Transitory microbial habitat in the hyperarid Atacama Desert.

Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: (i) a physico-chemical characterization of the soil habitability after an exceptional rain event, (ii) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], (iii) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and (iv) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today's extreme hyperaridity.

Research Trends and Future Perspectives in Marine Biomimicking Robotics.

Mechatronic and soft robotics are taking inspiration from the animal kingdom to create new high-performance robots. Here, we focused on marine biomimetic research and used innovative bibliographic statistics tools, to highlight established and emerging knowledge domains. A total of 6980 scientific publications retrieved from the Scopus database (1950-2020), evidencing a sharp research increase in 2003-2004. Clustering analysis of countries collaborations showed two major Asian-North America and European clusters. Three significant areas appeared: (i) energy provision, whose advancement mainly relies on microbial fuel cells, (ii) biomaterials for not yet fully operational soft-robotic solutions; and finally (iii), design and control, chiefly oriented to locomotor designs. In this scenario, marine biomimicking robotics still lacks solutions for the long-lasting energy provision, which presently hinders operation autonomy. In the research environment, identifying natural processes by which living organisms obtain energy is thus urgent to sustain energy-demanding tasks while, at the same time, the natural designs must increasingly inform to optimize energy consumption.

An origin-of-life reactor to simulate alkaline hydrothermal vents.

Chemiosmotic coupling is universal: practically all cells harness electrochemical proton gradients across membranes to drive ATP synthesis, powering biochemistry. Autotrophic cells, including phototrophs and chemolithotrophs, also use proton gradients to power carbon fixation directly. The universality of chemiosmotic coupling suggests that it arose very early in evolution, but its origins are obscure. Alkaline hydrothermal systems sustain natural proton gradients across the thin inorganic barriers of interconnected micropores within deep-sea vents. In Hadean oceans, these inorganic barriers should have contained catalytic Fe(Ni)S minerals similar in structure to cofactors in modern metabolic enzymes, suggesting a possible abiotic origin of chemiosmotic coupling. The continuous supply of H2 and CO2 from vent fluids and early oceans, respectively, offers further parallels with the biochemistry of ancient autotrophic cells, notably the acetyl CoA pathway in archaea and bacteria. However, the precise mechanisms by which natural proton gradients, H2, CO2 and metal sulphides could have driven organic synthesis are uncertain, and theoretical ideas lack empirical support. We have built a simple electrochemical reactor to simulate conditions in alkaline hydrothermal vents, allowing investigation of the possibility that abiotic vent chemistry could prefigure the origins of biochemistry. We discuss the construction and testing of the reactor, describing the precipitation of thin-walled, inorganic structures containing nickel-doped mackinawite, a catalytic Fe(Ni)S mineral, under prebiotic ocean conditions. These simulated vent structures appear to generate low yields of simple organics. Synthetic microporous matrices can concentrate organics by thermophoresis over several orders of magnitude under continuous open-flow vent conditions.

Marine Science Can Contribute to the Search for Extra-Terrestrial Life.

Life on our planet likely evolved in the ocean, and thus exo-oceans are key habitats to search for extraterrestrial life. We conducted a data-driven bibliographic survey on the astrobiology literature to identify emerging research trends with marine science for future synergies in the exploration for extraterrestrial life in exo-oceans. Based on search queries, we identified 2592 published items since 1963. The current literature falls into three major groups of terms focusing on (1) the search for life on Mars, (2) astrobiology within our Solar System with reference to icy moons and their exo-oceans, and (3) astronomical and biological parameters for planetary habitability. We also identified that the most prominent research keywords form three key-groups focusing on (1) using terrestrial environments as proxies for Martian environments, centred on extremophiles and biosignatures, (2) habitable zones outside of "Goldilocks" orbital ranges, centred on ice planets, and (3) the atmosphere, magnetic field, and geology in relation to planets' habitable conditions, centred on water-based oceans.

Microbial biomanufacturing for space-exploration-what to take and when to make.

As renewed interest in human space-exploration intensifies, a coherent and modernized strategy for mission design and planning has become increasingly crucial. Biotechnology has emerged as a promising approach to increase resilience, flexibility, and efficiency of missions, by virtue of its ability to effectively utilize in situ resources and reclaim resources from waste streams. Here we outline four primary mission-classes on Moon and Mars that drive a staged and accretive biomanufacturing strategy. Each class requires a unique approach to integrate biomanufacturing into the existing mission-architecture and so faces unique challenges in technology development. These challenges stem directly from the resources available in a given mission-class-the degree to which feedstocks are derived from cargo and in situ resources-and the degree to which loop-closure is necessary. As mission duration and distance from Earth increase, the benefits of specialized, sustainable biomanufacturing processes also increase. Consequentially, we define specific design-scenarios and quantify the usefulness of in-space biomanufacturing, to guide techno-economics of space-missions. Especially materials emerged as a potentially pivotal target for biomanufacturing with large impact on up-mass cost. Subsequently, we outline the processes needed for development, testing, and deployment of requisite technologies. As space-related technology development often does, these advancements are likely to have profound implications for the creation of a resilient circular bioeconomy on Earth.

Destruction of Raman biosignatures by ionising radiation and the implications for life detection on Mars.

Raman spectroscopy has proven to be a very effective approach for the detection of microorganisms colonising hostile environments on Earth. The ExoMars rover, due for launch in 2018, will carry a Raman laser spectrometer to analyse samples of the martian subsurface collected by the probe's 2-m drill in a search for similar biosignatures. The martian surface is unprotected from the flux of cosmic rays, an ionising radiation field that will degrade organic molecules and so diminish and distort the detectable Raman signature of potential martian microbial life. This study employs Raman spectroscopy to analyse samples of two model organisms, the cyanobacterium Synechocystis sp. PCC 6803 and the extremely radiation resistant polyextremophile Deinococcus radiodurans, that have been exposed to increasing doses of ionising radiation. The three most prominent peaks in the Raman spectra are from cellular carotenoids: deinoxanthin in D. radiodurans and ß-carotene in Synechocystis. The degradative effect of ionising radiation is clearly seen, with significant diminishment of carotenoid spectral peak heights after 15 kGy and complete erasure of Raman biosignatures by 150 kGy of ionising radiation. The Raman signal of carotenoid in D. radiodurans diminishes more rapidly than that of Synechocystis, believed to be due to deinoxanthin acting as a superior scavenger of radiolytically produced reactive oxygen species, and so being destroyed more quickly than the less efficient antioxidant ß-carotene. This study highlights the necessity for further experimental work on the manner and rate of degradation of Raman biosignatures by ionising radiation, as this is of prime importance for the successful detection of microbial life in the martian near subsurface.

Cyanobacteria and microalgae in supporting human habitation on Mars.

Establishing the first human presence on Mars will be the most technically challenging undertaking yet in the exploration beyond our planet. The remoteness of Mars from Earth, the inhospitable surface conditions including low atmospheric pressure and cold temperatures, and the need for basic resources including water, pose a formidable challenge to this endeavour. The intersection of multiple disciplines will be required to provide solutions for temporary and eventually permanent Martian habitation. This review considers the role cyanobacteria and eukaryotic microalgae (collectively referred to here as 'microalgae') may have in supporting missions to the red planet. The current research using these microorganisms in biological life support systems is discussed, with a systematic analysis of their usage in each system conducted. The potential of microalgae to provide astronauts with oxygen, food, bio-polymers and pharmaceuticals is considered. An overview of microalgal experiments in space missions across the last 60 years is presented, and the research exploring the technical challenges of cultivation on Mars is discussed. From these findings, an argument for culturing microalgae in subterranean bioreactors is proposed. Finally, future synthetic biology approaches for enhancing the cyanobacterial/microalgal role in supporting human deep-space exploration are presented. We show that microalgae hold significant promise for providing solutions to many problems faced by the first Martian settlers, however these can only be realised with significant infrastructure and a reliable power source.

Do responses to the COVID-19 pandemic anticipate a long-lasting shift towards peer-to-peer production or degrowth?

The COVID-19 pandemic simultaneously triggered a sudden, substantial increase in demand for items such as personal protection equipment and hospital ventilators whilst also disrupting the means of mass-production and international transport in established supply chains. Furthermore, under stay-at-home orders and with bricks-and-mortar retailers closed, consumers were also forced to adapt. Thus the pandemic offers a unique opportunity to study shifts in behaviour during disruption to industrialised manufacturing and economic contraction, in order to understand the role peer-to-peer production may play in a transition to long-term sustainability of production and consumption, or degrowth. Here, we analyse publicly-available datasets on internet search traffic and corporation financial returns to track the shifts in public interest and consumer behaviour over 2019 - 2020. We find a jump in interest in home-making and small-scale production at the beginning of the pandemic, as well as a substantial and sustained shift in consumer preference for peer-to-peer e-commerce platforms relative to more-established online vendors. In particular we present two case studies - the home-made facemasks supplied through Etsy, and the decentralised efforts of the 3D printer community - to assess the effectiveness of their responses to the pandemic. These patterns of behaviour are related to new modes of production in line with ecological economics and as such add capacity to a broader prefiguration of degrowth. We suggest an adoption of a new "fourth wave" of DIY culture defined by enhanced resilience and degrowth to continue to add capacity to a prefigurative politic of degrowth.

Infrared Spectroscopic Detection of Biosignatures at Lake Tírez, Spain: Implications for Mars.

The detection of potential biosignatures with mineral matrices is part of a multifaceted approach in the search for life on other planetary bodies. The 2020 ExoMars Rosalind Franklin rover includes within its payload three IR spectrometers in the form of ISEM (Infrared Spectrometer for ExoMars), MicrOmega, and Ma-MISS (Mars Multispectral Imager for Subsurface Studies). The use of this technique in the detection and characterization of biosignatures is of great value. Organic materials are often co-deposited in terrestrial evaporites and as such have been proposed as relevant analogs in the search for life on Mars. This study focuses on Ca-sulfates collected from the hypersaline Tírez Lake in Spain. Mid infrared and visible near infrared analysis of soils, salt crusts, and crystals with green and red layering indicative of microbial colonization of the samples was acquired from across the lake and identified the main mineral to be gypsum with inputs of carbonate and silica. Organic functional groups that could be attributed to amides and carboxylic acids were identified as well as chlorophyll; however, due to the strong mineralogical absorptions observed, these were hard to unambiguously discern. Taxonomical assignment demonstrated that the archaeal community within the samples was dominated by the halophilic extremophile Halobacteriaceae while the bacterial community was dominated by the class Nocardiaceae. The results of this research highlight that sulfates on Mars are a mixed blessing, acting as an effective host for organic matter preservation but also a material that masks the presence of organic functional groups when analyzed with spectroscopic tools similar to those due to fly on the 2020 ExoMars rover. A suite of complementary analytical techniques therefore should be used to support the spectral identification of any candidate extraterrestrial biosignatures.

Robustness of the p53 network and biological hackers.

The p53 protein interaction network is crucial in regulating the metazoan cell cycle and apoptosis. Here, the robustness of the p53 network is studied by analyzing its degeneration under two modes of attack. Linear Programming is used to calculate average path lengths among proteins and the network diameter as measures of functionality. The p53 network is found to be robust to random loss of nodes, but vulnerable to a targeted attack against its hubs, as a result of its architecture. The significance of the results is considered with respect to mutational knockouts of proteins and the directed attacks mounted by tumour inducing viruses.

Isolation of Radiation-Resistant Bacteria from Mars Analog Antarctic Dry Valleys by Preselection, and the Correlation between Radiation and Desiccation Resistance.

UNLABELLED: Extreme radiation-resistant microorganisms can survive doses of ionizing radiation far greater than are present in the natural environment. Radiation resistance is believed to be an incidental adaptation to desiccation resistance, as both hazards cause similar cellular damage. Desert soils are, therefore, promising targets to prospect for new radiation-resistant strains. This is the first study to isolate radiation-resistant microbes by using gamma-ray exposure preselection from the extreme cold desert of the Antarctic Dry Valleys (a martian surface analogue). Halomonads, identified by 16S rRNA gene sequencing, were the most numerous survivors of the highest irradiation exposures. They were studied here for the first time for both their desiccation and irradiation survival characteristics. In addition, the association between desiccation and radiation resistance has not been investigated quantitatively before for a broad diversity of microorganisms. Thus, a meta-analysis of scientific literature was conducted to gather a larger data set. A strong correlation was found between desiccation and radiation resistance, indicating that an increase in the desiccation resistance of 5 days corresponds to an increase in the room-temperature irradiation survival of 1 kGy. Irradiation at -79°C (representative of average martian surface temperatures) increases the microbial radiation resistance 9-fold. Consequently, the survival of the cold-, desiccation-, and radiation-resistant organisms isolated here has implications for the potential habitability of dormant or cryopreserved life on Mars. KEY WORDS: Extremophiles-Halomonas sp.-Antarctica-Mars-Ionizing radiation-Cosmic rays.

Fluorescence characterization of clinically-important bacteria.

Healthcare-associated infections (HCAI/HAI) represent a substantial threat to patient health during hospitalization and incur billions of dollars additional cost for subsequent treatment. One promising method for the detection of bacterial contamination in a clinical setting before an HAI outbreak occurs is to exploit native fluorescence of cellular molecules for a hand-held, rapid-sweep surveillance instrument. Previous studies have shown fluorescence-based detection to be sensitive and effective for food-borne and environmental microorganisms, and even to be able to distinguish between cell types, but this powerful technique has not yet been deployed on the macroscale for the primary surveillance of contamination in healthcare facilities to prevent HAI. Here we report experimental data for the specification and design of such a fluorescence-based detection instrument. We have characterized the complete fluorescence response of eleven clinically-relevant bacteria by generating excitation-emission matrices (EEMs) over broad wavelength ranges. Furthermore, a number of surfaces and items of equipment commonly present on a ward, and potentially responsible for pathogen transfer, have been analyzed for potential issues of background fluorescence masking the signal from contaminant bacteria. These include bedside handrails, nurse call button, blood pressure cuff and ward computer keyboard, as well as disinfectant cleaning products and microfiber cloth. All examined bacterial strains exhibited a distinctive double-peak fluorescence feature associated with tryptophan with no other cellular fluorophore detected. Thus, this fluorescence survey found that an emission peak of 340nm, from an excitation source at 280nm, was the cellular fluorescence signal to target for detection of bacterial contamination. The majority of materials analysed offer a spectral window through which bacterial contamination could indeed be detected. A few instances were found of potential problems of background fluorescence masking that of bacteria, but in the case of the microfiber cleaning cloth, imaging techniques could morphologically distinguish between stray strands and bacterial contamination.

Ionizing radiation and life.

Ionizing radiation is a ubiquitous feature of the Cosmos, from exogenous cosmic rays (CR) to the intrinsic mineral radioactivity of a habitable world, and its influences on the emergence and persistence of life are wide-ranging and profound. Much attention has already been focused on the deleterious effects of ionizing radiation on organisms and the complex molecules of life, but ionizing radiation also performs many crucial functions in the generation of habitable planetary environments and the origins of life. This review surveys the role of CR and mineral radioactivity in star formation, generation of biogenic elements, and the synthesis of organic molecules and driving of prebiotic chemistry. Another major theme is the multiple layers of shielding of planetary surfaces from the flux of cosmic radiation and the various effects on a biosphere of violent but rare astrophysical events such as supernovae and gamma-ray bursts. The influences of CR can also be duplicitous, such as limiting the survival of surface life on Mars while potentially supporting a subsurface biosphere in the ocean of Europa. This review highlights the common thread that ionizing radiation forms between the disparate component disciplines of astrobiology.

Degradation of cyanobacterial biosignatures by ionizing radiation.

Primitive photosynthetic microorganisms, either dormant or dead, may remain today on the martian surface, akin to terrestrial cyanobacteria surviving endolithically in martian analog sites on Earth such as the Antarctic Dry Valleys and the Atacama Desert. Potential markers of martian photoautotrophs include the red edge of chlorophyll reflectance spectra or fluorescence emission from systems of light-harvesting pigments. Such biosignatures, however, would be modified and degraded by long-term exposure to ionizing radiation from the unshielded cosmic ray flux onto the martian surface. In this initial study into this issue, three analytical techniques--absorbance, reflectance, and fluorescence spectroscopy--were employed to determine the progression of the radiolytic destruction of cyanobacteria. The pattern of signal loss for chlorophyll reflection and fluorescence from several biomolecules is characterized and quantified after increasing exposures to ionizing gamma radiation. This allows estimation of the degradation rates of cyanobacterial biosignatures on the martian surface and the identification of promising detectable fluorescent break-down products.

Low-temperature ionizing radiation resistance of Deinococcus radiodurans and Antarctic Dry Valley bacteria.

The high flux of cosmic rays onto the unshielded surface of Mars poses a significant hazard to the survival of martian microbial life. Here, we determined the survival responses of several bacterial strains to ionizing radiation exposure while frozen at a low temperature characteristic of the martian near-subsurface. Novel psychrotolerant bacterial strains were isolated from the Antarctic Dry Valleys, an environmental analogue of the martian surface, and identified by 16S rRNA gene phylogeny as representatives of Brevundimonas, Rhodococcus, and Pseudomonas genera. These isolates, in addition to the known radioresistant extremophile Deinococcus radiodurans, were exposed to gamma rays while frozen on dry ice (-79°C). We found D. radiodurans to exhibit far greater radiation resistance when irradiated at -79°C than was observed in similar studies performed at higher temperatures. This greater radiation resistance has important implications for the estimation of potential survival times of microorganisms near the martian surface. Furthermore, the most radiation resistant of these Dry Valley isolates, Brevundimonas sp. MV.7, was found to show 99% 16S rRNA gene similarity to contaminant bacteria discovered in clean rooms at both Kennedy and Johnson Space Centers and so is of prime concern to efforts in the planetary protection of Mars from our lander probes. Results from this experimental irradiation, combined with previous radiation modeling, indicate that Brevundimonas sp. MV.7 emplaced only 30 cm deep in martian dust could survive the cosmic radiation for up to 100,000 years before suffering 106 population reduction.

Survey on astrobiology research and teaching activities within the United kingdom.

While astrobiology is apparently growing steadily around the world, in terms of the number of researchers drawn into this interdisciplinary area and teaching courses provided for new students, there have been very few studies conducted to chart this expansion quantitatively. To address this deficiency, the Astrobiology Society of Britain (ASB) conducted a questionnaire survey of universities and research institutions nationwide to ascertain the current extent of astrobiology research and teaching in the UK. The aim was to provide compiled statistics and an information resource for those who seek research groups or courses of study, and to facilitate new interdisciplinary collaborations. The report here summarizes details gathered on 33 UK research groups, which involved 286 researchers (from undergraduate project students to faculty members). The survey indicates that around 880 students are taking university-level courses, with significant elements of astrobiology included, every year in the UK. Data are also presented on the composition of astrobiology students by their original academic field, which show a significant dominance of physics and astronomy students. This survey represents the first published systematic national assessment of astrobiological academic activity and indicates that this emerging field has already achieved a strong degree of penetration into the UK academic community.