Mickael Baqué

Sustainable life support on Mars – the potential roles of cyanobacteria

Even though technological advances could allow humans to reach Mars in the coming decades, launch costs prohibit the establishment of permanent manned outposts for which most consumables would be sent from Earth. This issue can be addressed by in situ resource utilization: producing part or all of these consumables on Mars, from local resources. Biological components are needed, among other reasons because various resources could be efficiently produced only by the use of biological systems. But most plants and microorganisms are unable to exploit Martian resources, and sending substrates from Earth to support their metabolism would strongly limit the cost-effectiveness and sustainability of their cultivation. However, resources needed to grow specific cyanobacteria are available on Mars due to their photosynthetic abilities, nitrogen-fixing activities and lithotrophic lifestyles. They could be used directly for various applications, including the production of food, fuel and oxygen, but also indirectly: products from their culture could support the growth of other organisms, opening the way to a wide range of life-support biological processes based on Martian resources. Here we give insights into how and why cyanobacteria could play a role in the development of self-sustainable manned outposts on Mars.

Investigation of Low-Energy Proton Effects on Aptamer Performance for Astrobiological Applications

Biochips are promising instruments for the search for organic molecules in planetary environments. Nucleic acid aptamers are powerful affinity receptors known for their high affinity and specificity, and therefore are of great interest for space biochip development. A wide variety of aptamers have already been selected toward targets of astrobiological interest (from amino acids to microorganisms). We present a first study to test the resistance of these receptors to the constraints of the space environment. The emphasis is on the effect of cosmic rays on the molecular recognition properties of DNA aptamers. Experiments on beam-line facilities have been conducted with 2 MeV protons and fluences much higher than expected for a typical mission to Mars. Our results show that this irradiation process did not affect the performances of DNA aptamers as molecular recognition tools.

Irradiation effects on antibody performance in the frame of biochip-based instruments development for space exploration

Several instruments based on immunoassay techniques have been proposed for life-detection experiments in the framework of planetary exploration but few experiments have been conducted so far to test the resistance of antibodies against cosmic ray particles. We present several irradiation experiments carried out on both grafted and free antibodies for different types of incident particles (protons, neutrons, electrons and 12C) at different energies (between 9 MeV and 50 MeV) and different fluences. No loss of antibodies activity was detected for the whole set of experiments except when considering protons with energy between 20 and 30 MeV (on free and grafted antibodies) and fluences much greater than expected for a typical planetary mission to Mars for instance. Our results on grafted antibodies suggest that biochip-based instruments must be carefully designed according to the expected radiation environment for a given mission. In particular, a surface density of antibodies much larger than the expected proton fluence would prevent significant loss of antibodies activity and thus assuring a successful detection.

Biochip-based instruments development for space exploration: influence of the antibody immobilization process on the biochip resistance to freeze-drying, temperature shifts and cosmic radiations

Due to the diversity of antibody (Ab)-based biochips chemistries available and the little knowledge about biochips resistance to space constraints, immobilization of Abs on the surface of the biochips dedicated to Solar System exploration is challenging. In the present paper, we have developed ten different biochip models including covalent or affinity immobilization with full-length Abs or Ab fragments. Ab immobilizations were carried out in oriented/non-oriented manner using commercial activated surfaces with N-hydroxysuccinic ester (NHS-surfaces) or homemade surfaces using three generations of dendrimers (dendrigraft of poly L-lysine (DGL) surfaces). The performances of the Ab -based surfaces were cross-compared on the following criteria: (i) analytical performances (expressed by both the surface density of immobilized Abs and the amount of antigens initially captured by the surface) and (ii) resistance of surfaces to preparation procedure (freeze-drying, storage) or spatial constraints (irradiation and temperature shifts) encountered during a space mission. The latter results have been expressed as percentage of surface binding capacity losses (or percentage of remaining active Abs). The highest amount of captured antigen was achieved with Ab surfaces having full-length Abs and DGL-surfaces that have much higher surface densities than commercial NHS-surface. After freeze-drying process, thermal shift and storage sample exposition, we found that more than 80% of surface binding sites remained active in this case. In addition, the resistance of Ab surfaces to irradiation with particles such as electron, carbon ions or protons depends not only on the chemistries (covalent/affinity linkages) and strategies (oriented/non-oriented) used to construct the biochip, but also on the type, energy and fluence of incident particles. Our results clearly indicate that full-length Ab immobilization on NHS-surfaces and DGL-surfaces should be preferred for potential use in instruments for planetary exploration.

Synthetic Biology for Space Exploration: Promises and Societal Implications

Synthetic biology can greatly accelerate the development of human space exploration, to the point of allowing permanent human bases on Mars within our lifetime. Among the technological issues to be tackled is the need to provide the consumables required to sustain crews, and using biological systems for the on-site production of resources is an attractive approach. However, all organisms we currently know have evolved on Earth and most extraterrestrial environments stress the capabilities of even terrestrial extremophiles. Two challenges consequently arise: organisms should survive in a metabolically active state with minimal maintenance requirements, and produce compounds of interest while relying only on inputs found in the explored areas. A solution could come from the tools and methods recently developed within the field of synthetic biology. The societal implications are complex: there are implications with synthetic biology and human space colonization independently, and together there are potentially more issues. Establishing colonies relying to a large extent on modified organisms and transferring the developed technologies to terrestrial applications raises a wide range of critical ethical questions and unprecedented societal impacts, on Earth as well as on colonized planetary bodies. The scenario of humans as a multi-planet species should be addressed now, as technologies aimed at making it happen are already under development. Here we give a brief overview of the synthetic biology technologies that are being developed to aid human space exploration, before discussing the impacts of proposed medium-term scenarios on the evolution of our society.

Desert Cyanobacteria - Potential for Space and Earth Applications

Cyanobacterial-dominated hypolithic and endolithic communities occur in cold and hot deserts, often referred to as Mars analogues, where life is pushed to its physical limits due to extreme water deficit and challenging temperatures. The endurance of desert cyanobacteria is currently tested under ground-based space and Martian-simulated conditions as well as in low Earth orbit outside the International Space Station with the aim to: (i) understand the limits of life and potential habitability of the solar system and beyond; (ii) identify suitable biosignatures for searching for past or extant life on Mars; (iii) validate the lithopanspermia theory, i.e., the possibility of interplanetary transport of life by means of material ejected by asteroid and meteorite impacts; (iv) improve the procedures for planetary protection, to avoid contamination of bodies of interest in our solar system with terrestrial life via probes and rovers; and (v) design life-support systems for beyond-Earth settlements, eventually utilizing in situ resources, whose principles could be transferred to Earth for the development of sustainable industrial processes based on carbon dioxide, solar energy, water, and minerals.

The Development of an Effective Bacterial Single-Cell Lysis Method Suitable for Whole Genome Amplification in Microfluidic Platforms

Single-cell sequencing is a powerful technology that provides the capability of analyzing a single cell within a population. This technology is mostly coupled with microfluidic systems for controlled cell manipulation and precise fluid handling to shed light on the genomes of a wide range of cells. So far, single-cell sequencing has been focused mostly on human cells due to the ease of lysing the cells for genome amplification. The major challenges that bacterial species pose to genome amplification from single cells include the rigid bacterial cell walls and the need for an effective lysis protocol compatible with microfluidic platforms. In this work, we present a lysis protocol that can be used to extract genomic DNA from both gram-positive and gram-negative species without interfering with the amplification chemistry. Corynebacterium glutamicum was chosen as a typical gram-positive model and Nostoc sp. as a gram-negative model due to major challenges reported in previous studies. Our protocol is based on thermal and chemical lysis. We consider 80% of single-cell replicates that lead to >5 ng DNA after amplification as successful attempts. The protocol was directly applied to Gloeocapsa sp. and the single cells of the eukaryotic Sphaerocystis sp. and achieved a 100% success rate.