Detection of Macromolecules in Desert Cyanobacteria Mixed with a Lunar Mineral Analogue After Space Simulations

Abstract

In the context of future exposure missions in Low Earth Orbit and possibly on the Moon, two desert strains of the cyanobacterium Chroococcidiopsis, strains CCMEE 029 and 057, mixed or not with a lunar mineral analogue, were exposed to fractionated fluencies of UVC and polychromatic UV (200–400 nm) and to space vacuum. These experiments were carried out within the framework of the BIOMEX (BIOlogy and Mars EXperiment) project, which aims at broadening our knowledge of mineral-microorganism interaction and the stability/degradation of their macromolecules when exposed to space and simulated Martian conditions. The presence of mineral analogues provided a protective effect, preserving survivability and integrity of DNA and photosynthetic pigments, as revealed by testing colony-forming abilities, performing PCR-based assays and using confocal laser scanning microscopy. In particular, DNA and pigments were still detectable after 500 kJ/m2 of polychromatic UV and space vacuum (10−4 Pa), corresponding to conditions expected during one-year exposure in Low Earth Orbit on board the EXPOSE-R2 platform in the presence of 0.1 % Neutral Density (ND) filter. After exposure to high UV fluencies (800 MJ/m2) in the presence of minerals, however, altered fluorescence emission spectrum of the photosynthetic pigments were detected, whereas DNA was still amplified by PCR. The present paper considers the implications of such findings for the detection of biosignatures in extraterrestrial conditions and for putative future lunar missions.

Tolerances ofDeinococcus geothermalisBiofilms and Planktonic Cells Exposed to Space and Simulated Martian Conditions in Low Earth Orbit for Almost Two Years

“…This is an indication that the Mars regolith simulant significantly increased the UV radiation tolerance of D. geothermalis biofilms, presumably due to physical shielding from radiation. This is in line with previous reports on the protective effects of S-MRS (Gómez et al, 2010;Baqué et al, 2013) or other mineral additives (de la Vega et al, 2007) during irradiation and under comparable conditions (Billi et al, 2000(Billi et al, , 2011Baqué et al, 2014). In general, RAPD profiles were not affected by exposure to vacuum or artificial Mars gas mixture in the dark and led to unaltered PCR profiles compared with the dried or liquid laboratory controls.…”

Sustainable life support on Mars – the potential roles of cyanobacteria

“…Chroococcidiopsis species (see Fig. 7) have also been suggested as BLSS components , as they are dominant in terrestrial sites considered as Mars analogues due to radiation, rock composition, drought and extreme temperatures, and have been shown to be highly resistant to various simulated space and Martian conditions (Thomas et al 2006;Cockell et al 2011;Baqué et al 2013Baqué et al , 2014. Another advantage comes from their resistance to longterm desiccation (Billi 2009), which is of strong interest for long-term storage: cells could be carried in a dry state and be rehydrated upon arrival.…”

“…2011; Baqué et al . 2013, 2014). Another advantage comes from their resistance to long-term desiccation (Billi 2009), which is of strong interest for long-term storage: cells could be carried in a dry state and be rehydrated upon arrival.…”

The evaluation of time‐resolved Raman spectroscopy for the suppression of background fluorescence from space‐relevant samples

“…This helps to shield the organisms from katabatic winds and desiccation, as well as UV radiation. Because of their remarkable survivability, lichens, cyanobacteria, and/or their components are recognized as space‐relevant candidate biomarkers for potential extant or extinct extraterrestrial life in astrobiological research …”

“…In ground‐based simulation experiments of space and/or Mars‐like conditions, the mixture of a lichen ( B . frigida ) with Mars analogue material and a cyanobacterium ( Chroococcidiopsis ) with Mars and Moon analogue material were studied by Meeßen et al and Baqué et al, respectively.…”