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Modern fungicides and mechanism of their action
Zaleš, František ; Gabriel, Jiří (advisor) ; Ptáček, Petr (referee)
Fungicides are compounds, which are able to kill a fungi (they are therefore fungicidal), or they are able to slow or stop growth of a fungi (they are therefore fungistatic). Some fungicides also have insecticidal properties and can offer dual protection. This bachelor thesis is mainly dealing with fungicides, which are used to protect wood and wooden constructions from wood decaying fungi. Part of this bachelor thesis is a brief overview of wood decaying fungi and also an insight into the history of fungicides, but the main goal of this thesis is to offer a survey of currently used fungicides for wood protection against wood decaying fungi and also describe the mechanism of their action. Keywords: fungi, fungicides, buildings, general threat, wood decay, mode of action
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Toxicity of perfluorinated hydrocarbons
Leifertová, Karolína ; Cajthaml, Tomáš (advisor) ; Innemanová, Petra (referee)
Perfluorinated hydrocarbons are manmade chemicals used to make fluoropolymer coatings and products resistant to stains, oil, heat and water. Perfluorinated compounds such as perfluorooctane acid (PFOA) perfluorooctane sulfonate (PFOS) have been recognized as emerging environmental pollutants due to their persistance and ubiquity in the environment, biota and also humans. This paper focuses on toxicity of perfluorinated hydrocarbons, mainly PFOS and PFOA. A special attention is given to mechanism of toxicity of perfluorinated compounds, which have not yet been fully elucidated. Further studies should be performed to reveal the environmental risk assessment and mechanism of toxicity of perfluorinated compounds.
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Modern fungicides and mechanism of their action
Zaleš, František ; Gabriel, Jiří (advisor) ; Ptáček, Petr (referee)
Fungicides are compounds, which are able to kill a fungi (they are therefore fungicidal), or they are able to slow or stop growth of a fungi (they are therefore fungistatic). Some fungicides also have insecticidal properties and can offer dual protection. This bachelor thesis is mainly dealing with fungicides, which are used to protect wood and wooden constructions from wood decaying fungi. Part of this bachelor thesis is a brief overview of wood decaying fungi and also an insight into the history of fungicides, but the main goal of this thesis is to offer a survey of currently used fungicides for wood protection against wood decaying fungi and also describe the mechanism of their action. Keywords: fungi, fungicides, buildings, general threat, wood decay, mode of action
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Mechanisms and mode of action of essential oils on fungi
Ježková, Tereza ; Koukol, Ondřej (advisor) ; Čmoková, Adéla (referee)
Essential oils are volatile compounds from plants with a wide range of effects. Many of them exhibit antifungal activity. As the resistance of pathogenic fungi to antimycotics is increasing, finding new antifungal agents for the treatment of fungal infections is highly desirable. In order to use essential oils for the production of new drugs, it is necessary to know the exact mechanism of their action. Although it is known a lot about the effects of essential oils on fungi, the particular target in a cell is not always described. In this thesis I summarize the present knowledge about the mechanisms of actions on fungi. I gradually deal with effects of essential oils on cell wall, plasma membrane, mitochondrion, nucleus, quorum sensing, virulence factors, mycotoxin production and fungal development. Generally essential oils do not act on one structure but affect multiple structures and processes at the same time. In the last chapter I mention possible directions for further research of these substances. Key words: essential oils, fungi, antifungal activity, mechanism of action, mode of action
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Role of cytoplasmic membrane and cell wall in bacterial resistance to cationic antimicrobial peptides
Havlová, Noemi ; Seydlová, Gabriela (advisor) ; Vopálenská, Irena (referee)
Cationic antimicrobial peptides are part of the innate immune system of all organisms. Their properties such as structure, charge, amphipathicity and hydrophobicity make them promising agents with the potential for use not only in treatment of bacterial infections but also against some viruses, parasites, fungi and cancer cells. One of their possible targets is the cytoplasmic membrane, which they permeabilize. This mode of action has several advantages. The important feature of antimicrobial peptides is their selectivity for bacterial membranes, which makes them harmless to eukaryotic host cells. Another advantage is that the development of bacterial resistance against these peptides is more difficult since the action of antimicrobial peptides is rapid. Nevertheless, there appeared some bacterial strains that are insensitive to already used antimicrobial peptides. By using target modification resistant bacteria are able to prevent the bactericidal effects of the antimicrobial peptides. At the level of cytoplasmic membrane bacteria can alter its electrostatic or structural properties of membrane lipids and thus the antimicrobial peptides lose their ability to interact with the membrane and permeabilize it. Understanding the mode of action of antimicrobial peptides and mechanisms by which bacteria...
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Mode of action of antimicrobial lipopeptides produced by Bacillus subtilis
Pinkas, Dominik ; Seydlová, Gabriela (advisor) ; Žíla, Vojtěch (referee)
Increasing bacterial resistance to classical antibiotics and emergence of multi-resistant strains impose a constant threat. Antimicrobial compounds of bacterial origin are an important source of new antibacterial therapeutic agents needed to answer this issue. Three families of lipopeptides produced by Bacillus subtilis - surfactins, fengycins and iturins represent an interesting class of such compounds. They exert a wide range of biological activities and possess a good potential for modifications and improvement of their structure and function. Lipopeptides produced by B. subtilis are surface active compounds capable of reducing surface/interface tension. The variety of their biological activities stems from their ability to insert into lipid membranes leading to disruption and permeabilization of the membrane. Specific mode of action differs between the three families but the common feature is that it is concentration dependent. First, lipopeptides induce ion leakage, pore formation and then the increasing concentration eventually causes complete solubilisation of the membrane in a detergent-like manner. In addition, surfactin can inhibit some enzymes by chelating divalent cations required for their activity. These properties make the B. subtilis lipopeptides promising compounds for commercial applications.
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