Cyprien Verseux

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.

A Question of Attire: Dressing Up Bacteriophage Therapy for the Battle Against Antibiotic-Resistant Intracellular Bacteria

More and more bacteria are developing severe antibiotic resistance. Among them are important intracellular pathogens such as Mycobacterium tuberculosis. Alternatives to classical antibiotics are urgently needed and bacteriophage therapy is a promising candidate for alternative or supplemental treatment. Until now, bacteriophages have been thought to be non-suitable for therapy against intracellular pathogens. Still, a few studies have been carried out to assess the efficacy of bacteriophage therapy against intracellular pathogens both in vitro and in vivo, with variable results. Recently, some successful studies have been conducted, in which bacteriophages were carried into infected cells by different bacterial vectors and killed intracellular pathogens. In this review, we aim to recapitulate the existing literature on bacteriophage therapy of intracellular pathogens and discuss possible ways of bacteriophage entry into infected cells, including different Trojan horse strategies and the question of whether free bacteriophages are able to enter mammalian cells. Finally, we sum up attempts of bacteriophage microencapsulation and speculate about the advantages of artificial vectorization for efficient and targeted intracellular delivery.

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.