). This occurence in the USA was a warning sign of how easily could Ebola virus travel to other continents. If it was one of the deadly strains, the results would be fatal. Ebola virus is a threat and it is necessary to develop effective vaccine and drug. This bachelor's thesis is about the Ebola virus, its genome, life cycle and mainly about the options of therapy of the ebola virus disease. It is focused on presently tested vaccines and drugs against the Ebola virus.
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The relation between microbial diversity and biodegradation of organic pollutants in soils
Adámek, Michael ; Svobodová, Kateřina (advisor) ; Matyska Lišková, Petra (referee)
This work sums up the knowledge of the currently studied microorganisms capable of degradation of organic compounds contaminating soil and of the impact of biodiversity on biodegradation efficiency. As documented in many studies effective soil remediation can be achieved by mixed-species consortia isolated from polluted soils. However, use of these cultures for bioaugumentation requires further research on their influence on the biodiversity of autochthonic soil microflora. Though bioaugumentation provably affects bioremediation effectivity no ideal carrier for microbes has been found yet that would provide survival of the introduced organisms in the competitive soil environment. Next, selection of suitable bioaugumentation agents should be based on previous analyses of autochthonic microbes in the targeted contaminated soils. Further, this work shows that the presence of key species might be more important for the biodegradation efficiency than biodiversity of soil microflora. Biodiversity is more related to the functionality of soil ecosystems which can be affected by the presence of contaminants leading to positive selection of taxa capable of pollutant degradation. However, there are just a few studies on the relationship between biodiversity and degradation of pollutants. Its further research...
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Biofilm formation in Streptococcus pneumoniae
Jarošová, Václava ; Petráčková, Denisa (advisor) ; Matyska Lišková, Petra (referee)
Biofilm is a structured community of cells adhered to the surface or to each other and surrounded by extracellular matrix. Biofilm is fomed in several steps starting from single cells adhered to the surface up to microcolonies linked by channels. Because of a higher resistance to antibiotics the current hot topics in the biofilm research are formation of biofilms on medical materials and treatment of bacterial infections associated with biofilms. This work is focused on a biofilm forming bacteria Streptococcus pneumoniae. It is a potentially pathogenic bacterium which colonizes the upper respiratory tract and causes a number of diseases. Biofilms formed by S. pneumoniae exhibit increased resistance to antibiotics, therefore, alternative antimicrobial agents have been recently studied. For biofilm formation studies both open and closed systems are used. The flow cell and biofilm reactors represent commonly used open systems. Closed cultivation systems are for example a Calgary biofilm device and a micro titer plate-system developed by Christensen et al.
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The role of Interferon regulatory factors in virus infections
Suchý, Tomáš ; Forstová, Jitka (advisor) ; Matyska Lišková, Petra (referee)
Viruses are intracellular parasites, which expose their proteins and nucleic acids during their interaction with a cell. Thanks to co-evolution the host immune system developed mechanims how to recognize these components and subsequently activate defensive mechanisms. This work summarizes the knowledge about selected transcription factors with interferon regulatory function. Induction of the antiviral state is complicated and strictly regulated process. Primary function of selected transcription factors is to connect virus detection and synthesis of cellular molecules with antiviral potential. The work includes information about the direct interaction of viral proteins with interferon regulatory factors. These facts enable us insight into the molecular struggle between a host and a virus. As the name of factors suggests, the most important function is to influence the interferon production. Gathering of information about coordination of the immune system is beneficial for humane medicine and future therapeutic purposes. Key words: interferon regulatory factors; viral infection; regulation of innate immunity; interferon; pathogen recognition
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Photosystem I: from bacteria to green plants
Palovská, Markéta ; Holá, Dana (advisor) ; Matyska Lišková, Petra (referee)
Type I Photosystems (PS) are characterized by a Fe-S cluster that serves as the terminal electron acceptor. They are present in 4 prokaryotic groups and all photosynthetic eukaryotes. This work summarizes the knowledge on the structure and function of PS I subunits. The simplest PS (homodimeric; only 2 subunits) is present in Heliobacteria. PS of green sulphur bacteria is also homodimeric and consists of 4 proteins including a membrane-bound cytochrome. The homodimeric PS of Candidatus Chloracidobacterium thermophilum is functional in aerobic conditions. The reaction center of the well-characterized PS I of Cyanobacteria has a heterodimeric structure; the same applies for the eukaryotic PS I. Cyanobacterial PS consists of 12 proteins and forms trimers under low light conditions. The trimer formation is completely suppressed in green plants. Their PS I (at least 15 proteins) is adapted to bind light-harvesting membrane proteins. The PS I of Glaukophyta and Rhodophyta is slightly different from green plants. Various hypotheses about the evolutionary origin of PS I exist. The last common ancestor of all PSs probably shared features of both Type I and Type II. The purpose and the origin of a PS I heterodimer is also discussed in this work. A further understanding of PS I evolutionary history would be helped by...
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Mechanisms of MLSB resistance in Staphylococcus aureus in patients with cystic fibrosis
Bukáčková, Eva ; Melter, Oto (advisor) ; Matyska Lišková, Petra (referee)
The aim of this thesis is to summarize the mechanisms of resistance of Staphylococcus aureus to MLSB antibiotics (macrolides, lincosamides and streptogramins B type) which are used to treat respiratory infections in cystic fibrosis patients. This pathogen evolved during time many various strategies of resistance to these proteosynthesis inhibitors. The most common mechanisms are target site modification, modification of the antibiotic itself or antibiotic eflux out of the bacterial cell. Apart from these mechanisms based on acquisition of genes, a mutation of specific genes can also result in resistance of the strain. In the lungs of CF patients, long-term antibiotic treatment together with immune system defects result in development of a unique niche. It is colonized (besides other bacteria) by S. aureus, which is well adapted to this environment and also uses different mechanisms of resistance as hypermutation or switching to dwarf phenotype (small colony variants) enabling intracellular persistence. MLSB antibiotics as well as beta-lactams are being applied as the treatment of choice for respiratory infections in CF patients. Studying the mechanisms of MLSB resistance is therefore of extraordinary importance.
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