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Signalization in the ontogeny of bacterial colonies
Čepl, Jaroslav ; Markoš, Anton (advisor) ; Kuthan, Martin (referee)
Bacterial bodies (colonies) can develop complex patterns of color and structure. These patterns may arise as a result of both colony-autonomous processes (self-patterning) and environmental influences, including those generated by neighbor bodies. We have studied the interplay of intra-colony signaling (self-patterning) and inter-colony influences in related clones of Serratia rubidaea on rich media. We show that the mutual influencing of colonies, present in a common morphospace, is communicated by at least two putative signals. A model accounting for some aspects of colony morphogenesis and inter-colony interactions is proposed. Key words bacteria; Serratia sp.; airborne signals; colony morphogenesis
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Bacterial adhesion to surfaces
Budil, Jakub ; Beranová, Jana (advisor) ; Kuthan, Martin (referee)
Bacterial adhesion is a process of attachment of a planktonic cell to the surface and the necessary step for further biofilm formation. Most bacterial species are capable of biofilm formation. Bacteria within biofilm exhibit increased resistance to antibiotics and other external factors, which makes the eradication of adhered bacteria rather difficult. Bacterial adhesion is very complex process affected by many physical and chemical factors as well as by the adhesive molecules present on the substrate and cell surface. Accurate description of these factors enables to design appropriate modifications of both the substrate and the environment with the aim to fabricate the antiadhesive and antibacterial surfaces or to increase the efficiency in bacteria-based biotechnological processes. Whereas in medical applications the main goal is to decrease bacterial adhesion, the increased adhesion is desirable in certain processes employing bacteria, as is for example the wastewater treatment. This thesis reviews main theories used for prediction of bacterial adhesion, describes the process of adhesion and physical, chemical and biological factors that influence it. It also contains an overview of antiadhesive and antibacterial surfaces. Key words: Bacteria, adhesion, pili, flagellum, antiadhesive and...
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The Persistence of Human Polyomaviruses
Blažková, Kristýna ; Drda Morávková, Alena (advisor) ; Kuthan, Martin (referee)
Despite years of research, even the most scrutinized Polyomaviruses - BK and JC - have not yet been thoroughly understood. With a number of new Polyomaviruses - KIV, WUV, MCV, HPyV6, HPyV7, TSV and HPyV9 described in the past few years, the need to understand how Polyomaviruses operate in their hosts has become even more urgent. The probable route of transmission appears to be either respiratory or faecal-oral. The initial infection occurs most likely in the early childhood or early-adolescence and is followed by a life-long persistence. The seroprevalence of Human Polyomaviruses among healthy adult population is high: BKV (81-97 %), JCV (35-69 %), KIV (55 %), WUV (69 %), MCV (25-46 %) and TSV (70-80 %). Human Polyomaviruses can cause fatal diseases in immunocompromised patients. The site of persistence in humans probably varies depending on the specific Polyomavirus. BK and JC are known to persist in kidneys and the urinary tract. Human Polyomaviruses have been detected in the lymphatic tissues, blood, respiratory, urinary, and gastrointestinal systems. It is not clear, however, if they persist in all of these sites. Mechanisms which Polyomaviruses use to establish and maintain persistent infection could include the viral miRNA and viral agnoprotein, which would result in a modulation of viral...
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Screening for the HCV IRES interacting proteins
Roučová, Kristina ; Pospíšek, Martin (advisor) ; Kuthan, Martin (referee)
Hepatitis C virus (HCV) is a worldwide spread pathogen infecting up to 3 % of the human population. Nowadays, research of new drugs against this virus is focused on the individual steps in its life cycle, including the translation initiation. In the case of HCV translation initiation is dependent on the internal ribosome entry site (IRES). Besides of components of the translational machinery also other components of the cell, so called IRES trans-acting factors (ITAF), contribute to its proper progress. This work continues in previous research of our laboratory focused on searching for new ITAF. In order to search for potential ITAF increasing HCV IRES activity new recombinant plasmid vectors and reference strains were prepared and selection conditions of the selection system were optimized. The differences in the growth characteristics of the reference strains were analyzed and quantified under selective and non-selective conditions. A set of pilot high efficiency transformations of the yeast strain pJ69-4A carrying bicistronic construct with HCV IRES were conducted using human expression cDNA library in order to optimize the efficiency of transformation and selection conditions and to attempt to identify new ITAF. Several dozens of randomly selected clones from these transformations obtained under...
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Extracellular matrix in yeast populations
Novotná, Pavla ; Kuthan, Martin (advisor) ; Dvořáček, Lukáš (referee)
The microorganisms in a natural environment are frequently found in multicellular forms, most commonly in biofilms. Biofilm is characterized as a community of cells living at the interface of two environments, embedded in the extracellular matrix. ECM is a significant component of biofilms in yeast populations. Extracellular matrix acts as a protective barrier and allows cells to survive under adverse conditions and better compete with other microorganisms. It also forms an effective barrier against antibiotics and other harmful substances, what makes biofilms a serious problem in medicine and industry. Formation of the matrix may be influenced by the morphological forms of colonies. Increased formation of ECM is commonly connected in phenotypic switching in response to changes of their living conditions. The compositeion of the ECM is a genus-and species-specific. The main component of the matrix consists of polysaccharides and proteins.
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