From extreme environments on Earth to space: Buttiauxella sp. MASE-IM-9 and Salinisphaera shabanensis as new model organisms in Astrobiology

Mars analogue environments are some of the most extreme locations on Earth. Their unique combination of multiples extremes (e.g. high salinity, anoxia, and low nutrient availability) make them a valuable source of new polyextremophilic microbes in general and for exploring the limits of life. These are seen as vital sources of information for Astrobiology, with implications for planetary protection and the search for life outside our planet. [...

Surviving Mars: new insights into the persistence of facultative anaerobic microbes from analogue sites

Mars analogue environments are some of the most extreme locations on Earth. Their unique combination of multiples extremes (e.g. high salinity, anoxia and low nutrient availability) make them valuable sources for finding new polyextremophilic microbes, and for exploring the limits of life. Mars, especially at its surface, is still considered to be very hostile to life but it probably possesses geological subsurface niches where the occurrence of (polyextremophilic) life is conceivable. Despite their well-recognized relevance, current knowledge on the capability of (facultative) anaerobic microbes to withstand extraterrestrial/Martian conditions, either as single strains or in communities, is still very sparse. Therefore, space experiments simulating the Martian environmental conditions by using space as a tool for astrobiological research are needed to substantiate the hypotheses of habitability of Mars. Addressing this knowledge gap is one of the main goals of the project MEXEM (Mars EXposed Extremophiles Mixture), where selected model organisms will be subjected to space for a period of 3 months. These experiments will take place on the Exobiology facility (currently under development and implementation), located outside the International Space Station. Such space experiments require a series of preliminary tests and ground data collection for the selected microbial strains. Here, we report on the survivability of Salinisphaera shabanensis and Buttiauxella sp. MASE-IM-9 after exposure to Mars-relevant stress factors (such as desiccation and ultraviolet (UV) radiation under anoxia). Both organisms showed survival after anoxic desiccation for up to 3 months but this could be further extended (nearly doubled) by adding artificial Mars regolith (MGS-1S; 0.5% wt/v) and sucrose (0.1 M). Survival after desiccation was also observed when both organisms were mixed before treatment. Mixing also positively influenced survival after exposure to polychromatic Mars-like UV radiation (200–400 nm) up to 12 kJ m−2, both in suspension and in a desiccated for

Horizontal gene transfer in space - a potential thread for astronauts?

Horizontal gene transfer (HGT) enables microorganisms to transmit genetic information to neighboring cells. On Earth, different mechanisms are known including conjugation which permits bacteria to rapidly adapt to environmental conditions, for example by conveying antibiotic resistances. This advantageous ability poses a huge threat to humans on Earth as well as in space as multiresistant strains are on the rise and only few new antibiotics are being discovered. In regard to long-term space missions, the issue of microorganisms developing antibiotic resistances compromises the health of astronauts as they can only rely on limited medical support. Even though, the driving force of emerging antibiotic resistances by bacterial conjugation, has been studied on Earth, but it has not been studied extensively in space. The experiment Bacterial Conjugation in Space is a microscope experiment that will utilize the Live Cell Imaging facility FLUMIAS on board the International Space Station which was developed by the German Space Agency. The experiment aims to shed light on bacterial conjugation in microgravity compared to Earth gravity by microscopic fluorescence observation. The results of these experiments are of high importance to ensure the safety and health of astronauts during future long-term missions. However, the heavy technical and experiment constrains imposed by space conditions require a meticulous planning and procedure development to guarantee a campaign with significant results. The presented study was designed to determine the optimal experiment parameters to track the conjugation. The model organism E. coli will carry different plasmids, each encoding a different fluorescent protein, to visualize the transconjugants, hence the conjugation. It was shown that within the set constrains it is possible to observe bacterial growth and fluorescence, as well as that within the defined field of view (350µm x 400µm) and available objectives of FLUMIAS it is possible to observe a sufficient cell number. With an average of 7500 cells per field of view and an expected conjugation rate up to 4.1% it will be possible to visualize 200 transconjugants in an adequate resolution. It was shown that the experiment will work within the borders of the set constrains. Furthermore, it was tested which growth conditions are advantageous for biofilm formation and how different circumstances, such as donor or recipient in biofilm, and simulated µ-gravity can influence the conjugation rate, and how storage conditions influence the stability of the plasmid. The presented study delivers a proof of concept for the setup within the set of constrains. Moreover, it is the precursor to ensure that health and medical supply for astronauts on long term space missions can be assured

Is the repair kinetics of radiation induced DNA damages influenced by microgravity? Preparation of the space experiment LUX-in-Space

In space, all organisms are exposed to and affected by space radiation and microgravity. This applies for microorganisms, plants and animals used as components of bioregenerative life support systems, for cells, tissues and organoids investigated in scientific space experiments and for astronauts. Radiation and microgravity were identified as two of the five most important hazards for manned spaceflight. Therefore, the knowledge of biological space radiation effects as well as the impact of microgravity on enzymatic repair processes is mandatory for risk assessment, especially in view of long duration missions to Mars or permanently inhabited bases on the Moon. The repair kinetics of radiation induced DNA damages will be investigated with a bioassay, the DLR-developed SOS-Lux Test, in the space experiment LUX-in-Space on the ISS. Bacteria serve as model organisms. They possess the same type of nucleotid excision repair as all other living organisms including humans. Salmonella enterica subsp. enterica (ATCC 53648) cells are transformed with the pBR322-derived plasmid pPLS-1, carrying the promoterless lux operon of Photobacterium leiognathi as the reporter element controlled by a DNA damage-dependent SOS promoter as sensor element. Due to safety issues, UV radiation was chosen for DNA damage induction. It causes defined types of DNA damage, e.g. cyclobutan pyrimidine dimers, which are among those also induced by ionising radiation. In response to exposure to radiation the SOS promoter is activated. Due to the genetic modification, the connected so-called lux genes are expressed, resulting in the emission of measurable bioluminescence proportional to the applied dose of radiation. The DNA repair kinetics are followed by bioluminescence and optical density measurements. The experiment specific hardware for the BIOLAB facility is under development by industry and the results of the rigorous testing and optimisation program will be presented. LUX-in-Space is the first space experiment where the whole series of events from DNA damage induction in metabolically active cells to the different steps of enzymatic repair will take place in real microgravity and the repair kinetics will be monitored in situ by optical measurements. The effects of microgravity will be clearly separated from other spaceflight factors by comparison with parallel samples on an onboard 1g centrifuge in the Biolab facility on the ISS and in a parallel ground control experiment with identical samples in flight-identical hardware

Deciphering late Devonian–early Carboniferous P–T–t path of mylonitized garnet-mica schists from Prins Karls Forland, Svalbard

Quartz‐in‐garnet inclusion barometry integrated with trace element thermometry and calculated phase relations is applied to mylonitized schists of the Pinkie unit cropping out on the island of Prins Karls Forland, western part of the Svalbard Archipelago. This approach combines conventional and novel techniques and allows deciphering of the pressure–temperature (P–T) evolution of mylonitic rocks, for which the P–T conditions could not have been easily deciphered using traditional methods. The results obtained suggest that rocks of the Pinkie unit were metamorphosed under amphibolite facies conditions at 8–10 kbar and 560–630°C and mylonitized at ~500 to 550°C and 9–11 kbar. The P–T results are coupled with in‐situ Th–U‐total Pb monazite dating, which records amphibolite facies metamorphism at c. 359–355 Ma. This is the very first evidence of late Devonian–early Carboniferous metamorphism in Svalbard and it implies that the Ellesmerian Orogeny on Svalbard was associated with metamorphism up to amphibolite facies conditions. Thus, it can be concluded that the Ellesmerian collision between the Franklinian margin of Laurentia and Pearya and Svalbard caused not only commonly accepted brittle deformation and weak greenschist facies metamorphism, but also a burial and deformation of rock complexes at much greater depths at elevated temperatures

Geochemical composition of bentonite layers and U-Pb ages of detrital zircons from the Paleogene Basilika Formation (Svalbard) and Mount Lawson Formation (Ellesmere Island)

Major and trace element composition as well as Sm-Nd isotopes of whole-rock samples and clay fractions (<2 µm) of bentonite layers and U-Pb ages of detrital zircons from the Paleogene Basilika Formation (Svalbard) and Mount Lawson Formation (Ellesmere Island)

Stratigraphy of the uppermost Old Red Sandstone of Svalbard (Mimerdalen Subgroup)

Between the fjords Dicksonfjorden and Billefjorden in central Spitsbergen, Svalbard's youngest deposits (Early Givetian to Famennian in age) of the Old Red Sandstone—the Mimerdalen Subgroup—are exposed. They form a narrow outcrop area parallel to the Billefjorden Fault Zone and overlie unconformably the multicoloured sandstones of the Lower Devonian Wood Bay Formation. Stratigraphic rank and subdivision of the succession were changed repeatedly since its first mention in 1910. Based on student work in 1996, as well as regional mapping by the authors in 1993 and 2003, the present work formalizes the stratigraphic framework of the succession. This framework has already been applied in recent geological maps. At the same time it is a continuation of the lithostratigraphic standardization carried out by the Committee on the Stratigraphy of Svalbard (1999), where only post-Devonian rocks were considered. Except for some small-pebble conglomerate layers in the Wood Bay Formation, the upper part of the Mimerdalen Subgroup contains the first coarse-grained deposits in Svalbard's Old Red since the lowermost Devonian Red Bay Group. Faulting between its formations as well as conglomerate pebbles derived from the Lower Devonian Wood Bay Formation indicate the onset of the Svalbardian Event after the tectonic stability during the deposition of the Wood Bay Formation. The Mimerdalen Subgroup is probably the detrital fill of a small foreland basin derived from erosion during the uplift of the Ny-Friesland Block to the east of the Billefjorden Fault Zone. It was later affected by compressional tectonic movements during the Svalbardian Event