A new semi-quantitative Surface-Enhanced Raman Spectroscopy (SERS) method for detection of maleimide (2,5-pyrroledione) with potential application to astrobiology

Nitrogen-containing heterocyclic compounds are fundamental biochemical components of all life on Earth and,presumably,life elsewhere in our solar system.Detection and characterization of these compounds by traditional solvent extraction,chromatographic separation,and GC-MS analysis require more sample mass than will be available from samples returned to Earth from Mars.With its small sample mass requirement,Surface Enhanced Raman Spectroscopy could be an appropriate technique for analysis of returned samples.We have developed a SERS method for the detection of maleimide(2,5-pyrroledione),an N-containing heterocycle with a structure that is widespread in biochemicals.This semi-quantitative methodology accurately determines maleimide concentration in the range from 60 mg/mL to 120 mg/mL.We present a maleimide SERS standard spectrum which will be useful as a reference for future works.The present work demonstrates an easy,accurate,and effective method for the non-destructive qualitative and semi-quantitative study of maleimide as a first step toward developing a method for analysis of related compounds.

Geomorphologic Characteristics of Polygonal Features on Chloride-Bearing Deposits on Mars: Implications for Martian Hydrology and Astrobiology

Over 600 chloride-bearing deposits(chlorides) have been identified on the southern highlands of Mars. These chlorides have critical implications for hydrology and astrobiology: they are indicators of an evaporating super saturated solution, and they could have provided habitat environments for halophilic microorganisms and preserved organic matter. One of the prominent geomorphology characteristics of these chloridebearing regions is the polygonal features within them. The origin of these polygonal features is still in debate. In this study, we have surveyed 153 locations of chlorides using 441 high resolution imaging science experiment(Hi RISE) images to characterize the geomorphology of polygonal features. We identified 3 types of polygonal features of distinct geomorphologic characteristics: fractures, raised ridges, and transitional polygons between fractures and raised ridges. We evaluate previously proposed hypotheses of the formation of the polygonal features, and suggest that the 3 types of polygonal features are indicators of different stages of salt crust formation. Salt crust is usually formed through multiple groundwater activities, and it often occurs in playa environment on Earth. The unique hydrological and astrobiological implications of the chlorides with polygonal features make these deposits of high priority for future landed on and/or sample return exploration missions of Mars.

Origins of building blocks of life: A review

How and where did life on Earth originate？ To date, various environments have been proposed as plausible sites for the origin of life. However, discussions have focused on a limited stage of chemical evolution, or emergence of a specific chemical function of proto-biological systems. It remains unclear what geochemical situations could drive all the stages of chemical evolution, ranging from condensation of simple inorganic compounds to the emergence of self-sustaining systems that were evolvable into modern biological ones. In this review, we summarize reported experimental and theoretical findings for prebiotic chemistry relevant to this topic, including availability of biologically essential elements（N and P） on the Hadean Earth, abiotic synthesis of life＇s building blocks（amino acids, peptides, ribose, nucleobases, fatty acids, nucleotides, and oligonucleotides）, their polymerizations to bio-macromolecules（peptides and oligonucleotides）, and emergence of biological functions of replication and compartmentalization. It is indicated from the overviews that completion of the chemical evolution requires at least eight reaction conditions of（1） reductive gas phase,（2） alkaline pH,（3） freezing temperature,（4）fresh water,（5） dry/dry-wet cycle,（6） coupling with high energy reactions,（7） heating-cooling cycle in water, and（8） extraterrestrial input of life＇s building blocks and reactive nutrients. The necessity of these mutually exclusive conditions clearly indicates that life＇s origin did not occur at a single setting; rather, it required highly diverse and dynamic environments that were connected with each other to allow intratransportation of reaction products and reactants through fluid circulation. Future experimental research that mimics the conditions of the proposed model are expected to provide further constraints on the processes and mechanisms for the origin of life.

Mapping of Compositional Diversity and Chronological Ages of Lunar Farside Multiring Mare Moscoviense Basin:Implications to the Middle Imbrian Mare Basalts

The Mare Moscoviense is an astonishing rare flatland multi-ring basin and one of the recognizable mare regions on the Moon's farside.The mineralogical,chronological,topographical and morphological studies of the maria surface of the Moon provide a primary understanding of the origin and evolution of the mare provinces.In this study,the Chandrayaan-1 M^(3)data have been employed to prepare optical maturity index,FeO and TiO^(2)concentration,and standard band ratio map to detect the mafic indexes like olivine and pyroxene minerals.The crater size frequency distribution method has been applied to LROC WAC data to obtain the absolute model ages of the Moscoviense basin.The four geological unit ages were observed as 3.57 Ga(U-2),3.65 Ga(U-1),3.8 Ga(U-3)and 3.92 Ga(U-4),which could have been formed between the Imbrian and Nectarian epochs.The M^(3)imaging and reflectance spectral parameters were used to reveal the minerals like pyroxene,olivine,ilmenite,plagioclase,orthopyroxene-olivine-spinel lithology,and olivine-pyroxene mixtures present in the gabbroic basalt,anorthositic and massive ilmenite rocks,and validated with the existing database.The results show that the Moscoviense basin is dominated by intermediate TiO^(2)basalts that derived from olivine-ilmenite-pyroxene cumulate depths ranging from 200 to 500 km between 3.5 Ga and 3.6 Ga.

Quantum chemical analysis for the formation of glycine in the interstellar medium

Glycine （C2H5NO2） was the first amino acid to be detected in space by the stardust space probe in Comet Wild2, and is used by living organisms to make proteins. We discuss three different reaction paths for the formation of glycine in interstellar space from some simpler molecules detected in the interstellar medium. The possibility of the formation of glycine in interstellar space is considered by radicalradical and radical-molecule interaction schemes using quantum chemical calculations with density functional theory at the B3LYP/6-31G （d,p） level. In the chemical pathways we discuss, a few reactions are found to be totally exothermic and barrierless while others are endothermic with a very small reaction barrier, thus giving rise to a high probability of forming glycine in interstellar space.

The Basic Principles of Creation of Habitable Planets around Stars in the Milky Way Galaxy

The principle of habitable planets creation of near stars in our galaxy was developed. It was shown that the Earth and the Moon formed as a result of thermal nuclear explosion (TNE) after a collision with a small comet. The comet has broken through the proto-Earth crust, and created conditions for liquid-drop division into the Earth and the Moon. It is shown that the comet impact on the proto-Earth led to formation of continents as well as to formation of the Moon, seas, oceans and atmosphere and to creation of conditions for life origin. The analysis of kimberlitic pipes distribution, as markers of comet fragments motion under a crust, shows that the comet has broken up under crust with formation of many gas bubbles. An analysis of the Martian topography revealed that the comet hit Mars not under a glancing angle. As a result, the products of TNE remained under the Marian crust. The track of the comet movement under the Venus crust was also established. It is shown that the planet surface near comet track is spotted by numerous cracks.

Enigmatic Glass-Like Carbon from the Alpine Foreland, Southeast Germany: A Natural Carbonization Process

Unusual carbonaceous matter, termed here chiemite, composed of more than 90% C from the Alpine Foreland at Lake Chiemsee in Bavaria, southeastern Germany has been investigated using optical and atomic force microscopy, X-ray fluorescence spectroscopy, scanning and transmission electron microscopy, high-resolution Raman spectroscopy, X-ray diffraction and differential thermal analysis, as well as by δ13 C and 14 C radiocarbon isotopic data analysis. In the pumice-like fragments, poorly ordered carbon matter co-exists with high-ordering monocrystalline α-carbyne, and contains submicrometersized inclusions of complex composition. Diamond and carbyne add to the peculiar mix of matter. The required very high temperatures and pressures for carbyne formation point to a shock event probably from the recently proposed Holocene Chiemgau meteorite impact. The carbon material is suggested to have largely formed from heavily shocked coal, vegetation like wood, and peat from the impact target area. The carbonization/coalification high PT process may be attributed to a strong shock that instantaneously caused the complete evaporation and loss of volatile matter and water, which nevertheless preserved the original cellular structure seen fossilized in many fragments. Relatively fresh wood encapsulated in the purported strongly shocked matter point to quenched carbon melt components possibly important for the discussion of survival of organic matter in meteorite impacts, implying an astrobiological relationship.

Karite-diamond fossil:A new type of natural diamond

Impact diamond is one of perspective natural type of superhard carbon materials,forming huge resources sometimes,such as Popigai impact structure counting the largest diamond storage on the Earth.By present,there are two known types of impact diamonds-after-graphitic and after-coal varieties formed from different carbon precursors.Here we present for the first time a new impact diamond type-diamond fossils,named by "karite",formed about 70 Ma from unmetamorphosed organics in the giant Kara impact crater(Pay-Khoy,Russia).A full complex of the diamond fossil characteristics is described proving its nature and phase state.Karite is presented with supernanocrystalline diamond aggregates,nicely preserves tiny cell morphology and relict features of lignin and cellulose.The diamond fossils are spread widely through the Kara impactites,point to possible wider distribution of impact diamonds within large impact occurrences around the world,can be used for impact modeling,astrobiological and material studies.

Theoretical approach to study the formation of C2H4O2 isomers in interstellar medium through reaction between interstellar formaldehyde molecules

The three isomers of C2H4O2,viz.,glycolaldehyde(HCOCH2 OH),acetic acid(CH3 COOH)and methyl formate(HCOOCH3),have been detected in copious amounts in the interstellar medium(ISM).The possibility for formation of these molecules through interstellar formaldehyde(HCHO)has been explored by using the quantum chemical approach described by density functional theory(DFT)and second order Moller-Plesset perturbation(MP2)theory with a 6–311 G(d,p)basis set in the gas phase as well as in icy grains.The associated molecule-molecule interactions have been discussed to study the formation of isomers of C2H4O2 in ISM.The reactions of two formaldehyde molecules exhibit a considerable potential barrier but due to quantum tunneling,these reactions could be possible in ISM.The chemical pathway is exothermic,which gives rise to a high probability for the formation of all three isomers,viz.glycolaldehyde,methyl formate and acetic acid,in interstellar space.Anharmonic rotational vibration,centrifugal distortion constants and coupling constants are also calculated and results suggest that the vibrations are harmonic in nature.

Cyanobacteria from Extreme Deserts to Space

The development of space technology makes the exposure of organisms and molecules to the space environment possible by using the ESA Biopan and Expose facilities and NASA nanosatellites;the aim is to decipher the origin, evolution and distribution of life on Earth and in the Universe. The study of microbial communities thriving in lithic habitats in cold and hot deserts is gathering appreciation when dealing with the limits of life as we know it, the identification of biosignatures for searching life beyond Earth and the validation of the (litho)-Panspermia theory. Cyanobacteria of the genus Chroococcidiopsis dominate rock-dwelling communities in extreme deserts that are considered terrestrial analogues of Mars, like the Dry Valleys in Antarctica, the Atacama Desert in Chile or the Mojave Desert in California. The extraordinary tolerance of these cyanobacteria towards desiccation, ionizing and UV radiation makes them suitable experimental strains which have been already used in astrobiological experiments and already selected for future space missions. Evidence gained so far supports the use of desert cyanobacteria to develop life support systems and insitu resource utilization for the human space exploration and settlement on the Moon or Mars.

Agency of Life, Entropic Gravity and Phenomena Attributed to “Dark Matter”

Entropic gravity theories propose that spacetime and gravity emerge from quantum information entanglements. Vacuum spacetime emerges in the ground state and its area law for entanglement entropy is due to short-range entanglement of neighbouring microscopic degrees of freedom. Matter changes the entanglement entropy in this vacuum and leads to Einstein gravity. Additionally, in a positive dark energy de Sitter Universe, where each conscious agent has a cosmological horizon, a volume law contribution to entanglement entropy is divided evenly over the same degrees of freedom and is caused by long-range entanglement. I propose these complementary shortrange and long-range entanglement contributions form a nested small-world network which provides the topological quantum computing foundation for relativistic multi-agent correlations which weave together a universal physics of Nature. The volume law contribution to entanglement entropy surpasses the area law for entanglement entropy at an agent’s cosmological horizon. Verlinde interprets gravitational “dark matter” phenomena as polymer-like memory effects caused by the volume contribution to the entanglement entropy. I propose these phenomena are instead multi-agent quantum computational consensus effects due to an equivalent volume contribution to the entanglement entropy. Life is correlated with its environment. Phenomena attributed to unseen “dark matter” particles are proposed here to be founded upon nested observer halos, “spheres of influence or correlation”, caused by the consensus Agency of Life. Suitable cosmological conditions for earliest Life in the Universe occurred some 10 billion years ago and older galaxies do not exhibit “dark matter” phenomena. Also, galactic rotation curves flatten beyond their high-radiation centres, due to astrobiology and the Agency of Life living in outlying low-radiation habitable zones. Where baryonic matter is in motion, then the Agency of Life stores its baryonic matter-lagging memory in skewed trails of apparent “dark matter” phenomena in spacetime.

“Snake”: New Object of Hypothetical Venusian Fauna

On March 1 and 5, 1982, experiments in television photography instrumented by the landers VENERA-13 and 14 returned panoramas of the Venus surface at the landing site. Over the past 31 years, no similar missions have been sent to Venus. In connection with the renewed interest in what was occurring during the experiment and to the discovery of manifestations of possible life revealed on some of the pictures, the panoramas were re-examined.?Analysis of treated once again VENERA-14 panoramic images revealed a?“snake”?object about 40 cm in size possessing apparent terramorphic features. The snake’s body stands out with its honeycomb, spotty surface against the stone plates close by. The “snake”?can be included into the list of the most significant findings of the hypothetical Venusian fauna. Apart from that, of interest is a?“dove”?object, although details of its structure cannot be discerned. The snake’s body show slow movements, which is another evidence of the Venusian fauna’s very slow style of activity, which appears to be associated with its energy constraints, and that is more likely, with the properties of its internal medium. The terramorphic features of the fauna, if they are confirmed, may point out outstandingly important and yet undiscovered general laws of the animated nature.

Planetary Heating by Neutrinos: Long-Term Habitats for Aquatic Life if Dark Energy Decays Favourably

The potential cosmological and astrobiological implications of neutrinos are considered. Dark energy drives the current phase of accelerating cosmic expansion. Like inflation, it may decay in time to matter and radiation. However, since its energy density is minuscule in comparison, decay would be unlikely to inject such a rich variety of particles into the universe, and may instead be limited to the lowest energy fermions. Nonrelativistic neutrinos have the capacity to form stable, galaxy-engulfing haloes supported by degeneracy pressure, much like white dwarves and neutron stars. Conversely, bodies of mass can indefinitely rely on Coulomb forces for weight support. Opportunities for the mutual annihilation of electron neutrinos are largely confined to planets containing iron in the hcp phase. If dark energy decays primarily to neutrinos in 40 ~ 100 Gyr, then oceanic planets orbiting within the resulting haloes could provide long-term habitats for aquatic life with only lax constraints on the neutrino mass, . Various considerations now favour the possibility that neutrinos are Majorana particles with an inverted mass hierarchy and an electron neutrino mass in the vicinity of 50 meV. Sterile neutrinos of eV-mass may already be a significant component of dark matter, and could enhance planetary heating when active neutrino haloes become heavily depleted. An intriguing mechanism capable of regulating oceanic heat flux over a wide range of planetary masses is also described.

Shallow subsurface habitats across the Mars-analog Qaidam Basin

Searching for life is one of the most important targets of Mars exploration missions. It has been considered that the Martian subsurface, away from the extreme surface environment, is a potentially habitable region for microbial growth.However, the distribution pattern of potential microbial habitats in the Martian subsurface has yet to be evaluated. Here, we investigate the subsurface habitats to depths of 20–60 cm from various landscapes, including slopes, gullies, channels, playas,and alluvial fans across the Mars-analog Qaidam Basin, NW China. We characterize subsurface niches by measuring microbial biomass and radiocarbon ages, and correlate them with soil properties including depth, moisture content, total organic carbon content, electric conductivity, pH, evaporite and clay mineral contents. We find more habitable niches for microbial colonization at depths of 5–25 cm as compared with the surface and deep subsurface across the hyperarid Qaidam Basin. Maximum biomass and biotic activity could be correlated with physical stability, limited radiation, and short-term moderate water availability in the shallow subsurface in hyperarid deserts. The findings of this study provide new perspectives on subsurface microbial habitats in Mars-analog hyperarid deserts and ongoing biosignature detection on Mars.

Distribution characteristics of lipids from salt sediments in Qaidam Basin and their astrobiological significance

On Earth,salt environments are the most relevant analogues to Martian salt deposits with regard to the search for preserved biomolecules.In this study,we analyzed the distribution of lipids in salt samples from Dalangtan and Qarhan in the Qaidam Basin,which is the most important area to carry out analog research of Mars in China.Furthermore,we compared the lipids distribution results with that from other typical Martian analog sites such as the Atacama Desert.Salt samples in the Qaidam Basin are enriched with fatty acid compounds,including normal fatty acids,unsaturated fatty acids,branched fatty acids,and acyclic isoprene acids.In addtion,glycerol dialkyl glycerol tetraethers(GDGTs)and archaeol compounds were also detected in these salt samples.Compared with the hypersaline samples,the clay samples not only have higher abuandance of fatty acids,GDGTs and archaeol compounds,but also a more diversed lipids composition.Only a few lipids were detected in the pure-saline samples,such as archaeol compounds.These clues suggest that content of salt minerals is the major factor affecting the distribution of lipids.This study provides an analogy for detecting and evaluating the traces of life that may exist on Mars.