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One Health approach to understand emerging zoonotic pathogens in the Trichophyton benhamiae complex
Čmoková, Adéla ; Hubka, Vít (advisor) ; Buchta, Vladimír (referee) ; Gené, Josepa (referee)
The Trichophyton benhamiae complex encompasses several zoonotic pathogens that are of increasing concern to the scientific community due to their epidemic spread among pets and their owners. Of particular concern is the sudden appearance and rapid spread of T. benhamiae yellow phenotype strains in Europe. Considerable genetic and phenotypic variability has been revealed in the pathogens from the complex, yet the species limits and host spectra have not been clearly elucidated. To explore the diversity, epidemiology, and taxonomy of the T. benhamiae complex, my colleagues and I formed an international, cross-disciplinary team and applied a holistic One Health approach. We collected a large dataset of strains from several continents, along with associated data about host, clinical picture, and locality. Due to the high level of clonality in commonly used DNA sequence markers, I developed a new typing schema based on ten microsatellite markers and four DNA sequence markers. We then used a polyphasic approach combining data from independent analyses to decide on species limits in the T. benhamiae complex, including phylogenetic and population-genetic analyses, phenotypic and physiological analyses, mating-type gene characterization, ecological data and MALDI- TOF mass spectrometry analysis. Thanks to...
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Dermatophytes isolated from the hair of free-living rodents
Žárová, Štěpánka ; Čmoková, Adéla (advisor) ; Mašínová, Tereza (referee)
Dermatophytes (order Onygenales, Ascomycota) are microscopic filamentous keratinophilic fungi that can cause skin infections known as dermatophytosis. The most diverse but not very studied genus Arthroderma has been revised recently (Míková 2018) which was essential for further research. This genus comprises mostly species with a supposed reservoir in soil. Lack of information about their ecology and frequent isolation of some species from the hair of free- living mammals (mainly rodents) may testify a strong host association. Rodents could thus represent the hidden reservoir of this species. For this thesis, I have chosen three ecologically distinct rodent species: Mus musculus, Apodemus flavicollis, and Clethrionomys glareolus. I obtained the material by brushing the hair of asymptomatic individuals and used this material for cultivation on selective medium. I identified the isolates of dermatophytes (n = 30) using molecular methods. I used sequences of three highly variable loci (ITS, tubb a tef1α) to incorporate these isolates in the phylogenetic analysis based on the monography of the genus Arthroderma (Míková 2018). I characterized the phenotype of selected strains based on morphological and physiological data including the ability to utilize keratin and the production of siderophores. The...
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Secondary metabolites in fungal pathogenesis
Veselý, Martin ; Čmoková, Adéla (advisor) ; Machová, Lenka (referee)
The ability of fungal pathogens to induce infection and later survive in its host is dependent on virulence factors. Often these factors are based on primary metabolites (hydrophobins, proteases, phospholipases, catalases etc.). Nonetheless many pathogen produced secondary metabolites are also involved in the infection process. Their true role during infection used to be rather undervalued. First part of this bachelor degree thesis aims to describe host-pathogen relation and afterwards introduce reader with some basic, commonly accepted virulence factors of fungi. In the second part of this thesis known roles of secondary metabolites are described in each stages of progressing infection. In the first stage a pathogen needs to create a suitable habitat on host tissues to ensure growth. This is in part done by antimicrobial substances (...). In later stages pathogen prevents phagocytosis of its spores by host (melanins). Successful infection is often accompanied with host tissue damage that is induced by production of cytotoxic substances (xanthomegnin, riboflavin) and immunoregulation of host immune system (gliotoxin, pseurotin). Last but not least there are virulence factors that ensure prolonged survival in host (siderophores). Fungal pathogens of poikiloterm animals are mostly not primary...
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Sexual system of the ascomycetes from order Pezizales
Janošík, Lukáš ; Koukol, Ondřej (advisor) ; Čmoková, Adéla (referee)
Sexual reproduction is essential part of life for numerous ascomycetes. Based on their requirement for opposite partner to produce fruiting bodies with ascospores, fungi can be in general divided into two mating systems - homothallism and heterothallism. However, several recent studies suggest that this division is clearly simplified and homothallism is an umbrella term for diverse sexual behaviours. First part of this thesis is focused on the reproduction, mating systems and their evolution in division Ascomycota. The main part summarizes present knowledge about the mating systems of the fungi from order Pezizales. Observations about the members of individual families are discussed, summed up and reviewed in the light of phylogeny and ecology.
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Fungal secondary metabollites with antiviral activity
Besedová, Alena ; Čmoková, Adéla (advisor) ; Kolařík, Miroslav (referee)
The past year 2020 has clearly shown how quickly some viral infections can reach pandemic proportions. Thus, there is still a need to discover new substances with antiviral activity. Such substances (eg. asteltoxin E, cytosporaquinone B) have been discovered in the past in several groups of fungi, however, their potential as a source of virostatic chemotherapeutics has not been much explored. The possible use of fungi as a source of substances with antiviral activity is also indicated by the use of some species (eg. Ganoderma linghzi, Lentinula edoles) in the alleviation or prevention of viral diseases in traditional medicine. In most cases, however, it was not possible to find substances responsible for this effect. Therefore, in my bachelor's thesis I will first analyse kinds of fungi traditionally used as treatment of viral infections in traditional medicine. I will also summarize the most important fungal substances for which antiviral activity has been demonstrated. The bachelor's thesis will provide a comprehensive overview of currently known secondary metabolites of fungi and their virostatic effects. The information summarized in the work may point to possible candidates in the fight against viral infections.
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Fungal metabolism modulation by plant substances
Sedláková, Vendula ; Čmoková, Adéla (advisor) ; Kolařík, Miroslav (referee)
Phytochemicals are bioactive substances by which plants affect organisms in their vicinity. Fungi often respond to their presence by metabolism alternation, which is manifested by the production of secondary metabolites, an increase in biomass or the regulation of virulence. These changes can be caused by phytochemicals (e.g. curcumin, EGCG) with abilities to modulate epigenetic information. The first half of the work is devoted to mechanisms of epigenetic modification (e.g. methylation, histone modification), which were studied in fungi. The second half summarizes studies focused on phytochemicals, in which the ability to modify epigenetic information in eukaryotic organisms was observed. The bachelor's thesis thus brings valuable knowledge about the possibility of modifying fungal metabolism by phytochemicals, which are often waste products of industry. Information summarized in this work can have a significant impact on improving biotechnological processes, where there is an effort to increase biomass yield or induce the production of secondary metabolites in cases where their production is normally suppressed. Key words: secondary metabolites, epigenetics, epigenetic modification, phytochemicals, filamentous fungi
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Virulence factors of the Trichophyton benhamiae complex
Machová, Lenka ; Čmoková, Adéla (advisor) ; Labuda, Roman (referee)
Dermatophytes are a group of fungi, some of which can cause skin diseases in humans and animals due to their ability to degrade keratinized tissue. Representatives of this group also include strains from the Trichophyton benhamiae complex, known to cause dermatophytosis especially of small rodents and rabbits. In the last decade, one of four populations of this complex has spread epidemically across Europe among guinea pigs and their breeders. To answer the question what stands behind the successful spread of this population, the gene expression and production of volatile organic compounds of epidemic and non-epidemic populations of T. benhamiae was investigated. Gene expression of three strains from each population was studied during growth in liquid medium and on ex vivo mouse skin models prepared according to a newly optimized protocol. RNAseq and RT-qPCR methods were chosen for the gene expression analysis. Based on the literature and the results of RNAseq preliminary analysis, several genes were selected for which specific primers were designed. The spectra of the produced volatile organic compounds of the same strains growing on sheep wool in vials were analyzed by GC-MS. While non-epidemic populations did not differ in gene expression and production of volatile organic compounds, the...
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Dermatophytes isolated from the hair of free-living rodents
Žárová, Štěpánka ; Čmoková, Adéla (advisor) ; Mašínová, Tereza (referee)
Dermatophytes (order Onygenales, Ascomycota) are microscopic filamentous keratinophilic fungi that can cause skin infections known as dermatophytosis. The most diverse but not very studied genus Arthroderma has been revised recently (Míková 2018) which was essential for further research. This genus comprises mostly species with a supposed reservoir in soil. Lack of information about their ecology and frequent isolation of some species from the hair of free- living mammals (mainly rodents) may testify a strong host association. Rodents could thus represent the hidden reservoir of this species. For this thesis, I have chosen three ecologically distinct rodent species: Mus musculus, Apodemus flavicollis, and Clethrionomys glareolus. I obtained the material by brushing the hair of asymptomatic individuals and used this material for cultivation on selective medium. I identified the isolates of dermatophytes (n = 30) using molecular methods. I used sequences of three highly variable loci (ITS, tubb a tef1α) to incorporate these isolates in the phylogenetic analysis based on the monography of the genus Arthroderma (Míková 2018). I characterized the phenotype of selected strains based on morphological and physiological data including the ability to utilize keratin and the production of siderophores. The...
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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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Sexual system of the ascomycetes from order Pezizales
Janošík, Lukáš ; Koukol, Ondřej (advisor) ; Čmoková, Adéla (referee)
Sexual reproduction is essential part of life for numerous ascomycetes. Based on their requirement for opposite partner to produce fruiting bodies with ascospores, fungi can be in general divided into two mating systems - homothallism and heterothallism. However, several recent studies suggest that this division is clearly simplified and homothallism is an umbrella term for diverse sexual behaviours. First part of this thesis is focused on the reproduction, mating systems and their evolution in division Ascomycota. The main part summarizes present knowledge about the mating systems of the fungi from order Pezizales. Observations about the members of individual families are discussed, summed up and reviewed in the light of phylogeny and ecology.
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