The International Space Station (ISS) is a unique habitat for humans and microorganisms. Here, we report the results of the ISS experiment EXTREMOPHILES, including the analysis of microbial communities from several areas aboard at three time points. We assess microbial diversity, distribution, functional capacity and resistance profile using a combination of cultivation-independent analyses (amplicon and shot-gun sequencing) and cultivation-dependent analyses (physiological and genetic characterization of microbial isolates, antibiotic resistance tests, co-incubation experiments). We show that the ISS microbial communities are highly similar to those present in ground-based confined indoor environments and are subject to fluctuations, although a core microbiome persists over time and locations. The genomic and physiological features selected by ISS conditions do not appear to be directly relevant to human health, although adaptations towards biofilm formation and surface interactions were observed. Our results do not raise direct reason for concern with respect to crew health, but indicate a potential threat towards material integrity in moist areas.

This study s goal was to examine if any salivary microbiome changes were observed in astronauts as a result of spaceflight. In addition this study looked for any microbiome signature that may be associated with viral reactivation in humans

Exposure to bioaerosols can negatively impact human health. On the International Space Station (ISS) this exposure differs to that on Earth due to lack of gravitational settling and differing microbial sources. It is unknown how microbes are influenced by different particle size fractions in microgravity. The goal of this study is to identify the microbial communities on different particle size fractions taken from the ISS.

Airborne microorganisms in the upper troposphere and lower stratosphere remain elusive due to a lack of reliable sample collection systems. To address this problem we designed installed and flight-validated a novel Aircraft Bioaerosol Collector (ABC) for NASA s C-20A that can make collections for microbiological research investigations up to altitudes of 13.7 km. Herein we report results from the first set of science flights xe2 x80 x94four consecutive missions flown over the United States (US) from 30 October to 2 November 2017. To ascertain how the concentration of airborne bacteria changed across the tropopause we collected air during aircraft Ascent/Descent (0.3 to 11 km) as well as sustained Cruise altitudes in the lower stratosphere (~12 km). Bioaerosols were captured on DNA-treated gelatinous filters inside a cascade air sampler then analyzed with molecular and culture-based characterization. Several viable bacterial isolates were recovered from flight altitudes including Bacillus sp. Micrococcus sp. Arthrobacter sp. and Staphylococcus sp. from Cruise samples and Brachybacterium sp. from Ascent/Descent samples. Using 16S V4 sequencing methods for a culture-independent analysis of bacteria the average number of total OTUs was 305 for Cruise samples and 276 for Ascent/Descent samples. Some taxa were more abundant in the flight samples than the ground samples including OTUs from families Lachnospiraceae Ruminococcaceae and Erysipelotrichaceae as well as the following genera: Clostridium Mogibacterium Corynebacterium Bacteroides Prevotella Pseudomonas and Parabacteroides. Surprisingly our results revealed a homogeneous distribution of bacteria in the atmosphere up to 12 km. The observation could be due to atmospheric conditions producing similar background aerosols across the western US as suggested by modeled back trajectories and satellite measurements. However the influence of aircraft-associated bacterial contaminants could not be fully eliminated and that background signal was reported throughout our dataset. Considering the tremendous engineering challenge of collecting biomass at extreme altitudes where contamination from flight hardware remains an ever-present issue we note the utility of using the stratosphere as a proving ground for planned life detection missions across the solar system.

The MARS500 project the longest ground-based space simulation ever provided us with a unique opportunity to trace the crew microbiota over 520 days of isolated confinement such as that faced by astronauts in real long-term interplanetary space flights and after returning to regular life for a total of 2 years.

Our study focuses on the hardiest microorganisms inhabiting the ISS in order to assess their diversity and capabilities to resist certain stresses. We specifically selected dust samples from the Russian modules that were obtained 8-10 years ago and stored since then under sealed conditions on Earth. Targeting long-time survivors and spore-forming microorganisms we assessed consequently the cultivable microbial community of these samples in order to obtain model microbial strains that could help to analyze specific adaptation towards environmental stresses such as desiccation and lack of nutrients. In this study we analyzed these microorganisms with respect to their resistance towards thermal stress and exposure to clinically relevant antibiotics. In addition we assessed the bacterial and archaeal community via molecular methods (NGS sequencing) and compared our new data with the previously derived information from the ISS microbiome.