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Role of the gut bacterium Akkermansia muciniphila in obesity
Balský, Šimon ; Hrdý, Jiří (advisor) ; Podzimek, Štěpán (referee)
Current scientific knowledge point to a key role of the gut microbiota (GM) in the pathogenesis of various obesity-related diseases. Akkermansia muciniphila (AM), a commensal intestinal bacterium present in the human digestive tract, has become the subject of many research projects. Studies using experimental animal models have shown that AM has significant functional capabilities, including reducing obesity, glucose intolerance, insulin resistance, hepatic steatosis and improved intestinal permeability. It can be assumed that similar effects will also be observed in humans, as already suggested by the first published studies. AM is currently identified as a next generation probiotic due to its ability to positively influence host health. The inclusion of GM modulation in the overall obesity treatment plan, particularly through AM, may significantly increase weight loss efficacy and improve metabolic parameters. This approach may include probiotic/postbiotic, dietary and pharmacological interventions, thereby promoting healthier GM composition and microbiome function in general. This bachelor thesis aims to provide a comprehensive review and analysis of research studies focused on AM in humans in order to gain a deeper understanding of its impact and functions. Based on the analysis of 10...
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The effect of the gut microbiota in eating disorders
Hlaváčková, Helena ; Roubalová, Radka (advisor) ; Černý, Viktor (referee)
The essential effect of microbiota on human health has been well known for a long time. Commensal microorganisms colonize virtually the entire surface of the human body, but the greatest amount of them can be found in the gut. The gut microbiota plays a crucial role in the digestion of certain food components, synthesis of various substances, or the immune system responses. In the last decade, attention has also been drawn to the mechanisms by which gut microorganisms can influence the human behaviour. One group of diseases, where this phenomenon is being explored, are eating disorders. This is a group of psychiatric disorders characterized by unhealthy eating behaviors. The aim of this thesis is to summarize current knowledge about the mechanisms by which gut microorganisms can interfere with host signaling and regulatory pathways and how these changes relate to the development and course of eating disorders. And from the opposite view, how the patients' behaviour impacts the composition and functioning of the gut microbiota.
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The role of Rorγt+ antigen presenting cells in peripheral tolerance to microbiota
Arutsev, Savva ; Dobeš, Jan (advisor) ; Somova, Veronika (referee)
The intestinal immune system needs mechanisms that provide a balance between suppression and tolerance to microbiota, regulating beneficial and inhibiting pathogenic ones. One such mechanism is based on microbiota-specific Rorγt+ T regulatory cells (Tregs), which can regulate immunity upon recognition of a specific antigen. Rorγt+ antigen-presenting cells (APCs) have been hypothesized to promote microbiota-specific Tregs development, but the specific mechanism was poorly understood until recently. In my bachelor thesis I provide an introduction to Tregs biology, compare and review in detail studies indicating a possible role of lymphoid tissue inducers like group 3 innate lymphoid cells, Janus cells and newly discovered Thetis cells in the generation of Rorγt+ Tregs as well as a possible molecular mechanism based on the integrins Itgav and Itgb8.
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Interspecific and intraspecific variation in gastrointestinal microbiota composition of parrots and its association with incidence of selected disorders
Černá, Kateřina ; Vinkler, Michal (advisor) ; Rychlík, Ivan (referee)
Captive parrots are susceptible to various digestive, metabolic, and behavioural disorders. Recent research in other vertebrates has suggested that these disorders can be linked to the gut microbiota, directly or through the microbiota-gut-brain axis. Although many commercial probiotic products intended for the use in parrots advertise beneficial effects on digestion and mental well- being, these statements are not sufficiently supported with publicly available scientific evidence, but probably rather based on the extrapolation of the knowledge of microbiota-gut-brain interactions in poultry, mice, and humans. However, there are substantial differences in the gastrointestinal tract morphology and gut microbiota composition between parrots and these model vertebrates. This thesis aimed to describe the interspecific and intraspecific variation in the gut microbiota composition of parrots and to link the variation in microbial communities to the incidence of eight selected behavioural and physiological disorders. The gut microbiota composition of 491 individuals from 85 parrot species was analysed using 16S rRNA metabarcoding. The host species, type of feed, and housing environment were identified as the main factors influencing the diversity and composition of the gut microbiota of parrots. A...
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Probiotics, prebiotics, synbiotics and postbiotics in breast milk and formulas.
ŠEBÍKOVÁ, Lucie
Intestinal microbiotics make up about 80 % of our immunity. The biggest colonization by these microorganisms happens in the first 1000 days in the life of a child, which is why it is important to maintain a balanced diet, to properly support growth and diversity of an intestinal flora. In the theoretic part of my thesis I will look closely on composition of breast milk and on other kinds of substitution of dairy nutrition. You will learn that many factors affect the composition of intestinal microbiotics. For if it comes to dysmicrobia, for example as a result of long-term use of antibiotics, it could lead to development of metabolic, immunologic and psychic issues. The goal of my bachelor thesis was to learn the contents of probiotics, prebiotics, postbiotics and synbiotics in breast milk, and in the formulas in the 1st, 6th, 12th and 18th month. My sources were professional literature and the websites of chosen dairy nutrition. For learning the exact intake of the observed substances I evaluated menus from 10 respondents. Breast milk is the most natural form of nutrition, which is why it is used as a template for making the substitution of dairy nutrition. The closest to breast milk in contents of synbiotics are brands Hipp BIO combiotik and BEBA COMFORT HM-O. Nutrilon advance has the most similar count of prebiotics, which was confirmed by observing the specific intake from menus. Nutrilon and Hami are only brands containing postbiotics thanks to the process of directed fermentation Lactofidus. This data should help in deciding what substitution of dairy nutrition to choose, if a child cannot be breastfed. But since this thesis does not evaluate the complete contents of the formulas, but rather the contains of the observed substances, we cannot presume the brands with the best results are the best option of nutrition. The choice of nutrition should be discussed with a pediatrician or a nutritionist.
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Induction of immune responses by intestinal segmented filamentous bacteria
Pacáková, Iva ; Dobeš, Jan (advisor) ; Schwarzer, Martin (referee)
The intestine is constantly exposed to a variety of pathogens, and therefore a proper function of the intestinal barrier is essential for the overall health of the body. Segmented filamentous bacteria are members of the gut microbiota residing in the terminal ileum of the small intestine, where they penetrate through the mucus layer and tightly associate with intestinal epithelial cells. This SFB association with the epithelium is accompanied by the formation of endocytic vesicles filled with an antigen that triggers the IgA production in the intestine and the Th17 cell dependent immune response. There are two steps for the induction of Th17 cells. First, SFB-dependent induction of Th17 cells requires antigen presentation by MHC class II molecules. Therefore, antigen-presenting cells migrate to the site of induction in mesenteric lymph nodes and prime antigen-specific naive T cells to become RORγt+ pre-Th17 T cells. Secondly, activated T cells migrate back to the lamina propria, where they undergo functional maturation by triggering cytokine production. As a result, Th17 cells accumulate in lamina propria, where they produce their effector cytokines IL-17 and IL-22, further affecting the gut's overall balance. However, the extensive Th17 polarization induced by SFB may subsequently contribute to...
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Ecological aspects affecting microbiota in the digestive tracts of birds
Schmiedová, Lucie ; Kreisinger, Jakub (advisor) ; Mrázek, Jakub (referee) ; Gvoždíková Javůrková, Veronika (referee)
The results indicate that songbird GM is dominated by the bacterial phyla Proteobacteria, Firmicutes, Actinobacteria, Tenericutes, Bacteroidetes and Chlamydia, a community that differs from that of mammals. A t the interspecies l evel, GM composition is mainly influenced by phylogeny and less so by sampling site. While ecological factors , and especially diet , are important GM predictors in mammals, the effect of ecological factors , including diet , have a much smaller effect on inte r - and intraspecific variability in songbird GM composition . Our data from barn swallows ( Hirundo rustica ) suggest an effect of social GM transmission among adults forming social pair s, as well as trans - generational transmission from a social mother to her own nestlings. At the same time, we observed differ ing GM in adults and nestlings, with no dramatic change in GM with nestling age, a process previously recognised in mammals. Part of the GM detected appears to remain stable over time , and is therefore su itable for further detailed study. To conclude, our studies demonstrate that s ongbird GM differs from that of mammals and that the factors influencing GM composition appear to differ from those in mammals , thereby highlighting the importance of study ing mu ltiple vertebrate groups (not just mammals ) when...
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The role of nutrition in the prevention of osteoporosis: calcium, proteins and gut microbiota
Holánová, Karolína ; Zikán, Vít (advisor) ; Vágnerová, Tereza (referee)
Introduction: Osteoporosis is defined as a systemic metabolic disease of skeleton. It is characterized by reduced amounts of bone mass and degradation of bone tissue microarchitecture with increased chances of fractures occurring. Women after menopause are affected by lack of estrogen and therefore have increased risk of osteoporosis. Goal: The goal of the diploma thesis is to evaluate the nutritional state of women after menopause with osteoporosis (With OP) and without osteoporosis (Without OP) focusing on calcium, proteins and nutrients which are affecting gut microbiota (prebiotics and probiotics). Methods: Nutritional state was evaluated based on three-day diet analysis and questionnaire about dietary preferences. Amounts of particular nutrients in respondents diets were obtained by using web page www.kaloricketabulky.cz. Bone material densities were measured by dual energy X-ray absorptiometry (DXA). Results: Nutritional breakdown of diets did not show any statistically significant differences in most of the cases. The only exception was protein and fiber intake, where the group without OP reported higher intake. Both sets of respondents reported higher intake of calories, fats and proteins then recommended. On the other hand, low intake of carbs, fiber, calcium and probiotics was discovered...
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Microbiota as a modulator of carcinogenesis
Benešová, Iva ; Kverka, Miloslav (advisor) ; Krulová, Magdaléna (referee)
Many studies show the ability of gut microbes to modulate the anti-tumour immune response by direct triggering the immune cells or by bacterial metabolites. Interestingly bacteria may even migrate to the tumour tissue and orchestrate the immune response on site. These anti-tumour effects can be improved by the administration of immune checkpoint inhibitors (ICI). Notably, some microbial effects occur only in the presence of ICI. On the contrary, microbiota may also promote tumour growth and negatively impact the effects of ICI therapy. We have disrupted the gut microbiota homeostasis by antibiotics (ATB) to study the effects of gut microbiota on the ICI. This disturbance led surprisingly to reduced tumour growth and enhanced pro-inflammatory immune response not only in the gut but also within the tumour tissue, where especially IFN-γ orchestrated the anti-tumour immune response. Importantly the anti-tumour immune response could be transferred through colonisation of germ-free mice by ATB-changed gut microbiota if concomitantly anti- programmed cell death protein 1 (αPD-1) monoclonal antibody was administrated. These mice had elevated levels of segmented filamentous bacteria (SFB), which induced systemic immune response with increased expression of IL-17 and elevated amounts of Th 17 cells,...
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