Due to the ability of (hyper-) thermophilic Bacteria and Archaea to live in extreme habitats
on Earth (e.g. boiling acidic springs, black smoker chimneys, hyper-salinic brines) one could
suggest, that these organisms can also outlast other harsh conditions, e.g. prevailing in space or
on Mars. On Mars the occurrence of different utilizable nutrition components is limited. The
Phoenix lander detected significant amounts (0.4 - 0.6 %) of perchlorate ions in Martian soil.
Therefore, we examined the ability of the perchlorate metabolizing Archaeon Archaeoglobus
fulgidus as well as phylogenetically deep-branching Bacterium Hydrogenothermus marinus to
survive and grow in the presence of perchlorate (NaClO4) and hydrogen peroxide (H₂O₂). The
investigated microorganisms were able to tolerate high concentrations of NaClO4 without any
changes in their growth pattern. After the addition of 280 mM perchlorate H. marinus showed
significant changes in cell morphology. This organism is normally growing as single motile short
rods; treated with high concentrations of perchlorate long chains were built. A. fulgidus can
tolerate concentrations up to 300 mM. On the contrary, both microorganisms were negatively
affected in their survival after a treatment with low concentrations (<50 mM) of H₂O₂. In
summary (hyper-) thermophiles have so far unknown high tolerances against cell damaging
treatments and may serve as model organisms for future space experiments.
BIOMEX (BIOlogy and Mars EXperiment) is an ESA/Roscosmos space exposure experiment housed within the exposure facility EXPOSE-R2 outside the Zvezda module on the International Space Station (ISS). The design of the multiuser facility supports—among others—the BIOMEX investigations into the stability and level of degradation of space-exposed biosignatures such as pigments, secondary metabolites, and cell surfaces in contact with a terrestrial and Mars analog mineral environment. In parallel, analysis on the viability of the investigated organisms has provided relevant data for evaluation of the habitability of Mars, for the limits of life, and for the likelihood of an interplanetary transfer of life (theory of lithopanspermia). In this project, lichens, archaea, bacteria, cyanobacteria, snow/permafrost algae, meristematic black fungi, and bryophytes from alpine and polar habitats were embedded, grown, and cultured on a mixture of martian and lunar regolith analogs or other terrestrial minerals. The organisms and regolith analogs and terrestrial mineral mixtures were then exposed to space and to simulated Mars-like conditions by way of the EXPOSE-R2 facility. In this special issue, we present the first set of data obtained in reference to our investigation into the habitability of Mars and limits of life. This project was initiated and implemented by the BIOMEX group, an international and interdisciplinary consortium of 30 institutes in 12 countries on 3 continents. Preflight tests for sample selection, results from ground-based simulation experiments, and the space experiments themselves are presented and include a complete overview of the scientific processes required for this space experiment and postflight analysis. The presented BIOMEX concept could be scaled up to future exposure experiments on the Moon and will serve as a pretest in low Earth orbit.
Is life out there? In order to assess the habitability of Mars, which is (or has been) the most Earth-like planet in our Solar System, the first step is to investigate microorganisms thriving in terrestrial biotops with Mars similar conditions (0.13% O₂ in the atmosphere, low nutrients, low temperatures, high salinity and oxidising compounds, acidity) and comparable multi-stresses. The MASE (Mars analogues for space exploration) consortium is a team of researchers from all over Europe, combining a broad spectrum of interdisciplinary expertise. Five major sampling sites (dedicated campaigns: cold sulfur springs in Germany, potash mine in England, cold acidic lake in Iceland; samples already available: Rio Tinto in Spain, permafrost samples from Svaldbard) were chosen with the major goal to cultivate and characterize novel anaerobic microorganisms which are specifically adapted to harsh conditions. Samples from these different Mars analogue areas on Earth were collected and anaerobic microorganisms adapted to these extreme conditions are being isolated. These new strains will be subjected to mars-relevant environmental stress factors alone and in combination in the laboratory under controlled conditions, e.g. radiation, high salt concentrations, low water activity, oxidising compounds. The aim is to understand how combined environmental stresses affect the habitability of a number of Mars analogue environments on Earth, specifically for anaerobic organisms and to find out, if these organisms are also able to survive under Martian conditions. Crucial to assessing the habitability of any environmental system is a detailed understanding of the geological, physiochemical and biological context in which the environment is set. One of the key outcomes of MASE is a comparison and synthesis of just such a collection of context data from a varied set of Mars analogue sites. The future experiments in the MASE project aim at the identification of the underlying cellular and molecular mechanisms and the comparison to other new isolates from Mars analogue environments on Earth.
BIOMEX (Biology and Mars Experiment) is a space experiment on the exposure platform EXPOSER2 launched by the Progress 56 mission on 24 July and placed on the outer side of the Russian Zvezda Module of the International Space Station (ISS). Twenty-five international institutes are working together and sharing different methods, planetary simulation facilities, and logistics to obtain information about the vitality of the tested microorganisms and the stability of biomolecules as possible biosignatures. This experiment comprises three investigational steps from the field to space: (i) field work with sample collection and habitat characterization at field sites with or without Mars analogy, (ii) Mars simulation experiments in the lab and (iii) exposure to real space conditions. For the second and third steps some of the microorganisms and bio-molecules are embedded in Marsanalog regolith mixtures, placed in compartments enriched with Mars-like CO 2 -atmosphere and exposed to solar irradiation levels approaching those affecting the surface of Mars to test habitability on Mars, as well as the ability to detect the selected, Mars-exposed bio-molecules. One of the aims of this experiment is to investigate the specific bio-related spectra of resistant molecules obtained by fluorescence analysis, Raman-spectroscopy, IR- and UV/VIS spectrometry before and after simulated and real space exposure. The obtained database of stable bio-molecules will support future exploration missions to Mars whose main goal is the search for life.
1. Introduction Physic-chemical processes of living organisms leave tell-tale signals in the environment. The search for these signatures is one of the main goals for Astrobiology and improving and optimizing its detection regarding Mars conditions is part of the MASE project objectives. Besides, the traces of some kinds of microorganisms can be well preserved, provided that they are rapidly mineralized and that the sediments in which they occur are rapidly cemented [1]. A developed antibody multiarray competitive immunoassay (MACIA) for the simultaneous detection of compounds of a wide range of molecular sizes or whole spores and cells [2] [3] is a suitable option for biomarker detection in samples with low biomass from Mars analogue sites as well as with biomineralized microorganism communi- ties. Moreover, biomineralization is often the first step of fossilization and produces particular chemical, structural and morphological features that can be preserved in fossil biominerals or microfossils [4] and some parameters as oxido-reduction potencial (ORP) or pH vary over the process. 2. Methods and objectives Samples from the three MASE campaigns in Iceland (Graenavatn Lake), United Kingdom (Boulby Mine) and Germany (Sippenauer Moor, Regensburg) and other one from an Alpin glacier were used to obtain enrichments and isolates as well as to extract and detect biomarkers in them. Some of the enrichments were exposed to mineralization to study, among others, the preservation of biosignatures by the assessment of antigen-antibody binding at different times. Simultaneously, the evolution of ORP through this process was monitored by two modules system (DTIVA: automated tools for microbial life detection) where ORP variations in those communities were followed through continuous measurements of nanosensors in closed chambers. An additional objective for MASE project is to develop a specific microarray with antibodies performanced from natural samples and isolates from MASE sampling sites. 3. Summary and Conclusions The presence of traces from some microbial metabolic groups were detected in the mineralized communities at three different times over the fossilization process. It was undertaken by us- ing a 168 antibody microarray for the immunoassay. There were observed variations in the resulting immunoprofiles. There seems to be a probably correlation between these changes and those in ORP through time. We consider that the simultaneous use of both approaches arises a promising tool to broaden our knowledge and improve the search for traces of life, present or past. Acknowledgements MASE is supported by European Community’s Seventh Framework Programme (FP7/2007-2013) under Grant Agreement n° 607297.
Introduction: The Mars Analogues for Space Ex-ploration (MASE) project is brining new insight about Mars potential habitability but also some new knowledge about Earth organisms and the functioning of extreme terrestrial ecosystems. The overall aim of the MASE project is to study a variety of Mars-like environments in order to further our understanding of Martian habitability, as well as our ability to detect organisms that might be present on Mars. This collabo-rative, 4 research project supported by the European Commission’s Seventh Framework Programme has been running since January 2014 and a variety of dis-semination and communication activities has been per-formed since then to increase visibility of Mars ana-logues research.
Life is a physico-chemical process by which tell-tale signals or traces are left on the environment. These signals are indicators of life and are known as biomarkers.
Besides, the traces of some kinds of microorganisms can be well preserved, provided that they are rapidly mineralized and that the sediments in which they occur are rapidly cemented [1].
The search for these traces of life is one of the main objectives of Mars exploration [1] and to improve and optimize the search and detection of them forms part of MASE project targets.
In MASE project (Mars Analogues for Space Exploration) we work to improve approaches and methods for biomarker detection in samples with low biomass from Mars analogue sites.
A developed antibody multiarray competitive immunoassay (MACIA) for the simultaneous detection of compounds of a wide range of molecular sizes or whole spores and cells [2] [3] has revealed as suitable option to achieve this purpose.
The concept of present and/or past extraterrestrial life is thrilling and tackled intensively throughout the last decades, yet remains notional. Some regions of extraterrestrial bodies (e.g. the Mars) are in general considered as habitable; however, are ruled by extreme physical and chemical variables, which constrain the possibility of life. Similar settings (at least to a certain extent) exist on Earth and function as analogue model sites in many studies to elucidate basic information on the limits of life. One crucial feature, which distinguishes Earth from extraterrestrial bodies, is the absence of oxygen in the atmosphere. Terrestrial Mars analogue, anoxic settings are hardly described, in par-ticular with respect on the hosted microbial communities.
The MASE (Mars Analogues for Space Exploration) project tackled to understand specifically anaerobic life thriving in a number of various Mars analogue settings. Within the frame of this project, a diverse set of extreme and anoxic Mars analogue environments were sampled and microbiologically investigated by combining cultivation based and cultivation-independent analyses. This study included (i) a widescale cultivation approach targeting the anaerobic microbial fraction and (ii) an amplicon sequencing approach focusing on the viable Archaeome and Bacteriome.
Assessing the habitability of Mars and detecting life, if it was ever there, depends on knowledge
of whether the combined environmental stresses experienced on Mars are compatible with life
and whether a record of that life could ever be detected. Many combinations of Mars relevant
stress factors, such as high radiation dose rates and high UV
uences combined with high salt
concentrations, and low water activity, have not been investigated. In particular, the response
of anaerobic organisms to Mars-like stress factors and combinations thereof are not known. In
the EC project MASE (Mars Analogues for Space Exploration) we address these limitations by
characterising different Mars analogue environments on Earth, isolating microorganisms from
these sites and exposing them to Mars relevant stress factors alone and in combination. We
want to find out, if these bacteria respond in an additive or synergistic way and if they would
be able to survive on Mars. So far, eight only distantly related microorganisms are under
detailed investigation, e.g Yersinia sp., Halanaerobium sp., Acidiphilum sp. Desulfovibrio sp..
Unexpectedly, a Yersinia strain turned out to be quite resistant, especially against desicca-
tion and oxidising compounds, whereas a Desulfovibrio sp. strain exhibit a relatively high
radiation resistance. The future experiments aim at the identification of the underlying cellu-
lar and molecular mechanisms and the comparison to other new isolates from Mars analogue
environments on Earth in the MASE project.
