Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Pausan, M.
Interacting microbes – the microcosmos in our body and our homes -.
PhD-Studium (Doctor of Philosophy); Humanmedizin; [ Dissertation ] Graz Medical University; 2020. pp. 136
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Krause Robert
- Moissl-Eichinger Christine
- Stadlbauer-Köllner Vanessa
- Altmetrics:
- Abstract:
- The human microbiome has become an essential topic for research in the last decade. Understanding the composition of the microbiome, how it interacts with its environment and especially with the host has been the main concern for many publications in the field of microbiome research. The main goal of this thesis was to address some of the questions regarding the interactions of the microbiome with the host and the environment, therefore we tried answering the following questions: Could the environment be a source of human-associated anaerobic microorganisms? Are anaerobic microorganisms able to survive in an aerobic environment? Is preterm labour linked with any changes in the vaginal and urinary microbiome or changes in the human milk oligosaccharides’ (HMOs) composition? Are there any associations between human milk oligosaccharides and the microbiome in urine and vagina? Are the microbiome universal approach methods sufficient to determine the archaeal communities within the human body? What is the composition of the archaeal communities in different body sites? Samples from all projects were analysed by different molecular methods, namely microbial amplicon sequencing and quantitative PCR, and some project-specific methods such as fluorescence in situ hybridization, oxygen tolerance test, and human milk oligosaccharides analysis. In the house microbiome project, we explored the composition of the microbial communities found on the bathroom floor and distinguished between free DNA and DNA obtained from cells with intact cell wall or membrane. By analysing both the bacterial and archaeal communities, we identified that most of the microorganisms present on the bathroom floor are often associated with the human skin or the gastrointestinal and genitourinary tract. Anaerobic microorganisms were also detected, even though the relative abundance of these microorganisms was decreased in the samples which contained DNA only from intact cells. Additionally, we showed that the methanogens present on the bathroom floor are of human origin and that methanogens could survive in an aerobic environment up to 24h. Therefore, the indoor environment could act as a source of anaerobic microorganisms. The results of the UMIC project showed that specific microorganisms found in the vaginal and urinary microbiome were associated with preterm labour, short cervix and preterm birth. Moreover, we observed associations between the sialylated HMOs, in particular, 3’sialyllactose, with preterm birth, high inflammation and short cervix, and confirmed that HMOs influence the microbiome profile. In the last project, the Human Archaeome, we demonstrated that the often-used universal approaches are unable to detect the archaeal communities in human samples, indicating the need of an archaeal-targeting approach for future microbiome studies. Also, we reconfirmed the body site specificity of the archaeal communities. Most body sites share specific taxa such as Methanobrevibacter, Methanobacterium and Methanosphaera, although some body sites have a high microbial diversity, especially the nasal cavity. This thesis expended the knowledge of microbiome regarding indoor environments, the microbiome composition in pregnancy and especially in women at high risk of preterm birth and the human archaeome. These results will contribute to the development of future studies addressing the human microbiome and how it interacts with its host and the environment.