Study of the effects of the outer space environment on dormant forms of microorganisms, fungi and plants in the ‘Expose-R’ experiment

Novikova, Natalia; Deshevaya, Elena; Levinskikh, Margarita; Polikarpov, N.; Poddubko, S. V.; Gusev, Oleg; Sychev, Vladimir

doi:10.1017/s1473550414000731

Cited by 30 publications

(26 citation statements)

References 15 publications

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“…1C), indicating that accumulated damage could not be overcome through repair and redundancy. In addition, Arabidopsis seeds were completely killed in a separate experiment on EXPOSE-R (Novikova et al, 2015). A survival endpoint was thus reached in Arabidopsis, and the results from EXPOSE-E, where exposure was lower and better survival occurred, were corroborated and extended.…”

Section: Discussionmentioning

confidence: 99%

Survival and DNA Damage in Plant Seeds Exposed for 558 and 682 Days outside the International Space Station

Tepfer¹,

Leach

2017

Astrobiology

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For life to survive outside the biosphere, it must be protected from UV light and other radiation by exterior shielding or through sufficient inherent resistance to survive without protection. We tested the plausibility of inherent resistance in plant seeds, reporting in a previous paper that Arabidopsis thaliana and tobacco (Nicotiana tabacum) seeds exposed for 558 days outside the International Space Station (ISS) germinated and developed into fertile plants after return to Earth. We have now measured structural genetic damage in tobacco seeds from this EXPOSE-E experiment by quantitatively amplifying a segment of an antibiotic resistance gene, nptII, inserted into the chloroplast genome. We also assessed the survival of the antibiotic resistance encoded by nptII, using marker rescue in a soil bacterium. Chloroplast DNA damage occurred, but morphological mutants were not detected among the survivors. In a second, longer mission (EXPOSE-R), a nearly lethal exposure was received by Arabidopsis seeds. Comparison between a ground simulation, lacking UV<200nm, and fully exposed seeds in space indicated severe damage from these short wavelengths and again suggested that DNA degradation was not limiting seed survival. To test UV resistance in long-lived, larger seeds, we exposed Arabidopsis, tobacco, and morning glory seeds in the laboratory to doses of UV254nm, ranging as high as 2420 MJ m−2. Morning glory seeds resisted this maximum dose, which killed tobacco and Arabidopsis. We thus confirm that a naked plant seed could survive UV exposures during direct transfer from Mars to Earth and suggest that seeds with a more protective seed coat (e.g., morning glory) should survive much longer space travel. Key Words: UV light—Flavonoids—Sinapate—DNA degradation—Arabidopsis—Tobacco—Seeds—Space—International Space Station—EXPOSE-E—EXPOSE-R. Astrobiology 17, 205–215.

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Section: Discussionmentioning

confidence: 99%

Survival and DNA Damage in Plant Seeds Exposed for 558 and 682 Days outside the International Space Station

Tepfer¹,

Leach

2017

Astrobiology

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“…In the context of spaceexploration missions, bacterial and fungal spores may act as an effective vehicle for the transfer of life from Earth to extraterrestrial locations in a dormant yet viable state (Rummel et al, 2014;Gibney, 2016;Nagler et al, 2016). Spores of aspergilli and closely related fungi are highly stress resistant (van Leeuwen et al, 2013;Rangel et al, 2015;Wyatt et al, 2015b) and can remain viable after exposure to space at least 22 months, as demonstrated by the EXPOSE-R experiment performed on the outer surface of the International Space Station (Novikova et al, 2015), though may potentially do so for decades. In the current study, production of aerial hyphae and/or conidiophores and lawns of (pigmented) spores were recorded on 10 out of the 18 germination media (Figs 1 and S4).…”

Section: Production Of Mycelium and Sporulation: The Culmination Of Dmentioning

confidence: 99%

Aspergillus penicillioides differentiation and cell division at 0.585 water activity

Stevenson

Hamill

O'Kane

et al. 2017

Environmental Microbiology

111

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SummaryWater availability acts as the most stringent constraint for life on Earth. Thus, understanding the water relations of microbial extremophiles is imperative to our ability to increase agricultural productivity (e.g., by enhancing the processing and turnover of dead organic matter in soils of arid regions), reduce human exposure to mycotoxins in buildings and our foodsupply chain, prevent the spoilage of foods/animal feeds, books, museum specimens and artworks and better control microbiology of industrial fermentations. Only a small number of microbial systems can retain activity at <0.710 water activity (ISME J 2015 9: 1333-1351). It has long-been considered that the most resilient of these is Xeromyces bisporus, which inhabits sugar-rich substrates (Appl Environ Microbiol 1968 16: 1853-1858. The current study focused on germination of Aspergillus penicillioides, a xerophile which is also able to grow under low humidity and saline conditions. Investigations of germination differed from those reported earlier: firstly, aerially borne conidia were harvested, and then used for inoculations, in their dry condition; secondly, cultures were incubated at 248C, i.e. below optimum germination temperature, to minimize the possibility of water loss from the substrate; thirdly, cultures remained sealed throughout the 73-day study period (microscopic examination was carried out directly 48 through the Petri plate lid); fourthly, the germination parameters determined were: rates and extent of conidial swelling, production of differentiated germinationstructures and septate germlings, and subsequent development of mycelium and/or sporulation; fifthly, assessments were carried out over a range of wateractivity values and time points to obtain a complete profile of the germination process. Conidia swelled, formed differentiated germination-structures and then produced septate germlings at a water-activity of just 0.585 (58.5% relative humidity), outside the currently understood thermodynamic window for life. Furthermore, analyses of these data suggest a theoretical water-activity minimum of 0.565 for germination of A. penicilliodes. In relation to astrobiology, these findings have an application in understanding the limits to life in extraterrestrial environments. In light of current plans for exploration missions to Mars and other places, and the need to safeguard martian scientific sites and potential resources (including water) for future human habitation, a knowledge-based and effective policy for planetary protection is essential. As it is, Mars-bound spacecraft may frequently be contaminated with aspergilli (including A. penicillioides) and other organisms which, when transported to other planetary bodies, pose a contamination risk. In crafting countermeasures to offset this, it is important to know as precisely as possible the capabilities of these potential interplanetary visitors.

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“…Also angiosperms have been tested for irradiation resistance under space conditions: 23% of Arabidopsis thaliana and Nicotina tabacum seeds developed viable plants after space exposure in LEO for 558 days, receiving irradiation doses of 7.4 · 10 5 kJ$m -2 UV 110-400nm (Tepfer et al, 2012). However, when A. thaliana seeds were exposed to higher doses of 10.3 · 10 5 kJ$m -2 UV 110-400nm for 682 days at the ISS EXPOSE-R platform, seeds hardly survived (Novikova et al, 2015;Tepfer and Leach, 2017). YIELD from before the investigation was used as a factor and compared with Yield values at the end of the experiment.…”

Section: Discussionmentioning

confidence: 99%

Mosses in Low Earth Orbit: Implications for the Limits of Life and the Habitability of Mars

et al. 2019

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As a part of the European Space Agency mission ''EXPOSE-R2'' on the International Space Station (ISS), the BIOMEX (BIOlogy and Mars EXperiment) investigates the habitability of Mars and the limits of life. In preparation for the mission, experimental verification tests and scientific verification tests simulating different combinations of abiotic space and Mars-like conditions were performed to analyze the resistance of a range of model organisms. The simulated abiotic space-and Mars-stressors were extreme temperatures, vacuum, and Mars-like surface ultraviolet (UV) irradiation in different atmospheres. We present for the first time simulated space exposure data of mosses using plantlets of the bryophyte genus Grimmia, which is adapted to high altitudinal extreme abiotic conditions at the Swiss Alps. Our preflight tests showed that severe UVR 200-400nm irradiation with the maximal dose of 5 and 6.8 · 10 5 kJ$m -2 , respectively, was the only stressor with a negative impact on the vitality with a 37% (terrestrial atmosphere) or 36% reduction (space-and Mars-like atmospheres) in photosynthetic activity. With every exposure to UVR 200-400nm 10 5 kJ$m -2 , the vitality of the bryophytes dropped by 6%. No effect was found, however, by any other stressor. As the mosses were still vital after doses of ultraviolet radiation (UVR) expected during the EXPOSE-R2 mission on ISS, we show that this earliest extant lineage of land plants is highly resistant to extreme abiotic conditions.

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Study of the effects of the outer space environment on dormant forms of microorganisms, fungi and plants in the ‘Expose-R’ experiment

Cited by 30 publications

References 15 publications

Survival and DNA Damage in Plant Seeds Exposed for 558 and 682 Days outside the International Space Station

Survival and DNA Damage in Plant Seeds Exposed for 558 and 682 Days outside the International Space Station

Aspergillus penicillioides differentiation and cell division at 0.585 water activity

Mosses in Low Earth Orbit: Implications for the Limits of Life and the Habitability of Mars

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