journal
MENU ▼
Read by QxMD icon Read
search

Astrobiology

journal
https://www.readbyqxmd.com/read/29227145/transport-induced-spatial-patterns-of-sulfur-isotopes-%C3%AE-34s-as-biosignatures
#1
Muammar Mansor, Khadouja Harouaka, Matthew S Gonzales, Jennifer L Macalady, Matthew S Fantle
Cave minerals deposited in the presence of microbes may host geochemical biosignatures that can be utilized to detect subsurface life on Earth, Mars, or other habitable worlds. The sulfur isotopic composition of gypsum (CaSO4·2H2O) formed in the presence of sulfur-oxidizing microbes in the Frasassi cave system, Italy, was evaluated as a biosignature. Sulfur isotopic compositions (δ34SV-CDT) of gypsum sampled from cave rooms with sulfidic air varied from -11 to -24‰, with minor deposits of elemental sulfur having δ34S values between -17 and -19‰...
December 11, 2017: Astrobiology
https://www.readbyqxmd.com/read/29189043/an-antarctic-extreme-halophile-and-its-polyextremophilic-enzyme-effects-of-perchlorate-salts
#2
Victoria J Laye, Shiladitya DasSarma
Effects of perchlorate salts prevalent on the surface of Mars are of significant interest to astrobiology from the perspective of potential life on the Red Planet. Halorubrum lacusprofundi, a cold-adapted halophilic Antarctic archaeon, was able to grow anaerobically on 0.04 M concentration of perchlorate. With increasing concentrations of perchlorate, growth was inhibited, with half-maximal growth rate in ca. 0.3 M NaClO4 and 0.1 M Mg(ClO4)2 under aerobic conditions. Magnesium ions were also inhibitory for growth, but at considerably higher concentrations, with half-maximal growth rate above 1 M...
November 30, 2017: Astrobiology
https://www.readbyqxmd.com/read/29189040/organic-haze-as-a-biosignature-in-anoxic-earth-like-atmospheres
#3
Giada Arney, Shawn D Domagal-Goldman, Victoria S Meadows
Early Earth may have hosted a biologically mediated global organic haze during the Archean eon (3.8-2.5 billion years ago). This haze would have significantly impacted multiple aspects of our planet, including its potential for habitability and its spectral appearance. Here, we model worlds with Archean-like levels of carbon dioxide orbiting the ancient Sun and an M4V dwarf (GJ 876) and show that organic haze formation requires methane fluxes consistent with estimated Earth-like biological production rates...
November 30, 2017: Astrobiology
https://www.readbyqxmd.com/read/29160728/selection-of-amino-acid-chirality-via-neutrino-interactions-with-14n-in-crossed-electric-and-magnetic-fields
#4
Michael A Famiano, Richard N Boyd, Toshitaka Kajino, Takashi Onaka
Previous work has suggested that the chirality of the amino acids could be established in the magnetic field of a nascent neutron star from a core-collapse supernova or massive collapsar. The magnetic field would orient the 14N nuclei, and the alignment of its nuclear spin with respect to those of the electron antineutrinos emitted from the collapsing star would determine the probability of destruction of the 14N nuclei by interactions with the antineutrinos. Subsequent work estimated the bulk polarization of the 14N nuclei in large rotating meteoroids in such an environment...
November 21, 2017: Astrobiology
https://www.readbyqxmd.com/read/29148825/on-the-growth-and-detectability-of-land-plants-on-habitable-planets-around-m-dwarfs
#5
Duo Cui, Feng Tian, Yuwei Wang, Changshen Li, Chaoqing Yu, Le Yu
One signature of life on Earth is the vegetation red edge (VRE) feature of land plants, a dramatic change of reflectivity at wavelength near 0.7 μm. Potentially habitable planets around M dwarfs are tidally locked, which can limit the distribution of land plants. In this study, we used a biogeochemical model to investigate the distribution of land plants on potentially habitable planets around M dwarfs driven by climate data produced in a general circulation model (GCM). When considering the effects of clouds, the observation time needed for VRE detection on nearby p = 1 exoplanets around nearby M dwarfs is on the order of days using a 25 m(2) telescope if a large continent faces Earth during observations...
November 17, 2017: Astrobiology
https://www.readbyqxmd.com/read/29148823/space-dust-collisions-as-a-planetary-escape-mechanism
#6
Arjun Berera
It is observed that hypervelocity space dust, which is continuously bombarding Earth, creates immense momentum flows in the atmosphere. Some of this fast space dust inevitably will interact with the atmospheric system, transferring energy and moving particles around, with various possible consequences. This paper examines, with supporting estimates, the possibility that by way of collisions the Earth-grazing component of space dust can facilitate planetary escape of atmospheric particles, whether they are atoms and molecules that form the atmosphere or larger-sized particles...
November 17, 2017: Astrobiology
https://www.readbyqxmd.com/read/29116818/pure-and-oxidized-copper-materials-as-potential-antimicrobial-surfaces-for-spaceflight-activities
#7
C Hahn, M Hans, C Hein, R L Mancinelli, F Mücklich, R Wirth, P Rettberg, C E Hellweg, R Moeller
Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth...
November 8, 2017: Astrobiology
https://www.readbyqxmd.com/read/29106312/nitrogen-concentrations-and-isotopic-compositions-of-seafloor-altered-terrestrial-basaltic-glass-implications-for-astrobiology
#8
G E Bebout, N R Banerjee, M R M Izawa, K Kobayashi, K Lazzeri, L A Ranieri, E Nakamura
Observed enrichments of N (and the δ(15)N of this N) in volcanic glasses altered on Earth's modern and ancient seafloor are relevant in considerations of modern global N subduction fluxes and ancient life on Earth, and similarly altered glasses on Mars and other extraterrestrial bodies could serve as valuable tracers of biogeochemical processes. Palagonitized glasses and whole-rock samples of volcanic rocks on the modern seafloor (ODP Site 1256D) contain 3-18 ppm N with δ(15)Nair values of up to +4.5‰...
November 6, 2017: Astrobiology
https://www.readbyqxmd.com/read/29058452/investigation-of-the-geochemical-preservation-of-ca-3-0-ga-permineralized-and-encapsulated-microfossils-by-nanoscale-secondary-ion-mass-spectrometry
#9
Frédéric Delarue, François Robert, Kenichiro Sugitani, Romain Tartèse, Rémi Duhamel, Sylvie Derenne
Observations of Archean organic-walled microfossils suggest that their fossilization took place through both encapsulation and permineralization. In this study, we investigated microfossils from the ca. 3.0 Ga Farrel Quartzite (Pilbara, Western Australia) using transmitted light microscopy, scanning electron microscopy, Raman microspectrometry, and nanoscale secondary ion mass spectrometry (NanoSIMS) ion microprobe analyses. In contrast to previous studies, we demonstrated that permineralized microfossils were not characterized by the micrometric spatial relationships between Si and C-N as observed in thin sections...
October 23, 2017: Astrobiology
https://www.readbyqxmd.com/read/29023147/nitrogen-oxides-in-early-earth-s-atmosphere-as-electron-acceptors-for-life-s-emergence
#10
Michael L Wong, Benjamin D Charnay, Peter Gao, Yuk L Yung, Michael J Russell
We quantify the amount of nitrogen oxides (NOx) produced through lightning and photochemical processes in the Hadean atmosphere to be available in the Hadean ocean for the emergence of life. Atmospherically generated nitrate (NO3(-)) and nitrite (NO2(-)) are the most attractive high-potential electron acceptors for pulling and enabling crucial redox reactions of autotrophic metabolic pathways at submarine alkaline hydrothermal vents. The Hadean atmosphere, dominated by CO2 and N2, will produce nitric oxide (NO) when shocked by lightning...
October 12, 2017: Astrobiology
https://www.readbyqxmd.com/read/29016193/the-possible-emergence-of-life-and-differentiation-of-a-shallow-biosphere-on-irradiated-icy-worlds-the-example-of-europa
#11
Michael J Russell, Alison E Murray, Kevin P Hand
Irradiated ice-covered ocean worlds with rocky mafic mantles may provide the conditions needed to drive the emergence and maintenance of life. Alkaline hydrothermal springs-relieving the geophysical, thermal, and chemical disequilibria between oceans and tidally stressed crusts-could generate inorganic barriers to the otherwise uncontrolled and kinetically disfavored oxidation of hydrothermal hydrogen and methane. Ionic gradients imposed across these inorganic barriers, comprising iron oxyhydroxides and sulfides, could drive the hydrogenation of carbon dioxide and the oxidation of methane through thermodynamically favorable metabolic pathways leading to early life-forms...
October 10, 2017: Astrobiology
https://www.readbyqxmd.com/read/29227156/the-characterization-of-biosignatures-in-caves-using-an-instrument-suite
#12
Kyle Uckert, Nancy J Chanover, Stephanie Getty, David G Voelz, William B Brinckerhoff, Nancy McMillan, Xifeng Xiao, Penelope J Boston, Xiang Li, Amy McAdam, David A Glenar, Arriana Chavez
The search for life and habitable environments on other Solar System bodies is a major motivator for planetary exploration. Due to the difficulty and significance of detecting extant or extinct extraterrestrial life in situ, several independent measurements from multiple instrument techniques will bolster the community's confidence in making any such claim. We demonstrate the detection of subsurface biosignatures using a suite of instrument techniques including IR reflectance spectroscopy, laser-induced breakdown spectroscopy, and scanning electron microscopy/energy dispersive X-ray spectroscopy...
December 2017: Astrobiology
https://www.readbyqxmd.com/read/29135301/microbialite-biosignature-analysis-by-mesoscale-x-ray-fluorescence-%C3%AE-xrf-mapping
#13
Michael M Tice, Kimbra Quezergue, Michael C Pope
As part of its biosignature detection package, the Mars 2020 rover will carry PIXL, the Planetary Instrument for X-ray Lithochemistry, a spatially resolved X-ray fluorescence (μXRF) spectrometer. Understanding the types of biosignatures detectable by μXRF and the rock types μXRF is most effective at analyzing is therefore an important goal in preparation for in situ Mars 2020 science and sample selection. We tested mesoscale chemical mapping for biosignature interpretation in microbialites. In particular, we used μXRF to identify spatial distributions and associations between various elements ("fluorescence microfacies") to infer the physical, biological, and chemical processes that produced the observed compositional distributions...
November 2017: Astrobiology
https://www.readbyqxmd.com/read/29135300/something-new-astrobiology-in-the-real-world
#14
Margaret S Race
No abstract text is available yet for this article.
November 2017: Astrobiology
https://www.readbyqxmd.com/read/29135299/oxygen-free-biochemistry-the-putative-chn-foundation-for-exotic-life-in-a-hydrocarbon-world
#15
Kong-Peng Lv, Lucy Norman, Yi-Liang Li
Since Earth's biochemistry is carbon-based and water-borne, the main strategies for searching for life elsewhere are "follow the carbon" and "follow the water." Recently, however, there is a growing focus on the prospect that putative exotic life on other planets could rely on unearthly biochemistries. Here, we hypothesize a novel oxygen-free organic chemistry for supporting potential exotic biosystems, which is named CHN biochemistry. This oxygen-free CHN biochemistry starts from simple oxygen-free species (including hydrocarbons, hydrogen cyanide, and nitriles) and produces a range of functional macromolecules that may function in similar ways to terran macromolecules, such as sugars (cyanosugars), acids (cyanoacids), amino acids (amino cyanoacids), and nucleobases (cyanonucleobases)...
November 2017: Astrobiology
https://www.readbyqxmd.com/read/29088549/arg1-functions-in-the-physiological-adaptation-of-undifferentiated-plant-cells-to-spaceflight
#16
Agata K Zupanska, Eric R Schultz, JiQiang Yao, Natasha J Sng, Mingqi Zhou, Jordan B Callaham, Robert J Ferl, Anna-Lisa Paul
Scientific access to spaceflight and especially the International Space Station has revealed that physiological adaptation to spaceflight is accompanied or enabled by changes in gene expression that significantly alter the transcriptome of cells in spaceflight. A wide range of experiments have shown that plant physiological adaptation to spaceflight involves gene expression changes that alter cell wall and other metabolisms. However, while transcriptome profiling aptly illuminates changes in gene expression that accompany spaceflight adaptation, mutation analysis is required to illuminate key elements required for that adaptation...
November 2017: Astrobiology
https://www.readbyqxmd.com/read/29039682/on-the-habitability-of-desert-varnish-a-combined-study-by-micro-raman-spectroscopy-x-ray-diffraction-and-methylated-pyrolysis-gas-chromatography-mass-spectrometry
#17
C Malherbe, I B Hutchinson, R Ingley, A Boom, A S Carr, H Edwards, B Vertruyen, B Gilbert, G Eppe
In 2020, the ESA ExoMars and NASA Mars 2020 missions will be launched to Mars to search for evidence of past and present life. In preparation for these missions, terrestrial analog samples of rock formations on Mars are studied in detail in order to optimize the scientific information that the analytical instrumentation will return. Desert varnishes are thin mineral coatings found on rocks in arid and semi-arid environments on Earth that are recognized as analog samples. During the formation of desert varnishes (which takes many hundreds of years), organic matter is incorporated, and microorganisms may also play an active role in the formation process...
November 2017: Astrobiology
https://www.readbyqxmd.com/read/28926282/bacterial-and-archaeal-lipids-recovered-from-subsurface-evaporites-of-dalangtan-playa-on-the-tibetan-plateau-and-their-astrobiological-implications
#18
Ziye Cheng, Long Xiao, Hongmei Wang, Huan Yang, Jingjing Li, Ting Huang, Yi Xu, Nina Ma
Qaidam Basin (Tibetan Plateau) is considered an applicable analogue to Mars with regard to sustained extreme aridity and abundant evaporites. To investigate the possibility of the preservation of microbial lipids under these Mars analog conditions, we conducted a mineralogical and organic geochemistry study on samples collected from two Quaternary sections in Dalangtan Playa, northwestern Qaidam Basin, which will enhance our understanding of the potential preservation of molecular biomarkers on Mars. Two sedimentary units were identified along two profiles: one salt unit characterized by a predominance of gypsum and halite, and one detrital unit with a decrease of gypsum and halite and enrichment in siliciclastic minerals...
November 2017: Astrobiology
https://www.readbyqxmd.com/read/28910143/the-lost-city-hydrothermal-field-a-spectroscopic-and-astrobiological-analogue-for-nili-fossae-mars
#19
Elena S Amador, Joshua L Bandfield, William J Brazelton, Deborah Kelley
Low-temperature serpentinization is a critical process with respect to Earth's habitability and the Solar System. Exothermic serpentinization reactions commonly produce hydrogen as a direct by-product and typically produce short-chained organic compounds indirectly. Here, we present the spectral and mineralogical variability in rocks from the serpentine-driven Lost City Hydrothermal Field on Earth and the olivine-rich region of Nili Fossae on Mars. Near- and thermal-infrared spectral measurements were made from a suite of Lost City rocks at wavelengths similar to those for instruments collecting measurements of the martian surface...
November 2017: Astrobiology
https://www.readbyqxmd.com/read/28910135/imaging-of-vanadium-in-microfossils-a-new-potential-biosignature
#20
Craig P Marshall, Alison Olcott Marshall, Jade B Aitken, Barry Lai, Stefan Vogt, Pierre Breuer, Philippe Steemans, Peter A Lay
The inability to unambiguously distinguish the biogenicity of microfossil-like structures in the ancient rock record is a fundamental predicament facing Archean paleobiologists and astrobiologists. Therefore, novel methods for discriminating biological from nonbiological chemistries of microfossil-like structures are of the utmost importance in the search for evidence of early life on Earth. This, too, is important for the search for life on Mars by in situ analyses via rovers or sample return missions for future analysis here on Earth...
November 2017: Astrobiology
journal
journal
39128
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"