Human presence impacts fungal diversity of inflated lunar/Mars analog habitat

Abstract

BackgroundAn inflatable lunar/Mars analog habitat (ILMAH), simulated closed system isolated by HEPA filtration, mimics International Space Station (ISS) conditions and future human habitation on other planets except for the exchange of air between outdoor and indoor environments. The ILMAH was primarily commissioned to measure physiological, psychological, and immunological characteristics of human inhabiting in isolation, but it was also available for other studies such as examining its microbiological aspects. Characterizing and understanding possible changes and succession of fungal species is of high importance since fungi are not only hazardous to inhabitants but also deteriorate the habitats. Observing the mycobiome changes in the presence of human will enable developing appropriate countermeasures with reference to crew health in a future closed habitat.ResultsSuccession of fungi was characterized utilizing both traditional and state-of-the-art molecular techniques during the 30-day human occupation of the ILMAH. Surface samples were collected at various time points and locations to observe both the total and viable fungal populations of common environmental and opportunistic pathogenic species. To estimate the cultivable fungal population, potato dextrose agar plate counts method was utilized. The internal transcribed spacer region-based iTag Illumina sequencing was employed to measure the community structure and fluctuation of the mycobiome over time in various locations. Treatment of samples with propidium monoazide (PMA; a DNA intercalating dye for selective detection of viable microbial populations) had a significant effect on the microbial diversity compared to non-PMA-treated samples. Statistical analysis confirmed that viable fungal community structure changed (increase in diversity and decrease in fungal burden) over the occupation time. Samples collected at day 20 showed distinct fungal profiles from samples collected at any other time point (before or after). Viable fungal families like Davidiellaceae, Teratosphaeriaceae, Pleosporales, and Pleosporaceae were shown to increase during the occupation time.ConclusionsThe results of this study revealed that the overall fungal diversity in the closed habitat changed during human presence; therefore, it is crucial to properly maintain a closed habitat to preserve it from deteriorating and keep it safe for its inhabitants. Differences in community profiles were observed when statistically treated, especially of the mycobiome of samples collected at day 20. On a genus level Epiccocum, Alternaria, Pleosporales, Davidiella, and Cryptococcus showed increased abundance over the occupation time.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-017-0280-8) contains supplementary material, which is available to authorized users.

Microbiome and Metagenome Analyses of a Closed Habitat During Human Occupation

“…To aid NASA in developing appropriate closed habitats (a built environment that has minimal atmospheric exchange with the surrounding environment), it will be necessary to characterize the microbial ecology across a variety of current built environments. In this regard, the microbial analysis of several closed systems has been performed, including the spacecraft assembly facilities (SAF) [7], Inflated Lunar/Mars Analogous Habitat (ILMAH) [8,9], long haul commercial aircraft cabin air [10], and the International Space Station (ISS) [11][12][13]. However, this is the first report of a pressure capsule (Analog habitat) closed off from the surrounding environment, as that of the space human habitat (Analog to ISS), is characterized for their molecular microbial communities.…”

The influence of bioregenerative life‐support system dietary structure and lifestyle on the gut microbiota: a 105‐day ground‐based space simulation in Lunar Palace 1

“…Hence, one of the major challenges in manned space exploration is protecting astronauts from microbiota dysbiosis. In recent years, with the development of high-throughput sequencing technology for complex microbial communities, both hostderived and environmental microbiome have frequently been studied, either in space stations (Checinska et al, 2015;Moissleichinger et al, 2016;Mora et al, 2016b;Be et al, 2017) or ground-based space simulations Mayer et al, 2016;Sun et al, 2016;Blachowicz et al, 2017;Schwendner et al, 2017;Turroni et al, 2017).…”

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“…Furthermore, research on fungi in indoor-closed space habitats is being done with respect to microbial contamination and diversity. For example, the human presence was also shown to impact fungal diversity of inflated lunar/Martian analogue habitats (Blachowicz et al 2017). A spaceflight experiment has also been developed to test the growth of the filamentous fungus P. rubens on different spacecraftrelevant surface materials (Zea et al 2018).…”