Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.893
Filtrar
1.
Nat Commun ; 11(1): 5523, 2020 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-33173035

RESUMO

Microorganisms are employed to mine economically important elements from rocks, including the rare earth elements (REEs), used in electronic industries and alloy production. We carried out a mining experiment on the International Space Station to test hypotheses on the bioleaching of REEs from basaltic rock in microgravity and simulated Mars and Earth gravities using three microorganisms and a purposely designed biomining reactor. Sphingomonas desiccabilis enhanced mean leached concentrations of REEs compared to non-biological controls in all gravity conditions. No significant difference in final yields was observed between gravity conditions, showing the efficacy of the process under different gravity regimens. Bacillus subtilis exhibited a reduction in bioleaching efficacy and Cupriavidus metallidurans showed no difference compared to non-biological controls, showing the microbial specificity of the process, as on Earth. These data demonstrate the potential for space biomining and the principles of a reactor to advance human industry and mining beyond Earth.


Assuntos
Bactérias/metabolismo , Reatores Biológicos/microbiologia , Exobiologia , Gravitação , Metais Terras Raras/metabolismo , Bacillus subtilis/metabolismo , Cupriavidus/metabolismo , Microbiologia Industrial , Marte , Mineração , Lua , Silicatos , Sphingomonas/metabolismo , Ausência de Peso
2.
Adv Genet ; 106: 1-4, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33081918

RESUMO

This current volume is, in many ways, a 2020 update to the important 1999-2000 compendium by Sir Fred Hoyle and Professor N. Chandra Wickramasinghe's "Astronomical Origins of life: Steps towards Panspermia." The emerging new paradigm of biology that connects life on Earth with the wider cosmos is covered in considerable depth showing that terrestrial biological evolution is best understood as a cosmically derived habitat and an interconnected genetic system. The various chapters here discuss all aspects of this interconnectedness, particularly relevant now in this time of the coronavirus pandemic (COVID-19) as the human race reacts to the many microbes and viral pathogens that arrive regularly from space.


Assuntos
Evolução Biológica , Meio Ambiente , Exobiologia , Interações Hospedeiro-Patógeno/fisiologia , Betacoronavirus/fisiologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Doença/etiologia , Ecossistema , Meio Ambiente Extraterreno , Humanos , Modelos Biológicos , Origem da Vida , Pandemias , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia
3.
Adv Genet ; 106: 75-100, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33081928

RESUMO

The origins and global spread of two recent, yet quite different, pandemic diseases is discussed and reviewed in depth: Candida auris, a eukaryotic fungal disease, and COVID-19 (SARS-CoV-2), a positive strand RNA viral respiratory disease. Both these diseases display highly distinctive patterns of sudden emergence and global spread, which are not easy to understand by conventional epidemiological analysis based on simple infection-driven human- to-human spread of an infectious disease (assumed to jump suddenly and thus genetically, from an animal reservoir). Both these enigmatic diseases make sense however under a Panspermia in-fall model and the evidence consistent with such a model is critically reviewed.


Assuntos
Evolução Biológica , Candidíase/etiologia , Doenças Transmissíveis Emergentes/etiologia , Infecções por Coronavirus/etiologia , Origem da Vida , Pneumonia Viral/etiologia , Animais , Betacoronavirus/isolamento & purificação , Betacoronavirus/fisiologia , Candida/isolamento & purificação , Candida/fisiologia , Candidíase/epidemiologia , Doenças Transmissíveis Emergentes/epidemiologia , Coronavirus/isolamento & purificação , Coronavirus/fisiologia , Infecções por Coronavirus/epidemiologia , Planeta Terra , Exobiologia , Meio Ambiente Extraterreno , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Pandemias , Pneumonia Viral/epidemiologia
4.
PLoS One ; 15(9): e0238606, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32936806

RESUMO

Given plans to revisit the lunar surface by the late 2020s and to take a crewed mission to Mars by the late 2030s, critical technologies must mature. In missions of extended duration, in situ resource utilization is necessary to both maximize scientific returns and minimize costs. While this present a significantly more complex challenge in the resource-starved environment of Mars, it is similar to the increasing need to develop resource-efficient and zero-waste ecosystems on Earth. Here, we make use of recent advances in the field of bioinspired chitinous manufacturing to develop a manufacturing technology to be used within the context of a minimal, artificial ecosystem that supports humans in a Martian environment.


Assuntos
Quitina/química , Exobiologia , Meio Ambiente Extraterreno , Marte
5.
Nature ; 585(7825): 354-355, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32939062
7.
Proc Natl Acad Sci U S A ; 117(35): 21031-21036, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817511

RESUMO

One of the major goals for astronomy in the next decades is the remote search for biosignatures (i.e., the spectroscopic evidence of biological activity) in exoplanets. Here we adopt a Bayesian statistical framework to discuss the implications of such future searches, both in the case when life is detected and when no definite evidence is found. We show that even a single detection of biosignatures in the vicinity of our stellar system, in a survey of similar size to what will be obtainable in the next 2 decades, would affect significantly our prior belief on the frequency of life in the universe, even starting from a neutral or pessimistic stance. In particular, after such discovery, an initially agnostic observer would be led to conclude that there are more than [Formula: see text] inhabited planets in the galaxy with a probability exceeding 95%. However, this conclusion would be somewhat weakened by the viability of transfer of biological material over interstellar distances, as in panspermia scenarios. Conversely, the lack of significant evidence of biosignatures would have little effect, leaving the assessment of the abundance of life in the galaxy still largely undetermined.


Assuntos
Exobiologia/métodos , Análise Espectral/métodos , Astronomia , Teorema de Bayes , Meio Ambiente Extraterreno , Galáxias , Origem da Vida , Planetas
9.
Nat Commun ; 11(1): 2731, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32518292

RESUMO

Identification of habitable planets beyond our solar system is a key goal of current and future space missions. Yet habitability depends not only on the stellar irradiance, but equally on constituent parts of the planetary atmosphere. Here we show, for the first time, that radiatively active mineral dust will have a significant impact on the habitability of Earth-like exoplanets. On tidally-locked planets, dust cools the day-side and warms the night-side, significantly widening the habitable zone. Independent of orbital configuration, we suggest that airborne dust can postpone planetary water loss at the inner edge of the habitable zone, through a feedback involving decreasing ocean coverage and increased dust loading. The inclusion of dust significantly obscures key biomarker gases (e.g. ozone, methane) in simulated transmission spectra, implying an important influence on the interpretation of observations. We demonstrate that future observational and theoretical studies of terrestrial exoplanets must consider the effect of dust.


Assuntos
Biomarcadores/análise , Poeira/análise , Exobiologia , Meio Ambiente Extraterreno , Minerais/análise , Planetas , Atmosfera , Clima , Simulação por Computador , Temperatura
10.
Proc Natl Acad Sci U S A ; 117(22): 11995-12003, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32424083

RESUMO

Life emerged on Earth within the first quintile of its habitable window, but a technological civilization did not blossom until its last. Efforts to infer the rate of abiogenesis, based on its early emergence, are frustrated by the selection effect that if the evolution of intelligence is a slow process, then life's early start may simply be a prerequisite to our existence, rather than useful evidence for optimism. In this work, we interpret the chronology of these two events in a Bayesian framework, extending upon previous work by considering that the evolutionary timescale is itself an unknown that needs to be jointly inferred, rather than fiducially set. We further adopt an objective Bayesian approach, such that our results would be agreed upon even by those using wildly different priors for the rates of abiogenesis and evolution-common points of contention for this problem. It is then shown that the earliest microfossil evidence for life indicates that the rate of abiogenesis is at least 2.8 times more likely to be a typically rapid process, rather than a slow one. This modest limiting Bayes factor rises to 8.7 if we accept the more disputed evidence of 13C-depleted zircon deposits [E. A. Bell, P. Boehnke, T. M. Harrison, W. L. Mao, Proc. Natl. Acad. Sci. U.S.A. 112, 14518-14521 (2015)]. For intelligence evolution, it is found that a rare-intelligence scenario is slightly favored at 3:2 betting odds. Thus, if we reran Earth's clock, one should statistically favor life to frequently reemerge, but intelligence may not be as inevitable.


Assuntos
Exobiologia , Origem da Vida , Teorema de Bayes , Evolução Biológica , Planeta Terra , Exobiologia/métodos , Exobiologia/estatística & dados numéricos , Inteligência
11.
J Vis Exp ; (159)2020 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-32449704

RESUMO

Spatially resolving exoplanet features from single-point observations is essential for evaluating the potential habitability of exoplanets. The ultimate goal of this protocol is to determine whether these planetary worlds harbor geological features and/or climate systems. We present a method of extracting information from multi-wavelength single-point light curves and retrieving surface maps. It uses singular value decomposition (SVD) to separate sources that contribute to light curve variations and infer the existence of partially cloudy climate systems. Through analysis of the time series obtained from SVD, physical attributions of principal components (PCs) could be inferred without assumptions of any spectral properties. Combining with viewing geometry, it is feasible to reconstruct surface maps if one of the PCs are found to contain surface information. Degeneracy originated from convolution of the pixel geometry and spectrum information determines the quality of reconstructed surface maps, which requires the introduction of regularization. For the purpose of demonstrating the protocol, multi-wavelength light curves of Earth, which serves as a proxy exoplanet, are analyzed. Comparison between the results and the ground truth is presented to show the performance and limitation of the protocol. This work provides a benchmark for future generalization of exoplanet applications.


Assuntos
Planeta Terra , Exobiologia/métodos , Meio Ambiente Extraterreno , Luz , Planetas , Processamento de Imagem Assistida por Computador , Fatores de Tempo
12.
Health Secur ; 18(2): 132-138, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32324071

RESUMO

The normal scope of an adequate public health response to released biological material is framed by working with biological vectors with known pathogenicity and virulence. Defining the scope of a response to the release of biological material with unknown pathogenicity and virulence enters into a novel and yet to be framed domain. A current case, in which extraterrestrial samples returned from a location such as Mars, which may harbor life as we know it, requires framing a public health response. An unintentional release of biological material with unknown pathogenicity and virulence may occur when biological containment mechanisms in the Earth-returning transport method are lost. This article raises initial public health and healthcare response questions during a return of extraterrestrial samples to Earth, in the event of its release from biological containment mechanisms: How does the public health community prepare for a response when there is release of samples that may contain potential extraterrestrial organisms from a planetary body or hardy terrestrial organisms surviving a round trip? If a mishap occurs during the return of these samples, what considerations need to be made to confine, decontaminate, and collect material in regions around the mishap? How will the public health community work with relevant government organizations to prepare the general public? The unknowns of exposure, potential extraterrestrial pathogenicity, and decontamination approaches underscore gaps in biopreparedness for this novel case from federal to local levels.


Assuntos
Contenção de Riscos Biológicos/métodos , Descontaminação/métodos , Exobiologia , Meio Ambiente Extraterreno , Contenção de Riscos Biológicos/normas , Descontaminação/normas , Planeta Terra , Contaminação de Equipamentos/prevenção & controle , Humanos , Astronave
13.
Sci Rep ; 10(1): 1671, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32015390

RESUMO

Abiotic emergence of ordered information stored in the form of RNA is an important unresolved problem concerning the origin of life. A polymer longer than 40-100 nucleotides is necessary to expect a self-replicating activity, but the formation of such a long polymer having a correct nucleotide sequence by random reactions seems statistically unlikely. However, our universe, created by a single inflation event, likely includes more than 10100 Sun-like stars. If life can emerge at least once in such a large volume, it is not in contradiction with our observations of life on Earth, even if the expected number of abiogenesis events is negligibly small within the observable universe that contains only 1022 stars. Here, a quantitative relation is derived between the minimum RNA length lmin required to be the first biological polymer, and the universe size necessary to expect the formation of such a long and active RNA by randomly adding monomers. It is then shown that an active RNA can indeed be produced somewhere in an inflationary universe, giving a solution to the abiotic polymerization problem. On the other hand, lmin must be shorter than ~20 nucleotides for the abiogenesis probability close to unity on a terrestrial planet, but a self-replicating activity is not expected for such a short RNA. Therefore, if extraterrestrial organisms of a different origin from those on Earth are discovered in the future, it would imply an unknown mechanism at work to polymerize nucleotides much faster than random statistical processes.


Assuntos
Planeta Terra , Exobiologia , Meio Ambiente Extraterreno , Origem da Vida , Planetas , Nucleotídeos/genética , Polimerização , Polímeros/metabolismo , RNA/genética
14.
Sci Rep ; 10(1): 6, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31913316

RESUMO

The current understanding of the Martian surface indicates that briny environments at the near-surface are temporarily possible, e.g. in the case of the presumably deliquescence-driven Recurring Slope Lineae (RSL). However, whether such dynamic environments are habitable for terrestrial organisms remains poorly understood. This hypothesis was tested by developing a Closed Deliquescence System (CDS) consisting of a mixture of desiccated Martian Regolith Analog (MRA) substrate, salts, and microbial cells, which over the course of days became wetted through deliquescence. The methane produced via metabolic activity for three methanogenic archaea: Methanosarcina mazei, M. barkeri and M. soligelidi, was measured after exposing them to three different MRA substrates using either NaCl or NaClO4 as a hygroscopic salt. Our experiments showed that (1) M. soligelidi rapidly produced methane at 4 °C, (2) M. barkeri produced methane at 28 °C though not at 4 °C, (3) M. mazei was not metabolically reactivated through deliquescence, (4) none of the species produced methane in the presence of perchlorate, and (5) all species were metabolically most active in the phyllosilicate-containing MRA. These results emphasize the importance of the substrate, microbial species, salt, and temperature used in the experiments. Furthermore, we show here for the first time that water provided by deliquescence alone is sufficient to rehydrate methanogenic archaea and to reactivate their metabolism under conditions roughly analogous to the near-subsurface Martian environment.


Assuntos
Exobiologia/métodos , Meio Ambiente Extraterreno , Marte , Metano/metabolismo , Methanosarcina/fisiologia , Sais/química , Água/química , Crescimento Quimioautotrófico , Metano/análise
15.
PLoS Pathog ; 16(1): e1008153, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31999804

RESUMO

Human space travel is on the verge of visiting Mars and, in the future, even more distant places in the solar system. These journeys will be also made by terrestrial microorganisms (hitchhiking on the bodies of astronauts or on scientific instruments) that, upon arrival, will come into contact with new planetary environments, despite the best measures to prevent contamination. These microorganisms could potentially adapt and grow in the new environments and subsequently recolonize and infect astronauts. An even more challenging situation would be if truly alien microorganisms will be present on these solar system bodies: What will be their pathogenic potential, and how would our immune host defenses react? It will be crucial to anticipate these situations and investigate how the immune system of humans might cope with modified terrestrial or alien microbes. We propose several scenarios that may be encountered and how to respond to these challenges.


Assuntos
Equipamentos e Provisões/microbiologia , Interações Hospedeiro-Patógeno , Sistema Imunitário/imunologia , Astronautas , Exobiologia , Meio Ambiente Extraterreno , Humanos , Voo Espacial , Astronave
16.
Genes (Basel) ; 11(1)2020 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-31936690

RESUMO

The MinION sequencer has made in situ sequencing feasible in remote locations. Following our initial demonstration of its high performance off planet with Earth-prepared samples, we developed and tested an end-to-end, sample-to-sequencer process that could be conducted entirely aboard the International Space Station (ISS). Initial experiments demonstrated the process with a microbial mock community standard. The DNA was successfully amplified, primers were degraded, and libraries prepared and sequenced. The median percent identities for both datasets were 84%, as assessed from alignment of the mock community. The ability to correctly identify the organisms in the mock community standard was comparable for the sequencing data obtained in flight and on the ground. To validate the process on microbes collected from and cultured aboard the ISS, bacterial cells were selected from a NASA Environmental Health Systems Surface Sample Kit contact slide. The locations of bacterial colonies chosen for identification were labeled, and a small number of cells were directly added as input into the sequencing workflow. Prepared DNA was sequenced, and the data were downlinked to Earth. Return of the contact slide to the ground allowed for standard laboratory processing for bacterial identification. The identifications obtained aboard the ISS, Staphylococcus hominis and Staphylococcus capitis, matched those determined on the ground down to the species level. This marks the first ever identification of microbes entirely off Earth, and this validated process could be used for in-flight microbial identification, diagnosis of infectious disease in a crewmember, and as a research platform for investigators around the world.


Assuntos
Sequenciamento por Nanoporos/métodos , RNA Ribossômico 16S/genética , Manejo de Espécimes/métodos , Bactérias/genética , DNA Bacteriano/genética , DNA Ribossômico/genética , Exobiologia/métodos , Meio Ambiente Extraterreno , Genoma Bacteriano/genética , Microbiota/genética , Nanoporos , Análise de Sequência de DNA/métodos , Astronave/instrumentação
18.
Curr Issues Mol Biol ; 38: 1-32, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31967574

RESUMO

Astrobiology asks three fundamental questions as outlined by the NASA Astrobiology Roadmap: 1. How did Life begin and evolve?; Is there Life elsewhere in the Universe?; and, What is the future of Life on Earth? As we gain perspective on how Life on Earth arose and adapted to its many niches, we too gain insight into how a planet achieves habitability. Here on Earth, microbial Life has evolved to exist in a wide range of habitats from aquatic systems to deserts, the human body, and the International Space Station (ISS). Landers, rovers, and orbiter missions support the search for signatures of Life beyond Earth, by generating data on surface and subsurface conditions of other worlds. These have provided evidence for water activity, supporting the potential for extinct or extant Life. To investigate the putative ecologies of these systems, we study extreme environments on Earth. Several locations on our planet provide analog settings to those we have detected or expect to find on neighboring and distant worlds. Whereas, the field of space biology uses the ISS and low gravity analogs to gain insight on how transplanted Earth-evolved organisms will respond to extraterrestrial environments. Modern genomics allows us to chronicle the genetic makeup of such organisms and provides an understanding of how Life adapts to various extreme environments.


Assuntos
Evolução Biológica , Exobiologia , Meio Ambiente Extraterreno/química , Origem da Vida , Água/metabolismo , Adaptação Biológica , Bactérias/crescimento & desenvolvimento , Bactérias/efeitos da radiação , Planeta Terra , Ecologia , Ecossistema , Ambientes Extremos , Humanos , Marte , Planetas , Estados Unidos , United States National Aeronautics and Space Administration , Água/análise , Água/química , Ausência de Peso/efeitos adversos
19.
Curr Issues Mol Biol ; 38: 53-74, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31967576

RESUMO

Carbon-based compounds are widespread throughout the Universe, including abiotic molecules that are the components of the life as we know it. This article reviews the space missions that have aimed to detect organic matter and biosignatures in planetary bodies of our solar system. While to date there was only one life-detection space mission, i.e., the Viking mission to Mars, several past and present space missions have searched for organic matter, paving the way for the future detection of signatures of extra-terrestrial life. This review also reports on the in-situ analysis of organic matter and sample-return missions from primitive bodies, i.e. comets and asteroids, providing crucial information on the conditions of the early solar system as well as on the building blocks of life delivered to the primitive Earth.


Assuntos
Carbono/química , Meio Ambiente Extraterreno/química , Compostos Orgânicos/química , Sistema Solar/química , Exobiologia , Cromatografia Gasosa-Espectrometria de Massas , História do Século XX , História do Século XXI , Marte , Meteoroides , Planetas Menores , Plutão , Saturno , Voo Espacial/história , Estados Unidos , United States National Aeronautics and Space Administration
20.
Curr Issues Mol Biol ; 38: 163-196, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31967580

RESUMO

The importance of hypopiezophilic and hypopiezotolerant microorganisms (i.e., life that grows at low atmospheric pressures; see section 2) in the field of astrobiology cannot be overstated. The ability to reproduce and thrive at Martian atmospheric pressure (0.2 to 1.2 kPa) is of high importance to both modeling the forward contamination of its planetary surface and predicting the habitability of Mars. On Earth, microbial growth at low pressure also has implications for the dissemination of microorganisms within clouds or the bulk atmosphere. Yet our ability to understand the effect of low pressure on microbial metabolism, growth, cellular structure and integrity, and adaptation is still limited. We present current knowledge on hypopiezophilic and hypopiezotolerant microorganisms, methods for isolation and cultivation, justify why there should be more focus for future research, and discuss their importance for astrobiology.


Assuntos
Bactérias/isolamento & purificação , Dessecação/métodos , Meio Ambiente Extraterreno , Adaptação Biológica/genética , Pressão Atmosférica , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Sobrevivência Celular , Dessecação/instrumentação , Exobiologia , Regulação da Expressão Gênica/genética , Marte , Filogenia , Temperatura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA