Taxonomic and functional analyses of intact microbial communities thriving in extreme, astrobiology-relevant, anoxic sites

Background: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to infer habitability of extraterrestrial settings. In contrast to Earth’s ecosystems, potential extraterrestrial biotopes are usually characterized by a lack of oxygen. Methods: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort. Results: The information retrieved from microbiome analyses on the intact microbial community thriving in the MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites compared to moderate environments. The microorganisms were characterized by an impressive machinery to withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant cosmopolitan group of 34 poly-extremophiles thriving in all sites. Conclusions: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental, terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living microorganisms in extreme environments with a high adaptation potential within habitability borders

Connecting beneficial microbes and environmental biodiversity in a functional hospital setting

In Gesundheitseinrichtungen erworbene Infektionen (healthcare-associated infections - HAIs) stellen weltweit ein ernstes Problem dar. In Europa treten jährlich 8,9 Millionen HAIs in Krankenhäusern und anderen Gesundheitseinrichtungen auf und die Zahl der Infektionen steigt stetig. Diese Tatsache weist darauf hin, dass derzeitige Ansätze zum Schutz der PatientInnen unzureichend sind. Es wurde gezeigt, dass strenge Hygiene- und Reinigungsverfahren zu einem Verlust der mikrobiellen Diversität und dies wiederum zu einer höheren Diversität von Resistenzgenen führt. Daher könnte eine Erhöhung der mikrobiellen Diversität könnte dazu beitragen, Infektionen vorzubeugen und das Krankenhaus Mikrobiom, durch Einbringung nützlicher Mikroben, zu unterstützen. Frühere Studien zeigten, dass Pflanzen möglicherweise als Übertragungsquelle für Mikroben fungieren und somit dazu beitragen können, das Risiko der Proliferation und Ansiedlung schädlicher Bakterien zu verringern. In diesem Projekt sollte getestet werden, ob die mikrobielle Diversität durch Pflanzen erhöht und damit die mikrobielle Dynamik im Krankenhaus positiv beeinflusst werden kann. Die Pflanzen wurden in drei verschiedene Krankhausräumlichkeiten positioniert. Diese Bereiche und die Pflanzen wurden über fünf Monate beprobt, um Veränderungen innerhalb der mikrobiellen Gemeinschaften zu eruieren. Entgegen unserem Ziel, ergab die Mikrobiom-Analyse, dass die mikrobielle Diversität durch die Zimmerpflanzen nicht erhöht und dass kein signifikanter Anstieg nützlicher Bakterien im Krankenhaus beobachtet werden konnte. Die Untersuchung, bestimmter Gattungen zu allen Zeitpunkten, zeigte keinen signifikanten Mikrobiomaustausch zwischen den verschiedenen Probenahmestellen. Diese Ergebnisse zeigten, dass es nicht möglich war, nützliche Mikroben mit Hilfe von einem kleinen Set an Zimmerpflanzen in die verschiedenen Krankenhausbereiche zu transferieren.Healthcare-associated infections (HAIs) are a serious problem worldwide. In Europe, annually 8.9 million HAIs occur in hospitals and other healthcare facilities, and the number of infections are still increasing. This fact indicates that current approaches are not sufficient to protect the patients. It was shown that strict hygiene and cleaning procedures are associated with a loss of microbial diversity and this leads to higher diversity in resistance genes. The enrichment of microbial diversity could help to prevent infections and support the microbiome of a functional hospital setting by increasing beneficial microbes. Plants already showed in previous studies, that they might have the potential to function as a dispersal source for microbes, and hence might help to reduce the risk of proliferation and settlement of harmful bacteria. In this project, the aim was to test if we can increase the microbial diversity through plants, and therefore positively influence the microbiome dynamics in hospital indoor environment. The plants were positioned into three different areas in the hospital. These locations and the plants were sampled over five months, to evaluated changes within the microbial communities. Contrary to our aim, the microbiome analysis revealed that it was not possible to increase the microbial diversity through the indoor plants and no significant increase of beneficial plant bacteria in the hospital areas could be observed. By looking into specific genera and time-points it showed no significant microbiome exchange between the various sampling sites. Therefore, this study shows that it was not possible to transfer beneficial microbes into the different hospital areas with the help of a small set of indoor plant.Arbeit an der Bibliothek noch nicht eingelangt - Daten nicht geprüftAbweichender Titel laut Übersetzung des Verfassers/der VerfasserinKarl-Franzens-Universität Graz, Masterarbeit, 2020(VLID)486861

Methionine supplementation for multi-organ dysfunction in MetRS-related pulmonary alveolar proteinosis

International audienceIntroduction Pulmonary alveolar proteinosis related to mutations in the methionine tRNA synthetase ( MARS1 ) gene is a severe, early-onset disease that results in death before the age of 2 years in one-third of patients. It is associated with a liver disease, growth failure and systemic inflammation. As methionine supplementation in yeast models restored normal enzymatic activity of the synthetase, we studied the tolerance, safety and efficacy of daily oral methionine supplementation in patients with severe and early disease. Methods Four patients received methionine supplementation and were followed for respiratory, hepatic, growth, and inflammation-related outcomes. Their course was compared to those of historical controls. Reactive oxygen species (ROS) production by patient monocytes before and after methionine supplementation was also studied. Results Methionine supplementation was associated with respiratory improvement, clearance of the extracellular lipoproteinaceous material, and discontinuation of whole-lung lavage in all patients. The three patients who required oxygen or non-invasive ventilation could be weaned off within 60 days. Liver dysfunction, inflammation, and growth delay also improved or resolved. At a cellular level, methionine supplementation normalised the production of reactive oxygen species by peripheral monocytes. Conclusion Methionine supplementation was associated with important improvements in children with pulmonary alveolar proteinosis related to mutations in the MARS1 gene. This study paves the way for similar strategies for other tRNA synthetase deficiencies